Vehicle control system

Abstract

This vehicle control system (1) is provided to a vehicle (2) and comprises: a steering operator (21) and front wheels (WFL, ＷFR) serving as steered wheels, where the steering operator (21) and the front wheels (WFL, ＷFR) are mechanically independent of each other; a steering angle detection unit (24) that detects the steering angle of the steering operator (21); a rack gear (31), a steering actuator (32), and a pinion gear (33) that serve as a steered angle changing unit for changing the steered angles of the front wheels (WFL, ＷFR); a steered angle detection unit (34) that detects the steered angle of the front wheels (WFL, ＷFR); and a control unit (50) that controls the steered angle changing unit on the basis of the steering angle, wherein the control unit (50) executes auxiliary control for matching the steered angle to an angle corresponding to the steering angle.

Description

Vehicle control system

[0001] This invention relates to a technique for matching the steering angle and the turning angle in a steer-by-wire vehicle.

[0002] In recent years, development has been underway on vehicles that use electric power to perform or assist steering, such as steer-by-wire and electric power steering. Patent document 1 describes a technology that prohibits engine restart in steering conditions where there is a risk of insufficient current supplied to the electric power steering system, and allows engine restart when such steering conditions end.

[0003] International Publication No. 2015 / 087613

[0004] In steer-by-wire vehicles, miniaturization of the steering actuator is conceivable. However, a miniaturized steering actuator may not be able to steer the steering wheels to a steering angle corresponding to the maximum steering angle when the steering wheel is turned to its maximum steering angle while the vehicle is stopped, potentially failing to achieve the turning radius necessary for the vehicle to travel (the minimum turning radius as a performance measure of the steering mechanism). The method of prohibiting or allowing engine restarts described in Patent Document 1 cannot address this situation.

[0005] The present invention has been made in view of the above points, and aims to provide a vehicle control system that can suitably achieve the minimum turning radius of a vehicle, and thereby further improve traffic safety and contribute to the development of a sustainable transportation system.

[0006] To solve the aforementioned problems, the vehicle control system of the present invention comprises a steering control element and a wheel provided on a vehicle and mechanically independent of each other; a steering angle detection unit for detecting the steering angle of the steering control element; a steering angle changing unit for changing the steering angle of the wheel; a steering angle detection unit for detecting the steering angle of the wheel; and a control unit for controlling the steering angle changing unit based on the steering angle, wherein the control unit performs auxiliary control to match the steering angle to the angle corresponding to the steering angle.

[0007] According to the present invention, the minimum turning radius of a vehicle can be suitably achieved, and this can contribute to the development of a sustainable transportation system.

[0008] This is a schematic plan view showing a vehicle to which the vehicle control system according to an embodiment of the present invention is applied. This is a diagram illustrating an example of a graph showing the limit power characteristics as a relationship between rotational speed and torque of a steering actuator according to a comparative example, as well as examples of steering angle and steering angle. This is a diagram illustrating an example of a graph showing the limit power characteristics as a relationship between rotational speed and torque of a steering actuator according to an embodiment of the present invention during stationary steering of a vehicle, as well as examples of steering angle and steering angle. This is a diagram illustrating an example of a vehicle starting in a parking lot, as well as examples of a graph showing the limit power characteristics as a relationship between rotational speed and torque of a steering actuator according to an embodiment of the present invention during starting after stationary steering. This is a schematic plan view showing an example of a vehicle starting in a parking lot. This is a tree diagram showing the types of auxiliary control of the steering control unit according to an embodiment of the present invention. This is a flowchart illustrating an example of the operation of the vehicle control system according to an embodiment of the present invention.

[0009] Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In the reference drawings, "front and rear" refers to the front-rear direction in the direction of travel of the vehicle, and "left and right" refers to the left-right direction (vehicle width direction) as seen from the driver's seat.

[0010] As shown in Figure 1, the vehicle 2 to which the vehicle control system 1 according to the embodiment of the present invention is applied has the left and right front wheels W as the wheels W. ＦＬ , W ＦＲ And the left and right rear wheels W ＲＬ , W ＲＲ It is a four-wheeled vehicle equipped with the following: In vehicle 2, the left and right front wheels W serve as steering wheels. ＦＬ , W ＦＲ The steering control 21, described later, is not mechanically connected to it, and they are mechanically independent of each other. In other words, vehicle 2 employs a so-called steer-by-wire system. Note that in Figure 1, the mechanical and electrical connections of various parts have been omitted where appropriate.

