CN118961061A - Dynamic test of sprung mass parameter and early warning method and system for safe running of vehicle - Google Patents
Dynamic test of sprung mass parameter and early warning method and system for safe running of vehicle Download PDFInfo
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Abstract
The application relates to the technical field of vehicle engineering, in particular to a method and a system for dynamic testing of sprung mass parameters and early warning of safe running of a vehicle, which are used for actively suspending the vehicle, wherein the method comprises the following steps: calculating the mass center position of the sprung mass under a vehicle body coordinate system; in a horizontal state of the vehicle, performing pitching and rolling motions of the vehicle, and respectively calculating pitching moment of inertia and rolling moment of inertia according to the supporting force of the hydraulic cylinder and the angular velocity of the gyroscope; in the process of uniform turning running of the vehicle, braking the vehicle, and calculating yaw moment of inertia according to the yaw rate and braking force of the vehicle body; and calculating a safety threshold range based on the centroid position, the pitching moment of inertia, the rolling moment of inertia, the yaw moment of inertia and the running working condition of the vehicle, and carrying out early warning on the driver based on the safety threshold range. The application overcomes the defect that the chassis controller cannot effectively control the vehicle by using fixed design parameters, and provides the chassis controller with optimized control effect of the whole vehicle.
Description
Technical Field
The application relates to the technical field of vehicle engineering, in particular to a method and a system for dynamic testing of sprung mass parameters and early warning of safe running of a vehicle.
Background
The position of the mass center of the vehicle is the most important factor influencing the control of the vehicle, the mass center of the vehicle is close to the front axle, the problem of understeer can be generated during steering, and particularly, when the vehicle runs on a road with low adhesion such as rain, snow, sand and the like, the driver cannot follow the intention easily, and a curve is easy to rush out of the road. When the cargoes of the vehicle are excessively loaded, the barycenter is caused to be close to the rear axle, the steering is excessive when the vehicle runs, the emergency rotation is caused, and the control is lost. In addition, the mass center of the large-sized vehicle is higher, so that the driving speed of a curve cannot be too high, and side turning is easy to occur. When the vehicle is designed, the mass center position is measured in detail, but in actual use, many occasions exceed the design specification of the vehicle, such as large-sized vehicles, too much loaded cargoes, uneven cargo loading and the like, so that the dynamic on-line measurement of the mass center of the vehicle and the large deviation early warning are one of important contents for ensuring the running safety of the vehicle.
The traditional method for measuring the plane coordinates of the mass center of the vehicle is to place an electronic weighing sensor under each wheel of the vehicle, calculate the distance from the mass center to the front and rear axles according to the weight of the whole vehicle shared by the front wheel and the rear wheel, and calculate the distance from the mass center to the left and right sides according to the weight of the whole vehicle shared by the left wheel and the right wheel. The method for measuring the height of the mass center is to park the vehicle on a slope with a certain gradient, and the electronic weighing sensors are required to be placed under each wheel, and the height of the mass center is calculated according to the angle of the slope and the numerical value of each weighing sensor. Also, the above measurement method can be implemented on a dedicated test stand, and it is necessary to ensure that the test stand is level and fix a certain inclination angle. In the conventional moment of inertia test method, a vehicle is placed on a special swing test stand, and a load sensor is installed under each wheel. The whole test bed is subjected to pitching, rolling and swaying control, certain-frequency reciprocating motion is applied to the test bed, angular velocity control is performed according to the installed acceleration sensor, meanwhile, stress of the connecting part is measured, and moment of inertia is obtained according to a moment balance relation.
The traditional method has the advantages of good testing environment, no other interference and relatively accurate measurement result, however, the method has the defects that various changing factors in the actual use process of the vehicle cannot be considered, especially when the vehicle carries more people and loads, the safety range of the moment of inertia of the vehicle is exceeded, the height of the mass center is reduced due to load change, the moment of inertia is increased, and the like. In addition, the accuracy of the measurement results is also affected by the state of motion of the vehicle, such as roll when the vehicle is turning to travel, resulting in deviation of the centroid position, and the like. The control effect of chassis safety control systems such as an anti-lock braking system (ABS), a cornering vehicle body stability control system (ESC), an active suspension control system (ASS) and the like is greatly reduced, and even the control system fails. Thus, dynamic online measurement of vehicle inertia is one of the key to ensuring the control capability of a vehicle chassis control system.
Disclosure of Invention
The embodiment of the application provides a method and a system for dynamically testing sprung mass parameters and early warning safe running of a vehicle, which make up for the defect that a chassis controller cannot effectively control the vehicle due to the use of fixed design parameters, provide the chassis controller, and optimize the control effect of the whole vehicle.
In order to solve the above technical problems, in a first aspect, an embodiment of the present application provides a method for dynamically testing sprung mass parameters and early warning safe driving of a vehicle, for actively suspending the vehicle, including the steps of: firstly, calculating the mass center position of the sprung mass under a vehicle body coordinate system according to the supporting force of a hydraulic cylinder, a driving ramp angle and the position of a hydraulic cylinder fulcrum under the vehicle body coordinate system in a driving state of a vehicle; the centroid position comprises a transverse position, a longitudinal position and a vertical position of the centroid under a vehicle body coordinate system; then, in the horizontal state of the vehicle, performing pitching and rolling motions of the vehicle, and respectively calculating pitching moment of inertia and rolling moment of inertia according to the supporting force of the hydraulic cylinder and the angular velocity of the gyroscope; then, in the process of uniform turning running of the vehicle, braking the vehicle, and calculating yaw moment of inertia according to the yaw rate and braking force of the vehicle body; and finally, calculating a safety threshold range based on the centroid position, the pitching moment of inertia, the rolling moment of inertia, the yaw moment of inertia and the running working condition of the vehicle, and early warning the driver based on the safety threshold range.
In some exemplary embodiments, calculating a centroid position of the sprung mass in a vehicle body coordinate system from a support force of the hydraulic cylinder, a travel ramp angle, and a position of a hydraulic cylinder fulcrum in the vehicle body coordinate system in a traveling state of the vehicle includes: if the vehicle runs on a straight road at a constant speed or at a small acceleration, controlling an active hydraulic suspension to keep the vehicle horizontal, and respectively calculating the transverse position and the longitudinal position of the sprung mass center under the vehicle body coordinate system according to the supporting force of each hydraulic cylinder and the position of the hydraulic cylinder fulcrum in the vehicle body coordinate system; if the vehicle generates larger longitudinal and lateral acceleration or the vehicle runs on a road with larger gradient at a constant speed, the offset of the mass center generates load transfer on the hydraulic cylinders, and the vertical position of the mass center of the sprung mass is calculated according to the supporting force of each hydraulic cylinder, the angle of the running ramp and the position of the hydraulic cylinder in a vehicle body coordinate system.
