JP6834584B2 - Vehicle control device - Google Patents

Description

The present invention relates to a vehicle control device.

Conventionally, as described in Patent Document 1, there is known a vehicle control device that predicts the slip of a driver's hand with respect to the steering wheel and notifies the driver of the slip prediction.
In the above-mentioned vehicle control device, the grip strength of the driver who holds the steering wheel is calculated, and the reaction force applied to the steering wheel is calculated. Based on the calculated grip strength and reaction force, the slip of the driver's hand with respect to the steering wheel is predicted.

JP-A-2005-119539

However, even if the driver is notified of the prediction of the driver's hand slipping on the steering wheel and the driver is aware of it, the driver may keep turning the steering wheel depending on the driving situation so that the hand becomes the steering wheel. It may slip against it. In that case, the self-aligning torque may cause the steering wheel to be returned to the steering neutral position regardless of the driver's intention.

An object of the present invention is to provide a vehicle control device capable of suppressing an unintended return of the steering wheel to a neutral position when the driver's hand slips on the steering wheel.

The vehicle control device that can achieve the above object is premised on a vehicle control device that controls a motor that generates an assist force based on a state quantity indicating a running state of the vehicle and an operating state of the steering wheel. The driver's hand with respect to the steering wheel from the contact information of the driver's hand detected through the control unit that generates a control signal for driving the motor based on the state amount and the sensor mounted on the steering wheel. When it is determined by the slip determination unit that the driver's hand has slipped on the steering wheel, the control unit has been applied to the steering wheel by the driver. The gist is to generate an assist force that holds the torque.

If the driver's hand slips against the steering wheel while the vehicle is running, the steering wheel may be automatically returned to the steering neutral position.
According to the above configuration, when the slip determination unit determines that the driver's hand has slipped, the control unit controls the motor so as to hold the torque applied to the steering wheel by the driver. Therefore, even if the driver's hand slips on the steering wheel, it is possible to suppress the driver's unintended return to the neutral position of the steering wheel.

In the vehicle control device, the motor has a rotation angle sensor that detects the rotation angle, and the control unit calculates a command value for driving the motor based on the state amount. When the slip determination unit determines that the driver's hand has slipped on the steering wheel, the slip determination unit has the steering wheel at the rotation angle when the driver's hand slips on the steering wheel. It is preferable to calculate a correction value for correcting the command value by feedback control so as to hold the torque applied to the wheel.

It is preferable that the slip determination unit determines the slip of the driver's hand with respect to the steering wheel when at least the steering torque as the state quantity becomes a specified value or more.
The state in which the driver's hand may slip with respect to the steering wheel is a state in which the steering torque becomes large to some extent, that is, the driver cuts the steering wheel to the left or right to some extent.

According to the above configuration, when the steering torque becomes equal to or higher than the specified value, the slip of the driver's hand with respect to the steering wheel is determined. Therefore, for example, except when the driver intentionally slides his / her hand on the steering wheel, the driver's hand on the steering wheel is only when the driver's hand can slip on the steering wheel. The slip can be judged. Therefore, the reliability of the driver's hand slip determination with respect to the steering wheel of the vehicle control device is improved.

The slip determination unit is said by the driver after a predetermined time has elapsed from the time when the driver's hand is determined to have slipped on the steering wheel and after it is determined that the driver's hand is touching the steering wheel. It is preferable to stop the control for holding the torque applied to the steering wheel.

In the above-mentioned vehicle control device, when the driver's hand slips on the steering wheel, the control unit controls the motor so as to hold the torque applied to the steering wheel by the driver. However, when the driver tries to operate the steering wheel again, the driver may feel uncomfortable in steering.

According to the above configuration, when the slip determination unit determines that a predetermined time has elapsed from the time when the driver's hand slipped on the steering wheel and the driver's hand is in contact with the steering wheel. By stopping the control of the driver to hold the torque applied to the steering wheel, when the driver tries to steer the steering wheel again, the driver's steering feeling can be smoothed.

According to the vehicle control device of the present invention, it is possible to suppress an unintended return of the steering wheel when the driver's hand slips on the steering wheel.

The schematic diagram in the 1st Embodiment of a vehicle control device. The functional block diagram of the control device for a vehicle of 1st Embodiment. A map that defines the relationship between the steering torque and the basic current command value used when calculating the basic current command value by the vehicle control device of the first embodiment. The control flow diagram which shows the procedure of the correction value calculation processing in the control device for a vehicle of 1st Embodiment. The functional block diagram of the control device for a vehicle of 2nd Embodiment. The functional block diagram of the control device for vehicles of 3rd Embodiment. The schematic diagram which showed the structure of the drive circuit and the motor of one Embodiment.