[0011] The vehicle 2, that is, the vehicle control system 1 includes an internal combustion engine 11 as an example of a power source of the vehicle 2, a generator 12, an accelerator operator 13, an accelerator operation amount detection unit 14, a plurality of wheel speed detection units 15, and a plurality of electrical components 16.

[0012] The internal combustion engine 11 generates power for the running of the vehicle 2 according to the operation amount of the accelerator operator 13 by the driver. The generated power is transmitted to the drive wheels among the left and right front wheels W ＦＬ , W ＦＲ and the left and right rear wheels W ＲＬ , W ＲＲ through a drive shaft or the like (not shown). The generator 12 generates electricity by the power of the internal combustion engine 11. Further, the amount of power generated by the generator 12 (the electric power generated by the generator 12) is configured to be changeable based on a control signal from a control unit 50 described later. The generated electric power (current) is supplied to a plurality of electrical components 16 (including a reaction force actuator 23 and a steering actuator 32) through a harness 17 or the like as a component related to electrical resistance. Also, a part of the generated electric power is stored in a battery (not shown). Note that the vehicle 2 of the present invention may be configured to include an electric motor as a power source instead of the internal combustion engine 11, or may be configured to include an internal combustion engine 11 and an electric motor as power sources

[0013] The accelerator operator 13 is, for example, an accelerator pedal and is depressed by the driver. The accelerator operation amount detection unit 14 is a sensor that detects the operation amount of the accelerator operator 13. The detected operation amount is output to the control unit 50.

[0014] The wheel speed detection unit 15 is a rotational speed sensor that detects the wheel speed, that is, the rotational speed of the corresponding wheel W. The detected wheel speed is output to the control unit 50.

[0015] The electrical component 16 is, for example, an air conditioner or the like, and operates using the electric power (current) from the generator 12 based on a control signal from a control unit 50 described later. The electrical component 16 is electrically connected to the generator 12 through a harness 17 as a component related to electrical resistance. In FIG. 1, one electrical component 16 is described as an example.

[0016] <Steering Mechanism> The vehicle 2, that is, the vehicle control system 1, includes a steering control element 21, a steering shaft 22, a reaction force actuator 23, and a steering angle detection unit 24 as the steering mechanism.

[0017] The steering control element 21 is, for example, a steering wheel, which is rotated by the driver. The steering shaft 22 is a shaft that supports the steering control element 21.

[0018] The reaction force actuator 23 is composed of, for example, an electric motor, and based on the control signal from the control unit 50 described later, it controls the front wheel W as a steering wheel. ＦＬ , W ＦＲ A reaction force is generated in accordance with the steering angle. The generated reaction force is transmitted to the steering control element 21 via the steering shaft 22. The steering angle is defined as a value where one side (for example, clockwise as seen from the driver's perspective) is positive and the other side (for example, counterclockwise as seen from the driver's perspective) is negative.

[0019] The steering angle detection unit 24 is a rotation angle sensor that detects the steering angle of the steering control element 21, that is, the rotation angle of the steering shaft 22. The detected rotation angle is output to the control unit 50.

[0020] The steering control 21 may be a non-rotating control. In this case, the steering angle detection unit 24 uses an operating amount sensor that detects the amount of operation of the steering control 21 and outputs it to the control unit 50 as a parameter related to the steering angle. The control unit 50, which will be described later, calculates the steering angle based on this operating amount.

[0021] <Steering Mechanism> The vehicle 2, that is, the vehicle control system 1, includes a rack gear 31, a steering actuator 32, a pinion gear 33, and a steering angle detection unit 34 as the steering mechanism. The rack gear 31, steering actuator 32, and pinion gear 33 are connected to the left and right front wheels W as the steering wheels. ＦＬ , W ＦＲIt constitutes a steering angle changing unit that changes the steering angle. The rack gear 31 and the pinion gear 33 constitute an example of a steering angle changing mechanism. The steering actuator 32 constitutes a steering angle actuating unit that operates the steering angle changing mechanism. Note that the steering angle changing mechanism is not limited to the rack gear 31 and the pinion gear 33.