In some exemplary embodiments, performing pitch and roll motions of a vehicle in a vehicle horizontal state, calculating pitch moment of inertia and roll moment of inertia from a support force of a hydraulic cylinder and a gyro angular velocity, respectively, includes: under the horizontal state of the vehicle, controlling the active hydraulic suspension to generate pitching motions with different angular accelerations, and obtaining accurate pitching moment of inertia according to different pitching moment of inertia measured under the condition of various angular accelerations; the different pitching moment of inertia comprises the supporting force, displacement, pitching and side inclination angles, angular velocity and lateral acceleration of the hydraulic cylinder; in a horizontal state of the vehicle, controlling the active hydraulic suspension to generate roll motions with different angular accelerations, and obtaining accurate roll moment of inertia according to different roll moment of inertia measured under the condition of various angular accelerations; the different roll moments of inertia include the hydraulic cylinder support force, displacement, pitch and roll angles, angular velocity and lateral acceleration.
In some exemplary embodiments, braking the vehicle during constant-speed turning of the vehicle, calculating yaw moment of inertia from a yaw rate and a braking force of the vehicle body, comprising: when the vehicle turns, the vehicle body is kept horizontal, the vehicle is braked, the yaw moment of inertia of the vehicle is calculated according to the change of the yaw angular acceleration of the vehicle body and the braking force, and the yaw moment of inertia is calculated for a plurality of times to obtain the accurate yaw moment of inertia.
In some exemplary embodiments, the calculation of the centroid position includes calculation of the centroid horizontal position and calculation of the centroid height, wherein the centroid horizontal position is calculated as follows:
FLF+FRF+FLR+FRR＝Msg
(FLF+FRF)L＝Msg LR
(FLR+FRR)L＝Msg LF
(FLF+FLR)T＝Msg TR
(FRF+FRR)T＝Msg TL
Wherein F LF,FRF,FLR,FRR is the supporting force of the left front, right front, left back and right back suspension hydraulic cylinders respectively; m s g is the weight of the vehicle, and M s is the mass of the vehicle; t L,TR is the distance from the mass center to the fulcrum of the left-side and right-side suspension hydraulic cylinder respectively; l R,LF is the distance from the mass center to the fulcrum of the front and rear axle hydraulic cylinders respectively; t=t L+TR, T is the distance between the left and right fulcrums of the hydraulic cylinder; l=l F+LR, L is the distance between the front and rear fulcrums of the hydraulic cylinder.
In some exemplary embodiments, when measuring the height of the centroid, the vehicle is respectively measured at a maximum pitch angle and a maximum roll angle, and the total of four vehicle body attitudes are respectively +alpha max,-αmax,+βmax,-βmax, and the obtained heights of the centroids are respectively Z 1,Z2,Z3,Z4; the centroid height is calculated as follows:
(FLF+FRF)L＝Msg(LF-Z1 sinαmax)
(FLR+FRR)L＝Msg(LR-Z2 sinαmax)
(FLF+FLR)T＝Msg(TR-Z3 sinβmax)
(FRF+FRR)T＝Msg(TL-Z4 sinβmax)
after deriving centroid height Z 1,Z2,Z3,Z4, based on the mean An accurate centroid height is determined.
In some exemplary embodiments, the measurements of the pitch moment of inertia, the roll moment of inertia, and the yaw moment of inertia are calculated by a pitch motion equation, a roll motion equation, and a yaw motion equation, respectively; wherein,
The pitch motion equation of the vehicle is:
the roll motion equation of the vehicle is:
The yaw motion equation of the vehicle is:
Wherein, I y,Ix,Iz is the pitch moment of inertia, the roll moment of inertia and the yaw moment of inertia of the vehicle respectively; The pitch angle acceleration, the roll angle acceleration and the yaw angle acceleration of the vehicle are respectively; f LF,FRF,FLR,FRR is the supporting force of the left front, right front, left back and right back suspension hydraulic cylinders respectively; t L,TR is the distance from the mass center to the fulcrum of the left-side and right-side suspension hydraulic cylinder respectively; l R,LF is the distance from the mass center to the fulcrum of the front and rear axle hydraulic cylinders respectively; r LF,RRF,RLR,RRR is the braking force of the left front, right front, left rear and right rear wheels respectively; b L,BR is the distance from the center of mass to the left and right wheel center ground connection line.
In some exemplary embodiments, the calculation of the safety threshold range includes: calculating a driving condition early warning index; calculating a safety threshold range based on the driving condition early warning index; the calculation formula of the running condition early warning index is as follows:
J＝ω1V+ω2ay+ω3δ+ω4ΔIx+ω5ΔIy+ω6ΔIz+ω7ΔX+ω8ΔY+ω9ΔZ
Wherein J is a driving condition early warning index; v is the vehicle speed, a y is the lateral acceleration, delta is the steering wheel rotation angle, delta I x,ΔIy,ΔIz is the deviation of the moment of inertia exceeding the design value, delta X, delta Y and delta Z are the deviation of the centroid position exceeding the design value; omega 1,ω2,…ω9 is the weighting coefficient obtained by adding the parameters according to the weight.
In a second aspect, an embodiment of the present application provides a sprung mass key parameter dynamic test and vehicle safe driving early warning system, where the sprung mass key parameter dynamic test and vehicle safe driving early warning method described in the foregoing embodiment is used to test and early warn, and the method includes: the system comprises a hydraulic cylinder, a gyroscope, a steering wheel angle sensor, a brake pipeline pressure sensor and a data acquisition and calculation controller; the hydraulic cylinder is used for supporting the vehicle, and respectively controlling the compression and rebound of each suspension to realize the control of heave, pitch, roll and torsion of the vehicle; the steering wheel angle sensor is used for measuring the steering wheel angle when the vehicle runs so as to identify the driving intention of a driver, and calculating the steering radius, the running track and the side deflection angle of the vehicle body and the wheels according to the steering wheel angle; the gyroscope is used for measuring longitudinal acceleration, lateral acceleration, vertical acceleration, pitch angle speed, roll angle speed and yaw angle speed when the vehicle moves; the brake pipeline pressure sensor is used for measuring the pressure of a hydraulic pipeline during vehicle braking, converting a pressure signal into a voltage or current signal, and sending the voltage or current signal to the data acquisition and calculation controller for calculating the braking moment; the data acquisition and calculation controller is used for acquiring the pressure of two cavities of each hydraulic cylinder of the vehicle suspension in real time, calculating the supporting force on the vehicle body according to the pressure difference, acquiring the displacement of the hydraulic cylinders as control input, reading parameter data measured by the gyroscope, the brake pipeline pressure sensor and the steering wheel angle sensor, realizing the automatic lifting control of the hydraulic cylinders of each suspension of the vehicle, meeting the requirements of on-line testing of the mass center position and the rotational inertia, and giving early warning of driving working conditions according to the driving speed, the lateral acceleration, the steering wheel rotation angle, the deviation data of the mass center position and the rotational inertia beyond the design, and weighting average.