<First Embodiment>
Hereinafter, an embodiment in which the vehicle control device is embodied as a control device for a column-assist type electric power steering device (hereinafter referred to as “EPS”) will be described.

As shown in FIG. 1, the EPS 1 includes a steering mechanism 2, an assist force applying mechanism 3, a control device 5, and various sensors.
The steering mechanism 2 steers the steering wheels 4 and 4 based on the operation of the steering wheel 20 by the driver. The steering mechanism 2 has a steering shaft 21 that rotates integrally with the steering wheel 20 and a rack shaft 23. The steering shaft 21 includes a column shaft 21a connected to the steering wheel 20, an intermediate shaft 21b connected to the lower end of the column shaft 21a, and a pinion shaft 21c connected to the lower end of the intermediate shaft 21b. doing. The lower end of the pinion shaft 21c is connected to the rack shaft 23 via a rack and pinion mechanism 22. The rack and pinion mechanism 22 is formed by meshing the pinion teeth provided at the lower end of the pinion shaft 21c and the rack teeth on the rack shaft 23 with each other. Therefore, the rotational motion of the steering shaft 21 is converted into a reciprocating linear motion in the axial direction (horizontal direction in FIG. 1) of the rack shaft 23 via the rack and pinion mechanism 22. The reciprocating linear motion is transmitted to the left and right steering wheels 4 and 4 via the tie rods 24 and 24 connected to both ends of the rack shaft 23, respectively, so that the steering angles of the steering wheels 4 and 4 change. To do.

The assist force applying mechanism 3 includes a speed reduction mechanism 31 connected to the column shaft 21a and a motor 30 having a rotating shaft. The rotational force of the rotating shaft of the motor 30 is transmitted to the column shaft 21a via the reduction mechanism 31. The motor 30 is used as a source of an assist force that assists the operation of the steering wheel 20. As the motor 30, for example, a three-phase brushless motor is adopted.

Various sensors are provided for the purpose of detecting the amount of operation of the steering wheel 20 and the amount of state of the vehicle. For example, various sensors include a torque sensor 7, a vehicle speed sensor 8, a rotation angle sensor 9, and a touch sensor 65.

The torque sensor 7 is provided between the steering wheel 20 on the column shaft 21a and the assist force applying mechanism 3. The torque sensor 7 periodically detects the steering torque Th as a state amount (a state amount indicating the operating state of the steering wheel 20) generated on the steering shaft 21 by the operation of the steering wheel 20 by the driver. The vehicle speed sensor 8 detects the vehicle speed V of the vehicle. The rotation angle sensor 9 is provided in the motor 30. The rotation angle sensor 9 detects the rotation angle θm of the rotation axis of the motor 30. A plurality of touch sensors 65 are provided over the entire circumference of the steering wheel 20 in the circumferential direction. The touch sensor 65 detects the contact of the steering wheel 20 by the driver's hand holding the steering wheel 20 and the position of the driver's hand with respect to the steering wheel, and is an electric signal according to the contact state of the hand with the steering wheel 20. Generate contact information Touch. The contact information Touch is the number of points where the driver's hand is touching the steering wheel 20 (one place if the driver is touching the steering wheel 20 with one hand, and the steering wheel 20 with both hands). Information indicating the position of the driver's hand on the steering wheel 20 (for example, when holding the steering wheel 20 with both hands, the position at 2:20 following the positions of the long and short hands of the clock, etc.) Is.

The control device 5 takes in the outputs from various sensors and controls the drive of the motor 30 based on the outputs. Based on the contact information Touch, the control device 5 determines how the driver's hand is displaced after grasping the steering wheel 20. For example, in the control device 5, the driver's hand is repeatedly grasping and releasing the steering wheel 20 while moving on the steering wheel 20, or the driver's hand is in contact with the steering wheel 20. Determines whether the vehicle is moving on the steering wheel 20. The movement means that the driver is changing the position of the hand on the steering wheel 20 when the steering wheel 20 is rotated. It is said that the driver's hand is slipping on the steering wheel 20 when the driver's hand is moving on the steering wheel 20 while the driver's hand is in contact with the steering wheel 20.

