Control device, control procedure and control system

Abstract

A control device, a control method, and a control system according to the present invention each actively enable the modification of the change in the yaw rate generated in the vehicle in response to a steering operation, per unit of time in a vehicle comprising a cable steering device, based on a first physical quantity relating to operational information at a cable steering input device and a second physical quantity relating to the acceleration and deceleration of the vehicle. This makes it possible to increase the ease of steering or improve steering accuracy.

Description

TECHNICAL FIELD

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

[0002] A target steering angle calculation part of a steering device of a vehicle according to Patent Document 1 calculates a target steering angle δ* based on a steering angle θ and the turning speed V of the vehicle.

[0003] In addition, the target turning angle calculation part calculates a transfer function K(s) having as input a target turning speed δ*' obtained by time-deriving the target turning angle δ* and as output a correction turning angle δc corresponding to the vehicle speed V, using the difference between a transfer function G(s) having as input a turning angle δ and as output a yaw rate γ of the vehicle, and a stationary component G(0) of this transfer function G(s).

[0004] The target turning angle calculation part then multiplies the transfer function K(s) and the target turning speed δ*' to calculate the correction turning angle δc, and a target turning angle calculation part 53 sums the target turning angle δ* and the correction turning angle δc to calculate a final target turning angle δd. LIST OF REFERENCE DOCUMENTSPATENT SPECIFICATION

[0005] Patent Document 1: JP 5126357 B SUMMARY OF THE INVENTION TASK TO BE SOLVED BY THE INVENTION

[0006] Furthermore, the amount of change in the yaw rate per unit time affects the driver's steering ability, and the yaw rate is generated in a vehicle in response to the driver's steering operation. When the amount of change in the yaw rate (in other words, the rate of change of the yaw rate) per unit time is large, it is generally difficult to perform an appropriate steering operation.

[0007] For example, a vehicle has the characteristic that the amount of change in yaw rate per unit time differs during deceleration and lateral acceleration. As the amount of change increases, steering ease and steering accuracy may decrease.

[0008] The present invention was developed in view of these conventional circumstances. It is an object of the present invention to provide a control device, a control method, and a control system each capable of increasing steering ease or improving steering accuracy. MEANS TO SOLVE THE PROBLEM

[0009] One aspect of the invention according to the present invention includes a control device, a control method, and a control system, each applied to a vehicle including a steer-by-wire steering device. The steer-by-wire steering device includes a steering operation input device and a steering device having a steering actuator. Based on a first physical quantity related to operation information of the steering operation input device and a second physical quantity related to the acceleration and deceleration of the vehicle, a change amount of a yaw rate per unit time can be actively changed, and the yaw rate is generated in the vehicle in response to the steering operation. EFFECTS OF THE INVENTION

[0010] According to the present invention, it is possible to increase the ease of steering or to enhance the steering accuracy. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram of a vehicle incorporating a steer-by-cable steering apparatus. Fig. 2 is a block diagram illustrating a control function of a steering motor. Fig. 3 is a line graph showing a correlation between lateral acceleration and deceleration and a change amount Δγ of a yaw rate γ per unit time. Fig. Figure 4 is a flowchart illustrating a control process that allows the change amount Δγ to be actively changed. Fig. Figure 5 is a line graph illustrating a correlation between lateral acceleration and deceleration and a gain Gst. Fig. 6 is a time chart illustrating the differences between the steering angle δ of the front wheel, the yaw rate γ and the change amount Δγ by the Δγ-variable control. Fig. 7 is a flowchart illustrating a process performed when the control enabling active change of the change amount Δγ is performed based on the driving ability of a driver. METHOD FOR CARRYING OUT THE INVENTION

[0011] An embodiment of a control apparatus, a control method and a control system according to the present invention will be described below with reference to the drawings.

[0012] Fig. 1 is a schematic representation of a vehicle 100 to which a steer-by-cable steering device 200 is mounted.

[0013] The vehicle 100 is a four-wheeled automobile including a pair of left and right front wheels 101 and 102 and a pair of left and right rear wheels 103 and 104 as wheels.

[0014] The wire-to-wire steering device 200 includes a steering operation input device 300 that receives a steering operation of a driver of the vehicle 100, a steering device 400 having a steering actuator that applies a steering force to a wheel of the vehicle 100, and a control device 500 that controls an actuator of the steering device 200.

[0015] The steering operation input device 300 and the steering device 400 are then mechanically separated from each other.

[0016] 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.

[0017] The steering wheel 310 is a steering control element operated by a driver of the vehicle 100.

[0018] The reaction force motor 330 is a reaction force actuator that applies a reaction torque to the steering wheel 310.

[0019] The operating angle sensor 340 detects the rotation angle of the steering shaft 320 as a steering angle θ of the steering wheel 310.

[0020] Note that the operation angle θ detected by the operation angle sensor 340 is a physical quantity related to operation information of the steering operation input device 300.

