Steering system

Abstract

A steering system is disclosed, comprising a control unit. The control unit comprises: a manual steering angle command value setting unit; a first weighting unit; a reaction combination angle command value calculation unit; a rotation combination angle command value calculation unit; a reaction force control unit configured to make the rotation angle of a reaction motor (13) consistent with the reaction combination angle command value; and a rotation angle control unit configured to make the rotation angle of a rotation motor (19) consistent with the rotation combination angle command value.

Description

Technical Field

[0001] The present invention relates to a steering system in which a rotating mechanism is driven by a rotating motor in a state in which the rotating mechanism is not mechanically coupled with a steering member operated for steering. Background Art

[0002] Japanese Unexamined Patent Application Publication No. 2004-224238 (JP 2004-224238 A) discloses a steer-by-wire system in which a turning mechanism is driven by a turning motor (steering motor) while a steering member operated for steering and the turning mechanism are not mechanically coupled to each other. The steer-by-wire system described in JP 2004-224238 A includes: an operating unit including an operating reaction motor; a turning unit including the turning motor; an operating reaction control unit that controls the operating unit; a turning control unit that controls the turning unit; and an automatic tracking system. The turning control unit controls the turning motor based on a final target turning angle.

[0003] In the automatic tracking system described in JP 2004-224238 A, the final target rotation angle is set as follows. When the automatic tracking system is not in operation, the target rotation angle calculated based on the operating angle of the steering wheel is set to the final target rotation angle (manual steering mode). When the automatic tracking system is in operation and the steering torque is equal to or greater than a first threshold value, or when the automatic tracking system is in operation and the operating angle is equal to or greater than a second threshold value, the target rotation angle calculated based on the operating angle of the steering wheel is multiplied by a predetermined value greater than 1 and the value obtained is set to the final target rotation angle (transition mode). When the automatic tracking system is in operation, the steering torque is less than the first threshold value and the operating angle is less than the second threshold value, the target steering angle that the automatic tracking system is set to is set to the final target rotation angle (transition mode). Summary of the Invention

[0004] The present invention provides a steering system capable of switching between a cooperative steering mode that controls a rotary motor based on a cooperative steering command value calculated in consideration of an automatic steering angle command value and a manual steering angle command value, and an automatic steering mode or a manual steering mode.

[0005] According to a first aspect of the present invention, a steering system is provided, comprising: a steering member; a rotating mechanism mechanically separated from the steering member; a reaction motor configured to apply a reaction torque to the steering member; a rotary motor configured to drive the rotary mechanism; a steering torque detection unit configured to detect the steering torque applied to the steering member; and a control unit configured to control the drive of the reaction motor and the rotary motor. The control unit includes: a manual steering angle command value setting unit, which is configured to set the manual steering angle command value based on the steering torque; a first weighting unit, which is configured to perform weighted processing on the manual steering angle command value according to predetermined first information; a reaction combination angle command value calculation unit, which is configured to calculate the reaction force combination angle command value based on the reaction automatic steering angle command value and the manual steering angle command value weighted by the first weighting unit; a rotation combination angle command value calculation unit, which is configured to calculate the rotation combination angle command value based on the rotation automatic steering angle command value and the manual steering angle command value weighted by the first weighting unit; a reaction force control unit, which is configured to make the rotation angle of the reaction motor consistent with the reaction combination angle command value; and a rotation angle control unit, which is configured to make the rotation angle of the rotation motor consistent with the rotation combination angle command value.

[0006] Using this configuration, it is possible to switch between a collaborative steering mode in which the rotating motor is controlled based on a combined angle command value and an automatic steering mode in which the rotating motor is controlled only based on an automatic steering angle command value, wherein the combined angle command value is a collaborative steering command value calculated taking into account the automatic steering angle command value and the manual steering angle command value.

[0007] According to a second aspect of the present invention, a steering system is provided, comprising: a steering member; a rotating mechanism mechanically separated from the steering member; a reaction motor configured to apply a reaction torque to the steering member; a rotary motor configured to drive the rotary mechanism; a steering torque detection unit configured to detect the steering torque applied to the steering member; and a control unit configured to control the drive of the reaction motor and the rotary motor. The control unit includes: a manual steering angle command value setting unit, which is configured to set the manual steering angle command value based on the steering torque; a second weighting unit, which is configured to perform weighted processing on the reaction automatic steering angle command value and the rotation automatic steering angle command value according to predetermined second information; a reaction combination angle command value calculation unit, which is configured to calculate the reaction force combination angle command value based on the manual steering angle command value and the reaction automatic steering angle command value weighted by the second weighting unit; a rotation combination angle command value calculation unit, which is configured to calculate the rotation combination angle command value based on the manual steering angle command value and the rotation automatic steering angle command value weighted by the second weighting unit; a reaction force control unit, which is configured to make the rotation angle of the reaction motor consistent with the reaction combination angle command value; and a rotation angle control unit, which is configured to make the rotation angle of the rotation motor consistent with the rotation combination angle command value.

