KR100854765B1 - Method and device for controlling motor by using interlock circuit in vehicle steering system - Google Patents

Abstract

A method and a device for controlling a motor using an interlock circuit in a vehicle steering system are provided to prevent a shock transmitted to a driver by forming the interlock circuit composed of a pre-driver and a relay. A device for controlling a motor using an interlock circuit in a vehicle steering system includes a calculation unit, a control unit, and a drive unit. The drive unit includes an interlock circuit constituted by a pre-driver(226) and a relay(228). The interlock circuit is inter-locked to a motor(130) to drive the motor under the control of the control unit. The pre-driver is previously operated before the relay. If correlation between steering information and current is an interlock condition above a normal section, an electronic control device temporarily turns off a pulse width modulation signal outputted from the pre-driver.

Description

Method and Device for Controlling Motor by Using Interlock Circuit in Vehicle Steering System

1 is a configuration diagram of an electric power assist steering device of a vehicle according to the prior art,

2A is a block diagram of an electronic controller;

2B is a block diagram of a drive means of the electronic controller;

3 is a flowchart of a motor control method for preventing sudden steering using an interlock circuit according to the present invention;

4 is a graph showing a correlation between steering information and a motor driving current used in the present invention, and relates to torque in steering information.

<Description of Symbols for Main Parts of Drawings>

100: steering system 130: motor

200: electronic control device 210: multiple sensors

220: calculation means 222: control means

224: drive means 226: pre-drive device

228: relay

The present invention relates to a motor control method and apparatus using an interlock circuit. More specifically, by determining the correlation between the steering information detected by a plurality of sensors and the current flowing in the motor, by controlling the motor drive using the interlock circuit formed of the pre-drive device and the relay to reduce the amount of impact delivered to the driver The present invention relates to a motor control method and apparatus.

Steering system of the vehicle (Steering System) is a device for the driver to freely change the driving direction of the vehicle by turning the steering wheel. Therefore, the steering system is closely related to the front axle or the front wheel alignment, and it is a very important device for driving safety together with the brake system. In general, the steering system should be small so as to have a turning radius, the vehicle's turning should be stable at high speeds, and the steering operation should be light and free.

As automobiles become more advanced, low-pressure tires are used, and the ground resistance of the front wheels increases due to the automation of large vehicles, and the steering wheel is required to operate, and the power assisted steering assists the steering wheel's operation by installing a power source in the steering system. A device (Power Steering Appratus) has been developed.

Generally, as a power assist steering device of a vehicle, a hydraulic power steering steering system using hydraulic pressure of a hydraulic pump has been used, but since the 1990s, an electric power steering steering system using an electric motor has been used. It is becoming more and more common.

Conventional hydraulic power assisted steering system consumes energy regardless of whether the steering wheel is rotated by the hydraulic pump driven by the engine, which is the power source to assist the power, whereas the electric power assisted steering system rotates the steering wheel to increase torque. When generated, a motor driven by electrical energy provides steering assistance. Therefore, when the electric power assisted steering device is used, energy efficiency can be improved compared to the hydraulic power assisted steering device.

1 is a block diagram of an electric power assist steering device of a vehicle according to the prior art.

As shown in FIG. 1, an electric power assisted steering device generally includes a steering system 100 that extends from the steering wheel 102 to both wheels 112 and an auxiliary power mechanism that provides steering assistance power to the steering system. .

The steering system 100 comprises a steering shaft 104, one side of which is connected to the steering wheel 102 to rotate with the steering wheel 102 and the other side of which is connected to the pinion shaft 106. In addition, the pinion shaft 106 is connected to the rack bar 118 through the rack-pinion mechanism part, and both ends of the rack bar 118 are connected to both wheels 112 of the vehicle through the tie rod 108 and the knuckle arm 110. )

The rack-pinion mechanism part is formed by engaging the pinion gear part 114 formed on the pinion shaft 106 and the rack gear part 115 formed on one side of the outer circumferential surface of the rack bar 118 with each other, thereby allowing the driver to steer the wheels 102. ), The torque is generated in the steering system 100, and the wheel is steered through the rack-pinion mechanism part and the tie rod 108 by the generated torque.

The auxiliary power mechanism includes a vehicle speed sensor 122 that detects a vehicle speed and outputs an electrical signal proportional to the detected vehicle speed, a steering angle sensor 124 that detects a steering angle and outputs an electrical signal proportional to the detected steering angle, and a driver steer wheel Torque sensor 126 that senses torque applied to 102 and outputs an electrical signal proportional to the sensed torque, and each electrical signal sensed by vehicle speed sensor 122, steering angle sensor 124, and torque sensor 126. An electronic control unit (ECU) 120 that generates a control signal based on the control signal generated by the electronic control unit (ECU) 120, a motor 130 that generates auxiliary power by a control signal transmitted from the electronic control device 120, and It comprises a transmission 140 for transmitting the auxiliary power to the rack bar 118.

