Control device, control method, and control system

Abstract

The control device, control method, and control system according to the present invention actively vary, in a vehicle provided with a steer-by-wire type steering device, the amount of change per unit time of the yaw rate generated in the vehicle in response to a steering operation on the basis of a first physical amount relating to operation information on a steering operation input device and a second physical amount relating to the acceleration and deceleration of the vehicle. Consequently, an increase in the ease of operation and an increase in operation accuracy can be achieved.

Description

[Technical Field]

[0001] The present invention relates to a control device, a control method, and a control system. [Background technology]

[0002] In the vehicle steering device of Patent Document 1, a target steering angle calculation unit calculates a target steering angle δ* based on a steering angle θ and a vehicle speed V. Furthermore, the corrected steering angle calculation unit uses the difference between a transfer function G(s) that takes steering angle δ as an input and vehicle yaw rate γ as an output and the steady-state component G(0) of this transfer function G(s) to calculate a transfer function K(s) that takes target steering speed δ*', which is obtained by time-differentiating target steering angle δ*, as an input and corrected steering angle δc as an output, in accordance with vehicle speed V. Then, the corrected steering angle calculation unit multiplies the transfer function K(s) by the target steering speed δ*' to calculate the corrected steering angle δc, and the final target steering angle calculation unit 53 adds the target steering angle δ* and the corrected steering angle δc to calculate the final target steering angle δd. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5126357 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, the amount of change per unit time in the yaw rate that occurs in a vehicle in response to a steering operation by the driver affects the driver's maneuverability, and generally, if the amount of change per unit time in the yaw rate (in other words, the rate of change in the yaw rate) is large, it becomes difficult to perform appropriate steering operation. For example, when a vehicle decelerates and turns, the amount of change in yaw rate per unit time varies depending on the deceleration and lateral acceleration, and when the amount of change becomes large, there is a possibility that the ease of maneuvering and the accuracy of maneuvering may decrease.

[0005] The present invention has been made in consideration of the current situation, and its purpose is to provide a control device, a control method, and a control system that can improve ease of operation or improve operation accuracy. [Means for solving the problem]

[0006] In one aspect, the present invention provides a control device, a control method, and a control system that are applied to a vehicle equipped with a steer-by-wire steering device having a steering operation input device and a steering device equipped with a steering actuator, and that actively varies the amount of change per unit time of a yaw rate generated in the vehicle in response to the steering operation based on a first physical quantity related to operation information of the steering operation input device and a second physical quantity related to acceleration / deceleration of the vehicle. [Effects of the Invention]

[0007] According to the present invention, it is possible to improve ease of control or control accuracy. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of a vehicle equipped with a steer-by-wire steering device. [Figure 2] FIG. 3 is a block diagram showing a control function of a steering motor. [Figure 3] FIG. 10 is a diagram showing the correlation between lateral acceleration and deceleration and the amount of change Δγ in yaw rate γ per time. [Figure 4] 10 is a flowchart showing a control process for actively varying the amount of change Δγ. [Figure 5] FIG. 10 is a diagram showing the correlation between lateral acceleration and deceleration and a gain Gst. [Figure 6] 10 is a time chart showing the difference in the front wheel steering angle δ, the yaw rate γ, and the amount of change Δγ under Δγ variable control. [Figure 7] 10 is a flowchart showing a process when control for actively varying the amount of change Δγ is performed based on the driving skill of the driver. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a control device, a control method, and a control system according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing an embodiment of a vehicle 100 equipped with a steer-by-wire steering device 200. As shown in FIG. The vehicle 100 is a four-wheeled automobile equipped with a pair of left and right front wheels 101, 102 and a pair of left and right rear wheels 103, 104 as wheels.

[0010] The steer-by-wire steering device 200 has a steering operation input device 300 to which the steering operation of the driver of the vehicle 100 is input, a steering device 400 equipped with a steering actuator that applies a steering force to the wheels of the vehicle 100, and a control device 500 that controls the actuator of the steering device 200. The steering operation input device 300 and the steering device 400 are mechanically separated.

[0011] The steering operation input device 300 includes a steering wheel 310 , a steering shaft 320 , a reaction force motor 330 , and an operation angle sensor 340 . The steering wheel 310 is a steering operation input member operated by the driver of the vehicle 100. The reaction motor 330 is a reaction actuator that applies a reaction torque to the steering wheel 310 .

[0012] The steering angle sensor 340 detects the rotation angle of the steering shaft 320 as the steering angle θ of the steering wheel 310 . The operation angle θ detected by the operation angle sensor 340 is a physical quantity related to the operation information of the steering operation input device 300 .

[0013] The steering device 400 includes a steering motor 410 as a steering actuator, a steering mechanism 420 that changes the steering angle of the front wheels 101, 102 using the steering torque generated by the steering motor 410, and a steering angle sensor 430 that detects the front wheel steering angle δ, which is the turning angle of the front wheels 101, 102, from the position of the steering motor 410 or the position of the steering mechanism 420. The steering device 400 is a device that can steer the front wheels 101 and 102, which are the steered wheels of the vehicle 100, by operating the steering motor 410.

