KR101491171B1 - Device and method controlling motor position and creep of fuel cell vehicle - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a motor position and creep control apparatus for an electric vehicle and a control method thereof, and more particularly, The present invention relates to a motor position and creep control device for an electric vehicle, and a control method thereof, which can prevent the motor from being pushed and released when the vehicle is stopped and restarted on the back road by allowing the motor position control or the creep torque control to be performed.

To this end, the present invention provides a vehicle control apparatus comprising: a jumping determination unit for detecting a situation in which a vehicle is pushed back when a brake is released after a vehicle is stopped; A motor position control unit for calculating a motor torque for maintaining the motor position and maintaining the position of the motor; A creep torque control unit that generates a creep torque of the motor through a time delay and controls the motor speed to a constant level; And a controller for controlling the motor position and the creep of the electric vehicle.

Fuel cell, vehicle, motor, position, jungle judgment, creep, torque, backlash, brake

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a motor position and creep control apparatus for an electric vehicle,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a motor position and creep control apparatus for an electric vehicle and a control method thereof, and more particularly, The present invention relates to a motor position and creep control device for an electric vehicle, and a control method thereof, which can prevent the motor from being pushed and released when the vehicle is stopped and restarted on the back road by allowing the motor position control or the creep torque control to be performed.

Since the idle torque of the engine is transmitted to the torque converter and the transmission even in the case where the ordinary gasoline engine vehicle does not step on the excel pedal and the brake pedal while the vehicle is running, creep traveling is performed while the vehicle keeps running at a small speed.

As shown in the attached FIG. 5, the vehicle in the running state of the backlit road is subjected not only to the rolling resistance but also to the slope resistance as mgsinθ. Due to the tilting resistance, After stopping, release the brake pedal and the vehicle will be pushed back.

In order to get out of the situation where the vehicle is pushed backward, the driver operates again to prevent the vehicle from being pushed, such as by stepping on the brake pedal or operating the accelerator pedal.

In order to prevent the inconvenience of the operation for preventing the vehicle from being pushed back from the back road running, a certain amount of frictional brakes are maintained to prevent the throttle from being applied even when the excel pedal and the brake pedal are not applied. A creep control technique for releasing a friction brake and switching to a normal operation state is introduced.

On the other hand, since the electric vehicle travels only by the configuration of the motor drive system (motor, speed reducer, wheel) without a separate engine, idle torque by the motor is not automatically generated when the vehicle is stopped, and creep does not occur like the gasoline engine vehicle .

Therefore, the creep function must be realized through the motor torque control in order to make the creep function of the gasoline engine vehicle to the electric vehicle.

That is, a pure electric vehicle driven by a motor such as a fuel cell vehicle requires a creep control algorithm for generating a torque similar to an engine idle torque in order to satisfy the same running feeling as a general gasoline mass-produced vehicle, and a creep control algorithm Algorithm development as well as a technique to prevent jumping when stopping and restarting after a stoppage are also being studied.

Of course, in a vehicle driven by a motor alone such as a fuel cell vehicle and an electric vehicle, the control of the motor driving force (for example, a method of increasing the motor driving torque by determining the backing length) It is possible to realize the prevention of the skidding of the vehicle.

That is, as shown in FIG. 4, it is possible to implement a method of determining the backlash by applying an angle sensor or a threshing judgment algorithm to the fuel cell and the electric vehicle, and increasing the motor torque according to the determined result, The method can be implemented simply because it is easy to directly control the motor driving force.

However, there is a need for a portion for calculating the necessary motor torque amount, and the amount of calculation depends on various parameters such as the angle of back and the number of passengers, thus requiring a lot of errors and experiments.

Particularly, when it is judged that the existing creep torque control logic is maintained, it is difficult to accurately calculate the amount of additional motor torque to be increased, and it is difficult to accurately maintain the position of the vehicle , The number of passengers, the angle of backing, etc. If the given environment changes, the amount of motor torque must be calculated again to maintain the position of the vehicle. Otherwise, the vehicle may be pushed forward or excessively pushed forward.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a position control or creep torque control of a motor for maintaining a stopped position by executing a jumping judgment logic when a brake is released after a vehicle is stopped, And the creep torque control is performed after checking the stabilization of the motor position at the stop position at the time of the motor position control. By doing so, it is possible to maintain the jumping at a minimum on the backing plate without operation of the brake pedal and the accelerator pedal, A creep control device and a control method thereof, which can maintain the present position of the vehicle irrespective of a change in the number of passengers, the number of passengers, and the like, and then naturally switch to the creep torque mode.