As shown in FIG. 2, the control device 5 is a drive that converts DC power supplied from a power source (power supply voltage “+ Vb”) of an in-vehicle battery or the like into three-phase (U-phase, V-phase, W-phase) AC power. It includes an inverter circuit 50 as a circuit, a microcomputer 51 that outputs a control signal for driving the inverter circuit 50 by PWM (pulse width modulation) to the inverter circuit 50, and a memory 59 as a storage unit.

The inverter circuit 50 converts DC power supplied from a power source into three-phase AC power based on a control signal (PWM drive signal) from the microcomputer 51. This three-phase AC power is supplied to the motor 30 via the feeder line WL. The feeder line WL is provided with a current sensor 52 that detects each phase current value I of the motor 30. In FIG. 2, for convenience, the feeder line WL of each phase and the current sensor 52 of each phase are shown together. The inverter circuit 50 is connected to the ground GND.

The memory 59 stores a program executed by the microcomputer 51 to drive the motor 30.
The microcomputer 51 controls the drive of the motor 30 by executing the program stored in the memory 59. The microcomputer 51 generates a control signal for driving the motor 30 based on the steering torque Th, the vehicle speed V, the rotation angle θm, each phase current value I, and the contact information Touch of the driver's hand detected by various sensors. .. The microcomputer 51 PWM-drives the inverter circuit 50 by outputting the generated control signal to the inverter circuit 50.

Next, the microcomputer 51 will be described in detail.
As shown in FIG. 2, the microcomputer 51 includes a current command value calculation unit 53 and a control signal generation unit 54. The current command value calculation unit 53 calculates the current command value based on the steering torque Th, the vehicle speed V, and the contact information Touch of the driver's hand. The current command value is a target value of the current to be supplied to the motor 30, and indicates the d-axis current command value Id * on the d-axis and the q-axis current command value Iq * on the q-axis in the d / q coordinate system, respectively. ing. Of these, the q-axis current command value Iq * is the target value of the assist force generated by the motor 30. The d-axis current command value Id * is fixed to "0".

The current command value calculation unit 53 includes a basic current command value calculation unit 55 as a command value calculation unit, a slip determination unit 56, and an adder 58.
The basic current command value calculation unit 55 calculates the basic current command value Is *, which is a basic component of the q-axis current command value Iq *, based on the steering torque Th and the vehicle speed V. The basic current command value Is * is a basic command value corresponding to an assist force that assists the driver in operating the steering wheel 20.

As shown in the graph of FIG. 3, the basic current command value calculation unit 55 has a map that defines the relationship between the steering torque Th, the vehicle speed V, and the basic current command value Is *. As shown in this map, the basic current command value calculation unit 55 sets the absolute value of the basic current command value Is * to a larger value as the absolute value of the steering torque Th increases and the vehicle speed V becomes slower.

As shown in FIG. 2, the slip determination unit 56 calculates the correction value Irb * based on the steering torque Th, the contact information Touch of the driver's hand, and the rotation angle θm. The correction value Irb * is set so that when the driver's hand slips on the steering wheel 20, the steering wheel 20 is maintained at the position when the driver's hand slips (so-called steering wheel 20 by the driver). This is a correction value that corrects the basic current command value Is * (so as to maintain the applied steering torque Th). More specifically, the correction value Irb * is the rotation angle θm detected by the rotation angle sensor 9 of the motor 30 and the rotation angle θm of the motor 30 when the driver's hand slides on the steering wheel 20. It is a correction value that corrects the basic current command value Is * so as to maintain it.

When the steering torque Th is equal to or higher than the specified value, the slip determination unit 56 determines whether or not the driver's hand has slipped on the steering wheel 20 based on the contact information Touch. When the slip determination unit 56 determines that the driver's hand has slipped on the steering wheel 20, the slip determination unit 56 calculates a correction value Irb *. When the slip determination unit 56 determines that the driver's hand is not slipping with respect to the steering wheel 20, the correction value Irb * is set to 0. When the steering torque Th is not equal to or higher than the specified value, the slip determination unit 56 sets the correction value Irb * to 0 without performing the slip determination. Here, the specified value in the steering torque Th is an experimental verification of the value of the steering torque Th that the driver's hand can slip on the steering wheel 20 when the driver's hand is operating the steering wheel 20. It is set by When the steering torque Th is not equal to or higher than the specified value, the slip determination unit 56 determines that the steering torque Th is not equal to or higher than the specified value from the viewpoint that the driver's hand does not slip with respect to the steering wheel 20, and sets the correction value Irb *. Set to 0.