[0014] The steering motor 410 is integrally provided with a motor drive device 440 that controls the steering motor 410 . The motor drive device 440 controls the power provided to the steering motor 410, in other words, the steering torque generated by the steering motor 410, so that the front wheel steering angle δ detected by the steering angle sensor 430 approaches the steering angle command value δtg obtained from the control device 500. The control device 500 may be integrally provided with the motor driving device 440.

[0015] The control device 500 is an electronic control device that mainly includes a microcomputer 510 . The microcomputer 510 includes a microprocessor unit (MPU), a read-only memory (ROM), and a random access memory (RAM).

[0016] Microcomputer 510 then performs arithmetic processing of various signals acquired from the outside to determine a control signal for reaction force motor 330 and a control signal for steering motor 410, and outputs the determined control signals. In other words, the microcomputer 510 functions as a control unit that controls the steering motor 410 and the reaction motor 330 .

[0017] Here, in controlling steering motor 410, microcomputer 510 calculates steering angle command value δtg, which is a target value for front wheel steering angle δ, based on information such as operation angle θ of steering wheel 310. Microcomputer 510 then outputs a signal of steering angle command value Δtg to motor drive device 440 as a control signal for steering motor 410.

[0018] The vehicle 100 also includes wheel speed sensors 621-624 that detect the wheel speed, which is the rotation speed of each of the wheels 101-104. The vehicle 100 also includes a longitudinal acceleration sensor 630 that detects the longitudinal acceleration αx of the vehicle 100 (specifically, the acceleration / deceleration in the traveling direction of the vehicle 100). The vehicle 100 also includes a yaw rate sensor 640 that detects the yaw rate γac of the vehicle 100 . Furthermore, the vehicle 100 includes a mode selection switch 650 . As will be described in detail later, the mode selection switch 650 is a user interface that allows the driver to arbitrarily select the response characteristics of the vehicle behavior in response to the operation of the steering wheel 310 by the driver.

[0019] FIG. 2 is a block diagram showing one embodiment of the control function of the steering motor 410 by the microcomputer 510. As shown in FIG. The microcomputer 510 includes a model following control unit 511 , a gain calculation unit 512 , and a multiplication unit 513 .

[0020] The model following control unit 511 performs control (hereinafter referred to as yaw rate control) to set the steering angle command value δtg* so that the yaw rate γ generated in the vehicle 100 follows the target yaw rate γtg corresponding to the amount of operation of the steering wheel 310. The model following control unit 511 estimates the yaw rate γ occurring in the vehicle 100 using a vehicle model that uses the front wheel steering angle δ as an input value.

[0021] In detail, the model following control unit 511 has a target yaw rate calculation unit 511A, a comparison unit 511B, a vehicle model 511C, a first gain unit 511D, a second gain unit 511E, and an addition unit 511F. The target yaw rate calculation unit 511A acquires information about the operation angle θ of the steering wheel 310 from the operation angle sensor 340, and calculates the target yaw rate γtg based on the acquired information about the operation angle θ.

[0022] For example, the target yaw rate calculation unit 511A obtains the reference front wheel steering angle δbs (δbs=θ / N) from the operation angle θ and the steering gear ratio N, and calculates the target yaw rate γtg based on the reference front wheel steering angle δbs using a first-order delay transfer function expressed by the steady-state yaw rate gain and a time constant. Vehicle model 511C has steering angle command value δtg* as an input value, and has estimated yaw rate γes and estimated vehicle body slip angle βes as output values. In other words, the model following control unit 511 obtains an estimated yaw rate γes, which is an estimated value of the yaw rate γ occurring in the vehicle 100, using the vehicle model 511C.

[0023] The comparison unit 511B acquires the signal of the estimated yaw rate γes output by the vehicle model 511C and the signal of the target yaw rate γtg output by the target yaw rate calculation unit 511A, and calculates the deviation γer between the estimated yaw rate γes and the target yaw rate γtg. First gain section 511D multiplies estimated vehicle body slip angle βes output by vehicle model 511C by gain K1, and second gain section 511E multiplies deviation γer by gain K2.

[0024] Then, an adding section 511F adds the output of the first gain section 511D and the output of the second gain section 511E to obtain a steering angle command value δtg* which is a command value for the front wheel steering angle δ. Here, the steering angle command value δtg* is the front wheel steering angle δ required to make the estimated yaw rate γes follow the target yaw rate γtg.

[0025] Adder 511F outputs the determined steering angle command value δtg* to vehicle model 511C, causing vehicle model 511C to estimate yaw rate γ and vehicle body slip angle β when controlled to steering angle command value δtg*. Moreover, the addition unit 511F outputs the obtained steering angle command value Δtg* to the multiplication unit 513. The process of setting the steering angle command value δtg* is not limited to the model following control in which the estimated yaw rate γes output by the vehicle model 511C is used as a feedback signal.