[0022] The rack gear 31 is a rod-shaped member that extends between the left and right front wheels W ＦＬ , W ＦＲ serving as steering wheels. Both ends of the rack gear 31 are connected to either one of the left and right front wheels W ＦＬ , W ＦＲ serving as steering wheels via tie rods, joints, and knuckle arms, respectively. The rack gear 31 changes the steering angle of the left and right front wheels W ＦＬ , W ＦＲ serving as steering wheels by moving in the axial direction. The steering angle is a value that makes one side (for example, the right side) of the left and right positive and the other side (for example, the left side) of the left and right negative, similar to the steering angle described above.

[0023] The steering actuator 32 is constituted by, for example, an electric motor, and rotates the output shaft forward and backward based on a control signal from a control unit 50 described later. The pinion gear 33 is attached to the output shaft of the steering actuator 32 and meshes with the rack gear 31.

[0024] The steering angle detection unit 34 is a sensor that detects the steering angle of the front wheels W ＦＬ , W ＦＲ serving as steering wheels. The steering angle detection unit 34 may be a rotary encoder that detects the rotation angle of the output shaft of the steering actuator 32 as a parameter corresponding to the steering angle, or may be a position sensor that detects the position of the rack gear 31 in the vehicle width direction as a parameter corresponding to the steering angle.

[0025] <Attitude changing unit> The vehicle 2, that is, the vehicle control system 1, includes the left and right front wheels W ＦＬ , W ＦＲ and the left and right rear wheels W ＲＬ , W ＲＲCorresponding to each of them, a variable damper 41 is provided. The variable damper 41 suspension-supports the wheel W with respect to the vehicle body of the vehicle 2 and changes the damping force based on a control signal from a control unit 50 described later.

[0026] Further, the variable damper 41 is an example of a vehicle height changing unit that changes the attitude of the vehicle 2 around the left-right axis (pitch axis). The variable damper 41 changes the vehicle height of the portion where the variable damper 41 is provided by changing the vertical length based on a control signal from a control unit 50 described later. That is, the plurality of variable dampers 41 can change the attitude of the vehicle 2 around the left-right axis (and the front-rear axis, that is, the roll axis).

[0027] <Cooling unit> The vehicle 2, that is, the vehicle control system 1 includes a cooling unit 42. The cooling unit 42 cools components related to electrical resistance that are electrically connected to the steering actuator 32 based on a control signal from a control unit 50 described later. Examples of such components related to electrical resistance include a harness 17 that electrically connects the steering actuator 32 and the generator 12 (or the battery) and supplies power to the steering actuator 32.

[0028] <Control unit> The control unit 50 is a so-called ECU (Electronic Control Unit) constituted by a CPU (Central Processing Unit), a ROM (Read-Only Memory), a RAM (Random Access Memory), an input / output circuit, and the like. The control unit 50 controls the internal combustion engine 11 based on the detection result of the accelerator operation amount detection unit 14, or controls the electrical component 16 based on the operation result of an operation unit (not shown) by the occupant of the vehicle 2. Further, the control unit 50 includes a vehicle speed calculation unit 51 and a steering control unit 52 as functional units related to the present invention.

[0029] The vehicle speed calculation unit 51 calculates the vehicle body speed, that is, the vehicle speed of the vehicle 2 based on the detection result, that is, the rotation speed, of the wheel speed detection unit 15. The vehicle speed calculation unit 51 and the wheel speed detection unit 15 together constitute an example of a vehicle speed detection unit that detects the vehicle speed.

[0030] The steering control unit 52 controls the steering actuator 32 based on the detection result of the steering angle detection unit 24, i.e., the steering angle, thereby controlling the front wheel W as a steering wheel. ＦＬ , W ＦＲ The steering angle is changed to an angle corresponding to the steering angle of the steering control 21. Here, the steering control unit 52 has a database, calculation formulas, etc. that show the relationship between the steering angle and the steering angle (or parameters correlated with the steering angle) set in advance. The steering control unit 52 can calculate the steering angle (or parameters correlated with the steering angle) using the detected steering angle and the database, calculation formulas, etc., and control the steering actuator 32 based on the calculated steering angle (or parameters correlated with the steering angle).

