JP2009227036A - Suspension control device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a suspension control device for compatibly attaining control stability required by a driver and riding comfort required by other occupants. <P>SOLUTION: The suspension control device is provided with a damper for increasing/reducing damping force to suppress the movement of a vehicle body relative to each wheel. It comprises a sky hook control base value setting part 61 for setting target damping force in accordance with the moving condition of the vehicle body, a vehicle property setting part 63 for setting vehicle property regarding the required degree of control stability and riding comfort in accordance with one of the instructing operation of the occupant with an operation switch 15 and the discrimination result of a get-in condition discriminating part 67 for discriminating the getting-in condition of the occupant, and a damping force correcting part 64 for correcting the target damping force set by the damping force setting means for every damper provided on each wheel depending on the vehicle property set by the vehicle property setting means. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a suspension control device provided with a damper capable of increasing or decreasing a damping force that suppresses relative motion between each wheel and a vehicle body.

  In recent years, suspensions for automobiles have adopted variable damping force dampers that can increase or decrease the damping force in order to improve vehicle handling stability and the ride comfort of each occupant.

In this type of damping force variable damper control, the damping force of each damper is controlled individually, and each damping coefficient is set so that the extension / contraction speed of each damper is the same. This technique is known (see Patent Document 1). According to this, the same ride comfort can be ensured regardless of which seat the occupant is seated on, and the speed of load movement is uniform between the front, rear, left and right wheels, so that steering stability during turning is also ensured. be able to.
JP 2005-41289 A

  However, in the conventional technique, if the damping force of the damper is set large in order to realize the handling stability required by the driver, the damping force for each wheel increases as a whole. Riding comfort may deteriorate, and conversely, if the damping force is set small with an emphasis on the riding comfort required by other occupants, operability with poor response may occur and steering stability may be reduced. Thus, with the conventional technology, it is difficult to achieve both the handling stability required by the driver and the riding comfort required by other occupants.

  The present invention has been devised to solve such problems of the prior art, and its main purpose is to achieve both the handling stability required by the driver and the riding comfort required by other passengers. It is an object of the present invention to provide a suspension control device and a control method configured to achieve the above.

  In order to solve such a problem, according to the present invention, a damper (4) capable of increasing / decreasing a damping force that suppresses relative motion between the vehicle body (1) and each wheel (3) is provided. In the suspension control apparatus, a damping force setting means (skyhook control base value setting unit 61) for setting a target damping force based on the motion state of the vehicle body, an occupant instruction operation, and an occupant riding state are determined. Vehicle characteristic setting means (vehicle characteristic setting unit 63) for setting vehicle characteristics relating to the required degree of driving stability and riding comfort based on at least one of the determination results in the riding state determination means (riding state determination unit 67). The target damping force set by the damping force setting means is corrected for each damper provided on each of the wheels according to the vehicle characteristics set by the vehicle characteristic setting means. A damping force correction means (damping force correcting unit 64), and to those with a.

  According to this, because the damping force for each damper is individually increased or decreased based on the vehicle characteristics related to the handling stability and the degree of demand for riding comfort, the handling stability required by the driver and the riding comfort required by other passengers Can be achieved.

  For example, when the vehicle characteristic set by the vehicle characteristic setting means gives priority to steering stability, an increase correction is made so that the target damping force of the damper on the front wheel side is increased, thereby suppressing the deterioration of the driver's steering feel. , Can improve steering stability. On the other hand, when the vehicle characteristics set by the vehicle characteristic setting means are given priority to ride comfort, the vehicle body vertical acceleration at high frequencies is reduced by reducing and correcting so that the target damping force of the damper on the rear wheel side is reduced. Can be improved.

  In addition, since the vehicle characteristics are set based on the occupant's instruction operation, it is possible to cope with differences in the preference regarding the occupant's steering stability and ride comfort. In addition, since the vehicle characteristics are set based on the determination result by the riding state determining means for determining the riding state of the occupant, appropriate steering stability and riding comfort can be ensured according to the occupant's riding state.