[0026] Instead of the model following control unit 511, the microcomputer 510 can be provided with a feedback control unit that uses the yaw rate γac of the vehicle 100 detected by the yaw rate sensor 640 as a feedback signal and sets the steering angle command value δtg* so that the yaw rate γac follows the target yaw rate γtg. However, in the case of model following control, the control delay is smaller than when the yaw rate γac, which is the detection value of the yaw rate sensor 640, is used as the feedback signal, and the yaw rate generated in the vehicle 100 can be made to stably follow the target yaw rate γtg.

[0027] The multiplication unit 513 acquires the steering angle command value Δtg* calculated by the addition unit 511F and the gain Gst calculated by the gain calculation unit 512. Then, multiplication unit 513 multiplies steering angle command value Δtg* by gain Gst to obtain a final steering angle command value Δtg (Δtg=Δtg*×Gst), and outputs the obtained steering angle command value Δtg to motor drive device 440. As will be described in detail later, the multiplication unit 513 and the gain calculation unit 512 constitute a functional unit for actively varying the amount of change per unit time of the yaw rate γ generated in the vehicle 100 in response to the steering operation by the driver.

[0028] The gain calculation unit 512 acquires a signal of the longitudinal acceleration αx detected by the longitudinal acceleration sensor 630, a signal of the yaw rate γac detected by the yaw rate sensor 640, a signal of the vehicle speed V calculated from the detection signals of the wheel speed sensors 621-624, and mode selection information which is the operation position information of the mode selection switch 650. Then, the gain calculation unit 512 calculates a gain Gst, which is a control gain for yaw rate control, based on the acquired various information, and outputs a signal of the calculated gain Gst to the multiplication unit 513.

[0029] The reference value of the gain Gst is 1.0. When the gain Gst is smaller than 1.0, the steering angle command value δtg is set to a value smaller than the steering angle command value δtg*, and when the gain Gst is larger than 1.0, the steering angle command value δtg is set to a value larger than the steering angle command value δtg*.

[0030] The control for actively varying the amount of change in the yaw rate γ per unit time will be described in detail below. FIG. 3 is a diagram in which the x-axis represents the lateral acceleration αy of the vehicle 100, the y-axis represents the deceleration αx of the vehicle 100, and the z-axis represents the amount of change Δγ in the yaw rate γ from the start of deceleration until a unit time has elapsed. The diagram shows the characteristics of the amount of change Δγ when the steering angle command value δtg* calculated by the model following control unit 511 is used as the final steering angle command value δtg (δtg*=δtg) to control the steering motor 410.

[0031] The diagram in FIG. 3 shows the characteristic that the amount of change Δγ in the turning direction increases as the lateral acceleration αy increases during slow deceleration. A situation in which the vehicle 100 is decelerating slowly and the lateral acceleration αy is large occurs when the vehicle 100 is avoiding an obstacle while traveling on a public road, or when a lane change is performed by a driver who drives a little recklessly.

[0032] In such a situation, if the change amount Δγ of the yaw rate γ in the turning direction of the vehicle 100 is large, the vehicle 100 may be induced to spin. Here, if the driver of vehicle 100 is an experienced driver with high driving skills, he or she will be able to perform appropriate steering operations after understanding the vehicle characteristics related to the amount of change Δγ, i.e., the characteristic that the amount of change Δγ becomes large when deceleration is slow and the lateral acceleration αy is large.

[0033] However, for an average driver who has lower driving skills than an experienced driver, it is difficult to perform appropriate steering operation when the change amount Δγ becomes large, and there is a possibility that the vehicle 100 may fall into a situation where the anti-skid device is activated. Therefore, the microcomputer 510 performs control to actively vary the amount of change in the yaw rate γ per unit time in response to the steering operation by the driver, thereby preventing a situation in which an anti-skid device would intervene, for example, and achieving steering characteristics that are easy for an average driver to handle.

[0034] That is, the microcomputer 510 actively varies the change amount Δγ per unit time of the yaw rate γ in response to the steering operation for each combination region of the deceleration αx and the lateral acceleration αy shown in FIG. 3, thereby suppressing an increase in the change amount Δγ and smoothing the connection of the change amount Δγ for each region. This makes it possible to make the change in yaw rate γ per unit time in response to steering operation gentler, for example, in a situation where deceleration is slow and lateral acceleration αy is large, thereby reducing the difficulty of steering operation and improving safety for the average driver.

[0035] On the other hand, in the case of an experienced driver (or a professional driver), it becomes possible to set the responsiveness of the vehicle behavior to suit the driver's preferences by stopping the control that suppresses the increase in the change amount Δγ or by implementing control that actively increases the change amount Δγ. The microcomputer 510 realizes the control of actively varying the amount of change Δγ per unit time of the yaw rate γ in response to the steering operation by the setting process of the gain Gst by the gain calculation unit 512, as described above.

[0036] Next, a specific description will be given of the control for actively varying the amount of change per unit time of the yaw rate γ. FIG. 4 is a flowchart showing a control process for actively varying the amount of change Δγ, which is carried out by the microcomputer 510, in other words, a setting process of the gain Gst, which is carried out by the gain calculation unit 512.

[0037] In step S701, the microcomputer 510 determines whether the vehicle 100 is decelerating and lateral acceleration is occurring, in other words, whether the vehicle 100 is in a region where deceleration αx and lateral acceleration αy are combined. Here, the microcomputer 510 determines whether the vehicle 100 is decelerating based on the longitudinal acceleration αx of the vehicle 100 detected by the longitudinal acceleration sensor 630.