[0021] The steering device 400 includes a steering motor 410 serving as a steering actuator, a steering mechanism 420 changing the steering angle of the front wheels 101 and 102 with the steering torque generated by the steering motor 410, and a steering angle sensor 430 detecting a turning angle δ of the front wheel, which is the turning angle of the front wheels 101 and 102 from the position of the steering motor 410 or the position of the steering mechanism 420.

[0022] The steering device 400 is then a device capable of steering the front wheels 101 and 102, which are the steered wheels of the vehicle 100, by actuating the steering motor 410.

[0023] The steering motor 410 integrally includes a motor drive device 440 that controls the steering motor 410.

[0024] The motor drive device 440 controls the electric power to be supplied to the steering motor 410, in other words, the steering torque generated by the steering motor 410, in order to bring the steering angle δ of the front wheel detected by the steering angle sensor 430 closer to a steering angle target value δtg detected by the control device 500.

[0025] Additionally, the control device 500 may include a motor drive device 440.

[0026] The control device 500 is an electronic control device whose main component is a microcomputer 510.

[0027] The microcomputer 510 includes an MPU (Microprocessor Unit), a ROM (Read Only Memory) and a RAM (Random Access Memory).

[0028] The microcomputer 510 then performs calculation processing on a plurality of signals detected from the outside to obtain a control signal of the reaction force motor 330 and a control signal of the steering motor 410, and outputs the obtained control signals.

[0029] That is, the microcomputer 510 has the function of a controller that controls the steering motor 410 and the reaction force motor 330.

[0030] Here, the microcomputer 510 calculates the steering angle command value δtg, which is a target value of the steering angle δ of the front wheel, based on information about the steering angle θ or the like of the steering wheel 310 when controlling the steering motor 410.

[0031] The microcomputer 510 then outputs the signal of the steering angle command value δtg to the motor drive device 440 as a control signal of the steering motor 410.

[0032] In addition, the vehicle 100 includes road wheel speed sensors 621 to 624 that detect wheel speeds that are the speeds of the respective wheels 101 to 104.

[0033] In addition, the vehicle 100 includes a longitudinal acceleration sensor 630 that detects the longitudinal acceleration αx (if described in detail, the acceleration and deceleration of the vehicle 100 in the direction of travel) of the vehicle 100.

[0034] Furthermore, the vehicle 100 includes a yaw rate sensor 640 that detects a yaw rate γac of the vehicle 100.

[0035] In addition, the vehicle 100 includes an operating mode selector switch 650.

[0036] As described in detail below, the mode selector switch 650 is a user interface for a driver to optionally select the response characteristic of a vehicle's behavior with respect to a driver's operation of the steering wheel 310.

[0037] Fig. 2 is a block diagram illustrating an aspect of a control function of the steering motor 410 by the microcomputer 510.

[0038] The microcomputer 510 includes a model following control section 511, a gain calculation section 512, and a multiplication section 513.

[0039] The model following control section 511 performs control (hereinafter referred to as yaw rate control) to set a steering angle command value δtg* to cause a yaw rate γ generated in the vehicle 100 to follow a target yaw rate γtg corresponding to the operation amount of the steering wheel 310.

[0040] It should be noted that the model following control section 511 estimates the yaw rate γ generated in the vehicle 100 by using a vehicle model having the steering angle δ of the front wheel as an input value.

[0041] If described in detail, the model following control section 511 includes a target yaw rate calculation section 511A, a comparison section 511B, a vehicle model 511C, a first gain section 511D, a second gain section 511E, and an addition section 511F.

[0042] The target yaw rate calculation section 511A acquires the information on the steering angle θ of the steering wheel 310 from the operation angle sensor 340 and determines the yaw rate γtg based on the acquired information on the steering angle θ.

[0043] The target yaw rate calculation section 511A obtains, for example, a basic front wheel steering angle δbs (δbs = θ / N) from, for example, the operating angle θ and a steering gear ratio N, and calculates the target yaw rate γtg based on the basic front wheel steering angle δbs using a first-order transfer function expressed by a steady-state yaw rate gain and a time constant.

[0044] The vehicle model 511C has the steering angle command δtg* as input value and has an estimate of the yaw rate γes and an estimated vehicle body slip angle βes as output values.

[0045] In other words, the model following control section 511 obtains the estimate of the yaw rate γes, which is an estimated value of the yaw rate γ generated in the vehicle 100, using the vehicle model 511C.

[0046] The comparison section 511B detects the signal of the yaw rate estimate γes output from the vehicle model 511C and the signal of the target yaw rate γtg output from the target yaw rate calculation section 511A, and calculates a deviation γer between the yaw rate estimate γes and the target yaw rate γtg.

[0047] The first amplifying section 511D multiplies the estimated vehicle body slip angle βes output from the vehicle model 511C by a gain factor K1, and the second amplifying section 511E multiplies the deviation ver by a gain factor K2.