  In this case, the damping force correction means obtains a correction amount for the target damping force based on the vehicle characteristics set by the vehicle characteristic setting means, for example, a correction rate (correction gain) when correcting by multiplication, and this correction amount. The target damping force may be corrected with

  In the suspension control device, as shown in claim 2, vehicle body posture control and vibration suppression control relating to the damping force of the damper are executed in parallel, and the vehicle characteristic set by the vehicle characteristic setting means is given priority to ride comfort. In this case, it is possible to adopt a configuration in which the damping force correction means related to the damping control performs a reduction correction so that the target damping force of the damper becomes small while the vehicle body posture control is given priority to steering stability.

  According to this, while giving priority to the steering stability to the vehicle body posture control (roll control and pitch control), which has a high contribution to steering stability, on-spring and under-spring damping control (sky), which has a high contribution to riding comfort. By reducing and correcting the target damping force of the damper by hook control), it is possible to improve ride comfort while ensuring steering stability.

  In the suspension control device, as shown in claim 3, when the damping force correcting means has vehicle characteristics that require both steering stability and riding comfort, the target damping force of the damper on the front wheel side is The increase correction can be performed so as to increase, and the reduction correction can be performed so that the target damping force of the damper on the rear wheel side becomes small.

  According to this, it is possible to improve the ride comfort for the occupant of the rear seat while suppressing a decrease in steering stability felt by the driver.

  In the suspension control device, as described in claim 4, the vehicle characteristic setting means determines the vehicle characteristics when the riding state determination means determines that the occupant is not sitting in the rear seat. Prioritized, the damping force correction means may be configured to make an increase correction so that the target damping forces of the dampers on both the front wheel side and the rear wheel side are increased.

  According to this, since the occupant is not sitting in the rear seat, it is not necessary to secure the ride comfort for the occupant of the rear seat, while the driver places importance on the steering stability, so the front side and the rear wheel side The driver's request can be satisfied by increasing both damping forces and improving the steering stability.

  In this case, a seat photographing means for photographing each seat and a seat load detecting means for detecting the load of each seat are provided, and the riding state determining means uses the photographed image of the seat photographing means and the detection load of the seat load detecting means. Based on this, the presence or absence of a passenger sitting in each seat may be determined. According to this, the presence or absence of a passenger in the rear seat can be accurately determined.

  The suspension control device includes an occupant operating means (operation switch 15) that allows the occupant to select a vehicle characteristic, and the vehicle characteristic setting means is determined by the occupant state determining means. The vehicle characteristics specified by the operation switch can be adopted in preference to the boarding state.

  According to this, when the vehicle characteristics according to the riding state of the occupant determined by the riding state determination means and the vehicle characteristics specified by the occupant's instruction operation using the operation switch are different, the occupant's instruction operation is given priority. Thus, since the vehicle characteristics are set so as to match the passenger's preference, the passenger can be satisfied.

  According to the present invention, in the suspension control method provided with a damper capable of increasing or decreasing the damping force for suppressing the relative motion between the vehicle body and each wheel, a target based on the motion state of the vehicle body is provided. A vehicle related to the required degree of driving stability and ride comfort based on at least one of a damping force setting process for setting damping force, an instruction operation by the occupant, and a determination result in the riding state determination process for determining the riding state of the occupant A vehicle characteristic setting process for setting a characteristic, and a target damping force set by the damping force setting process according to the vehicle characteristic set by the vehicle characteristic setting process for each of the dampers provided on each of the wheels. And a damping force correcting process for correcting to.

  According to this, because the damping force for each damper is individually increased or decreased based on the vehicle characteristics related to the handling stability and the degree of demand for riding comfort, the handling stability required by the driver and the riding comfort required by other passengers Can be achieved.

  As described above, according to the present invention, since the damping force for each damper is individually increased or decreased based on the vehicle characteristics relating to the handling stability and the degree of ride comfort, the handling stability required by the driver and other occupants This makes it possible to achieve both the ride comfort required by the car.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram showing a schematic configuration of a four-wheeled vehicle to which the present invention is applied. Here, with respect to the four wheels and members disposed therewith, that is, tires, suspensions, and the like, subscripts indicating front, rear, left, and right are attached to the reference numerals, for example, wheel 3fl (front left), wheel 3fr, for example. (Right front), wheel 3rl (left rear), wheel 3rr (right rear), on the other hand, when generically referred to, for example, wheel 3.