[0038] Furthermore, microcomputer 510 determines lateral acceleration αy from yaw rate γac detected by yaw rate sensor 640 and vehicle speed V detected by wheel speed sensors 621-624, and determines whether lateral acceleration is occurring. If the vehicle 100 is equipped with a lateral acceleration sensor that detects the lateral acceleration αy, the microcomputer 510 can determine whether or not lateral acceleration is occurring based on the lateral acceleration αy detected by the lateral acceleration sensor.

[0039] When the vehicle 100 is decelerating and no lateral acceleration is occurring, the microcomputer 510 proceeds to step S702 and stops the Δγ variable control that actively varies the change amount Δγ by changing the gain Gst. Here, in step S702, the microcomputer 510 performs processing to fix the value of the gain Gst to 1.0, and sets the steering angle command value δtg* calculated by the model following control unit 511 as the final steering angle command value δtg as is, thereby substantially stopping the Δγ variable control that actively varies the change amount Δγ.

[0040] On the other hand, when the vehicle 100 is decelerating and lateral acceleration is occurring, the microcomputer 510 proceeds to step S703 and sets the implementation of Δγ variable control that actively varies the change amount Δγ, that is, variable control of the gain Gst. Next, the microcomputer 510 proceeds to step S704, and executes Δγ variable control for actively varying the amount of change Δγ, that is, variable processing of the gain Gst.

[0041] FIG. 5 is a diagram with the x-axis representing deceleration αx, the y-axis representing lateral acceleration αy of the vehicle 100, and the z-axis representing gain Gst, and shows one aspect of the characteristics of gain Gst for each combination range of deceleration αx and lateral acceleration αy. The characteristics of the gain Gst shown in FIG. 5 correspond to the characteristics of the variation Δγ shown in FIG. 3, and are set so as to suppress an increase in the variation Δγ.

[0042] In other words, the microcomputer 510 (gain calculation unit 512) sets the gain Gst to a smaller value as the lateral acceleration αy increases during slow deceleration of the vehicle 100, because the amount of change Δγ in the turning direction increases as the lateral acceleration αy increases during slow deceleration. In other words, for a combination of deceleration αx and lateral acceleration αy in which the amount of change Δγ is large in the characteristic diagram of Figure 3, the gain Gst is made smaller than for a combination of deceleration αx and lateral acceleration αy in which the amount of change Δγ is relatively small in the characteristic diagram of Figure 3.

[0043] When the gain Gst is reduced (more specifically, when the gain Gst is made smaller than 1.0), the increase in the steering angle command value δtg in the direction of turning the steering wheel is delayed, and the increase in the change amount Δγ can be suppressed compared to when control is not performed to actively vary the change amount Δγ by changing the gain Gst (more specifically, when the gain Gst is 1.0). In this way, when vehicle 100 is decelerating and lateral acceleration is occurring, microcomputer 510 variably sets gain Gst for each combination of deceleration αx and lateral acceleration αy so as to suppress an increase in amount of change Δγ.

[0044] As a result, the change amount Δγ per unit time of the yaw rate γ in response to steering operation can be suppressed even in situations where deceleration is gradual and the lateral acceleration αy is large, and the change amount Δγ for each combination of deceleration αx and lateral acceleration αy can be made smoother, thereby reducing the difficulty of steering operation and improving safety for an average driver. In other words, by suppressing the increase in the amount of change Δγ through Δγ variable control, even an average driver can perform appropriate steering operation, and it is possible to prevent the vehicle 100 from falling into a situation where the anti-skid device is activated.

[0045] FIG. 6 is a time chart showing an example of changes in deceleration, lateral acceleration, yaw rate, etc. in a situation where Δγ variable control is operating, which actively varies the amount of change Δγ by changing the gain Gst. The solid line in FIG. 6 shows the characteristics when the Δγ variable control is stopped, that is, when the gain Gst is fixed to 1.0.

[0046] Moreover, the dotted line in FIG. 6 indicates the characteristics when the increase in the variation Δγ is actively suppressed by making the gain Gst smaller than 1.0. Furthermore, the dashed dotted line in FIG. 6 indicates the characteristics when the amount of change Δγ is actively increased by increasing the gain Gst to a value greater than 1.0.

[0047] At time t1 when vehicle 100 is traveling straight at a substantially constant speed, vehicle 100 begins to decelerate, and from time t2 thereafter, the driver begins to turn steering wheel 310 from the neutral position to either the left or right. Then, the driver turns the steering wheel 310 further between time t2 and time t4, and after time t4, the steering wheel 310 enters a holding state in which the operating angle θ at time t4 is maintained. That is, until time t2, the steering wheel 310 is in the neutral position, and between time t2 and time t4, the steering wheel 310 is steered to the right or left.