[0048] The addition section 511F then sums the output of the first amplifying section 511D and the output of the second amplifying section 511E to obtain the steering angle command value δtg*, which is a command value of the steering angle δ of the front wheel.

[0049] The steering angle command value δtg* serves as the front wheel steering angle δ, which is required for the yaw rate estimation γes to follow the target yaw rate γtg.

[0050] The addition section 511F outputs the obtained steering angle command value δtg* to the vehicle model 511C and causes the vehicle model 511C to estimate the yaw rate γ and a slip angle β of the vehicle body, which are obtained when the steering angle δ of the front wheel is controlled to the steering angle command value δtg*.

[0051] In addition, the addition section 511F outputs the obtained steering angle command value δtg* to the multiplication section 513.

[0052] It should be noted that the processing of setting the steering angle command value δtg* is not limited to the model following control, which has the estimation of the yaw rate γes output from the vehicle model 511C as a feedback signal.

[0053] It is possible that the microcomputer 510, instead of the model following control section 511, has a feedback control section that has the yaw rate γac of the vehicle 100 detected by the yaw rate sensor 640 as a feedback signal and adjusts the steering angle target value δtg* to cause the yaw rate γac to follow the target yaw rate γtg.

[0054] However, the model-following control has a smaller control delay than in a case where the yaw rate γac, which is a detection value of the yaw rate sensor 640, is used as a feedback signal, and makes it possible to cause the yaw rate generated in the vehicle 100 to stably follow the target yaw rate γtg.

[0055] The multiplication section 513 receives the steering angle command value δtg* obtained from the addition section 511F and a gain value Gst calculated by the gain calculation section 512.

[0056] The multiplication section 513 then multiplies the steering angle command value δtg* by the gain Gst to obtain the final steering angle command value δtg (δtg = δtg* x Gst), and outputs the obtained steering angle command value δtg to the motor drive device 440.

[0057] As described in detail below, the multiplication section 513 and the gain calculation section 512 are included in a functional section to actively enable the amount of change of the yaw rate γ generated in the vehicle 100 in response to a steering operation by a driver to be changed per unit time.

[0058] The gain calculation section 512 acquires the longitudinal acceleration signal αx detected by the longitudinal acceleration sensor 630, the yaw rate signal γac detected by the yaw rate sensor 640, the vehicle speed signal V obtained from the detection signals of the road wheel speed sensors 621 to 624, and the mode selection information, which is mode selector information, 650.

[0059] The gain calculation section 512 then obtains the gain Gst, which is a control gain of the yaw rate control, based on the various types of detected information, and outputs the signal of the obtained gain Gst to the multiplication section 513.

[0060] The reference value for the gain Gst is 1.0.

[0061] In a case where the gain Gst is less than 1.0, the steering angle command value δtg is set to a value smaller than the steering angle command value δtg*. In a case where the gain Gst is greater than 1.0, the steering angle command value δtg is set to a value greater than the steering angle command value δtg*.

[0062] The control that allows to actively change the amount of change of the yaw rate γ per unit of time is described in more detail below.

[0063] Fig. 3 is a line graph 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 an amount of change Δγ of the yaw rate γ between the start of deceleration and the elapse of the unit time. Fig. 3 illustrates the characteristics of the change amount Δγ in a case where the steering motor 410 is controlled using the steering angle command value δtg* obtained from the model-following control section 511 as the final steering angle command value δtg (δtg* = δtg).

[0064] The line chart in Fig. Figure 3 illustrates the characteristic that the amount of change Δγ in a turning direction increases as the lateral acceleration αy increases at the time of slow deceleration.

[0065] The situation of slow deceleration and high lateral acceleration αy occurs, for example, when the vehicle 100 avoids an obstacle on a normal road or when a driver who is driving somewhat roughly changes lanes.

[0066] Such a situation may cause the vehicle 100 to skid if the amount Δγ of change in the yaw rate γ in the turning direction of the vehicle 100 is large.

[0067] Here, when a driver of the vehicle 100 is an experienced driver who has high driving ability, it is possible to understand the vehicle characteristics related to the change amount Δγ, that is, the characteristics that the change amount Δγ increases at the time of slow deceleration and high lateral acceleration αy, and then perform appropriate steering operation.

[0068] However, in the case of an ordinary driver who has lower driving ability than an experienced driver, it is difficult to perform appropriate steering as the change amount Δγ increases. An ordinary driver may find himself in a situation where an anti-skid device of the vehicle 100 is activated.

[0069] Accordingly, the microcomputer 510 performs control to actively allow the amount of change of the yaw rate γ per unit time to be changed in response to a steering operation by a driver, thereby avoiding, for example, the situation of intervention of the skid prevention device and achieving steering characteristics that are easy to handle for an ordinary driver.