In some exemplary embodiments, the sprung mass parameter dynamic test and vehicle safe driving early warning system further includes: the hydraulic power unit, the servo valve, the first pressure sensor, the second pressure sensor, the displacement sensor and the energy accumulator; the hydraulic power unit is used for providing pressure oil for the hydraulic system; the servo valve is used for driving the hydraulic cylinder to lift; the first pressure sensor and the second pressure sensor are transmitters for measuring working pressure of two cavities of the oil cylinder, convert pressure signals into current signals, and input the current signals into the data acquisition and calculation controller; the displacement sensor is a sensor for measuring the telescopic travel of the hydraulic cylinder, is arranged on the shell of the hydraulic cylinder through a fixed part and is connected with the hydraulic rod through a follow-up part; when the hydraulic rod stretches, the displacement sensor measures the change of displacement in real time and starts corresponding voltage or current signals to the data acquisition and calculation controller; the energy accumulator is an energy storage component of a hydraulic system, and can rapidly supply a large amount of hydraulic oil when the vehicle continuously acts through storing hydraulic energy, so that the requirements on the displacement and total power of the hydraulic pump are reduced.
The technical scheme provided by the embodiment of the application has at least the following advantages:
The embodiment of the application provides a method and a system for dynamic testing of sprung mass parameters and early warning of safe running of a vehicle, which are used for actively suspending the vehicle, and the method comprises the following steps: firstly, calculating the mass center position of the sprung mass under a vehicle body coordinate system according to the supporting force of a hydraulic cylinder, a driving ramp angle and the position of a hydraulic cylinder fulcrum under the vehicle body coordinate system in a driving state of a vehicle; the centroid position comprises a transverse position, a longitudinal position and a vertical position of the centroid under a vehicle body coordinate system; then, in the horizontal state of the vehicle, performing pitching and rolling motions of the vehicle, and respectively calculating pitching moment of inertia and rolling moment of inertia according to the supporting force of the hydraulic cylinder and the angular velocity of the gyroscope; then, in the process of uniform turning running of the vehicle, braking the vehicle, and calculating yaw moment of inertia according to the yaw rate and braking force of the vehicle body; and finally, calculating a safety threshold range based on the centroid position, the pitching moment of inertia, the rolling moment of inertia, the yaw moment of inertia and the running working condition of the vehicle, and early warning the driver based on the safety threshold range.
The sprung mass parameter dynamic test and vehicle safe running early warning method and system provided by the application can calculate the mass center position and the moment of inertia according to the principle of vehicle dynamics by controlling the pitching and the rolling of the vehicle and according to the supporting force, the displacement, the pitching and the rolling angles, the angular velocity, the lateral acceleration and the like obtained by the measurement and control system. The dynamic test method provided by the application is not only suitable for the two-axle vehicle provided with the active hydraulic suspension, but also suitable for the multi-axle vehicle provided with the active suspension, wherein the forefront axle and the rearmost axle of the multi-axle vehicle are calculated as the two-axle vehicle, and the middle axle converts actual displacement according to the roll and the pitch angle in proportion, so that the supporting points of the oil cylinders of the vehicle body are all in the same plane.
Drawings
One or more embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, which are not to be construed as limiting the embodiments unless specifically indicated otherwise.
Fig. 1 is a flow chart of a dynamic test of sprung mass parameters and a vehicle safety driving early warning method according to an embodiment of the application.
Fig. 2 is a schematic diagram of a system for dynamic testing of sprung mass parameters and early warning of safe driving of a vehicle according to an embodiment of the application.
Fig. 3 is a schematic diagram of two-axis vehicle coordinate system and parameter definition according to an embodiment of the application.
Fig. 4 is a schematic diagram of a multi-axis vehicle coordinate system and parameter definition according to an embodiment of the application.
Detailed Description
As known from the background art, the conventional method has the technical problem that various changing factors in the actual use process of the vehicle and the accuracy of the measurement result cannot be considered and the accuracy of the measurement result is affected by the motion state of the vehicle.
Dynamic on-line measurement of the mass center of the vehicle and large deviation early warning are one of important contents for ensuring the running safety of the vehicle. Another aspect of the vehicle center of mass position variation affecting the vehicle chassis safety control effect is the resulting moment of inertia variation. In the control of dynamic driving of a vehicle (such as turning vehicle body stability control (ESC), brake anti-lock system (ABS), active suspension control (ASS) system, etc.), moment of inertia plays a critical role in control effect, and ESC, ABS, ASS controllers all use factory default and fixed centroid positions and moment of inertia.
The conventional method cannot take various changing factors in the actual use process of the vehicle into consideration, and particularly when the vehicle is more in manned and loaded with cargoes, the safety range of the rotational inertia of the vehicle is exceeded. The decrease in the height of the centroid, the increase in the moment of inertia, and the like caused by the change in the load are also affected by the state of motion of the vehicle, such as the roll when the vehicle is turning, resulting in the shift of the centroid position, and the like. ABS, ESC, ASS and the like, the control effect of the chassis safety control system is greatly reduced, and even the chassis safety control system fails. The chassis control system using the centroid fixed coordinates and the constant rotational inertia is greatly reduced in effect during control due to the change factors, dangerous working conditions such as insufficient control or excessive control occur, in addition, for a driver, the vehicle stability coefficient is reduced due to the change of the centroid and the inertia of the vehicle, and the situation that the vehicle is out of control due to the conventional safe driving experience, such as the idle or half-load safe turning speed, is caused when the vehicle is full-load is also caused, so that the monitoring of the change of the centroid position and the inertia and the early warning prompt of the driver are important contents for improving the safe control of the vehicle.
The existing chassis control system adopts the centroid position and fixed inertia for control when the vehicle is designed, and the control effect evaluation is carried out under ideal conditions and standard test working conditions, so that the centroid position and the inertia value which change in real time cannot be comprehensively measured.