[0048] When the steering angle θ changes in accordance with the steering operation of the steering wheel 310 by the driver, the microcomputer 510 sets the target yaw rate γtg according to the steering angle θ, and sets the steering angle command value δtg* so that the estimated yaw rate γes (or yaw rate γac) follows the target yaw rate γtg. Then, the front wheels 101, 102 are steered in accordance with the steering angle command value δtg, which causes lateral acceleration in the vehicle 100 and further causes a yaw rate.

[0049] Here, the microcomputer 510 sets the gain Gst to a value smaller than 1.0 depending on the deceleration and lateral acceleration, thereby changing the final steering angle command value δtg to a value smaller than the steering angle command value δtg* calculated by the model following control unit 511, as shown by the dotted line in Figure 6. In this application, the magnitude of the front wheel steering angle δ specifically refers to the magnitude of the absolute value of the steering angle, and reducing the steering angle command value δtg brings the steering angle command value δtg closer to the neutral position.

[0050] By correcting the steering angle command value δtg using the gain Gst, the change in the steering angle of the front wheels 101, 102 in response to the steering operation of the steering wheel 310 becomes slower than when the correction process is not performed (in other words, when the gain Gst is fixed at 1.0), and as a result, the change amount Δγ of the yaw rate γ per unit time is kept smaller than when the correction process is not performed. In other words, the characteristic shown by the dotted line in the time chart of Figure 6 indicates the characteristic that, when the driver's steering operation is input to the steering operation input device 300 from a state in which the vehicle 100 is decelerating while traveling straight, the microcomputer 510 outputs the steering angle command value δtg (in other words, the control signal for the steering motor 410) so as to suppress an increase in the change amount Δγ per unit time of the yaw rate γ.

[0051] In this way, if the Δγ variable control that suppresses the increase in the change amount Δγ of the yaw rate γ per unit time is implemented, steering characteristics that are easy for an average driver to handle can be realized, and the average driver can easily perform appropriate steering operation. Furthermore, since the microcomputer 510 sets the gain Gst in accordance with the deceleration and lateral acceleration in response to the magnitude of the change amount Δγ changing in accordance with the deceleration and lateral acceleration, the change amount Δγ can be changed smoothly in response to changes in the deceleration and lateral acceleration.

[0052] On the other hand, as shown by the dashed line in Figure 6, in the correction process of the steering angle command value δtg using the gain Gst, the microcomputer 510 can change the final steering angle command value δtg to a value larger than the steering angle command value δtg* calculated by the model following control unit 511 using the gain Gst (Gst > 1.0). Then, by changing the steering angle command value δtg to a value greater than the steering angle command value δtg*, the microcomputer 510 can make the change amount Δγ of the yaw rate γ per unit time greater than when correction by the gain Gst is not performed.

[0053] If the correction process of the steering angle command value δtg using the gain Gst is not performed, the characteristics of the change amount Δγ are uniquely determined by the specifications and parameters of the vehicle 100, and therefore the driver needs to perform a steering operation that is suited to the vehicle characteristics. In contrast, if Δγ variable control is implemented to correct the steering angle command value δtg using the gain Gst, the characteristics of the change amount Δγ can be changed to suit the driver's preferences and skills, thereby improving the ease of steering or the steering accuracy.

[0054] The microcomputer 510 can perform a process of actively increasing the change amount Δγ through Δγ variable control when a counter-steering operation is performed, which is a steering operation of the steering wheel 310 in the direction opposite to the turning direction of the vehicle 100. For example, when the vehicle 100 is making a steady turn with a constant steering angle and vehicle speed, if the driver applies the brakes, causing the rear wheels 103, 104 to skid, the driver will perform counter-steering by operating the steering wheel 310 in the opposite direction to the turning direction of the vehicle 100.

[0055] At this time, the steering angle θ of the steering wheel 310 does not change until the driver applies the brakes, so the front wheel steering angle is maintained, and after a counter-steer steering input is made, the front wheel steering angle δ moves in the direction opposite to the turning direction. If there is a delay in the change in the front wheel steering angle δ in response to the countersteering operation by the driver, the behavior of the vehicle 100 becomes unstable because skidding of the rear wheels 103, 104 cannot be sufficiently suppressed.

[0056] Therefore, the microcomputer 510 performs Δγ variable control to actively increase the amount of change Δγ per unit time of the yaw rate γ in response to a counter-steering operation during a turn, thereby preventing a delay in the change in the front wheel steering angle δ during the counter-steering operation and preventing skidding of the rear wheels 103, 104. In other words, the microcomputer 510 actively increases the amount of change Δγ in response to the counter-steering operation, thereby assisting the driver in performing the counter-steering operation.

[0057] Meanwhile, if the driver is an experienced or professional driver whose driving skills are higher than the standard, the microcomputer 510 can stop the Δγ variable control that actively varies the change amount Δγ (specifically, fix the gain Gst to 1.0). In the case of an experienced driver or a professional driver, it is possible to perform appropriate steering operation after understanding the vehicle characteristics related to the change amount Δγ of the yaw rate γ per unit time, or to perform steering operation that makes use of the vehicle characteristics, and in some cases, it is possible to perform better steering operation without implementing the Δγ variable control.