[0070] That is, the microcomputer 510 actively enables the change amount Δγ of the yaw rate γ per unit time corresponding to one steering operation for each range determined by combining the Fig. 3, whereby an increase in the amount of change Δγ is suppressed and the amounts of change Δγ of the respective areas are merged more smoothly.

[0071] This makes it possible to make the change of the yaw rate γ per unit time corresponding to a steering operation more gradual, for example, in the situation of slow deceleration and high lateral acceleration αy, and to reduce the difficulty of a steering operation and increase safety for a normal driver.

[0072] In the case of an experienced driver (or a professional driver), stopping the control to suppress an increase in the change amount Δγ or performing the control to actively increase the change amount Δγ further allows setting a responsiveness of a vehicle behavior that corresponds to the driver's preferences.

[0073] It should be noted that the microcomputer 510 achieves the control for actively allowing a change in the amount Δγ of the yaw rate γ per unit time corresponding to one steering operation by processing the setting of the gain Gst by the gain calculation section 512 as described above.

[0074] The following specifically describes the control for actively allowing the change in the amount of change of the yaw rate γ per unit time.

[0075] Fig. Fig. 4 is a flowchart illustrating a process of the control for actively allowing the change in the change amount Δγ, which is executed by the microcomputer 510. In other words, Fig. 4 is a flowchart illustrating a process of setting the gain Gst performed by the gain calculation section 512.

[0076] The microcomputer 510 determines in step S701 whether the vehicle 100 is decelerating and lateral acceleration is generated or not, in other words, whether the vehicle 100 is in a range resulting from the combination of the deceleration αx and the lateral acceleration αy or not.

[0077] Here, the microcomputer 510 determines whether the vehicle 100 is decelerating or not based on the longitudinal acceleration αx of the vehicle 100 detected by the longitudinal acceleration sensor 630.

[0078] In addition, the microcomputer 510 obtains the lateral acceleration αy from the yaw rate γac detected by the yaw rate sensor 640 and the vehicle speed V detected by the road wheel speed sensors 621 to 624, and determines whether or not lateral acceleration is generated.

[0079] Note that in a case where the vehicle 100 includes a lateral acceleration sensor that detects the lateral acceleration αy, it is possible for the microcomputer 510 to determine whether or not lateral acceleration is generated based on the lateral acceleration αy detected by the lateral acceleration sensor.

[0080] When the vehicle 100 is not in the state where the vehicle 100 is decelerating and lateral acceleration is generated, the microcomputer 510 proceeds to step S702 and stops the Δγ variable control to actively allow the change amount Δγ to be changed by changing the gain Gst.

[0081] Here, the microcomputer 510 executes the processing of setting the value of the gain Gst to 1.0 in step S702 and sets the steering angle command value δtg* obtained from the model following control section 511 as the final steering angle command value δtg as it is, thereby making it possible to substantially stop the Δγ variable control for actively allowing the change in the change amount Δγ.

[0082] On the other hand, when the vehicle 100 is in the state where the vehicle 100 is decelerating and lateral acceleration is generated, the microcomputer 510 proceeds to step S703 and makes settings to execute the Δγ-variable control for actively allowing a change in the change amount Δγ, that is, the control for allowing a change in the gain Gst.

[0083] Subsequently, the microcomputer 510 proceeds to step S704 and executes the Δγ change control to actively allow the change amount Δγ to be changed, that is, the processing of allowing the change of the gain Gst.

[0084] Fig. 5 is a line graph in which the x-axis represents the deceleration αx, the y-axis represents the lateral acceleration αy of the vehicle 100, and the z-axis represents the gain Gst. Fig. Figure 5 shows an aspect of the characteristics of the gain Gst for each region obtained by combining the deceleration αx and the lateral acceleration αy.

[0085] The Fig. The characteristics of the reinforcement Gst shown in Figure 5 correspond to those shown in Fig. 3 and are set to suppress an increase in the amount of change Δγ.

[0086] That is, since the amount of change Δγ in the turning direction increases with increasing lateral acceleration αy when the vehicle 100 is slowly decelerating, the microcomputer 510 (gain calculating section 512) sets the gain Gst to a smaller value as the lateral acceleration αy increases at the time of slow deceleration.

[0087] In other words, the gain Gst is calculated for a combination of the deceleration αx and the lateral acceleration αy for which the amount of change Δγ in the characteristic diagram of Fig. 3, compared to a combination of the deceleration αx and the lateral acceleration αy, for which the amount of change Δγ in the characteristic diagram of Fig. 3 is relatively small, reduced.

[0088] When the gain Gst is reduced (when described in detail, the gain Gst is reduced to less than 1.0), an increase in the steering angle command value δtg in the steering increase direction is delayed and it is possible to suppress an increase in the change amount Δγ, compared with a case where the control for actively allowing a change in the change amount Δγ by changing the gain Gst is not performed (in the case of a gain Gst of 1.0 when described in detail).