  The vehicle V includes four front and rear wheels 3 on which tires 2 are mounted, and each wheel 3 is suspended from the vehicle body 1 by a suspension 5 including a suspension arm, a spring, a damper 4, and the like.

  In addition, the vehicle V is provided with an ECU (Electronic Control Unit) 7 and an EPS (Electric Power Steering) 8 which are the control body of the suspension system, a vehicle speed sensor 9 for detecting the vehicle speed, a lateral acceleration. A lateral G sensor 10 for detecting the longitudinal acceleration, a longitudinal G sensor 11 for detecting longitudinal acceleration, a yaw rate sensor 12 for detecting yaw rate, and the like are installed at appropriate positions of the vehicle body 1, and a stroke sensor 13 for detecting the amount of expansion and contraction of the damper 4. A vertical G sensor 14 for detecting vertical acceleration in the vicinity of the wheel house is installed for each wheel 3.

  The ECU 7 includes a microcomputer, a ROM, a RAM, a peripheral circuit, an input / output interface, various drivers, and the like. The damper 4 and the sensors 9 to 9 of each wheel 3 are connected via a communication line (CAN (Controller Area Network)). 14.

  The damper 4 is a damping force variable damper that uses a magneto-rheological fluid (hereinafter referred to as MRF) as a working fluid, and the ECU 7 determines each wheel 3 based on the detection results of the sensors 9 to 14. The damping force for each of the dampers 4 is individually controlled.

  FIG. 2 is a longitudinal sectional view of the damper 4 shown in FIG. The damper 4 is a monotube type (de carvone type), a cylindrical cylinder tube 21 filled with MRF, a piston rod 22 that moves axially relative to the cylinder tube 21, and a piston rod. A piston 26 which is attached to the tip of the cylinder 22 and divides the inside of the cylinder tube 21 into an upper oil chamber 24 and a lower oil chamber 25; a free piston 28 which defines a high-pressure gas chamber 27 below the cylinder tube 21; and a piston rod The main components are a cover 29 that prevents dust from adhering to 22 and the like, and a bump stop 30 that performs buffering during full bouncing.

  The cylinder tube 21 is connected to the upper surface of the trailing arm 35 that is a wheel side member via a bolt 31 that is fitted into the eyepiece 21a at the lower end. The piston rod 22 has a pair of upper and lower bushes 36 and a nut 37, and a stud 22a at the upper end thereof is connected to a damper base (upper part of the wheel house) 38 which is a vehicle body side member.

  The piston 26 includes a communication passage 39 that communicates the upper oil chamber 24 and the lower oil chamber 25, and a magnetic fluid valve (hereinafter referred to as MLV) disposed along the communication passage 39. An MLV coil 40 is provided. When an electric current is supplied from the ECU 7 to the MLV coil 40, a magnetic field is applied to the MRF passing through the communication path 39, and the ferromagnetic fine particles form a chain cluster, and the apparent MRF passing through the communication path 39 appears. The viscosity increases and the damping force increases accordingly.

  FIG. 3 is a schematic diagram showing an arrangement of operation switches, seat photographing cameras, and seat load sensors in the vehicle V shown in FIG. The vehicle V includes an operation switch (occupant operation means) 15 that allows an occupant sitting in each seat Sf / Sr to select vehicle characteristics, a seat photographing camera (seat photographing means) 16 that photographs each seat Sf / Sr, A seat load sensor (seat load detecting means) 17 for detecting a load acting on each seat Sf / Sr is provided. The operation switch 15, the seat photographing camera 16 and the seat load sensor 17 are connected to the ECU 7.

  FIG. 4 is a block diagram showing a schematic configuration of a main part related to damping force control in the ECU 7 shown in FIG. FIG. 5 is a block diagram showing a schematic configuration of the skyhook control unit 57 shown in FIG. FIG. 6 is a diagram showing an example of vehicle characteristics in the present invention. FIG. 7 is a target current map used in the drive current setting unit shown in FIG.