Therefore, in the electric power assist steering device of the vehicle, the torque generated by the rotation of the steering wheel 102 is transmitted to the rack bar 118 via the rack-pinion mechanism part, and the assist power generated by the motor in accordance with the torque is ball screwed by the transmission. It is formed to be delivered to the rack bar 118 via the portion 150. That is, the torque generated from the steering system 100 and the auxiliary power generated from the motor 130 are combined to move the rack bar 118 in the axial direction.

Referring to the operation principle of the electric power assisted steering device, the motor control current is calculated by the electronic controller 120 from the torque of the steering wheel 102, the vehicle speed, and the steering angle information detected by the sensor, and the motor 130 is actually By detecting the value of the current flowing, and compares the calculated motor control current and the actual current of the motor and transmits a current corresponding to the difference to the motor 130 to drive the motor 130 to assist the steering operation of the driver. As the driver applies torque to the steering wheel 102, the current delivered to the motor 130 increases to assist the driver's steering operation. The motor driving of such an electronic control device requires a steering operation of the driver and preparation for various situations required for driving a vehicle.

The electric power assisted steering system is controlled by vehicle speed sensing, temperature measurement, angular velocity / angular acceleration compensation, and motor current control for smooth motor operation.

When the vehicle reaches a speed above a certain range, the motor current is limited to increase the sensitivity of the driver to operate the steering wheel to control the vehicle to be safe.

Abnormal continuous steering at vehicle standstill causes high current to the motor to generate heat. In this case, the electronic controller directly measures the internal temperature and limits the current after a certain time to prevent the circuit from thermal failure.

When the motor operates in the stopped state or stops in the operating state, the angular speed of the motor changes and accordingly the angular acceleration changes. In order to precisely control the motor, compensation is performed according to the angular velocity or angular acceleration of the motor. This compensation control improves the feeling of steering.

In addition, unexpected steering may occur due to a system failure when the vehicle is driven at a medium / high speed. To prevent this risk, control to set the current limit range to prevent current from flowing in the motor.

Particularly, in case of steer steering due to system abnormality, steering assist force greater than normal steering assistance force is loaded on the driver's steering operation when the driver is driving the vehicle at high speed. If you say. In order to prevent such sudden steering, a control method of reducing or blocking current of a motor is generally used.

In the prior art, a control method is used to prevent sudden steering by turning off the electronic control unit so that the motor driving is momentarily stopped. However, in this manner, when the motor drive is stopped, the steering wheel rotates in the opposite direction to the steering operation of the driver in progress, which causes a problem that gives the driver a strong shock.

In order to solve this problem, the present invention is to determine the correlation between the steering information detected by a plurality of sensors and the current flowing in the motor, to control the motor drive by using an interlock circuit formed of a pre-drive device and a relay Its main purpose is to provide a motor control method and apparatus for reducing the amount of impact transmitted to the vehicle.

In order to achieve the above object, the present invention, in the motor control apparatus of a vehicle including a steering shaft and a motor, a pre-drive device for controlling the motor, interlocked with a plurality of sensors, and outputs a pulse width modulated signal to drive the motor ( And an electronic controller including a pre-set and a relay configured to relay the current delivered to the motor, wherein the pre-drive system forms an interlock circuit that operates in preference to the relay. The control device compares the steering information by a plurality of sensors with the current of the motor to determine whether the correlation is a normal section, and if it is determined to be abnormal, turns off the pulse width modulation signal of the pre-drive device of the interlock circuit to drive the motor. The interlock circuit may be disconnected at an instant, and it may be determined whether the abnormal correlation is greater than or equal to the set time. This should allow provide a motor control apparatus using the interlock circuit, comprising a step of blocking the current delivered to the motor to prevent shake-up the other.