[0089] In this way, the microcomputer 510 sets the gain Gst so that the gain Gst can be changed for each combination of the deceleration αx and the lateral acceleration αy, in order to suppress an increase in the change amount Δγ in the state where the vehicle 100 is decelerating and lateral acceleration is generated.

[0090] This makes it possible to suppress the amount of change Δγ of the yaw rate γ per unit time corresponding to a steering operation even in situations of slow deceleration and high lateral acceleration αy, and to more smoothly connect the amounts of change Δγ of the respective ranges obtained by combining the deceleration αx and the lateral acceleration αy. This reduces the difficulty of a steering operation and increases safety for a normal driver.

[0091] That is, the Δγ variable control suppresses an increase in the change amount Δγ, whereby even an ordinary driver can perform an appropriate steering operation and it is possible to avoid a situation in which the anti-skid device of the vehicle 100 is operated.

[0092] Fig. 6 is a time chart illustrating an example of changes in deceleration, lateral acceleration, a yaw rate, and the like in a situation where the Δγ variable control for actively allowing the change amount Δγ to change by changing the gain Gst comes into operation.

[0093] It should be noted that the solid line in Fig. 6 shows the characteristics obtained when the Δγ-variable control is stopped, ie, when the gain Gst is fixed to 1.0.

[0094] In addition, a dashed line in Fig. 6 features obtained by actively suppressing an increase in the amount of change Δγ by reducing the gain Gst to less than 1.0.

[0095] In addition, the dashed line in Fig. 6 shows the characteristics obtained when actively increasing the amount of change Δγ by increasing the gain Gst to more than 1.0.

[0096] The vehicle 100 begins to decelerate at time t1, at which time the vehicle 100 is traveling straight ahead at a substantially constant speed. At the subsequent time t2, the driver begins to operate the steering wheel 310 from the neutral position in one of the two directions.

[0097] The driver then continues to turn the steering wheel 310 between time t2 and time t4. After time t4, the driver enters a steering wheel hold state in which he maintains the operating angle θ obtained at time t4.

[0098] That is, the steering wheel 310 is in the neutral position before time t2. Between time t2 and time t4, the steering wheel 310 undergoes a steering operation in the right or left direction.

[0099] When the steering angle θ changes along with the driver's steering operation on the steering wheel 310, the microcomputer 510 sets the target yaw rate γtg in accordance with the steering angle θ and sets the steering angle command value δtg* to cause the yaw rate estimate γes (or the yaw rate γac) to follow the target yaw rate γtg.

[0100] The front wheels 101 and 102 are then steered according to the steering angle command value δtg, thereby generating a lateral acceleration and a further yaw rate in the vehicle 100.

[0101] Here, the microcomputer 510 sets the gain Gst to less than 1.0 in accordance with the deceleration and the lateral acceleration, thereby changing the final steering angle target value δg to a value smaller than the steering angle target value δtg* obtained by the model following control section 511 as shown by a dashed line in Fig. 6 is displayed.

[0102] It should be noted that in the present application, the exact value depends on whether the front wheel steering angle δ has a large or small absolute value. Decreasing the steering angle command δtg brings the steering angle command δtg closer to the neutral position.

[0103] The processing of correcting the steering angle command value δtg with the gain Gst slows down the change in the steering angle of the front wheels 101 and 102 corresponding to a steering operation of the steering wheel 310 compared to a case where the correction processing is not performed (in other words, a case where the gain Gst is set to 1.0). Furthermore, the amount of change Δγ of the yaw rate γ per unit time is suppressed, so it is small compared to a case where the correction processing is not performed.

[0104] That is, the time represented by a dashed line in the time diagram of Fig. 6 indicate that when a driver's steering operation is input to the steering operation input device 300 from the state where the vehicle 100 is decelerated while traveling straight, the microcomputer 510 outputs the steering angle command value δtg (in other words, a control signal of the steering motor 410) to suppress an increase in the amount Δγ of change in the yaw rate γ per unit time.

[0105] In this way, when the Δγ variable control for suppressing an increase in the amount Δγ of change in the yaw rate γ per unit time is performed, it is possible to achieve the steering characteristics that are easy to handle for an ordinary driver, and it is possible for the ordinary driver to easily perform an appropriate steering operation.

[0106] Furthermore, the microcomputer 510 adjusts the gain Gst in response to the deceleration and lateral acceleration in accordance with an increase and decrease in the change amount Δγ corresponding to the deceleration and lateral acceleration. In this way, it is possible to continuously change the change amount Δγ depending on the changing deceleration and lateral acceleration.

[0107] In addition, as indicated by a dashed line in Fig. 6, it is possible for the microcomputer 510 to change the final steering angle command value δtg with the gain Gst (Gst > 1.0) to a value larger than the steering angle command value δtg* obtained by the model-following control section 511 when processing the correction of the steering angle command value δtg with the gain Gst.