In order to solve the technical problems, the embodiment of the application provides a method and a system for dynamic testing of sprung mass parameters and early warning of safe running of a vehicle, which are used for actively suspending the vehicle, and the method comprises the following steps: firstly, calculating the mass center position of the sprung mass under a vehicle body coordinate system according to the supporting force of a hydraulic cylinder, a driving ramp angle and the position of a hydraulic cylinder fulcrum under the vehicle body coordinate system in a driving state of a vehicle; the centroid position comprises a transverse position, a longitudinal position and a vertical position of the centroid under a vehicle body coordinate system; then, in the horizontal state of the vehicle, performing pitching and rolling motions of the vehicle, and respectively calculating pitching moment of inertia and rolling moment of inertia according to the supporting force of the hydraulic cylinder and the angular velocity of the gyroscope; then, in the process of uniform turning running of the vehicle, braking the vehicle, and calculating yaw moment of inertia according to the yaw rate and braking force of the vehicle body; and finally, calculating a safety threshold range based on the centroid position, the pitching moment of inertia, the rolling moment of inertia, the yaw moment of inertia and the running working condition of the vehicle, and early warning the driver based on the safety threshold range. According to the application, the center of mass, the moment of inertia and the deviation of design parameters of the vehicle are dynamically measured on line in the actual running process, the safety threshold is evaluated according to the running working condition of the vehicle, and after the threshold is exceeded, an alarm is given to remind a driver of safely operating the vehicle.
The development of vehicle chassis control technology has led to the development of more and more vehicles equipped with active suspensions, which can be classified into air spring active suspensions, hydraulic active suspensions, electromechanical active suspensions, etc., according to the type of active suspension. The air suspension can realize the on-line measurement of the mass center position, and the control rate of the vehicle suspension is very slow due to the compressibility of the gas, so that the quick measurement cannot be realized. Because of incompressibility of hydraulic oil, the hydraulic suspension can realize rapid movement of the vehicle suspension, and not only can realize on-line measurement of mass center position, but also can realize on-line measurement of inertia. The mass of the whole vehicle varies depending on the location, including the sprung mass (the weight supported by the suspension, which may also be referred to as the sprung mass), the unsprung mass (the suspension and the wheel portion, which may also be referred to as the unsprung mass). When the motion of the chassis of the vehicle is controlled, the position and the weight of the unsprung mass are not changed due to the contact of the tire and the ground, the change of the mass center position and the moment of inertia of the whole vehicle is not influenced, and the change of the mass and the distribution of the sprung mass relative to the ground is influenced. Therefore, the mass center position and the moment of inertia measurement of the sprung mass are determining factors of the change of the mass center position and the moment of inertia of the whole vehicle. The dynamic measurement method provided by the application is based on the mass center position and the moment of inertia measurement of the sprung mass, and the calculation of the mass center and the moment of inertia of the whole vehicle can be calculated through the addition of unsprung weight and distribution.
Embodiments of the present application will be described in detail below with reference to the attached drawings. However, it will be understood by those of ordinary skill in the art that in various embodiments of the present application, numerous specific details are set forth in order to provide a thorough understanding of the present application. The claimed application may be practiced without these specific details and with various changes and modifications based on the following embodiments.
Referring to fig. 1, an embodiment of the application provides a method and a system for dynamic testing of sprung mass parameters and early warning of safe running of a vehicle, which are used for actively suspending the vehicle, and comprise the following steps:
Step S1, calculating the mass center position of the sprung mass under a vehicle body coordinate system according to the supporting force of a hydraulic cylinder, the angle of a driving ramp and the position of a fulcrum of the hydraulic cylinder under the vehicle body coordinate system in the driving state of the vehicle; the centroid position includes a lateral position, a longitudinal position, and a vertical position of the centroid in the vehicle body coordinate system.
And S2, performing pitching and rolling motions of the vehicle in a horizontal state of the vehicle, and respectively calculating pitching moment of inertia and rolling moment of inertia according to the supporting force of the hydraulic cylinder and the angular velocity of the gyroscope.
And S3, braking the vehicle in the uniform-speed turning running process of the vehicle, and calculating yaw moment of inertia according to the yaw rate and the braking force of the vehicle body.
And S4, calculating a safety threshold range based on the mass center position, the pitching moment of inertia, the rolling moment of inertia, the yaw moment of inertia and the running working condition of the vehicle, and early warning the driver based on the safety threshold range.
The method and the system for dynamically testing the sprung mass parameter and pre-warning the safe running of the vehicle are used for actively suspending the vehicle, and can be realized on the vehicle (hydraulic, pneumatic, electric and the like) provided with the all-active suspension for the change of the mass center position and the moment of inertia caused by the large change of the load of the vehicle. Because the pitching and the rolling of the vehicle can be independently controlled, the mass center position and the moment of inertia can be calculated according to the supporting force, the displacement, the pitching and the rolling angles, the angular velocity, the lateral acceleration and the like obtained by the measurement and control system and the dynamics principle of the vehicle.
In some embodiments, step S1 calculates a centroid position of the sprung mass in the vehicle body coordinate system from a supporting force of the hydraulic cylinder, a traveling ramp angle, and a position of a fulcrum of the hydraulic cylinder in the vehicle body coordinate system in a traveling state of the vehicle, including:
And step S101, if the vehicle runs on a straight road at a constant speed or at a small acceleration, controlling the active hydraulic suspension to keep the vehicle horizontal, and respectively calculating the transverse position and the longitudinal position of the mass center of the sprung mass under the vehicle body coordinate system according to the supporting force of each hydraulic cylinder and the position of the hydraulic cylinder fulcrum on the vehicle body coordinate system.
And S102, if the vehicle generates larger longitudinal and lateral acceleration or the vehicle runs on a road with larger gradient at a uniform speed, the offset of the mass center generates load transfer on the hydraulic cylinders, and the vertical position of the mass center of the sprung mass is calculated according to the supporting force of each hydraulic cylinder, the angle of the running ramp and the position of the hydraulic cylinder in a vehicle body coordinate system.
In some embodiments, step S2 performs a pitch and roll motion of the vehicle in a horizontal state of the vehicle, and calculates a pitch moment of inertia and a roll moment of inertia based on a supporting force of the hydraulic cylinder and a gyroscope angular velocity, respectively, including:
Step S201, under the horizontal state of the vehicle, controlling the active hydraulic suspension to generate pitching motions with different angular accelerations, and obtaining accurate pitching moment of inertia according to different pitching moment of inertia measured under the condition of various angular accelerations; the different moment of inertia of pitch includes the support force, displacement, pitch and roll angles, angular velocity and lateral acceleration of the hydraulic cylinder.
Step S202, under the horizontal state of the vehicle, controlling the active hydraulic suspension to generate roll motions with different angular accelerations, and obtaining accurate roll moment of inertia according to different roll moment of inertia measured under the condition of various angular accelerations; the different roll moments of inertia include the support force, displacement, pitch and roll angles, angular velocity and lateral acceleration of the hydraulic cylinder.