[0058] Therefore, the microcomputer 510 acquires information indicating the mode selection state of the mode selection switch 650 as information regarding the driver's driving skill, and when the mode selection state indicates that the driver is an expert or professional, the microcomputer 510 stops the Δγ variable control. Mode selection switch 650 is provided on vehicle 100 as a switch for the driver to arbitrarily select the responsiveness of the front wheel steering angle to the steering operation of steering wheel 310 (in other words, the responsiveness of the vehicle behavior).

[0059] The mode selection switch 650 is configured to allow selection between, for example, a normal mode that specifies a responsiveness suitable for a driver of average skill, and a sport mode that specifies a responsiveness that is higher than that in the normal mode and allows an experienced driver with driving skill higher than the standard to perform appropriate steering operation. In other words, microcomputer 510 obtains information about the driver's driving skill by obtaining information about the mode selected by mode selection switch 650, and the function of obtaining mode selection information in mode selection switch 650 corresponds to the driving skill information obtaining unit.

[0060] FIG. 7 is a flowchart showing the process of setting the gain Gst, and shows the process of setting the gain Gst, including the process of determining the mode selected by the mode selection switch 650, in other words, the process of determining the driving skill of the driver. The processes in steps S802 to S805 in the flowchart of FIG. 7 are the same as the processes in steps S701 to S704 in the flowchart of FIG. 4 described above, and therefore detailed description thereof will be omitted.

[0061] In step S801, the microcomputer 510 determines whether the mode selection switch 650 has selected the sports mode that specifies high response. If the driver has selected the sport mode with the mode selection switch 650, the microcomputer 510 presumes that the driver's driving skill is higher than the standard, and proceeds to step S803.

[0062] Then, in step S803, the microcomputer 510 stops the Δγ variable control that actively varies the change amount Δγ by changing the gain Gst, specifically, the control that suppresses the increase in the change amount Δγ. That is, when the driver's driving skill is higher than the standard, the microcomputer 510 controls the steering motor 410 using the steering angle command value δtg* calculated by the model following control unit 511 as the final steering angle command value δtg as is.

[0063] Therefore, if the driver's driving skill is higher than the standard, the yaw rate γ generated in the vehicle 100 in response to the steering operation of the steering wheel 310 will change in a manner that is uniquely determined by the specifications and dimensions of the vehicle 100. A driver with a higher driving skill level than the standard level can perform an appropriate steering operation after understanding the vehicle characteristics related to the amount of change Δγ, or can perform a steering operation that makes the most of the vehicle characteristics. The Δγ variable control that the microcomputer 510 stops when the driver's driving skill is higher than the standard may include control that actively increases the amount of change Δγ during counter-steering.

[0064] On the other hand, if microcomputer 510 determines in step S801 that normal mode specifying slow response has been selected by mode selection switch 650 and that the driver is an ordinary driver whose driving skills are lower than the standard, microcomputer 510 proceeds to step S802. Then, when microcomputer 510 determines in step S802 that vehicle 100 is decelerating and lateral acceleration is occurring, it proceeds to step S804 and subsequent steps and performs Δγ variable control in which the change amount Δγ is actively varied by changing gain Gst. Therefore, for a typical driver, if he / she operates the mode selection switch 650 to select the normal mode, the steering operation can be performed under characteristics in which the increase in the variation amount Δγ is suppressed, and / or assistance in counter-steering operation can be obtained, thereby realizing easy-to-handle steering characteristics.

[0065] The technical ideas explained in the above embodiments can be used in appropriate combinations as long as no contradiction occurs. Furthermore, although the contents of the present invention have been specifically described with reference to preferred embodiments, it is obvious that a person skilled in the art can adopt various modified embodiments based on the basic technical idea and teachings of the present invention.

[0066] The driving skill information acquisition unit is not limited to a functional unit that acquires mode selection information from the mode selection switch 650 . For example, the microcomputer 510 may include a functional unit as a driving skill information acquisition unit that determines an index value of the driving skill from the history of the steering operation by the driver and the lateral acceleration, longitudinal acceleration, etc. generated by the steering operation. Then, by comparing the index value with a threshold value, the microcomputer 510 can determine whether the driver's skill is higher or lower than the standard, that is, whether the driver is an experienced driver or an average driver.

[0067] Furthermore, if the vehicle 100 is equipped with a switch that allows the driver to turn the anti-skid device on and off at will, the microcomputer 510 can treat the on state of the anti-skid device as a command to perform Δγ variable control (in other words, a signal indicating that the driver is an average driver), and the off state of the anti-skid device as a command to stop yaw rate control (in other words, a signal indicating that the driver is an experienced driver). In this case, the functional unit that acquires information on whether the anti-skid device is on or off corresponds to the driving skill information acquisition unit.

[0068] Furthermore, the microcomputer 510 is not limited to a configuration that classifies driving skills into two levels, high and low, but can acquire information that classifies driving skills into three or more levels and change the degree to which the change amount Δγ is actively varied into three or more levels. Here, the microcomputer 510 has multiple maps (or functions) of the gain Gst according to the deceleration and lateral acceleration as shown in FIG. 5, and can switch the map (or function) used for the Δγ variable control according to the level of driving skill.