[0031] Furthermore, the steering control unit 52 applies a reaction force corresponding to the steering angle to the steering control element 21 by controlling the reaction force actuator 23 based on the detection result of the steering angle detection unit 34, i.e., the steering angle. Here, the steering control unit 52 can calculate the steering angle based on the parameters corresponding to the steering angle as detected by the steering angle detection unit 34. The steering control unit 52 also has a database, calculation formulas, etc., that show the relationship between the steering angle and the reaction force (or parameters correlated with the reaction force) pre-set in it. The steering control unit 52 can calculate the reaction force (or parameters correlated with the reaction force) using the detected steering angle and the database, calculation formulas, etc., and control the reaction force actuator 23 based on the calculated reaction force (or parameters correlated with the reaction force).

[0032] If the steering angle and the turning angle are misaligned (more specifically, if the turning angle deviates from the angle corresponding to the steering angle), the steering control unit 52 controls the steering actuator 32 (and reaction force actuator 23) based on the detection results of the steering angle detection unit 24 and the turning angle detection unit 34, thereby controlling the front wheel W as a steering wheel. ＦＬ , W ＦＲ Control is performed to match the steering angle of the steering control 21 to the angle corresponding to the steering angle of the steering control 21.

[0033] Here, we will explain the steering angle and turning angle during a stationary steering operation, where the driver operates the steering control 21 while the vehicle 2 is stationary (vehicle speed 0 [km / h]). In Figures 2 to 4, the steering state of the steering wheels and the steering control operation state, which are shown on the right side of the graph, are drawn at positions corresponding to the magnitude of the torque in the graph.

[0034] As shown in Figure 2, the output of the steering actuator in the comparative example is sufficiently large, so the limit output characteristic A of the steering actuator exceeds the required maximum torque B corresponding to the maximum steering angle during stationary steering. Therefore, the steering actuator in the comparative example can steer the steering wheel to the maximum steering angle when the steering control element 21 is operated to the maximum steering angle during stationary steering.

[0035] On the other hand, as shown in Figure 3, since the steering actuator 32 according to the embodiment of the present invention is miniaturized, the limit output characteristic A of the steering actuator 32 is less than the required maximum torque B corresponding to the maximum steering angle during stationary steering. Therefore, in the steering actuator 32 according to this embodiment, when the steering control 21 is operated to the maximum steering angle during stationary steering, the steering wheel cannot be steered to the maximum steering angle, and the minimum turning radius as a performance of the steering mechanism cannot be achieved.

[0036] In contrast, as shown in Figure 4, when the vehicle 2 is in motion, the axial force of the rack gear 31 in the steering state decreases. When the axial force of the rack gear 31 decreases to a reference axial force that falls within the range of limit output characteristic A, the steering actuator 32 executes the auxiliary control described above, enabling the steering wheel to be steered to the maximum steering angle, thereby achieving the minimum turning radius.

[0037] <Auxiliary Control> The steering control unit 52 controls the front wheel W as the steering wheel. ＦＬ , W ＦＲThe discrepancy between the steering angle and the turning angle is eliminated by performing control to match the steering angle of the steering control element 21 to the angle corresponding to the steering angle of the steering control element 21. As shown in Figure 5, when the vehicle starts moving from a stationary steering operation up to the maximum steering angle in a parking lot or the like, the vehicle 2 may collide with an obstacle (wall, curb, etc.) before the discrepancy between the steering angle and the turning angle is eliminated. In response to this, the steering control unit 52 according to this embodiment performs auxiliary control to eliminate the discrepancy between the steering angle and the turning angle, including control to assist the operation of the turning angle changing unit and control to adjust the driving state of the vehicle 2 until such discrepancy is eliminated (see Figure 6). Here, the control to assist the operation of the turning angle changing unit is control to shorten the time (synchronization time) until the discrepancy between the steering angle and the turning angle is eliminated.

[0038] <Synchronization Time Reduction Control> As shown in Figure 6, the steering control unit 52 performs the following controls to shorten the synchronization time: a control to improve the output characteristics of the steering actuator 32 and a control to reduce the load on the steering actuator 32.