In order to accomplish the above object, the present invention provides a control system for a vehicle, comprising: a jumping determination unit for detecting a situation in which a vehicle is pushed backward when a brake is released after a vehicle is stopped; A motor position control unit for calculating a motor torque for maintaining the motor position and maintaining the position of the motor; A creep torque control unit that generates a creep torque of the motor through a time delay and controls the motor speed to a constant level; And a controller for controlling the motor position and the creep of the electric vehicle.

The preferred embodiment of the present invention is characterized in that the jumping determination unit comprises a gear shift speed detection unit for detecting that the gear is positioned in the forward gear and a wheel rotation direction detection unit for detecting that the wheel rotates in the reverse direction.

In another preferred embodiment, the motor position control unit sets a target input angle by adding an offset angle to compensate for a steady state angle error to the current angle of the motor at the time of entry of the motor position control, Is input to the PD controller to calculate the torque for maintaining the motor position.

In another preferred embodiment, the creep torque control unit includes a torque converter hydraulic pressure modeling unit that generates a creep torque of the motor through a time delay, a torque converter that controls the creep torque of the motor to a level for maintaining the motor speed constant, And a steady-state model unit.

In addition, a filter is connected to the final torque output end of the creep torque control unit to adjust the change in creep torque so that the sudden change does not occur.

According to another aspect of the present invention, there is provided a method of controlling a vehicle, comprising: a jumping determination step of determining whether a vehicle is pushed back when a brake is released; A motor position control step of entering a creep torque control step when the vehicle is not in a jam, and increasing a motor torque to maintain the motor position when it is determined that the vehicle is being pushed; A motor position stabilization check step of determining whether to continue the motor position or enter the creep torque control step after a predetermined time; A creep torque control step in which the motor torque is constantly increased from the stabilization torque for maintaining the motor position to the maximum creep torque as a starting point; The present invention provides a motor position and creep control method for an electric vehicle.

As a preferred embodiment of the present invention, there is provided a method of controlling a vehicle, comprising the steps of: calculating motor torque in consideration of backlash for prevention of shock to eliminate backlash when the vehicle is stopped at the time of braking while the vehicle is running; And a backlash compensation control step of controlling the backlash compensation.

The backlash compensation control step may include: setting a target input angle by adding an offset angle to compensate an error between a current angle of the motor and an angle of the steady state; Calculating a motor torque for maintaining a position of a motor by inputting a difference between a current angle and a target input angle to a PD controller and calculating a motor torque in consideration of backlash to prevent a shock; A process of applying a torque to a motor to eliminate backlash; .

The jumping determination step may include: detecting that the wheel rotates in a backward direction in a forward (D) step state of the gearshift range; Increasing the jumping judgment count and determining that the jumping judgment count is greater than the jumping judgment reference counter value; .

The step of controlling the motor position includes: setting a target input angle by adding an offset angle to compensate for a steady state angle error to the current angle of the motor at the time of entry of the motor position control; Calculating a motor torque for maintaining a position of a motor by inputting a difference between a current angle and a target input angle to a PD controller; A step of applying to the motor an increased torque to a level at which the motor position can be maintained; .

The motor position stabilization check step may include: determining that the motor position is stably maintained by performing the stabilization determination count if the torque change amount of the motor is smaller than the motor torque stabilization reference value and the amount of positional change of the motor is smaller than the motor position stabilization reference value ; Determining whether a shift to a creep torque control step should be performed; .

Further, when the stabilization torque for maintaining the motor position is smaller than the maximum creep torque, the mode is switched to the creep torque control mode, and when the stabilization torque for maintaining the motor position is larger than the creep torque, the motor position is maintained.

The motor position control and the creep torque control are immediately released when the accelerator pedal or the brake pedal is depressed.

Through the above-mentioned means for solving the problems, the present invention provides the following effects.