  As shown in FIG. 4, the ECU 7 includes an input interface 51 to which the above-described sensors 9 to 17 and the like are connected, the sensors 9 to 12 and 14, the operation switch 15, the seat photographing camera 16, the seat load sensor 17, and the like. The damping force setting unit 52 that sets the target damping force of each damper 4 based on the input signal of each of the dampers 4 and each damper 4 (MLV) according to the target damping force set by the damping force setting unit 52 and the detection result of the stroke sensor 13 A drive current setting unit 53 for setting a drive current to the coil 40), and an output interface 54 for outputting the drive current set by the drive current setting unit 53 to each damper 4.

  The damping force setting unit 52 includes a skyhook control unit 57, a roll control unit 58, and a pitch control unit 59. The roll control unit 58 and the pitch control unit 59 perform vehicle body posture control that optimizes the posture of the vehicle body by suppressing rolling during turning of the vehicle and pitching during sudden acceleration and deceleration of the vehicle. The target damping force is required with settings that prioritize handling stability. The skyhook control unit 57 performs ride comfort control (vibration control) that increases the ride comfort by suppressing the movement of the vehicle when overcoming the unevenness of the road surface. Here, as described below, the steering stability The target damping force is increased or decreased according to the vehicle characteristics relating to the priority of the performance and the ride comfort.

  As shown in FIG. 5, the skyhook control unit 57 includes a skyhook control base value setting unit (base value setting means) 61, a sprung speed calculation unit 62, a vehicle characteristic setting unit (vehicle characteristic setting means) 63, A damping force correction unit (damping force correction means) 64 is provided. The damping force correction unit 64 includes a gain setting unit 65 and a skyhook target value calculation unit 66. In order to obtain the target damping force for each damper 4, these perform calculations for each damper 4 as necessary.

  The skyhook control base value setting unit 61 sets the skyhook control base value based on the vehicle speed by the vehicle speed sensor 9, the vertical acceleration by the vertical G sensor 14, and the like. The sprung speed calculation unit 62 integrates the vertical acceleration by the vertical G sensor 14 to calculate the sprung speed. The gain setting unit 65 sets a correction gain for each damper 4 based on the sprung speed input from the sprung speed calculation unit 62 and the vehicle characteristics input from the vehicle characteristic setting unit 63. The skyhook target value calculation unit 66 multiplies the skyhook control base value input from the skyhook control base value setting unit 61 by the correction gain set by the gain setting unit 65 to obtain a skyhook control target value for each damper 4. Is calculated.

  The vehicle characteristic setting unit 63 includes a boarding state determination unit (boarding state determination unit) 67 that determines a passenger's boarding state. The vehicle characteristic setting unit 63 sets vehicle characteristics based on the determination result of the boarding state determination unit 67. The riding state discriminating unit 67 discriminates whether or not there is any object on the seat Sf / Sr by image analysis of the photographed image by the seat photographing camera 16 that photographs each seat Sf / Sr. In consideration of the detection result, the presence / absence of an occupant seated in each seat Sf / Sr is determined.

  Further, the vehicle characteristic setting unit 63 sets the vehicle characteristic based on a signal output from the operation switch 15 in response to an instruction operation by the occupant. Here, the vehicle characteristics designated by the operation switch 15 are adopted in preference to the occupant riding state determined by the riding state determination unit 67.

  As shown in FIG. 3, the operation switch 15 is arranged in the vicinity of each seat Sf · Sr, and a passenger seated in each seat Sf · Sr can select a vehicle characteristic according to preference. As described above, when the operation switch 15 gives the right to select the vehicle characteristic for each occupant, when the occupant obtains a vehicle characteristic that is different from the vehicle characteristic based on the occupant's riding state determined by the riding state determination unit 67, When the occupant obtains a vehicle characteristic different from that of the occupant, the desired vehicle characteristic can be selected by the operation switch 15 near the respective seats Sf and Sr.