[0039] <<Actuator Output Characteristic Improvement Control>> The steering control unit 52 performs at least one of the following controls to improve the output characteristics of the steering actuator 32: a control to reduce the current supplied to other electrical components 16, a control to increase the amount of power generated by the generator 12, and a control to cool components related to electrical resistance that are electrically connected to the steering actuator 32 (for example, the harness 17 that electrically connects the steering actuator 32 and the generator 12). By performing the control to reduce the current supplied to other electrical components 16, the steering control unit 52 increases the current supplied to the steering actuator 32, thereby improving the output characteristics, i.e., rotational characteristics, of the steering actuator 32. Furthermore, by performing the control to increase the amount of power generated by the generator 12, the steering control unit 52 increases the current supplied to the steering actuator 32, thereby improving the output characteristics, i.e., rotational characteristics, of the steering actuator 32. Furthermore, the steering control unit 52 increases the current supplied to the steering actuator 32 by performing a control to cool components related to electrical resistance that are electrically connected to the steering actuator 32 (for example, the harness 17 that electrically connects the steering actuator 32 and the generator 12), thereby improving the output characteristics, i.e., rotational characteristics, of the steering actuator 32. With improved output characteristics, the steering actuator 32 can change the steering angle in a relatively short time, and the synchronization time can be shortened.

[0040] <Load Reduction Control> The steering control unit 52 performs control to adjust the vehicle height of the vehicle 2 as a control to reduce the load on the steering actuator 32. The steering control unit 52 controls the front wheels W as the steering wheels. ＦＬ , W ＦＲ Control to lengthen the corresponding variable damper 41, and / or the rear wheel W ＲＬ , W ＲＲ By executing control to shorten the corresponding variable damper 41, the attitude of the vehicle 2 around the left and right axes is changed, reducing the load (weight) acting on the steering wheels, and consequently reducing the load on the steering actuator 32. With the load reduced, the steering actuator 32 can change the steering angle in a relatively short time, and the synchronization time can be shortened.

[0041] <Driving State Adjustment Control> The steering control unit 52 performs control to suppress the acceleration of the vehicle 2 as a control to adjust the driving state. The steering control unit 52 controls the internal combustion engine 11, which is the power source, to suppress the acceleration of the vehicle 2 until the steering angle matches the angle corresponding to the steering angle. More specifically, the steering control unit 52 controls the internal combustion engine 11, which is the power source, to suppress the acceleration of the vehicle 2 so that the vehicle speed does not reach a predetermined speed (for example, 15 [km / h]) until the steering angle matches the angle corresponding to the steering angle. With the acceleration of the vehicle 2 suppressed, the driver's discomfort in operation until the steering angle matches the angle corresponding to the steering angle can be reduced.

[0042] <Operation Example> Next, an operation example of the vehicle control system 1 according to an embodiment of the present invention will be described with reference to the flowchart in Figure 7.

[0043] As shown in Figure 7, the steering control unit 52 determines whether the vehicle 2 is stopped or not based on the vehicle speed (step S1). If it is determined that the vehicle 2 is stopped (Yes in step S1), the steering control unit 52 determines whether the steering angle deviates from the angle corresponding to the steering angle based on the detected steering angle and steering angle (step S2). If it is determined that the vehicle 2 is moving (No in step S1), this flow ends. If it is determined that the steering angle matches the angle corresponding to the steering angle (No in step S2), this flow also ends.

[0044] If it is determined that vehicle 2 is stopped and the steering angle is different from the angle corresponding to the steering angle (Yes in step S1 and Yes in step S2), the steering control unit 52 determines whether vehicle 2 has started moving based on the vehicle speed (step S3). For example, in step S3, the steering control unit 52 can determine that vehicle 2 has started moving if the vehicle speed has reached a specified speed (or is equal to or greater than the specified speed), and that vehicle 2 has not started moving if the vehicle speed is less than the specified speed. The specified speed is sufficiently smaller than the predetermined speed described later and is the speed required to detect the movement of vehicle 2 (for example, 0.5 [km / h]). If it is determined that vehicle 2 has started moving (Yes in step S3), the steering control unit 52 executes the auxiliary control described above (step S4). If it is determined that vehicle 2 remains stopped (No in step S3), this flow returns to step S2.