According to the present invention, when the electric vehicle running on only the motor is stopped, the shock prevention mode is performed in which the backlash compensation torque is applied, the jumping determination logic is executed, and the position control of the motor After the brake pedal is released, the motor position stabilization at the stopped position is checked and the creep torque control is performed so that the brake pedal and the accelerator pedal can be operated without any operation of the brake pedal and the accelerator pedal, It is possible to maintain the current position of the vehicle on the back road and to prevent the phenomenon such as jumping or sudden start regardless of changes in the angle and the number of passengers, thereby improving the driving stability.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a control block diagram showing a motor position and creep control device of an electric vehicle according to the present invention; FIG.

The present invention provides a motor position closed loop control method for maintaining the position of the motor (the rotor position of the motor) at the time of running on the back side while compensating for the disadvantages of the conventional motor torque open loop control. A shock suppression mode for applying a backlash compensating torque at the time of brake release is executed, a jumping determination logic is executed, a current position of the motor is fed back while being automatically switched to a position control mode upon release of a brake, The motor torque for maintaining the position is automatically calculated and used for maintaining the position of the vehicle.

The motor position and creep control apparatus 10 according to the present invention includes a jumping determination unit 40, a motor position control unit 20, and a creep torque control unit 30.

The gearshift determination unit 40 detects a state in which the vehicle is pushed back when the brake is released after stopping the vehicle. The gearshift determination unit 40 includes a gearshift range detecting unit for detecting that the gear is positioned in the forward gear, And a wheel rotation direction detecting unit.

The motor position control unit 20 controls the motor position (the rotor position of the motor). The motor position control unit 20 adjusts the offset angle to compensate for the current angle of the motor and the steady state angle error at the time of entry of the motor position control. In addition, the target input angle is set, and the difference between the current angle and the target input angle is inputted to the PD controller to automatically calculate the motor torque for maintaining the position of the vehicle, that is, the position of the motor.

The creep torque control unit 30 includes a torque converter hydraulic pressure modeling unit 32 for forming a hydraulic pressure such as an actual torque converter and a torque converter steady state model unit 34. The torque converter hydraulic pressure modeling unit 32) causes a creep torque of the motor to be generated through a time delay when the brake is released to release the brake pedal when the vehicle is stopped by stepping on the brake pedal.

That is, due to the process of forming the torque converter hydraulic pressure by the torque converter hydraulic pressure modeling unit 32, the creep torque of the motor appears through the time delay.

The torque converter steady state model unit 34 simulates the characteristic that the motor torque transmission force increases as the input / output speed difference of the torque converter hydraulic pressure model increases, The torque control is performed to reduce the torque according to the increase of the motor torque.

A filter 36 is additionally connected to the final torque output end of the creep torque control unit 30 to adjust the change in creep torque so that the sudden change does not occur.

Hereinafter, the motor position and creep control method of the present invention based on the above-described configuration will be described.

FIG. 3 is a control block diagram of a control method of a creep travel of an electric vehicle according to the present invention, showing control methods of the creep travel control method of an electric vehicle according to the present invention. And the change of the motor drive torque according to the change of the control mode.

The following logic for the creep travel control performed by the creep torque control unit and the motor position control unit is merely an example and various control logic can be implemented within a framework having the creep torque generating mode and the motor position maintaining mode.

A backlash compensating control step of removing a backlash for controlling a shock caused by backlash by stopping the vehicle by applying a brake pedal; a jumping determination step for determining that the vehicle is pushed back when the brake is released; A motor position control step of increasing the motor torque to maintain the motor position when the vehicle enters the creep torque control step and it is determined that the vehicle is being pushed, and a motor position stabilization check step and a creep torque control step It is a point to be able to prevent a phenomenon such as a jump or a sudden start in a back road without an operation of a brake pedal and an accelerator pedal, even in an electric vehicle that runs on a motor only.

First, in the backlit road traveling situation, when the brake pedal is depressed, the vehicle is stopped and the backlash compensation control step for unconditionally removing the backlash is performed, thereby performing the shock prevention control by the backlash.

That is, when a motor torque is suddenly applied in a situation where there is a backlash between the motor and the reducer or between the reducer and the traveling wheel, a great impact is applied to the reducer, so that the vehicle body is momentarily shaken. As a result, The motor position control is performed.