In some embodiments, step S3 of braking the vehicle during the constant-speed turning of the vehicle, calculating yaw moment of inertia according to the yaw velocity and braking force of the vehicle body, includes: when the vehicle turns, the vehicle body is kept horizontal, the vehicle is braked, the yaw moment of inertia of the vehicle is calculated according to the change of the yaw angular acceleration of the vehicle body and the braking force, and the yaw moment of inertia is calculated for a plurality of times to obtain the accurate yaw moment of inertia.
Referring to fig. 2, the embodiment of the application further provides a sprung mass key parameter dynamic test and vehicle safe driving early warning system, which adopts the sprung mass parameter dynamic test and vehicle safe driving early warning method described in the above embodiment to test and early warn, and the system comprises: hydraulic cylinder 304, gyroscope 8, steering wheel angle sensor 9, brake pipe pressure sensor 305, and data acquisition and calculation controller 7.
The hydraulic cylinders 304 are used to support the vehicle and control the compression and rebound of each suspension, respectively, to achieve heave, pitch, roll and torsion control of the vehicle.
The steering wheel angle sensor 9 is for measuring a steering wheel angle at the time of running of the vehicle, thereby recognizing the driving intention of the driver, and calculating a vehicle steering radius, a running track, and a vehicle body and wheel slip angle from the steering wheel angle.
The gyroscope 8 is used to measure the longitudinal acceleration, lateral acceleration, vertical acceleration, pitch angle speed, roll angle speed and yaw angle speed of the vehicle as it moves. The gyroscope 8 is a key sensor for vehicle chassis control.
The brake line pressure sensor 305 measures the pressure of the hydraulic line when the vehicle is braked, converts the pressure signal into a voltage or current signal, and transmits the voltage or current signal to the data acquisition and calculation controller 7 for calculating the braking torque.
The data acquisition and calculation controller 7 is used for acquiring the pressure of two cavities of each hydraulic cylinder of the vehicle suspension in real time, calculating the supporting force on the vehicle body according to the pressure difference, simultaneously acquiring the displacement of the hydraulic cylinders as control input, reading parameter data measured by the gyroscope 8, the brake pipeline pressure sensor 305 and the steering wheel angle sensor 9, realizing the automatic lifting control of the hydraulic cylinders of each suspension of the vehicle, meeting the requirements of on-line testing of the mass center position and the rotational inertia, and giving an early warning of the driving working condition according to the driving speed, the lateral acceleration, the steering wheel corner, and the deviation data of the mass center position and the rotational inertia beyond the design by weighted average.
In some embodiments, the sprung mass parameter dynamic test and vehicle safe driving early warning system further includes: the hydraulic power unit 6, the servo valve 4, the first pressure sensor 302, the second pressure sensor 303, the displacement sensor 301 and the accumulator 5.
The hydraulic power unit 6 is used for providing pressure oil for a hydraulic system; the hydraulic power unit 6 may be classified into an engine power, a motor drive, an external power supply, and the like according to a power generation source. Among these, engine power is the simplest power mode. The motor driving needs the system to be provided with a high-voltage battery and a special motor controller, and is a power generation mode of hybrid power and electric vehicles. The external power source supplies power, is suitable for a working system which needs an active suspension in specific occasions (such as vehicle getting rid of poverty, heavy cross-country, emergency rescue and the like), and can be divided into an external small-sized generator and a small-sized internal combustion engine direct drive hydraulic pump.
The servo valve 4 is used for driving the hydraulic cylinder 304 to lift, and a current or voltage signal output by the control system drives a pilot stage of the servo valve, so that the pressure and the flow of hydraulic oil flowing into the hydraulic cylinder are controlled.
The first pressure sensor 302 and the second pressure sensor 303 are transmitters for measuring working pressures of two cavities of the oil cylinder, convert pressure signals into current signals, and input the current signals into the data acquisition and calculation controller 7.
The displacement sensor 301 is a sensor for measuring the telescopic travel of the hydraulic cylinder 304, and the displacement sensor 301 is arranged on the shell of the hydraulic cylinder 304 through a fixed part and is connected with a hydraulic rod through a follow-up part; when the hydraulic rod expands and contracts, the displacement sensor 301 measures the change of the displacement in real time, and starts a corresponding voltage or current signal to the data acquisition and calculation controller 7.
The accumulator 5 is an energy storage component of the hydraulic system, and is a key component for buffering impact and accumulating hydraulic energy of the hydraulic system. The accumulator 5 can rapidly supply a large amount of hydraulic oil by storing hydraulic energy when the vehicle continuously acts, thereby reducing the requirements on the discharge capacity and total power of the hydraulic pump.
The vehicle coordinate system is shown in fig. 3. The wheel 1 is positioned below a suspension, is connected with the ground and is connected with a vehicle body through a connecting rod and a hydraulic cylinder 304 to restrain the wheel from moving up and down (also called unsprung mass, the vehicle body 2 is positioned above the suspension and is called sprung mass, the hydraulic cylinder 304 is positioned between the suspension connecting rod and the vehicle body, and can control the oil cylinder to stretch and retract and measure the telescopic displacement through an active suspension hydraulic system.
The pitch angle alpha of the vehicle is around the Y axis, and the front part of the vehicle is depressed and the rear part of the vehicle is lifted to be in a positive direction according to the right hand rule. The vehicle roll angle beta is around the X axis, and according to the right hand rule, the right side of the vehicle is lowered and the left side is lifted to be in the positive direction. The yaw angle gamma of the vehicle is around the Z axis, and the vehicle turns left in the positive direction. The location of the vehicle centroid G is (x, y, z).
The measurement of the horizontal position (x, y) of the mass center of the vehicle is determined according to the weight distribution borne by each suspension of the vehicle, for example, when the vehicle runs at a constant speed, the longitudinal and lateral accelerations of the vehicle are small, no load transfer occurs, and the value of the plane coordinate x, y of the mass center is determined by the supporting force of each suspension, the wheel track T and the wheel base L.
When the vehicle is braked suddenly or accelerated suddenly, load transfer occurs, under the condition of a certain acceleration, the action moment of the vertical position z of the mass center on the front and rear suspensions can be calculated, so that the vertical position z of the mass center can be measured by measuring the suspension supporting force and the known wheel track T and wheel base L.