[0045] As a first modification of step S3, the steering control unit 52 may be configured to determine whether the vehicle speed of the vehicle 2 has reached a specified speed and whether the absolute value of the steering angle is greater than a predetermined angle. If it is determined that the vehicle speed of the vehicle 2 has reached a specified speed and the absolute value of the steering angle is greater than a predetermined angle (Yes in step S3 of the first modification), the steering control unit 52 starts auxiliary control (step S4). If it is determined in step S3 of the first modification that the vehicle speed of the vehicle 2 has not reached a specified speed, this flow repeats step S3 of the first modification. If it is determined in step S3 of the first modification that the vehicle speed of the vehicle 2 has reached a specified speed and the absolute value of the steering angle is less than or equal to a predetermined angle, this flow ends. When adopting step S3 of this first modification, step S2 can be omitted. The predetermined angle can be appropriately set to the absolute value of the steering angle when the steering angle and steering angle are out of sync, or more specifically, the absolute value of the angle at which the steering angle deviates from the angle corresponding to the steering angle. This predetermined angle is set based on the output of the steering actuator 32 (limit output characteristic A), etc. The smaller the output of the steering actuator 32, the smaller the steering angle at which the deviation between the steering angle and steering angle occurs, so it is desirable to set the predetermined angle to be small.

[0046] As a second modification of step S3, the steering control unit 52 may be configured to determine whether the vehicle speed of the vehicle 2 has reached a specified speed and whether the steering angle is deviating from the angle corresponding to the steering angle. If it is determined that the vehicle speed of the vehicle 2 has reached a specified speed and the steering angle is deviating from the angle corresponding to the steering angle (Yes in step S3 of the second modification), the steering control unit 52 starts auxiliary control (step S4). If it is determined in step S3 of the second modification that the vehicle speed of the vehicle 2 has not reached a specified speed, this flow repeats step S3 of the second modification. If it is determined in step S3 of the second modification that the vehicle speed of the vehicle 2 has reached a specified speed and the steering angle is not deviating from (matches) the angle corresponding to the steering angle, this flow ends. When adopting step S3 of this second modification, step S2 can be omitted. In step S3 of the second modified example, the steering control unit 52 may be configured to determine whether the steering angle deviates from the angle corresponding to the steering angle, and whether the magnitude (absolute value) of the deviation between the steering angle and the angle corresponding to the steering angle is greater than or equal to a predetermined value.

[0047] After step S4, the steering control unit 52 determines whether the vehicle 2 is stopped or not based on the vehicle speed (step S5). If it is determined that the vehicle 2 is moving (No in step S5), the steering control unit 52 determines whether the steering angle matches the angle corresponding to the steering angle based on the detected steering angle and steering angle (step S6). If it is determined that the steering angle is different from the angle corresponding to the steering angle (No in step S6), this flow returns to step S4, and the steering control unit 52 continues auxiliary control. On the other hand, if it is determined that the vehicle 2 has stopped (Yes in step S5), the steering control unit 52 terminates auxiliary control, and this flow ends. Also, if it is determined that the steering angle matches the angle corresponding to the steering angle (Yes in step S6), the steering control unit 52 terminates auxiliary control, and this flow ends.

[0048] The vehicle control system 1 according to an embodiment of the present invention is provided on a vehicle 2 and comprises a steering control element 21 and wheels (front wheels W) which are mechanically independent of each other. ＦＬ , WＦＲ The vehicle control system 1 comprises a steering angle detection unit 24 for detecting the steering angle of the steering control element 21, a steering angle changing unit (rack gear 31, steering actuator 32 and pinion gear 33) for changing the steering angle of the wheels, a steering angle detection unit 34 for detecting the steering angle of the wheels, and a control unit 50 for controlling the steering angle changing unit based on the steering angle, wherein the control unit 50 performs auxiliary control to match the steering angle to the angle corresponding to the steering angle. Therefore, the vehicle control system 1 can resolve the discrepancy between the steering angle and the steering angle early or within the range of acceptable driving conditions, and can suitably achieve the minimum turning radius of the vehicle 2.