When the contact information Touch detected by the touch sensor 65 is not input to the slip determination unit 56, the driver's hand is not in contact with the steering wheel 20, that is, the driver's hand is slipping on the steering wheel 20. It is determined that there is no (correctly, not held), and the correction value Irb * is set to 0. The state in which the contact information Touch is not input to the slip determination unit 56 indicates that the driver does not intentionally grasp the steering wheel 20. This indicates, for example, when the driver is operating the steering wheel 20 in the direction of cutting left and right, and the driver intends to return the steering wheel 20 to the steering neutral position. At this time, when the driver releases his hand from the steering wheel 20, self-aligning torque is generated, and the steering wheel 20 is automatically turned back toward the steering neutral position. Therefore, it is determined that the driver does not intentionally grasp the steering wheel 20.

When the slip determination unit 56 determines that the driver's hand is in contact with the steering wheel 20, the number of places where the driver's hand is in contact with the steering wheel 20 according to the contact information Touch. To judge. That is, the slip determination unit 56 allows the driver to grasp the steering wheel 20 with both hands or one hand from the outputs (contact information Touch) of a plurality of touch sensors 65 arranged on the circumference of the steering wheel 20. Determine if.

When the driver's hand slips, the displacement of the driver's hand with respect to the steering wheel 20 can be estimated from the output changes of the plurality of touch sensors 65 in both one and both hands. The position where the driver's hand is holding the steering wheel 20 can also be estimated from the outputs of the plurality of touch sensors 65, and when the driver intentionally or unavoidably releases the steering wheel 20 as described above, It can be estimated from the fact that the outputs of the plurality of touch sensors 65 become zero.

Here, the slip determination in the slip determination unit 56 will be specifically described separately for the case where both hands of the driver slip on the steering wheel 20 and the case where one hand of the driver slips on the steering wheel 20. .. The reason for explaining separately the case where both hands slip on the steering wheel 20 and the case where one hand slips on the steering wheel 20 is that when both hands slip on the steering wheel 20, one of both hands This is to determine that the wheel is not slipping when only the hand slips. A detailed description will be described later.

First, consider the case where the slip determination unit 56 determines that the driver is holding the steering wheel 20 with both hands.
In the slip determination unit 56, both hands of the driver are slipping on the steering wheel 20 based on the contact information Touch, or one hand in both hands of the driver is slipping on the steering wheel 20 and the other hand is slipping. Determine if not. When the slip determination unit 56 determines that both hands of the driver have slipped on the steering wheel 20, the rotation angle θm of the motor 30 is set, and the rotation of the motor 30 when the driver's hands slip on the steering wheel 20. The correction value Irb * is calculated by feedback control so as to maintain the angle θm. When the slip determination unit 56 determines that both hands of the driver are not slipping on the steering wheel 20, the correction value Irb * is set to 0.

The slip determination unit 56 sets the correction value Irb * to 0 when it is determined that one of the driver's hands is slipping with respect to the steering wheel 20 and the other hand is not slipping. This is a state in which even if one of the two hands of the driver slips, the other hand holds the steering wheel 20, and the driver does not unintentionally return to the neutral position of the steering wheel 20. This is because it is determined that the driver's hand is not slipping on the steering wheel 20 from the viewpoint of.

Next, consider the case where the slip determination unit 56 determines that the driver is grasping the steering wheel 20 with one hand.
The slip determination unit 56 determines whether or not one hand of the driver is slipping on the steering wheel 20 based on the contact information Touch. When the slip determination unit 56 determines that one hand of the driver is slipping on the steering wheel 20, the rotation angle θm of the motor 30 is set, and the motor 30 when one hand of the driver slips on the steering wheel 20. The correction value Irb * is calculated by feedback control so as to maintain the rotation angle θm of. When the slip determination unit 56 determines that one hand of the driver is not slipping with respect to the steering wheel 20, the correction value Irb * is set to 0.

According to the slip determination with both hands or one hand of the driver with respect to the steering wheel 20 described above, when the slip determination unit 56 determines that the driver has slipped with all the hands in contact with the steering wheel 20, the rotation of the motor 30 The correction value Irb * is calculated by feedback-controlling the angle θm so as to maintain the rotation angle θm of the motor 30 when the driver's hand slides on the steering wheel 20.