In some embodiments, the calculation of the centroid position includes calculation of the centroid horizontal position and calculation of the centroid height, wherein the centroid horizontal position is calculated as follows:
ELF+FRF+FLR+FRR＝Msg
(FLF+FRF)L＝Msg LR
(FLR+FRR)L＝Msg LF
(FLF+FLR)T＝Msg TR
(FRF+FRR)T＝Msg TL
Wherein F LF,FRF,FLR,FRR is the supporting force of the left front, right front, left back and right back suspension hydraulic cylinders respectively; m s g is the weight of the vehicle, and M s is the mass of the vehicle; t L,TR is the distance from the mass center to the fulcrum of the left-side and right-side suspension hydraulic cylinder respectively; l R,LF is the distance from the mass center to the fulcrum of the front and rear axle hydraulic cylinders respectively; t=t L+TR, T is the distance between the left and right fulcrums of the hydraulic cylinder; l=l F+LR, L is the distance between the front and rear fulcrums of the hydraulic cylinder.
In some embodiments, when measuring the height of the centroid, the vehicle is respectively measured at a maximum pitch angle and a maximum roll angle, and the total of four vehicle body attitudes are respectively +alpha max,-αmax,+βmax,-βmax, and the obtained heights of the centroids are respectively Z 1,Z2,Z3,Z4; the centroid height is calculated as follows:
(FLF+FRF)L＝Msg(LF-Z1 sin αmax)
(FLR+FRR)L＝Msg(LR-Z2 sinαmax)
(FLF+FLR)T＝Msg(TR-Z3 sinβmax)
(FRF+FRR)T＝Msg(TL-Z4 sinβmax)
after deriving centroid height Z 1,Z2,Z3,Z4, based on the mean An accurate centroid height is determined.
In the calculation process of the inertia of the vehicle, the vehicle is required to be horizontal, the pitching and rolling motions of the vehicle are carried out according to a certain frequency, and the inertia can be obtained according to the supporting force of each hydraulic cylinder and the angular velocity of a gyroscope and the dynamics principle of the vehicle. When the yaw movement of the vehicle is measured, the vehicle is required to travel at a constant speed in a turning mode, in the traveling process, the vehicle is braked, the yaw speed and the braking force are measured, and meanwhile the yaw moment of inertia can be obtained according to a dynamic formula.
In some embodiments, the pitch moment of inertia, the roll moment of inertia, and the yaw moment of inertia are calculated by a pitch equation of motion, a roll equation of motion, and a yaw equation of motion, respectively; wherein,
The pitch motion equation of the vehicle is:
the roll motion equation of the vehicle is:
The yaw motion equation of the vehicle is:
Wherein, I y,Ix,Iz is the pitch moment of inertia, the roll moment of inertia and the yaw moment of inertia of the vehicle respectively; The pitch angle acceleration, the roll angle acceleration and the yaw angle acceleration of the vehicle are respectively; f LF,FRF,FLR,FRR is the supporting force of the left front, right front, left back and right back suspension hydraulic cylinders respectively; t L,TR is the distance from the mass center to the fulcrum of the left-side and right-side suspension hydraulic cylinder respectively; l R,LF is the distance from the mass center to the fulcrum of the front and rear axle hydraulic cylinders respectively; r LF,RRF,RLR,RRR is the braking force of the left front, right front, left rear and right rear wheels respectively; b L,BR is the distance from the center of mass to the left and right wheel center ground connection line.
When the hydraulic cylinder controls the pitching and rolling motions of the vehicle body, the application can change the motion direction and frequency of the hydraulic cylinder simultaneously, and realize different pitching and rolling angular accelerations when the vehicle moves. According to the kinematic formula, the moment of inertia corresponding to each angular acceleration is obtained, and the results of the dynamic tests are averaged to obtain more accurate moment of inertia.
Let pitch and roll accelerations be respectively(N, m are natural numbers greater than 2 and less than 10), the measured pitch and roll moments of inertia correspond to I y1,Iy2,…,Iyn,Ix1,Ix2,…,Ixm, respectively, (n, m are natural numbers greater than 2 and less than 10), the average pitch moment of inertia is:
Will be As a calibration value of the rotational inertia of the vehicle, the calibration value is provided to a chassis control system (such as ABS, ESC, ASS and the like) to improve the control effect.
The dynamic measurement method provided by the application is not only suitable for a two-axle vehicle provided with an active hydraulic suspension, but also suitable for a multi-axle vehicle provided with the active suspension, for the multi-axle vehicle, the roll and the pitch angle are calculated according to the first axle and the last axle as the two-axle vehicle, the displacement generated by the hydraulic cylinder of the intermediate axle is controlled to be in the middle of the displacement of the front and rear axle hydraulic cylinders, namely, the intermediate axle converts the actual displacement according to the roll and the pitch angle in proportion, and the supporting points of all the hydraulic cylinders are ensured to be on the same plane, so that the supporting force of each oil cylinder of the vehicle is uniformly distributed. The calculation formula of the mass center position and the rotational inertia of the two-axis vehicle can be used for reference, so that the mass center and the inertia parameters of the multi-axis vehicle can be obtained, and the result is shown in figure 4.
In some embodiments, the calculation of the safety threshold range includes: calculating a driving condition early warning index; calculating a safety threshold range based on the driving condition early warning index; the calculation formula of the running condition early warning index is as follows:
J＝ω1V+ω2ay+ω3δ+ω4ΔIx+ω5ΔIy+ω6ΔIz+ω7ΔX+ω8ΔY+ω9ΔZ
Wherein J is a driving condition early warning index; v is the vehicle speed, a y is the lateral acceleration, delta is the steering wheel rotation angle, delta I x,ΔIy,ΔIz is the deviation of the moment of inertia exceeding the design value, delta X, delta Y and delta Z are the deviation of the centroid position exceeding the design value; omega 1,ω2,…ω9 is the weighting coefficient obtained by adding the parameters according to the weight.
According to the application, the driving condition early warning index J is obtained by accumulating the parameters of the vehicle speed V, the lateral acceleration a y, the steering wheel rotation angle delta, the deviation delta I x,ΔIy,ΔIz of the moment of inertia exceeding the design value and the deviation delta X, delta Y and delta Z of the centroid position exceeding the design value according to weights, wherein the weighting coefficients are omega 1,ω2,…ω9 respectively.
The weight distribution is carried out according to the influence degree of each quantity on the safety factors of the vehicle, for example, a y and DeltaZ have great influence on the safety, and omega 2,ω9 can be distributed with larger values. And calculating according to the actual test data to obtain a safety threshold range [ J min Jmax ] so as to remind a driver of safely operating the vehicle.
If the deviation between the mass center position, the rotational inertia and the design time of the vehicle is very small, the safety running coefficient is only related to the vehicle speed V, the lateral acceleration a y and the steering wheel rotation angle delta, and the safety evaluation under the general running working condition can be carried out.