[0049] The control unit 50 executes the auxiliary control when the vehicle 2 starts moving while the vehicle 2 is stopped and the steering angle is deviating from the angle corresponding to the steering angle. Therefore, the vehicle control system 1 can quickly match the steering angle and the steering angle by assisting the operation of the steering angle changing unit, thereby suitably achieving the minimum turning radius of the vehicle 2. Furthermore, by quickly matching the steering angle and the steering angle (quickly eliminating the discrepancy between the steering angle and the steering angle), the vehicle control system 1 can suppress the driver's feeling of discomfort while operating the vehicle.

[0050] The control unit 50 starts the auxiliary control when the vehicle 2 has started moving, its speed has reached a specified speed, and the absolute value of the steering angle is greater than a predetermined angle. Therefore, the vehicle control system 1 can start the auxiliary control based on the steering angle without using the steering angle by setting a predetermined angle at which a discrepancy occurs between the steering angle and the turning angle during stationary steering.

[0051] The control unit 50 assists in the operation of the steering angle changing unit as an auxiliary control. Therefore, the vehicle control system 1 can quickly match the steering angle and the turning angle by accelerating the operation of the actuator. In other words, the vehicle control system 1 can suitably achieve the minimum turning radius of the vehicle 2.

[0052] The control unit 50 performs auxiliary control to improve the output characteristics of the actuator (steering actuator 32) that constitutes the steering angle changing unit. Therefore, the vehicle control system 1 can promote the operation of the actuator by improving the output characteristics of the actuator. In other words, the vehicle control system 1 can suitably achieve the minimum turning radius of the vehicle 2 by matching the steering angle and the turning angle at an early stage.

[0053] The control unit 50, as an auxiliary control, reduces the current supplied to other components (electrical components 16) of the vehicle 2. Therefore, the vehicle control system 1 can promote the operation of the actuator by ensuring a larger current is supplied to the actuator. In other words, the vehicle control system 1 can suitably achieve the minimum turning radius of the vehicle 2 by matching the steering angle and the turning angle at an early stage.

[0054] The control unit 50, as an auxiliary control, increases the power output of the generator 12 of the vehicle 2. Therefore, the vehicle control system 1 can promote the operation of the actuator by securing a larger current supplied to the actuator. In other words, the vehicle control system 1 can suitably achieve the minimum turning radius of the vehicle 2 by matching the steering angle and the turning angle at an early stage.

[0055] The vehicle control system 1 includes a cooling unit 42 for cooling a component (harness 17) related to electrical resistance that is connected to the actuator of the steering angle changing section, and the control unit 50 cools the component by controlling the cooling unit as an auxiliary control. Therefore, the vehicle control system 1 can promote the operation of the actuator by securing a larger current supplied to the actuator. In other words, the vehicle control system 1 can suitably achieve the minimum turning radius of the vehicle 2 by matching the steering angle and the turning angle at an early stage.

[0056] The vehicle control system 1 includes a posture changing unit (variable damper 41) that can change the posture of the vehicle 2 around its left and right axes, and the control unit 50, as auxiliary control, controls the posture changing unit to reduce the load acting on the wheel corresponding to the steering angle changing unit. Therefore, the vehicle control system 1 can promote the operation of the actuator by reducing the load on the actuator. In other words, the vehicle control system 1 can suitably achieve the minimum turning radius of the vehicle 2 by matching the steering angle and the turning angle at an early stage.

[0057] The control unit 50 adjusts the driving state of the vehicle as auxiliary control. Therefore, the vehicle control system 1 can suitably achieve the minimum turning radius of the vehicle 2 by matching the steering angle and the turning angle within a range of acceptable driving conditions.

[0058] The control unit 50, as an auxiliary control, suppresses the acceleration of the vehicle 2 until the steering angle matches the angle corresponding to the steering angle. Therefore, the vehicle control system 1 maintains a problem-free driving state until the steering angle and the steering angle match, and by matching the steering angle and the steering angle within the range of a problem-free driving state, the minimum turning radius of the vehicle 2 can be suitably achieved.

[0059] As auxiliary control, the control unit 50 suppresses the acceleration of the vehicle 2 so that the vehicle speed does not reach a predetermined speed until the steering angle matches the angle corresponding to the steering angle. Therefore, the vehicle control system 1 can suitably achieve the minimum turning radius of the vehicle 2 by ensuring a time margin until the predetermined speed is reached in which the steering angle and the steering angle must match, and by matching the steering angle and the steering angle within a range of acceptable driving conditions.