  By the way, as shown in FIG. 6, when adjusting the damping force on the front wheel side 3fl · 3fr and the rear wheel 3rl · 3rr side in three stages of hard, middle and soft, as shown in FIG. . In hardware, the gain setting unit 65 sets a high correction gain, and the correction is increased so that the target damping force increases. In the software, the gain setting unit 65 sets the correction gain to be low and corrects the correction so that the target damping force becomes small.

  When the front wheels 3fl and 3fr are set to be hard and the target damping force on the front wheels 3fl and 3fr is increased and corrected so as to increase, it is possible to suppress the deterioration of the driver's steering feeling and to ensure the steering stability. On the other hand, if the rear wheels 3rl and 3rr are set to be soft and the target damping force on the rear wheels 3rl and 3rr is reduced and corrected, the vehicle body vertical acceleration at a high frequency is reduced and the riding comfort can be improved.

  Here, when the vehicle characteristics based on the riding state of the occupant determined by the riding state determination unit 67 is the steering stability priority (hard), and the occupant of the rear seat Sr selects the riding comfort priority (soft) by the operation switch 15 Or, conversely, when the vehicle characteristic based on the passenger's riding condition is ride comfort priority (soft) and the driver selects the steering stability priority (hard) by the operation switch 15, the driver also operates the operation switch 15. When the steering stability priority (hard) is selected and the rider of the rear seat Sr selects the ride comfort priority (soft) by the operation switch 15, both the steering stability and the ride comfort are required.

  In this case, increase correction is performed so that the target damping force on the front wheels 3fl and 3fr side is increased, and reduction correction is performed so that the target damping force on the rear wheels 3rl and 3rr side is reduced (mode 7). As a result, it is possible to improve the ride comfort for the occupant of the rear seat while minimizing the decrease in steering stability felt by the driver.

  In addition, when it is determined by the riding state determination unit 67 that the occupant is not seated in the rear seat, the vehicle characteristics are set to give priority to steering stability, and both the front wheels 3fl and 3fr side and the rear wheels 3rl and 3rr side are set. Is increased so as to increase the target damping force (mode 9). In this case, since the occupant is not sitting in the rear seat Sr, there is no need to ensure the riding comfort for the occupant of the rear seat Sr. On the other hand, since the driver places importance on steering stability, the front wheels 3fl and 3fr side and The driver's request can be satisfied by increasing the damping force on both the rear wheels 3rl and 3rr side to improve the steering stability.

  In this example, the correction gain of the target damping force is changed between the front wheels 3fl and 3fr and the rear wheels 3rl and 3rr. However, the correction gain can be changed on the left and right. In this case, when different vehicle characteristics are obtained for the left and right occupants, the damper 4 near the occupant is operated with a damping force characteristic based on the vehicle characteristics required by each occupant, so that each occupant can respond to his / her preference. It is possible to provide a comfortable ride.

  Note that if the damping force differs between the left and right dampers 4, it affects the vehicle behavior when the vehicle turns, so it is preferable to change the damping force with the left and right dampers 4 only when the vehicle is traveling straight.

  In this way, the target damping force is obtained by the skyhook control unit 57. In parallel with this, the target damping force is also obtained by the roll control unit 58 and the pitch control unit 59, and the damper 4 operates to the extension side. The largest value among the three target damping forces obtained by skyhook control, roll control, and pitch control is adopted as the target damping force, and the damper 4 is operated to the contraction side. In the case where the target damping force is present, the smallest one of the three target damping forces is adopted as the target damping force.

  When the target damping force is set by the damping force setting unit 52 as described above, the target damping force obtained by the damping force setting unit 52 by the drive current setting unit 53 as shown in FIG. The target current is set with reference to the target current map shown in FIG. 7 from the stroke speed obtained from the detection value of the stroke sensor 13, and feedback is performed so that the actual current of the MLV coil 40 of each damper 4 approaches this target current. Be controlled.

  FIG. 8 is a graph showing the occurrence state of the vehicle body vertical acceleration when the rear wheel side damping force reduction control according to the present invention is performed. As described above, when the damping force on the rear wheels 3rl and 3rr side is reduced and corrected, the vertical acceleration of the vehicle body is reduced, so that the riding comfort is improved and the acceleration of the low frequency is increased. Can be issued.