[0069] In addition, the microcomputer 510 can actively vary the change amount Δγ by, for example, variably setting the feedback gain, which is the gain in the process of setting the manipulated variable based on the deviation between the target yaw rate γtg and the estimated yaw rate γes (or yaw rate γac). In other words, the means for actively varying the amount of change Δγ need only be capable of actively varying the amount of change Δγ in response to the driver's steering operation, and is not limited to means for correcting the steering angle command value δtg.

[0070] Furthermore, the steer-by-wire steering device 200 can be provided with a backup mechanism that mechanically couples the steering wheel 310 and the front wheels 101, 102 with a clutch or the like. Furthermore, the steer-by-wire steering device 200 can include a first control device that outputs a control signal for the steering motor 410 and a second control device that outputs a control signal for the reaction force motor 330. [Explanation of symbols]

[0071] 100...vehicle, 101, 102...front wheels (steering wheels), 200...steer-by-wire steering device, 300...steering operation input device, 340...operation angle sensor, 400...steering device, 410...steering motor (steering actuator), 500...control device, 510...microcomputer (control unit), 511...model following control unit, 512...gain calculation unit, 513...multiplication unit, 630...longitudinal acceleration sensor

Claims

1. A control device provided in a vehicle, The vehicle has a steer-by-wire type steering device including a steering operation input device to which a steering operation of a driver of the vehicle is input, and a steering device including a steering actuator that applies a steering force to wheels, the control device includes a control unit that outputs a control signal for the steering actuator, The control unit acquiring a first physical quantity related to operation information of the steering operation input device and a second physical quantity related to acceleration / deceleration of the vehicle; the control signal is output to actively vary a change amount per unit time of a yaw rate generated in the vehicle in response to the steering operation, based on the first physical quantity and the second physical quantity, calculating an estimated yaw rate that is an estimated value of a yaw rate generated in the vehicle using a vehicle model that uses the steering angle of the wheels as an input value; a yaw rate control for setting a command value of a steering angle of the wheels so that the estimated yaw rate follows a target yaw rate calculated based on the first physical quantity; Control device.

2. A control device provided in a vehicle, The vehicle has a steer-by-wire type steering device including a steering operation input device to which a steering operation of a driver of the vehicle is input, and a steering device including a steering actuator that applies a steering force to wheels, the control device includes a control unit that outputs a control signal for the steering actuator, The control unit acquiring a first physical quantity related to operation information of the steering operation input device and a second physical quantity related to acceleration / deceleration of the vehicle; the control signal is output to actively vary a change amount per unit time of a yaw rate generated in the vehicle in response to the steering operation, based on the first physical quantity and the second physical quantity, actively varying a change amount per unit time of a yaw rate generated in the vehicle in response to the steering operation when the vehicle is decelerating and lateral acceleration is generated in the vehicle; Control device.

3. The control device according to claim 2, The control unit actively varying a change amount per unit time of a yaw rate generated in the vehicle in response to the steering operation in accordance with the deceleration and lateral acceleration of the vehicle; Control device.

4. The control device according to claim 2, The control unit a driving skill information acquisition unit that acquires information about the driving skill of the driver; When the driving skill of the driver is higher than a reference level, the control for actively varying the amount of change per unit time of the yaw rate in response to the steering operation input is stopped. Control device.

5. A control device provided in a vehicle, The vehicle has a steer-by-wire type steering device including a steering operation input device to which a steering operation of a driver of the vehicle is input, and a steering device including a steering actuator that applies a steering force to wheels, the control device includes a control unit that outputs a control signal for the steering actuator, The control unit acquiring a first physical quantity related to operation information of the steering operation input device and a second physical quantity related to acceleration / deceleration of the vehicle; the control signal is output to actively vary a change amount per unit time of a yaw rate generated in the vehicle in response to the steering operation, based on the first physical quantity and the second physical quantity, when it is detected based on the first physical quantity and the second physical quantity that a steering operation has been performed in a direction opposite to a turning direction from a state in which the vehicle is decelerated during turning, the amount of change in the yaw rate per unit time in response to an input of the steering operation is actively increased; Control device.

6. A control device provided in a vehicle, The vehicle has a steer-by-wire type steering device including a steering operation input device to which a steering operation of a driver of the vehicle is input, and a steering device including a steering actuator that applies a steering force to wheels, the control device includes a control unit that outputs a control signal for the steering actuator, The control unit acquiring a first physical quantity related to operation information of the steering operation input device and a second physical quantity related to acceleration / deceleration of the vehicle; the control signal is output to actively vary a change amount per unit time of a yaw rate generated in the vehicle in response to the steering operation, based on the first physical quantity and the second physical quantity, a driving skill information acquisition unit that acquires information about the driving skill of the driver; When it is detected based on the first physical quantity and the second physical quantity that a steering operation by the driver has been input to the steering operation input device from a state in which the vehicle is decelerating while traveling straight, if the driver has high driving skill, the amount of change in the yaw rate per unit time is made larger than if the driver has low driving skill. Control device.