In addition, according to another object of the present invention, the electric power assist steering of a vehicle including an electronic control device for interlocking the steering shaft, the motor and a plurality of sensors, the interlock circuit consisting of a pre-drive device and a relay to control the motor An apparatus for controlling a motor using an interlock circuit, the method comprising: (a) recognizing vehicle information by a plurality of sensors in an electronic controller and comparing the current with a motor to determine whether the correlation is a normal section; (b) if it is determined that the correlation is out of the normal section, controlling the operation of the motor to be temporarily stopped by turning off the pulse width modulation signal of the pre-driver in the electronic controller; (c) determining whether the abnormal correlation is greater than or equal to a preset time in the electronic controller; And (d) if the abnormal correlation is determined to be greater than or equal to a predetermined time, preventing sudden steering by using an interlock circuit, wherein the electronic control device turns off the relay to stop the driving of the motor. It provides a motor control method.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First of all, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used as much as possible even if displayed on different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

2A is a block diagram of an electronic controller.

The electronic controller 200 includes a calculation means 220, a control means 222, and a driving means 224.

The electronic controller 200 generates a control signal based on electric signals transmitted from the plurality of sensors 210 to control the motor 130 to assist the steering force. The plurality of sensors 210 may be a vehicle speed sensor, a steering angle sensor, and a torque sensor, and each sensor detects a vehicle speed, detects a steering angle, and detects torque applied to a steering wheel by the driver to be related to the electronic controller 200. Send the information.

The computing means 220 of the electronic controller compares the steering information by the plurality of sensors 210 with the current flowing through the motor 130, recognizes the correlation, and determines whether it is a normal section. In addition, if it is determined that the correlation is out of the normal section, the maintenance time of the abnormal correlation is measured to determine once more whether the predetermined time is exceeded. In this way, the calculation means 220 generates a criterion of determination that the control means 222 and the driving means 224 can control the motor.

2B is a block diagram of a drive means of the electronic controller.

The driving means 224 of the electronic control device includes an interlock circuit consisting of a pre-drive device 226 and a relay 228, and interlocked with the motor 130 to control the motor (controlled by the control means 222). 130 is directly involved in driving. Here, interlocking means that other circuits do not open and operate when a circuit on the high priority side is turned on. Such a circuit is called an interlock circuit.

In the present invention, when the correlation between the steering information and the current is out of a certain normal section, it is determined that an unexpected sudden steering occurs due to a system abnormality, and the motor control using the interlock circuit is started.

In the interlock circuit, the pre-drive device 226 operates in preference to the relay 228. If it is determined that the correlation between the steering information and the current is an interlock condition or more, the electronic controller 200 temporarily turns off only the pulse width modulated signal output from the pre-drive device 226 so that the steering assistance force is cut off. . The driver who performs the steering operation at medium / high speed feels only a slight discontinuity in the steering wheel operation without a large impact amount on the control of the electronic control apparatus 200.

In addition, after measuring the time that the correlation out of the normal interval is maintained, it is determined whether or not the predetermined time or more, and if it is determined that the time maintained is more than the time, the relay 228 of the interlock circuit causes the motor The current transmitted to the 130 is interrupted to stop the driving of the motor 130.

In this way, the interlock circuit composed of the pre-drive device 226 and the relay 228 controls the driving of the motor 130 by the electronic control device 200 in a dual manner, and stops the driving of the motor 130 at once. The steering wheel can be rotated in the reverse direction to reduce the impact by preparing the impact amount to the driver in advance.

The control means 222 controls the interlock circuit of the driving means 224 and the driving of the motor 130 through the correlation recognized by the calculating means 220. In the main micro central unit (MCU) of the control means 222, if the correlation between the steering information determined by the calculation means 220 and the motor current is out of the normal range, the pulse width modulation of the pre-drive device 226 is immediately performed. ) To remove the signal and cut off the driving of the motor 130 instantaneously. In addition, the relay 228 constituting the interlock circuit together with the pre-drive device 226 is turned on to maintain the current transmitted to the motor 130.

If it is determined that the abnormal correlation is maintained over the set time by the calculation means 220, the sub-MCU of the control means 222 causes the relay 228 to cut off the current transmitted to the motor 130 to prevent the motor 130. ) Stop driving. When the driving of the motor 130 is stopped, the steering assistance force by the motor 130 is reduced to prevent self steering of the vehicle.

The electronic control apparatus 200 according to the preferred embodiment of the present invention receives the torque of the steering wheel sensed by the torque sensor as an electric signal and compares it with the current value flowing in the motor 130, and the correlation is normal. If it is determined that the deviation from the main MCU interrupts the pulse width modulated signal of the pre-drive device 226 or momentarily turn off the pulse width modulated signal to control the motor 130 to be instantaneously disconnected, abnormal correlation is set time, preferably For example, if it is maintained for 200ms, the sub-controller controls the motor 130 to stop by cutting off the current transmitted to the motor 130 by the relay 228.

3 is a flowchart of a motor control method for preventing sudden steering using an interlock circuit according to the present invention.