By the technical scheme, the embodiment of the application provides a method and a system for dynamic testing of sprung mass parameters and early warning of safe running of a vehicle, which are used for actively suspending the vehicle, and the method comprises the following steps: firstly, calculating the mass center position of the sprung mass under a vehicle body coordinate system according to the supporting force of a hydraulic cylinder, a driving ramp angle and the position of a hydraulic cylinder fulcrum under the vehicle body coordinate system in a driving state of a vehicle; the centroid position comprises a transverse position, a longitudinal position and a vertical position of the centroid under a vehicle body coordinate system; then, in the horizontal state of the vehicle, performing pitching and rolling motions of the vehicle, and respectively calculating pitching moment of inertia and rolling moment of inertia according to the supporting force of the hydraulic cylinder and the angular velocity of the gyroscope; then, in the process of uniform turning running of the vehicle, braking the vehicle, and calculating yaw moment of inertia according to the yaw rate and braking force of the vehicle body; and finally, calculating a safety threshold range based on the centroid position, the pitching moment of inertia, the rolling moment of inertia, the yaw moment of inertia and the running working condition of the vehicle, and early warning the driver based on the safety threshold range.
The sprung mass parameter dynamic test and vehicle safe running early warning method and system provided by the application can calculate the mass center position and the moment of inertia according to the principle of vehicle dynamics by controlling the pitching and the rolling of the vehicle and according to the supporting force, the displacement, the pitching and the rolling angles, the angular velocity, the lateral acceleration and the like obtained by the measurement and control system. The dynamic test method provided by the application is not only suitable for the two-axle vehicle provided with the active hydraulic suspension, but also suitable for the multi-axle vehicle provided with the active suspension, wherein the forefront axle and the rearmost axle of the multi-axle vehicle are calculated as the two-axle vehicle, and the middle axle converts actual displacement according to the roll and the pitch angle in proportion, so that the supporting points of the oil cylinders of the vehicle body are all in the same plane.
It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific examples of carrying out the application and that various changes in form and details may be made therein without departing from the spirit and scope of the application. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the application, and the scope of the application is therefore intended to be limited only by the appended claims.
Claims (10)
1. A dynamic test of sprung mass parameter and early warning method for safe running of vehicle are used for actively suspending vehicle, and are characterized by comprising the following steps:
Calculating the mass center position of the sprung mass under the vehicle body coordinate system according to the supporting force of the hydraulic cylinder, the driving ramp angle and the position of the hydraulic cylinder fulcrum under the vehicle body coordinate system in the driving state of the vehicle; the centroid position comprises a transverse position, a longitudinal position and a vertical position of the centroid under a vehicle body coordinate system;
In a horizontal state of the vehicle, performing pitching and rolling motions of the vehicle, and respectively calculating pitching moment of inertia and rolling moment of inertia according to the supporting force of the hydraulic cylinder and the angular velocity of the gyroscope;
In the process of uniform turning running of the vehicle, braking the vehicle, and calculating yaw moment of inertia according to the yaw rate and braking force of the vehicle body;
And calculating a safety threshold range based on the centroid position, the pitching moment of inertia, the rolling moment of inertia, the yaw moment of inertia and the running working condition of the vehicle, and early warning the driver based on the safety threshold range.
2. The method for dynamic testing of sprung mass parameters and early warning of safe driving of a vehicle according to claim 1, wherein calculating the centroid position of sprung mass in a vehicle body coordinate system based on the supporting force of a hydraulic cylinder, the driving ramp angle, and the position of a hydraulic cylinder fulcrum in the vehicle body coordinate system in the driving state of the vehicle comprises:
If the vehicle runs on a straight road at a constant speed or at a small acceleration, controlling an active hydraulic suspension to keep the vehicle horizontal, and respectively calculating the transverse position and the longitudinal position of the sprung mass center under the vehicle body coordinate system according to the supporting force of each hydraulic cylinder and the position of the hydraulic cylinder fulcrum in the vehicle body coordinate system;
If the vehicle generates larger longitudinal and lateral acceleration or the vehicle runs on a road with larger gradient at a constant speed, the offset of the mass center generates load transfer on the hydraulic cylinders, and the vertical position of the mass center of the sprung mass is calculated according to the supporting force of each hydraulic cylinder, the angle of the running ramp and the position of the hydraulic cylinder in a vehicle body coordinate system.
3. The method for dynamic testing of sprung mass parameters and early warning of safe running of a vehicle according to claim 1, characterized in that, in a horizontal state of the vehicle, pitch and roll motions of the vehicle are performed, and pitch moment of inertia and roll moment of inertia are calculated based on a supporting force of a hydraulic cylinder and a gyroscope angular velocity, respectively, comprising:
Under the horizontal state of the vehicle, controlling the active hydraulic suspension to generate pitching motions with different angular accelerations, and obtaining accurate pitching moment of inertia according to different pitching moment of inertia measured under the condition of various angular accelerations; the different pitching moment of inertia comprises the supporting force, displacement, pitching and side inclination angles, angular velocity and lateral acceleration of the hydraulic cylinder;
in a horizontal state of the vehicle, controlling the active hydraulic suspension to generate roll motions with different angular accelerations, and obtaining accurate roll moment of inertia according to different roll moment of inertia measured under the condition of various angular accelerations; the different roll moments of inertia include the hydraulic cylinder support force, displacement, pitch and roll angles, angular velocity and lateral acceleration.
4. The method for dynamic testing of sprung mass parameters and early warning of safe driving of a vehicle according to claim 1, wherein braking the vehicle during constant-speed turning driving of the vehicle, calculating yaw moment of inertia according to a yaw velocity and a braking force of the vehicle body, comprises:
When the vehicle turns, the vehicle body is kept horizontal, the vehicle is braked, the yaw moment of inertia of the vehicle is calculated according to the change of the yaw angular acceleration of the vehicle body and the braking force, and the yaw moment of inertia is calculated for a plurality of times to obtain the accurate yaw moment of inertia.
5. The method for dynamic testing of sprung mass parameters and early warning of safe driving of vehicle according to claim 1, characterized in that the calculation of the centroid position includes calculation of centroid horizontal position and calculation of centroid height, wherein,
The calculation formula of the centroid horizontal position is as follows:
FLF+FRF+FLR+FRR＝Msg
(FLF+FRF)L＝Msg LR
(FLR+FRR)L＝Msg LF
(FLF+FLR)T＝Msg TR
(FRF+FRR)T＝Msg TL
Wherein F LF,FRF,FLR,FRR is the supporting force of the left front, right front, left back and right back suspension hydraulic cylinders respectively; m sg is the weight of the vehicle, and M s is the mass of the vehicle; t L,TR is the distance from the mass center to the fulcrum of the left-side and right-side suspension hydraulic cylinder respectively; l R,LF is the distance from the mass center to the fulcrum of the front and rear axle hydraulic cylinders respectively; t=t L+TR, T is the distance between the left and right fulcrums of the hydraulic cylinder; l=l F+LR, L is the distance between the front and rear fulcrums of the hydraulic cylinder.