Therefore, in order to compensate for the error between the current angle of the motor and the steady state angle due to the backlash between the motor rotor and the speed reducer, i.e., when the brake is applied while the vehicle is running, the backlash is taken into consideration A backlash compensation control step is performed by a process of calculating a motor torque and a process of applying a calculated torque at a level capable of eliminating backlash to the motor.

At this time, motor torque for solving the backlash, that is, motor driving force (F1 in Fig. 3) for correcting the motor position error due to the backlash in the state in which the brake pedal is depressed is required to be small enough to eliminate backlash.

Next, when the brake is released to release the brake pedal while the shock prevention control due to backlash is performed, if the vehicle is on the backing plate, the backing load suddenly occurs.

In other words, when the brake pedal is released, the judgment of the back plate / flat land is carried out. It is possible to implement the throttle judging logic by performing the throttle judgment logic through the number of gears and the motor rotation direction, , And when it is judged that the motor is in the running (judgment of the back-running), the position control for maintaining the motor position is performed irrespective of the external load noise, thereby generating the motor torque necessary for maintaining the motor position.

At this time, if the vehicle is not in a throttle state, the control proceeds to the creep torque control step, and if it is determined that the vehicle is pushed, a motor position control step is performed to increase the motor torque to maintain the motor position.

More specifically, the jumping determination step detects the gear change speed stage as a forward (D-stage) end in the gear speed change stage detecting unit and at the same time senses that the wheel is rotating in the reverse direction in the wheel rotation direction detecting unit, If the jumping judgment count is larger than the jumping judgment reference counter value, the jumping judgment is finally made, and if it is determined that the vehicle is pushed backward, the motor position control mode advances to increase the motor torque to the calculated level so as to maintain the motor position.

At this time, the motor torque calculation for maintaining the motor position includes the steps of setting a target input angle by adding an offset angle to compensate for the angular error of the steady state to the current angle of the motor at the entry of the motor position control, And calculating the motor torque for maintaining the position of the motor by inputting the difference of the target input angle to the PD controller. The calculated torque to the level at which the motor position can be maintained is applied to the motor to control the motor position .

On the other hand, if the vehicle is not determined to be thrown, the following creep torque control is performed.

Therefore, the motor position control for maintaining the stopped position of the motor, that is, the current position of the motor, is performed irrespective of the backlash load causing the phenomenon that the vehicle is pushed on the backing road, A torque command for increasing the torque is issued.

At this time, when the brake pedal is released, the load of the backing plate is suddenly applied, so that the motor torque (F2 in Fig. 3) for maintaining the motor position in the motor position control mode is increased, It will remain stationary.

Then, after a predetermined time, the motor position stabilization check step proceeds as follows.

The step of checking the motor position stabilization is a step of determining whether a motor torque change amount and a position change amount have occurred, and determining whether the position of the vehicle, that is, the position of the motor, is continuously maintained or converted to a creep torque.

For the motor position stabilization check, if the torque change amount of the motor is smaller than the motor torque stabilization reference value or the motor position change amount is smaller than the motor position stabilization reference value, the stabilization determination count is increased and the stabilization determination count is set to the stabilization determination reference counter value , It is determined that the motor position is stably maintained.

Therefore, the motor position stabilization check step is started after releasing the brake, and if it is determined that the motor position is stably maintained, it is determined whether or not the shift to the creep torque control step is required.

That is, when it is determined that the motor position control is stabilized, when the stabilization torque for maintaining the motor position is smaller than the maximum creep torque, the mode is switched to the creep torque control mode so that the stabilization torque for maintaining the motor position is gradually increased And the creep torque control is performed.

More specifically, when the stabilization torque for maintaining the motor position is smaller than the creep torque, the control is switched to the creep torque control stage so that the stabilized motor torque for maintaining the motor position is increased from the starting point to the maximum creep torque by the motor torque ), The vehicle slowly moves. On the other hand, when the stabilization torque for maintaining the motor position is larger than the creep torque, the motor position remains unchanged.

At this time, the above-described control for maintaining the motor position and the creep torque control are released by pressing the accelerator pedal or the brake pedal.

As described above, when the electric vehicle running on only the motor drive runs on the backing path, the backlash is removed at the time of stoppage, and it is judged whether or not the swinging judgment is made when the brake is released again. The clutch is switched to the creep torque control mode. Thus, even if the vehicle restarts after stopping the start of the vehicle, the vehicle can be driven without running or jumping, thereby greatly improving the drivability.