The electronic controller compares the steering information with the driving current of the motor and determines whether the correlation is a normal section (S310). Regarding the determination of the normal section, it will be described in detail below with reference to FIG. 4.

The motor provides steering assistance to the driver's steering operation, and the current delivered to the motor is controlled by an output signal which is output after calculating steering information detected by a plurality of sensors as an input signal in an electronic controller. The steering assistance of such a motor generates a force greater than the steering assistance necessary for the steering operation of the driver when the driver is operating the vehicle at a medium / high speed, thereby causing the vehicle to steer itself. Other risks may occur. In order to prevent such a risk, the electronic control apparatus monitors whether the correlation between the steering information and the motor driving current is normal.

When it is determined that the correlation between the steering information and the motor driving current is out of the normal section, the pulse width modulation signal is turned off in the pre-drive device of the interlock circuit to control the motor driving to be temporarily cut off (S320).

In the electronic controller, the pre-drive device and the relay form an interlock circuit, and when the first interlock condition that requires control of the motor drive current is satisfied, that is, a condition where the correlation between the steering information and the motor drive current is abnormal, the relay is first turned on. While keeping it ON, the pre-drive system controls only the pulse width modulation signal to be turned off so that the driving of the motor is cut off. After that, the second interlock condition, that is, the correlation between the steering information and the motor driving current, is kept abnormal for more than the set time. When a condition is established, the relay causes the current to be delivered to the motor to be cut off to stop the driving of the motor.

It is determined whether the abnormal correlation between the steering information and the motor driving current is maintained for more than the set time (S330). If it is determined that the set time is longer than the set time, the relay stops driving of the motor by cutting off the current transmitted to the motor (S340). .

4 is a graph showing a correlation between steering information and a motor driving current used in the present invention, and relates to torque in steering information.

As shown, when the value of the motor driving current according to the torque is located in the white portion of the graph, the correlation is determined to be normal, and when it is located in the hatched portion, it is determined to be an abnormal state. In the above, only the relationship between the torque and the motor driving current is shown, but there is a similar correlation graph between each other steering information and the motor control current, and the electronic control apparatus of the present invention uses the steering graph to obtain steering information. Determine whether the correlation between the motor drive current and the motor is normal.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention but to describe the present invention, and the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

As described above, according to the present invention, when the driver drives the vehicle at a medium / high speed by forming the interlock circuit between the pre-drive device and the relay in the electronic control device, the motor is prevented from sudden steering due to an unexpected system error. This can reduce the amount of impact that can be caused to the driver due to the stop of operation.

Claims (3)

In the motor control apparatus of the vehicle steering system comprising a steering shaft and a motor, An electronic control device which controls the motor, is interlocked with a plurality of sensors, and outputs a pulse width modulated signal to drive a motor and a relay relaying a current transmitted to the motor. It includes, wherein the pre-drive device forms an interlock circuit that operates in preference to the relay, the electronic control device compares the steering information by the plurality of sensors and the current of the motor It is determined whether the correlation is a normal section, and if it is determined to be abnormal, the pulse width modulation signal of the pre-drive device of the interlock circuit is turned off to control the motor to be momentarily disconnected, and the abnormal correlation is set. It is determined whether or not more than the time, and if determined to be more than the set time, the motor control to prevent sudden steering by using the interlock circuit, characterized in that for the relay of the interlock circuit to cut off the current transmitted to the motor. Device. The method of claim 1, wherein the electronic control device, Main Micro Central Unit (MCU) and Sub MCU Including, but using the interlock circuit to control the drive current of the motor by turning off the pulse width modulated signal of the pre-drive device under the control of the main MCU, the relay by the control of the sub-MCU Motor control device to prevent sudden steering. In an electric power assisted steering device for a motor vehicle comprising an electronic control device for interlocking a steering shaft, a motor and a plurality of sensors, the interlock circuit comprising a pre-drive device and a relay to control the motor, wherein the interlock circuit is used. In the motor control method, (a) recognizing vehicle information by the plurality of sensors in the electronic controller and comparing the current with the current of the motor to determine whether the correlation is a normal section; (b) if it is determined that the correlation is out of the normal range, controlling the driving of the motor to be temporarily stopped by turning off the pulse width modulation signal of the pre-drive device in the electronic controller; (c) determining whether the abnormal correlation is greater than or equal to a preset time in the electronic control apparatus; And (d) if the abnormal correlation is determined to be longer than a predetermined time, controlling the driving of the motor to be stopped by turning off the relay in the electronic controller; Motor control method for preventing sudden steering by using an interlock circuit comprising a.

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