6. The method for dynamically testing sprung mass parameters and early warning safe driving of a vehicle according to claim 5, wherein when measuring the height of the mass center, the vehicle is respectively measured at a maximum pitch angle and a maximum roll angle, and four vehicle body attitudes are respectively +alpha max,-αmax,+βmax,-βmax, and the obtained heights of the mass centers are respectively Z 1,Z2,Z3,Z4;
the calculation formula of the centroid height is as follows:
(FLF+FRF)L＝Msg(LF-Z1 sinαmax)
(FLR+FRR)L＝Msg(LR-Z2 sinαmax)
(FLF+FLR)T＝Msg(TR-Z3 sinβmax)
(FRF+FRR)T＝Msg(TL-Z4 sinβmax)
after deriving centroid height Z 1,Z2,Z3,Z4, based on the mean An accurate centroid height is determined.
7. The sprung mass parameter dynamic test and vehicle safe driving early warning method according to claim 1, characterized in that the measurement of the pitch moment of inertia, the roll moment of inertia, and the yaw moment of inertia is calculated by a pitch motion equation, a roll motion equation, and a yaw motion equation, respectively; wherein,
The pitch motion equation of the vehicle is:
the roll motion equation of the vehicle is:
The yaw motion equation of the vehicle is:
Wherein, I y,Ix,Iz is the pitch moment of inertia, the roll moment of inertia and the yaw moment of inertia of the vehicle respectively; The pitch angle acceleration, the roll angle acceleration and the yaw angle acceleration of the vehicle are respectively; f LF,FRF,FLR,FRR is the supporting force of the left front, right front, left back and right back suspension hydraulic cylinders respectively; t L,TR is the distance from the mass center to the fulcrum of the left-side and right-side suspension hydraulic cylinder respectively; l R,LF is the distance from the mass center to the fulcrum of the front and rear axle hydraulic cylinders respectively; r LF,RRF,RLR,RRR is the braking force of the left front, right front, left rear and right rear wheels respectively; b L,BR is the distance from the center of mass to the left and right wheel center ground connection line.
8. The sprung mass parameter dynamic testing and vehicle safe driving warning method according to claim 1, characterized in that the calculation of the safe threshold range comprises:
Calculating a driving condition early warning index;
Calculating a safety threshold range based on the driving condition early warning index;
the calculation formula of the running condition early warning index is as follows:
J＝ω1V+ω2ay+ω3δ+ω4ΔIx+ω5ΔIy+ω6ΔIz+ω7ΔX+ω8ΔY+ω9ΔZ
Wherein J is a driving condition early warning index; v is the vehicle speed, a y is the lateral acceleration, delta is the steering wheel rotation angle, delta I x,ΔIy,ΔIz is the deviation of the moment of inertia exceeding the design value, delta X, delta Y and delta Z are the deviation of the centroid position exceeding the design value; omega 1,ω2,…ω9 is the weighting coefficient obtained by adding the parameters according to the weight.
9. A sprung mass critical parameter dynamic test and vehicle safe running early warning system, which adopts the sprung mass parameter dynamic test and vehicle safe running early warning method as set forth in any one of claims 1 to 8 for testing and early warning, and is characterized by comprising: a hydraulic cylinder (304), a gyroscope (8), a steering wheel angle sensor (9), a brake pipe pressure sensor (305) and a data acquisition and calculation controller (7);
the hydraulic cylinder (304) is used for supporting the vehicle and respectively controlling the compression and rebound of each suspension to realize the control of heave, pitch, roll and torsion of the vehicle;
The steering wheel angle sensor (9) is used for measuring the steering wheel angle when the vehicle runs so as to identify the driving intention of a driver and calculate the steering radius, the running track and the side angles of the vehicle body and the wheels according to the steering wheel angle; the gyroscope (8) is used for measuring longitudinal acceleration, lateral acceleration, vertical acceleration, pitch angle speed, roll angle speed and yaw angle speed when the vehicle moves;
The brake pipeline pressure sensor (305) is used for measuring the pressure of a hydraulic pipeline when the vehicle brakes, converting a pressure signal into a voltage or current signal, and sending the voltage or current signal to the data acquisition and calculation controller (7) for calculating the braking moment;
The data acquisition and calculation controller (7) is used for acquiring the pressure of two cavities of each hydraulic cylinder of the vehicle suspension in real time, calculating the supporting force on the vehicle body according to the pressure difference, simultaneously acquiring the displacement of the hydraulic cylinders as control input, reading parameter data measured by the gyroscope (8), the brake pipeline pressure sensor (305) and the steering wheel angle sensor (9), realizing the automatic lifting control of the hydraulic cylinders of each suspension of the vehicle, meeting the requirements of on-line testing of the mass center position and the rotational inertia, and giving early warning of the driving working condition according to the running speed, the lateral acceleration, the steering wheel corner, the deviation data of the mass center position and the rotational inertia beyond the design, and weighting average.
10. The sprung mass parameter dynamic testing and vehicle safe driving warning system according to claim 9, further comprising: the hydraulic power unit (6), the servo valve (4), the first pressure sensor (302), the second pressure sensor (303), the displacement sensor (301) and the energy accumulator (5);
the hydraulic power unit (6) is used for providing pressure oil for a hydraulic system;
The servo valve (4) is used for driving the hydraulic cylinder (304) to lift;
The first pressure sensor (302) and the second pressure sensor (303) are transmitters for measuring working pressure of two cavities of the oil cylinder, convert pressure signals into current signals, and input the current signals into the data acquisition and calculation controller (7);
The displacement sensor (301) is a sensor for measuring the telescopic travel of the hydraulic cylinder (304), and the displacement sensor (301) is arranged on the shell of the hydraulic cylinder (304) through a fixed part and is connected with the hydraulic rod through a follow-up part; when the hydraulic rod stretches, the displacement sensor (301) measures the change of displacement in real time and starts a corresponding voltage or current signal to the data acquisition and calculation controller (7);
the energy accumulator (5) is an energy storage component of a hydraulic system, and can rapidly supply a large amount of hydraulic oil when the vehicle continuously acts through storing hydraulic energy, so that the requirements on the displacement and total power of the hydraulic pump are reduced.
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| Publication Number | Publication Date |
|---|---|
| CN118961061A true CN118961061A (en) | 2024-11-15 |
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