[0108] It is then possible for the microcomputer 510 to increase the change amount Δγ of the yaw rate γ per unit time by changing the steering angle command value δtg to a value larger than the steering angle command value δtg*, compared with a case where the correction with the gain Gst is not performed.

[0109] In a case where the processing of correcting the steering angle command value δtg with the gain Gst is not performed, the characteristics of the change amount Δγ are uniquely defined by the characteristics and specifications of the vehicle 100, and a driver must therefore perform a steering operation that matches the vehicle characteristics.

[0110] On the other hand, if the Δγ-variable control for correcting the steering angle command value δtg is performed with the gain Gst, it is possible to change the characteristic of the change amount Δγ into a characteristic that suits the preference and ability of a driver, and to increase the steering comfort or improve the steering accuracy.

[0111] It is possible that the microcomputer 510 performs the processing of actively increasing the change amount Δγ under the Δγ-variable control when a counter-steering operation is performed, which is a steering operation on the steering wheel 310 in the direction opposite to the turning direction of the vehicle 100.

[0112] For example, if a driver's braking operation causes the rear wheels 103 and 104 to skid while the vehicle 100 is traveling steadily to turn at a constant steering angle and a constant turning speed, the driver performs the counter-steering operation by operating the steering wheel 310 in the direction opposite to the turning direction of the vehicle 100.

[0113] At this time, the operating angle θ of the steering wheel 310 does not change until the driver applies the brakes. Therefore, the steering angle of the front wheel is maintained. After the countersteering input, the steering angle δ of the front wheel moves in the direction opposite to the turning direction.

[0114] Here, if the change in the steering angle δ of the front wheel is delayed compared to the steering operation of the counter-steering by the driver, it is not possible to sufficiently reduce the tilting movements of the rear wheels 103 and 104, and the vehicle 100 exhibits unstable behavior.

[0115] Accordingly, the microcomputer 510 executes the Δγ variable control for actively increasing the amount Δγ of change in the yaw rate γ per unit time in the counter-steering operation performed while the vehicle 100 is turning, thereby preventing the change in the steering angle δ of the front wheel from being delayed in the counter-steering operation and preventing the rear wheels 103 and 104 from skidding.

[0116] In other words, the microcomputer 510 actively increases the change amount Δγ in response to the counter-steering operation to assist the driver in the counter-steering operation.

[0117] Incidentally, in a case where the driver is an experienced or professional driver who has a higher driving ability than a standard driving ability, it is possible that the microcomputer 510 stops the Δγ variable control to actively allow the change amount Δγ to be changed (specifically, the gain Gst is set to 1.0).

[0118] For an experienced or professional driver, it is possible to perform an appropriate steering action based on an understanding of the vehicle's characteristics in terms of the amount Δγ of change in the yaw rate γ per unit time, or a steering action that optimally utilizes the vehicle's characteristics. In some cases, it is possible to perform a favorable steering action without performing Δγ-variable control.

[0119] Accordingly, the microcomputer 510 acquires information indicating a mode selector switch state of the mode selector switch 650 as information related to a driver's driving ability. If the driver is judged to be an experienced or professional driver based on the mode selector state, the microcomputer 510 stops the Δγ variable control.

[0120] The mode selector switch 650 is provided in the vehicle 100 as a switch with which the driver can optionally select the responsiveness (in other words: the responsiveness of the vehicle behavior) of the steering angle of the front wheel to a steering operation on the steering wheel 310.

[0121] The mode selector switch 650 is then configured to select, for example, a normal mode for determining a responsiveness adapted to a driver with normal driving ability and a sport mode for determining a responsiveness higher than that of the normal mode and enabling an experienced driver with a driving ability beyond the standard driving ability to perform an appropriate steering operation.

[0122] That is, the microcomputer 510 acquires information about a mode selected by the mode selector switch 650 to acquire information related to a driver's driving ability. A function of the mode selector switch 650 for acquiring the mode selection information corresponds to a driving ability information acquisition section.

[0123] Fig. Figure 7 is a flowchart showing the process of adjusting the gain Gst. Fig. 7 illustrates the process of adjusting the gain Gst, which includes the processing of determining the state selected by the mode selector switch 650, in other words, the processing of determining the driving ability of a driver.

[0124] It should be noted that the processing of each of steps S802 to S805 in the flowchart of Fig. 7 of the processing of each of steps S701 to S704 in the above-described flowchart of Fig. 4, and a detailed description is therefore omitted.

[0125] The microcomputer 510 determines in step S801 whether the mode selector switch 650 selects the sport mode for determining high responsiveness or not.

[0126] In a case where a driver selects the sport mode with the mode selector switch 650, the microcomputer 510 estimates that the driver's driving ability is higher than the standard driving ability and proceeds to step S803.

[0127] The microcomputer 510 then stops, in step S803, the Δγ-variable control for actively allowing a change in the change amount Δγ by changing the gain Gst or the control for suppressing an increase in the change amount Δγ, if described in detail.