The slip determination unit 56 sets the correction value Irb * to 0 when the amount of change in the absolute value of the steering torque Th becomes positive again after the driver's hand slips on the steering wheel 20. .. When the driver's hand slips on the steering wheel 20, the steering wheel 20 is held again, and when the steering torque Th is started to be applied, the correction value Irb * is set to 0. The positive change in the absolute value of the steering torque Th means that the absolute value of the steering torque Th in the latest cycle is the absolute value of the steering torque Th in the latest cycle from the absolute value of the steering torque Th in the previous cycle in the steering torque Th periodically detected by the torque sensor 7. It is getting bigger. The previous cycle indicates the cycle immediately before the latest cycle. In the present embodiment, when the slip determination unit 56 determines that the driver's hand has slipped against the steering wheel 20, the steering wheel 20 is maintained at the position when the driver's hand slips. That is, when the driver's hand slips on the steering wheel 20, the amount of change in the absolute value of the steering torque Th generated on the steering shaft 21 via the steering wheel 20 becomes 0 or negative. Therefore, when the driver re-grasps the steering wheel 20 and operates it again, the amount of change in the absolute value of the steering torque Th generated on the steering shaft 21 via the steering wheel 20 becomes positive. Therefore, the correction value Irb * is set to 0 when the change in the absolute value of the steering torque Th becomes positive again after the driver's hand slips on the steering wheel 20. Therefore, there is no sense of discomfort in the steering feeling of the driver when the driver tries to continue the operation by holding and holding the steering wheel 20 again after the driver's hand slips on the steering wheel 20.

The adder 58 adds the basic current command value Is * calculated by the basic current command value calculation unit 55 and the correction value Irb * calculated by the slip determination unit 56 to obtain the q-axis current command value Iq *. Calculate.

The control signal generation unit 54 controls by executing current feedback control in the d / q coordinate system based on the d-axis current command value Id *, the q-axis current command value Iq *, each phase current value I, and the rotation angle θm. Generating a signal. Specifically, the control signal generation unit 54 maps each phase current value I to the d / q coordinate system based on the rotation angle θm, so that the d-axis current which is the actual current value of the motor 30 in the d / q coordinate system. Calculate the value and the q-axis current value. The control signal generation unit 54 performs current feedback control to make the d-axis current value follow the d-axis current command value Id * and to make the q-axis current value follow the q-axis current command value Iq *. Generate a control signal. When this control signal is output to the inverter circuit 50, a drive current corresponding to the control signal is supplied to the motor 30. Therefore, the motor 30 generates an assist force according to the q-axis current command value Iq *.

Next, the control flow of the control device 5 will be described.
As shown in FIG. 4, the control device 5 takes in the steering torque Th and the contact information Touch (step S101), and determines whether or not the steering torque Th is equal to or higher than the specified value (step S102). When it is determined that the steering torque Th is not equal to or higher than the specified value, the control device 5 sets the correction value Irb * to 0 (step S103). When the control device 5 determines that the steering torque Th is equal to or higher than the specified value, the control device 5 determines whether or not the driver's hand is in contact with the steering wheel 20 based on the contact information Touch (step S104). If the driver's hand is not in contact with the steering wheel 20, the control device 5 proceeds to step S103. When the control device 5 determines that the driver's hand is in contact with the steering wheel 20, it determines whether the driver's hand holding the steering wheel 20 is both hands or one hand. (Step S105), it is determined whether or not all the driver's hands (both hands or one hand) are slipping on the steering wheel 20 (step S106). When the control device 5 determines that all the hands of the driver are not slipping on the steering wheel 20, the control device 5 proceeds to step S103. When it is determined that all the hands of the driver are slipping on the steering wheel 20, the control device 5 calculates the correction value Irb * (step S107). Next, the control device 5 determines whether or not the driver's hand applies the steering torque Th to the steering wheel 20 again (step S108). When the control device 5 determines that the steering torque Th is not applied again, the control device 5 continues the calculation of the correction value Irb * until the steering torque Th is applied to the steering wheel 20. When the control device 5 determines that the steering torque Th is applied to the steering wheel 20, the control device 5 proceeds to step S103 and sets the correction value Irb * to 0.