[0060] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above and can be modified as appropriate without departing from the spirit of the invention. For example, the steering control unit 52 may be configured to increase the number of types of synchronization time reduction control performed as the difference between the steering angle and the steering angle increases.

[0061] Furthermore, the steering control unit 52 may be configured to omit steps S1 and S3 and execute auxiliary control if Yes is given in step S2. In this case, it is preferable to use a control that assists the operation of the steering angle changing unit as the auxiliary control. Even in such a configuration, the steering control unit 52 can quickly match the steering angle to the angle corresponding to the steering angle when the steering angle and the steering angle are misaligned due to stationary steering operation by starting the vehicle 2. In addition, the steering control unit 52 can quickly match the steering angle to the angle corresponding to the steering angle even when the steering angle and the steering angle are misaligned due to impacts to the steering wheels, etc., while the vehicle 2 is driving.

[0062] Furthermore, the steering control unit 52 may be configured to perform auxiliary control both when the vehicle 2 is moving forward and when it is moving backward, or it may be configured to perform auxiliary control when the vehicle 2 is moving forward but not when it is moving backward. Here, the steering control unit 52 can recognize the direction of travel of the vehicle 2 based on the rotation direction of the wheels W detected by the wheel speed detection unit 15.

[0063] 1. Vehicle control system 2. Vehicle 11. Internal combustion engine (power source) 12. Generator 16. Electrical components 17. Harness (components, components related to electrical resistance) 21. Steering control unit 24. Steering angle detection unit 31. Rack gear (steering angle changing unit) 32. Steering actuator (steering angle changing unit) 33. Pinion gear (steering angle changing unit) 41. Variable damper (attitude changing unit) 42. Cooling unit 50. Control unit W ＦＬ , W ＦＲ Front wheels (wheels, steering wheels)

Claims

1. A vehicle control system comprising: a steering control element and a wheel provided on the vehicle and mechanically independent of each other; a steering angle detection unit for detecting the steering angle of the steering control element; a steering angle changing unit for changing the steering angle of the wheel; a steering angle detection unit for detecting the steering angle of the wheel; and a control unit for controlling the steering angle changing unit based on the steering angle, wherein the control unit performs auxiliary control to match the steering angle to the angle corresponding to the steering angle.

2. The vehicle control system according to claim 1, characterized in that the control unit performs the auxiliary control when the vehicle starts moving while the vehicle is stopped and the steering angle is deviating from the angle corresponding to the steering angle.

3. The vehicle control system according to claim 2, characterized in that the control unit starts the auxiliary control when the vehicle has started moving and the vehicle speed has reached a specified speed, and the absolute value of the steering angle is greater than a predetermined angle.

4. The vehicle control system according to any one of claims 1 to 3, characterized in that the control unit assists in the operation of the steering angle changing unit as an auxiliary control.

5. The vehicle control system according to claim 4, characterized in that the control unit performs control to improve the output characteristics of the actuator constituting the steering angle changing unit as auxiliary control.

6. The vehicle control system according to claim 5, characterized in that the control unit reduces the current supplied to other parts of the vehicle as auxiliary control.

7. The vehicle control system according to claim 5, characterized in that the control unit increases the amount of power generated by the vehicle's generator as the auxiliary control.

8. The vehicle control system according to claim 5, further comprising a cooling unit for cooling components related to electrical resistance connected to the actuator of the steering angle changing unit, wherein the control unit cools the components by controlling the cooling unit as an auxiliary control.

9. The vehicle control system according to claim 5, comprising a posture changing unit capable of changing the posture of the vehicle around the left and right axes, wherein the control unit, as auxiliary control, controls the posture changing unit to reduce the load acting on the wheel corresponding to the steering angle changing unit.

10. The vehicle control system according to claim 2 or 3, characterized in that the control unit adjusts the operating state of the vehicle as the auxiliary control.

11. The vehicle control system according to claim 10, characterized in that the control unit suppresses the acceleration of the vehicle as auxiliary control until the steering angle matches the angle corresponding to the steering angle.

12. The vehicle control system according to claim 11, characterized in that the control unit, as auxiliary control, suppresses the acceleration of the vehicle so as not to reach a predetermined speed until the steering angle matches the angle corresponding to the steering angle.

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