[0128] That is, in a case where the driver's driving ability is higher than the standard driving ability, the microcomputer 510 controls the steering motor 410 by using the steering angle command value δtg* obtained from the model following control section 511 as the final steering angle command value δtg as it is.

[0129] Thus, in a case where the driver's driving ability is higher than the standard driving ability, the yaw rate γ generated in the vehicle 100 in response to a steering operation on the steering wheel 310 is changed by the characteristics uniquely defined by the characteristics and specifications of the vehicle 100.

[0130] It is then possible for the driver who has a higher driving ability than the standard driving ability to perform an appropriate steering operation based on the understanding of the vehicle characteristics with respect to the change amount Δγ or a steering operation that makes optimal use of the vehicle characteristics.

[0131] In addition, it is possible to include the control for actively increasing the change amount Δγ of a counter-steering operation in the Δγ-variable control stopped by the microcomputer 510 when the driver has a higher driving ability than the standard driving ability.

[0132] When the normal mode for determining low responsiveness is selected with the mode selector switch 650 in step S801 and the driver is judged to be an ordinary driver having a driving ability lower than the standard driving ability, the microcomputer 510 proceeds to step S802.

[0133] Then, when the microcomputer 510 determines in step S802 that the vehicle 100 is decelerating and lateral acceleration is generated, the microcomputer 510 proceeds to step S804 and subsequent steps and executes the Δγ variable control to actively allow the change amount Δγ to be changed by changing the gain Gst.

[0134] Thus, in the case of an ordinary driver, it is possible to perform a steering operation and / or receive the assistance for a counter-steering operation with the characteristic that an increase in the change amount Δγ is suppressed when the mode selector switch 650 is operated to select the normal mode, whereby it is possible to achieve the steering characteristics that are easy to handle.

[0135] It is possible to appropriately use the respective technical ideas described in the embodiment in combination as long as inconsistencies are avoided.

[0136] Moreover, the contents of the present invention have been specifically described with reference to the preferred embodiment, but it would be obvious to those skilled in the art that various modifications can be adopted based on the basic technical concepts and teachings of the present invention.

[0137] The driving ability information acquisition section is not limited to the functional section of the mode selection switch 650 that acquires the mode selection information.

[0138] For example, it is possible that the microcomputer 510, as a driving ability information acquiring section, includes a functional section that obtains an index value of driving ability from a steering operation by a driver and a history of lateral acceleration, front-rear acceleration, or the like generated by the steering operation.

[0139] It is then possible for the microcomputer 510 to determine, by comparing the index value with a threshold value, whether the driver's ability is higher or lower than the standard ability, that is, whether the driver is an experienced driver or an ordinary driver.

[0140] In a case where the vehicle 100 includes a switch that allows the driver to optionally turn the anti-skid device on and off, it is also possible for the microcomputer 510 to treat the turning on of the anti-skid device as a command (in other words, a signal indicating that the driver is a normal driver) to perform the Δγ-variable control and to treat the turning off of the anti-skid device as a command (in other words, a signal indicating that the driver is a skilled driver) to stop the yaw rate control.

[0141] In this case, a functional section that acquires information for turning the anti-skid device on and off corresponds to the driving ability information acquisition section.

[0142] Furthermore, the configuration in which the driving capability is divided into two stages, a high level and a low level, is not limiting. It is possible for the microcomputer 510 to acquire information for dividing the driving capability into three or more stages and to change the degree to which the change amount Δγ is allowed to be actively changed in the three or more stages.

[0143] Here, it is possible that the microcomputer 510 includes some kinds of maps (or functions) of the gain Gst corresponding to the deceleration and the lateral acceleration, as shown in Fig. 5, and switch the maps (or functions) used for the Δγ variable control in accordance with the levels of driving ability.

[0144] Furthermore, the microcomputer 510 may actively allow a change in the change amount Δγ by adjusting a feedback gain to allow a change in the feedback gain, for example, based on the deviation between the target yaw rate γtg and the estimated yaw rate γes (or the yaw rate γac). The feedback gain is a gain in processing the adjustment of an operation amount.

[0145] That is, means for actively allowing a change in the change amount Δγ are not limited to means for correcting the steering angle command value δtg, as long as it is possible to actively allow a change in the change amount Δγ in response to a driver's steering operation.

[0146] Furthermore, it is possible for the steering-by-cable steering device 200 to include a locking mechanism that mechanically couples the steering wheel 310 and the front wheels 101 and 102 with a clutch or the like.