As described in detail above, according to the present embodiment, the following effects can be obtained.
(1) When the slip determination unit 56 determines that the driver's hand has slipped on the steering wheel 20, the slip determination unit 56 maintains the steering wheel 20 at the position where the driver's hand has slipped. That is, the slip determination unit 56 calculates the correction value Irb * for the basic current command value Is * so as to maintain the rotation angle θm of the motor 30 when it is determined that the driver's hand has slipped on the steering wheel 20. .. Therefore, even if the driver's hand slips on the steering wheel 20, it is possible to suppress the driver's unintended return to the neutral position of the steering wheel.

(2) When the steering torque Th exceeds a specified value, the slip determination unit 56 determines the slip of the driver's hand with respect to the steering wheel 20. Therefore, for example, except for a state in which the driver intentionally slides his / her hand on the steering wheel 20, the driver with respect to the steering wheel 20 only when the driver's hand can slide on the steering wheel 20. The slip of the hand can be judged. Therefore, the reliability of the driver's hand slip determination with respect to the steering wheel 20 of the control device 5 is improved.

<Second embodiment>
Next, a second embodiment of the vehicle control device will be described. The change from the first embodiment is to carry out phase fixing control for forming a closed loop between the inverter circuit 50 and the motor 30. The same reference numerals are given to the same configurations as those in the first embodiment.

As shown in FIG. 5, in the control signal generation unit 54, a switching element corresponding to each phase (U phase, V phase, W phase) provided inside the inverter circuit 50 is provided between the inverter circuit 50 and the motor 30. A plurality of control signals (PWM drive signals) that open and close so as to form a closed loop are stored. Further, the control signal generation unit 54 monitors the energized phase of each phase of the motor 30 based on each phase current value I.

When the slip determination unit 56 determines that the driver's hand has slipped on the steering wheel 20 based on the contact information Touch, the slip determination unit 56 outputs a command signal Sm1 to the control signal generation unit 54. The command signal Sm1 is a signal that the control signal generation unit 54 temporarily stops the generation of the control signal based on the basic current command value Is * (q-axis current command value Iq *). The control signal generation unit 54 was calculated by the basic current command value calculation unit 55 when the command signal Sm1 output from the slip determination unit 56 was input (the driver's hand slipped against the steering wheel 20). The generation of the control signal based on the basic current command value Is * is temporarily stopped. The control signal generation unit 54 is energized when the command signal Sm1 is input among the control signals (PWM drive signals) that form a closed loop between the inverter circuit 50 and the motor 30 stored therein. A control signal for fixing the energization in the existing phase is output to the inverter circuit 50 (so-called phase fixing control).

As shown in FIG. 7, the inverter circuit 50 is configured by connecting three switching arms 50U, 50V, and 50W in parallel. The switching arm 50U is configured by connecting a switching element u1 on the power supply side and a switching element u2 on the ground side in series. The switching arm 50V is configured by connecting a switching element v1 on the power supply side and a switching element v2 on the ground side in series. The switching arm 50W is configured by connecting a switching element w1 on the power supply side and a switching element w2 on the ground side in series. The inverter circuit 50 connects the inverter circuit 50 and the motor 30 by opening and closing the switching elements u1, u2, v1, v2, w1, w2 based on a control signal that forms a closed loop between the inverter circuit 50 and the motor 30. A closed loop between them is realized. As a specific example, when the slip determination unit 56 determines that the driver's hand has slipped on the steering wheel 20, when the phases energized in the motor 30 are the U phase and the V phase, the switching element u1. By turning on v1 and turning off the other switching elements u2, v2, w1 and w2, only the winding 30u corresponding to the U phase of the motor 30 and the winding 30v corresponding to the V phase are formed. The electric power supplied from the power source is energized, and the winding 30w corresponding to the W phase is not energized. By fixing the energized phase of the motor 30, a strong attractive force is generated between the motor 30 and the permanent magnet (not shown) mounted inside the motor 30, so that the motor 30 does not rotate. The strong attractive force generated here is a braking force to the extent that the driver cannot operate the steering wheel by hand.

According to this embodiment, there are the following effects.
(3) A braking force is generated in the motor 30 by realizing a closed loop between the inverter circuit 50 and the motor 30. When the driver's hand slips against the steering wheel 20, the steering wheel 20 works so as to be automatically returned to the steering neutral position of the steering wheel 20 by the self-aligning torque, but the motor 30 controls it. Since the power works, the steering wheel 20 is hard to be returned. Therefore, even if the driver's hand slips on the steering wheel 20, it is possible to suppress the driver's unintended return to the neutral position of the steering wheel.