7. A control device provided in a vehicle, The vehicle has a steer-by-wire type steering device including a steering operation input device to which a steering operation of a driver of the vehicle is input, and a steering device including a steering actuator that applies a steering force to wheels, the control device includes a control unit that outputs a control signal for the steering actuator, The control unit acquiring a first physical quantity related to operation information of the steering operation input device and a second physical quantity related to acceleration / deceleration of the vehicle; the control signal is output to actively vary a change amount per unit time of a yaw rate generated in the vehicle in response to the steering operation, based on the first physical quantity and the second physical quantity, a driving skill information acquisition unit that acquires information about the driving skill of the driver; when it is detected, based on the first physical quantity and the second physical quantity, that a steering operation in a direction opposite to a turning direction has been performed from a state in which the vehicle is decelerating during turning; When the driving skill of the driver is higher than a reference level, the control for actively varying the amount of change per unit time of the yaw rate in response to the steering operation input is stopped. Control device.

8. A control method executed by a control unit mounted on a vehicle, comprising: The vehicle is equipped with a steer-by-wire steering device, The steer-by-wire steering device includes a steering operation input device to which a steering operation of a driver of the vehicle is input, and a steering device including a steering actuator that applies a steering force to wheels of the vehicle, The control method includes: acquiring a first physical quantity related to operation information of the steering operation input device and a second physical quantity related to acceleration / deceleration of the vehicle; a control process for outputting a control signal for the steering actuator, which actively varies a change amount per unit time of a yaw rate generated in the vehicle in response to the steering operation, based on the first physical quantity and the second physical quantity; The control process includes: calculating an estimated yaw rate that is an estimated value of a yaw rate generated in the vehicle using a vehicle model that uses the steering angle of the wheels as an input value; a process of performing yaw rate control to set a command value of a steering angle of the wheels so that the estimated yaw rate follows a target yaw rate calculated based on the first physical quantity, Control method.

9. A control method executed by a control unit mounted on a vehicle, comprising: The vehicle is equipped with a steer-by-wire steering device, The steer-by-wire steering device includes a steering operation input device to which a steering operation of a driver of the vehicle is input, and a steering device including a steering actuator that applies a steering force to wheels of the vehicle, The control method includes: acquiring a first physical quantity related to operation information of the steering operation input device and a second physical quantity related to acceleration / deceleration of the vehicle; a control process for outputting a control signal for the steering actuator, which actively varies a change amount per unit time of a yaw rate generated in the vehicle in response to the steering operation, based on the first physical quantity and the second physical quantity; The control process includes: actively varying a change amount per unit time of a yaw rate generated in the vehicle in response to the steering operation when the vehicle is decelerating and lateral acceleration is generated in the vehicle; Control method.

10. A control method executed by a control unit mounted on a vehicle, comprising: The vehicle is equipped with a steer-by-wire steering device, The steer-by-wire steering device includes a steering operation input device to which a steering operation of a driver of the vehicle is input, and a steering device including a steering actuator that applies a steering force to wheels of the vehicle, The control method includes: acquiring a first physical quantity related to operation information of the steering operation input device and a second physical quantity related to acceleration / deceleration of the vehicle; a control process for outputting a control signal for the steering actuator, which actively varies a change amount per unit time of a yaw rate generated in the vehicle in response to the steering operation, based on the first physical quantity and the second physical quantity; The control process includes: acquiring information about the driver's driving skill; and when it is detected based on the first physical quantity and the second physical quantity that a steering operation by the driver has been input to the steering operation input device from a state in which the vehicle is decelerating while traveling straight, if the driving skill of the driver is high, a change amount of the yaw rate per unit time is made larger than if the driving skill of the driver is low. Control method.

11. 1. A control system comprising: a steer-by-wire type steering device including a steering operation input device to which a steering operation of a vehicle driver is input, and a steering device including a steering actuator that applies a steering force to wheels of the vehicle; a control device including a control unit that outputs a control signal for the steering actuator; and The control unit acquiring a first physical quantity related to operation information of the steering operation input device and a second physical quantity related to acceleration / deceleration of the vehicle; the control signal is output to actively vary a change amount per unit time of a yaw rate generated in the vehicle in response to the steering operation, based on the first physical quantity and the second physical quantity, calculating an estimated yaw rate that is an estimated value of a yaw rate generated in the vehicle using a vehicle model that uses the steering angle of the wheels as an input value; a yaw rate control for setting a command value of a steering angle of the wheels so that the estimated yaw rate follows a target yaw rate calculated based on the first physical quantity; Control system.

12. 1. A control system comprising: a steer-by-wire type steering device including a steering operation input device to which a steering operation of a vehicle driver is input, and a steering device including a steering actuator that applies a steering force to wheels of the vehicle; a control device including a control unit that outputs a control signal for the steering actuator; and The control unit acquiring a first physical quantity related to operation information of the steering operation input device and a second physical quantity related to acceleration / deceleration of the vehicle; the control signal is output to actively vary a change amount per unit time of a yaw rate generated in the vehicle in response to the steering operation, based on the first physical quantity and the second physical quantity, actively varying a change amount per unit time of a yaw rate generated in the vehicle in response to the steering operation when the vehicle is decelerating and lateral acceleration is generated in the vehicle; Control system.

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