[0147] Furthermore, the steer-by-wire steering device 200 may include a first control device that outputs a control signal of the steering motor 410 and a second control device that outputs a control signal of the reaction force motor 330. REFERENCE SYMBOL 100 vehicles 101, 102 Front wheel (steered wheel) 200 Steering-by-cable steering device 300 Steering input device 340 Operating angle sensor 400 steering device 410 Steering motor (steering actuator) 500 control device 510 Microcomputer (control) 511 model following tax section 512 Gain calculation section 513 Multiplication section 630 Longitudinal acceleration sensor QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 5126357 B

[0005]

Claims

[1] A control device provided in a vehicle, the vehicle comprising a steer-by-wire steering device comprising a steering operation input device configured to receive a steering operation of a driver of the vehicle, and a steering device comprising a steering actuator configured to apply a steering force to a wheel, the control device comprising: a controller configured to output a control signal of the steering actuator, the controller: a first physical quantity relating to operation information on the steering operation input device and a second physical quantity relating to the acceleration and deceleration of the vehicle are detected, and outputs the control signal to actively allow a change amount of a yaw rate per unit time to be changed based on the first physical quantity and the second physical quantity, the yaw rate being generated in the vehicle in response to the steering operation. [2] The control device according to claim 1, wherein the controller, when detecting that the driver's steering operation is input to the steering operation input device from a state where the vehicle is decelerated while traveling straight ahead, based on the first physical quantity and the second physical quantity, outputs the control signal to suppress an increase in the amount of change of the yaw rate per unit time. [3] Control device according to claim 1, wherein: the controller comprises a driving ability information acquisition section configured to acquire information related to a driving ability of the driver, and when the controller detects, based on the first physical quantity and the second physical quantity, that the driver's steering operation is input to the steering operation input device from a state in which the vehicle is decelerated while traveling straight ahead, the controller increases the amount of change in the yaw rate per unit time when the driver has high driving ability, compared to the amount of change in the yaw rate per unit time when the driver has low driving ability. [4] The control device according to claim 1, wherein the controller, when detecting that a steering operation in a direction opposite to a turning direction is performed from a state in which the vehicle is decelerated upon turning based on the first physical quantity and the second physical quantity, actively increases the amount of change of the yaw rate per unit time in accordance with an input of the steering operation. [5] Control device according to claim 1, wherein: the controller comprises a driving ability information acquisition section configured to acquire information related to a driving ability of the driver, and when the controller detects, based on the first physical quantity and the second physical quantity, that a steering operation is performed in a direction opposite to a turning direction from a state where the vehicle is decelerated when making a turn, the controller stops the control to actively allow the amount of change of the yaw rate per unit time corresponding to an input of the steering operation to be changed when the driving ability of the driver is higher than a standard driving ability. [6] Control device according to claim 1, wherein the controller obtains an estimated yaw rate using a vehicle model having a steering angle of the wheel as an input value, wherein the estimated yaw rate is an estimate of the yaw rate generated in the vehicle, and the controller performs yaw rate control to adjust a command value of the steering angle of the wheel to cause the estimated yaw rate to follow a target yaw rate obtained based on the first physical quantity. [7] The control device according to claim 1, wherein the controller actively allows the amount of change of the yaw rate per unit time to be changed while the vehicle is decelerating and lateral acceleration is generated in the vehicle, the yaw rate being generated in the vehicle in response to the steering operation. [8] A control device according to claim 7, wherein the controller actively allows the amount of change of the yaw rate per unit time to be changed depending on the deceleration of the vehicle and the lateral acceleration of the vehicle, the yaw rate being generated in the vehicle in response to the steering operation. [9] Control device according to claim 7, wherein: the controller comprises a driving ability information acquisition section configured to acquire information related to a driving ability of the driver, and the controller stops steering to actively allow the amount of change in the yaw rate per unit time corresponding to an input of the steering operation to be changed when the driver's driving ability is higher than a standard driving ability. [10] Control method performed by a controller, the controller being mounted on a vehicle, wherein the vehicle comprises a steering-by-cable steering device, wherein the steering-by-wire steering device comprises a steering operation input device configured to receive a steering operation of a driver of the vehicle, and a steering device comprising a steering actuator configured to apply a steering force to a wheel of the vehicle, the tax procedure includes: detecting a first physical quantity relating to operation information on the steering operation input device and a second physical quantity relating to the acceleration and deceleration of the vehicle; and Outputting a control signal of the steering actuator, the control signal being for actively enabling a change in an amount of change of a yaw rate per unit time based on the first physical quantity and the second physical quantity, the yaw rate being generated in the vehicle in response to the steering operation. [11] Tax system comprising: a steer-by-wire steering device comprising a steering operation input device configured to receive a steering operation from a driver of a vehicle, and a steering device comprising a steering actuator configured to apply a steering force to a wheel of the vehicle; and a control device comprising a controller configured to output a control signal of the steering actuator, the controller: a first physical quantity relating to operation information on the steering operation input device and a second physical quantity relating to the acceleration and deceleration of the vehicle are detected, and outputs the control signal to actively enable a change amount of a yaw rate per unit time to be changed based on the first physical quantity and the second physical quantity, the yaw rate being generated in the vehicle in response to the steering operation.

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