<Third embodiment>
Next, a third embodiment of the vehicle control device will be described. The same reference numerals are given to the same configurations as those of the first and second embodiments.

As shown in FIG. 6, when the slip determination unit 56 determines that the driver's hand has slipped on the steering wheel 20, the control signal generation unit 54 temporarily generates a control signal based on the basic current command value Is *. The command signal Sm2 to be stopped is output to the control signal generation unit 54. At the same time, the slip determination unit 56 outputs a command signal Sm3 as a control signal for forming a closed loop between the inverter circuit 50 and the motor 30. The command signal Sm3 opens, for example, the switching elements u1, v1, w1 on the power supply side of the switching elements u1, u2, v1, v2, w1, w2 (see FIG. 7) of the inverter circuit 50 (so-called off state). This is a signal for closing the switching elements u2, v2, and w2 on the ground GND side (so-called on state).

As shown in FIG. 7, when the command signal Sm3 is input, the inverter circuit 50 uses the switching elements u2, v2, w2 on the ground GND side among the switching elements of the switching arms 50U, 50V, 50W of the inverter circuit 50. Turn all on, and turn off all switching elements u1, v1, w1 on the power supply side. Therefore, a closed loop is formed between the circuit on the ground GND side of the inverter circuit 50 and the windings 30u, 30v, 30w corresponding to each phase of the motor 30.

According to this embodiment, the following effects can be obtained.
(4) By realizing a closed loop between the circuit on the ground GND side of the inverter circuit 50 and the windings 30u, 30v, 30v corresponding to each phase of the motor 30, the steering wheel 20 is automatically operated by self-aligning torque or the like. Even if the steering wheel 20 tries to return, a braking force due to the induced power of the motor 30 acts on the side opposite to the direction in which the steering wheel 20 returns (so-called the direction originally cut by the driver), and the steering wheel 20 returns toward the neutral position. It becomes difficult to be done.

The present embodiment may be modified as follows as long as there is no technical contradiction.
In the present embodiment, the slip determination unit 56 applies steering torque Th to the steering wheel 20 again after the driver's hand slips on the steering wheel 20 (absolute value of steering torque Th). The correction value Irb * was set to 0 (when the amount of change is positive), but the present invention is not limited to this. For example, when the slip determination unit 56 determines that the driver's hand is in contact with the steering wheel 20 after a predetermined time has elapsed since the driver's hand slipped on the steering wheel 20, the correction value is corrected. Irb * may be set to 0. Here, the predetermined time is set by experimentally verifying the time from when the driver's hand slips on the steering wheel 20 to when the driver tries to hold the steering wheel 20 again and continue the operation. It was done. The predetermined time is set so that the driver does not feel uncomfortable when he / she tries to hold the steering wheel 20 again and continue the operation. Even after a predetermined time has elapsed since the driver's hand slipped on the steering wheel 20, the correction value Irb * is not set to 0 when the driver's hand is not in contact with the steering wheel 20. This is because when the driver's hand slips on the steering wheel 20, the driver's hand may move away from the steering wheel 20 in order to hold the steering wheel 20 again. This is because if the correction value Irb * is set to 0 when the driver does not hold the steering wheel 20, the steering feeling of the driver may be uncomfortable. Therefore, "the correction value Irb * is set to 0 when it is determined that a predetermined time has elapsed from the time when the driver's hand slips on the steering wheel 20 and the driver's hand is touching the steering wheel 20. By doing so, it is possible to smooth the steering feeling when the driver tries to continue the operation by holding the steering wheel 20 again after the driver's hand slips on the steering wheel 20. Further, along with this change, the process of step S108 in the control flow of the control device 5 shown in FIG. 4 is appropriately changed.

Further, for example, the slip determination unit 56 may set the correction value Irb * to 0 when it is no longer detected that the driver's hand is moving while touching the steering wheel 20. In this case as well, the process of step S108 in the control flow of the control device 5 shown in FIG. 4 is appropriately changed.

-In the present embodiment, when the steering torque Th is equal to or higher than the specified value, the slip determination unit 56 determines whether or not the driver's hand has slipped on the steering wheel 20, but the steering torque Th. May be smaller than the specified value. The specified value of the steering torque Th is set as the value of the steering torque Th that the driver's hand can slip on the steering wheel 20, but even if the steering torque Th is smaller than the specified value, the driver's hand is rare. May slip against the steering wheel 20. Therefore, the condition "steering torque Th is equal to or higher than the specified value", which is a condition for the slip determination unit 56 to determine whether or not the driver's hand has slipped on the steering wheel 20, may be omitted. Along with this change, step S102 in the control flow is omitted from the control device 5 shown in FIG. 4, the steering torque Th and the contact information Touch are taken in in step S101, and then the process proceeds to step S104.