1 is a control block diagram showing a motor position and creep control device of an electric vehicle according to the present invention;

FIGS. 2A and 2B are flowcharts for explaining a motor position and a creep control method of an electric vehicle according to the present invention;

FIG. 3 is a control block diagram of a motor position and creep control method of an electric vehicle according to the present invention,

FIG. 4 is a schematic view illustrating an example using an angle-of-inclination sensor or a forestry judgment algorithm in an existing electric vehicle;

5 is a schematic view for explaining a situation in which a vehicle is subjected to an inclined resistance during traveling on a back road.

Description of the Related Art

10: Motor position and creep control device

20: Motor position control section

30: Creep torque control section

32: Torque converter hydraulic forming model part

34: Torque converter steady state model part

36: Filter

40:

Claims (12)

A jumping determination unit for detecting a situation in which the vehicle is pushed back when the brake is released after the vehicle is stopped; A motor position control unit for calculating a motor torque for maintaining the motor position and maintaining the position of the motor; The torque converter hydraulic pressure modeling unit causes the torque torque of the motor to be generated through a time delay due to the hydraulic pressure forming process of the torque converter, and in order to maintain the speed of the motor at a constant speed by the torque converter steady state modeling unit, A creep torque control section for performing control to reduce the torque; And a controller for controlling the motor position and the creep of the electric motor. The method according to claim 1, Wherein the jumping determination unit comprises a gear position detecting unit for detecting that the gear is positioned in the forward gear and a wheel rotational direction detecting unit for detecting that the wheel is rotated in the backward direction. . The method according to claim 1, The motor position control unit sets a target input angle by adding an offset angle to compensate for the angular error of the steady state to the current angle of the motor at the entry of the motor position control and outputs the difference between the current angle and the target input angle to the PD controller And calculates a torque for inputting and holding the motor position. delete The method according to claim 1, Wherein a filter is connected to a final torque output end of the creep torque control unit to adjust a change in creep torque so that a sudden change does not occur. When the brake is released, proceeding to determine that the vehicle is pushed backward; A motor position control step of entering a creep torque control step when the vehicle is not jumping and applying a motor torque to maintain the motor position when it is determined that the vehicle is being pushed; A motor position stabilization check step of determining whether to continue the motor position or enter the creep torque control step after a certain time after entering the motor position control; A creep torque control step in which the motor torque is constantly increased from the stabilization torque for maintaining the motor position to the maximum creep torque as a starting point; And controlling the motor position and creep of the electric motor. The method according to claim 6, further comprising the steps of: calculating a motor torque in consideration of backlash to prevent shock when the brake is applied while the vehicle is stopped and for eliminating backlash; and applying torque to the motor for eliminating backlash And a backlash compensating control step of compensating the motor position and creep of the electric motor. 7. The method of claim 6, Detecting the rotation of the wheel in the forward direction in the forward (D) step state of the gear speed change stage; Increasing the jumping judgment count and determining that the jumping judgment count is greater than the jumping judgment reference counter value; And controlling the motor position and creep of the electric motor. 7. The method of claim 6, wherein the motor position control step comprises: Setting a target input angle by adding an offset angle to compensate for a steady state angle error to the current angle of the motor at the time of entry of the motor position control; Calculating a motor torque for maintaining a position of a motor by inputting a difference between a current angle and a target input angle to a PD controller; A step of applying to the motor an increased torque to the calculated torque to maintain the motor position; And controlling the motor position and creep of the electric motor. 7. The method of claim 6, wherein the step of checking the motor position stabilization comprises: Determining that the motor position is stably maintained by performing a stabilization judgment count if the torque change amount of the motor is smaller than the motor torque stabilization reference value and the position change amount of the motor is smaller than the motor position stabilization reference value; Determining whether a shift to a creep torque control step should be performed; And controlling the motor position and creep of the electric motor. The method of claim 10, And the motor position is maintained when the stabilization torque for maintaining the motor position is smaller than the maximum creep torque when the stabilization torque for maintaining the motor position is larger than the creep torque. Creep control method. The method of claim 6, Wherein the motor position control and the creep torque control are released as soon as the accelerator pedal or the brake pedal is depressed.

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