1 is a schematic diagram showing a schematic configuration of a four-wheeled vehicle to which the present invention is applied. It is a longitudinal cross-sectional view of the damper shown in FIG. It is a schematic diagram which shows the arrangement | positioning condition of the operation switch in the vehicle shown in FIG. 1, a seat imaging | photography camera, and a seat load sensor. It is a block diagram which shows schematic structure of the principal part which concerns on damping force control in ECU shown in FIG. It is a block diagram which shows schematic structure of the skyhook control part shown in FIG. It is a figure which shows an example of the vehicle characteristic in this invention. 5 is a target current map used in the drive current setting unit shown in FIG. It is a graph which shows the generation | occurrence | production state of the vehicle body vertical acceleration at the time of performing the rear-wheel side damping force reduction control by this invention.

Explanation of symbols

1 Body 3 Wheel 4 Damper 7 ECU
15 Operation switch (occupant operation means)
16 seat photography camera (seat photography means)
17 Seat load sensor (seat load detection means)
52 Damping force setting unit 53 Drive current setting unit 57 Skyhook control unit 58 Roll control unit 59 Pitch control unit 61 Skyhook control base value setting unit (damping force setting means)
63 vehicle characteristic setting unit (vehicle characteristic setting means)
64 Damping force correction unit (damping force correction means)
65 Gain setting unit 66 Skyhook target value calculation unit 67 Riding state determination unit (riding state determination unit)
V vehicle

Claims (6)

A suspension control device provided with a damper capable of increasing or decreasing a damping force that suppresses relative movement between the vehicle body and each wheel,
Damping force setting means for setting a target damping force based on the motion state of the vehicle body;
Vehicle characteristic setting means for setting a vehicle characteristic related to a required degree of steering stability and riding comfort based on at least one of an instruction operation by the occupant and a determination result by the riding state determination means for determining the riding state of the occupant;
Damping force correction means for correcting the target damping force set by the damping force setting means for each of the dampers provided on each of the wheels according to the vehicle characteristics set by the vehicle characteristic setting means; A suspension control device comprising the suspension control device. Car body posture control and vibration suppression control related to the damping force of the damper are executed in parallel,
When the vehicle characteristic set by the vehicle characteristic setting means gives priority to the ride comfort, the damping force correction means related to vibration suppression control keeps the vehicle body posture control priority to steering stability, and the target damping force of the damper is The suspension control device according to claim 1, wherein the correction is performed so as to reduce the suspension.   The damping force correcting means increases and corrects the target damping force of the damper on the front wheel side so that the target damping force on the front wheel side increases when the vehicle characteristics require both steering stability and ride comfort. The suspension control device according to claim 1, wherein the correction is performed so that the target damping force is reduced. The vehicle characteristic setting means sets the vehicle characteristic to steering stability priority when it is determined by the riding state determination means that the occupant is not sitting in the rear seat,
The suspension control according to any one of claims 1 to 3, wherein the damping force correction means performs an increase correction so that target damping forces of both the front-wheel and rear-wheel dampers are increased. apparatus. Equipped with occupant operation means that allows the occupant to select vehicle characteristics,
5. The vehicle characteristic setting means adopts the vehicle characteristic specified by the operation switch in preference to the occupant riding state determined by the riding state determination means. The suspension control device according to any one of the above. A suspension control method provided with a damper capable of increasing or decreasing a damping force that suppresses relative movement between a vehicle body and each wheel,
A damping force setting process for setting a target damping force based on the motion state of the vehicle body;
A vehicle characteristic setting process for setting a vehicle characteristic related to a required degree of driving stability and ride comfort based on at least one of the instruction operation of the occupant and the determination result in the riding state determination process for determining the riding state of the occupant;
A damping force correction process for correcting the target damping force set by the damping force setting process for each of the dampers provided on each of the wheels according to the vehicle characteristics set by the vehicle characteristic setting process. A suspension control method comprising:

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