-In the present embodiment, the slip determination unit 56 determines whether or not the driver's hand has slipped on the steering wheel 20 based on the contact information Touch, but "the change in the absolute value of the steering torque Th is The condition of "whether or not it changes from positive to negative" may also be added. A negative change in the absolute value of the steering torque Th means that in the steering torque Th that is periodically detected by the torque sensor 7, the absolute value of the steering torque Th in the previous cycle is changed to the absolute value of the steering torque Th in the latest cycle. Is getting smaller. The previous cycle indicates the cycle immediately before the latest cycle. Immediately before the driver's hand slides on the steering wheel 20, it is conceivable that the driver cuts the steering wheel 20 in a direction in which the steering torque Th increases. In this case, the change in the absolute value of the steering torque Th is positive. When the driver's hand slips on the steering wheel 20, the steering wheel 20 is returned to the side opposite to the direction in which the steering wheel 20 has been cut, so that the change in the absolute value of the steering torque Th becomes negative. Therefore, in determining whether or not the driver's hand has slipped on the steering wheel 20, the slip determination unit is determined by considering whether or not the change in the absolute value of the steering torque Th has changed from positive to negative. It is possible to improve the reliability of the hand slip determination of the 56 drivers. With the addition of the condition, "whether or not the change in the absolute value of the steering torque Th has changed from positive to negative" after step S105 or before step S107 in the control flow of the control device 5 shown in FIG. Add the judgment process of "?".

1 ... EPS, 5 ... Control device, 9 ... Rotation angle sensor, 20 ... Steering wheel, 30 ... Motor, 30u, 30v, 30w ... Winding, 50 ... Inverter circuit, 50U, 50V, 50W ... Switching arm, 54 ... Control Signal generation unit, 55 ... Basic current command value calculation unit, 56 ... Slip determination unit, 65 ... Touch sensor, u1, v1, w1 ... Power supply side switching element, u2, v2, w2 ... Ground side switching element, Is * ... basic current command value, Touch ... contact information, Irb * ... correction value, θm ... rotation angle, Th ... steering torque, GND ... ground.

Claims (3)

In a vehicle control device that controls a motor that generates an assist force based on a state quantity indicating the running state of the vehicle and the operating state of the steering wheel.
A control unit that generates a control signal for driving the motor based on the state quantity,
It has a slip determination unit that determines the slip of the driver's hand with respect to the steering wheel from the contact information of the driver's hand detected through the sensor mounted on the steering wheel.
If by the slippage determining portion driver's hand it is determined that the slip with respect to the steering wheel, the control unit is configured so that by generating an assist force for holding the torque applied to the steering wheel by the driver Has been
The motor has a rotation angle sensor that detects the rotation angle thereof.
The control unit has a command value calculation unit that calculates a command value for driving the motor based on the state quantity.
When the slip determination unit determines that the driver's hand has slipped on the steering wheel, the torque applied to the steering wheel at the rotation angle when the driver's hand slips on the steering wheel. the vehicle control device you calculating a correction value for correcting the command value by performing feedback control so as to hold the. In a vehicle control device that controls a motor that generates an assist force based on a state quantity indicating the running state of the vehicle and the operating state of the steering wheel.
A control unit that generates a control signal for driving the motor based on the state quantity,
It has a slip determination unit that determines the slip of the driver's hand with respect to the steering wheel from the contact information of the driver's hand detected through the sensor mounted on the steering wheel.
When the slip determination unit determines that the driver's hand has slipped on the steering wheel, the control unit is configured to generate an assist force for holding the torque applied to the steering wheel by the driver. And
The slip determination unit is said by the driver after a predetermined time has elapsed from the time when the driver's hand is determined to have slipped on the steering wheel and after it is determined that the driver's hand is touching the steering wheel. A vehicle control device that stops control that holds the torque applied to the steering wheel. The vehicle control device according to claim 1 or 2, wherein the slip determination unit determines the slip of the driver's hand with respect to the steering wheel when at least the steering torque as the state quantity becomes a specified value or more. ..

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