[0008] With this configuration, it is possible to switch between a collaborative steering mode in which the rotating motor is controlled based on a combined angle command value and a manual steering mode in which the rotating motor is controlled based only on a manual steering angle command value, wherein the combined angle command value is a collaborative steering command value calculated taking into account the automatic steering angle command value and the manual steering angle command value.

[0009] According to a third aspect of the present invention, a steering system is provided, comprising: a steering member; a rotating mechanism mechanically separated from the steering member; a reaction motor configured to apply a reaction torque to the steering member; a rotary motor configured to drive the rotary mechanism; a steering torque detection unit configured to detect the steering torque applied to the steering member; and a control unit configured to control the drive of the reaction motor and the rotary motor. The control unit includes: a manual steering angle command value setting unit, which is configured to set the manual steering angle command value based on the steering torque; a third weighting unit, which is configured to perform weighted processing on the manual steering angle command value according to predetermined third information; a fourth weighting unit, which is configured to perform weighted processing on the reaction automatic steering angle command value and the rotation automatic steering angle command value according to predetermined fourth information; a reaction combination angle command value calculation unit, which is configured to calculate the reaction combination angle command value based on the manual steering angle command value weighted by the third weighting unit and the reaction automatic steering angle command value weighted by the fourth weighting unit; a rotation combination angle command value calculation unit, which is configured to calculate the rotation combination angle command value based on the manual steering angle command value weighted by the third weighting unit and the rotation automatic steering angle command value weighted by the fourth weighting unit; a reaction force control unit, which is configured to make the rotation angle of the reaction motor consistent with the reaction combination angle command value; and a rotation angle control unit, which is configured to make the rotation angle of the rotation motor consistent with the rotation combination angle command value.

[0010] Using this configuration, it is possible to switch between a collaborative steering mode in which the rotating motor is controlled based on a combined angle command value, an automatic steering mode in which the rotating motor is controlled based only on an automatic steering angle command value, and a manual steering mode in which the rotating motor is controlled based only on a manual steering angle command value, where the combined angle command value is a collaborative steering command value calculated taking into account the automatic steering angle command value and the manual steering angle command value.

[0011] In a third aspect, the control unit may include: an automatic steering mode in which the reaction motor and the turning motor are controlled based on a reaction automatic steering angle command value and a turning automatic steering angle command value; a manual steering mode in which the reaction motor and the turning motor are controlled based on a manual steering angle command value; and a cooperative steering mode in which the reaction motor and the turning motor are controlled based on a reaction automatic steering angle command value and a manual steering angle command value, and a cooperative steering command value, the cooperative steering command value being a turning combined angle command value calculated in consideration of the turning automatic steering angle command value and the manual steering angle command value. The control unit may be configured to, when a condition in which the automatic steering mode is to be switched to the manual steering mode is detected during control in the automatic steering mode and a manual steering request is output to the driver at a point a first predetermined time or a first predetermined distance before the point in which the condition is reached, control the reaction motor and the turning motor in the cooperative steering mode unconditionally or when a predetermined condition is satisfied.

[0012] In a third aspect, the control unit may be configured to, when a manual steering request is output to the driver, weight the manual steering angle command value based on the driver's alertness using a third weighting unit, and control the reaction motor and the turning motor in the cooperative steering mode using the weighted manual steering angle command value. In the third aspect, the predetermined condition may be a condition that the driver's alertness is equal to or greater than a predetermined threshold.

[0013] In a third aspect, the control unit may be configured to, after a manual steering request has been output, output an automatic stop request when no steering performed by the driver is detected at or before a second predetermined time or a second predetermined distance before the point at which the condition is reached, the automatic stop request being used to generate an automatic steering angle command value for moving the vehicle and stopping it at a predetermined stop position.

[0014] The steering system according to the above aspect may further include a switching unit configured to switch the control mode of the reaction motor and the rotary motor to a manual steering mode based on an operation of a driver. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like elements, and in which:

[0016] Figure 1 is a diagram schematically showing the configuration of a steering system according to a first embodiment of the present invention;

[0017] Figure 2 is a block diagram showing the electrical configuration of the reaction ECU and the rotation ECU;

[0018] Figure 3 is a block diagram showing the configuration of a manual steering angle command value setting unit;

[0019] Figure 4 is a graph showing the response to the steering torque T d The assist torque command value T ac A graph showing an example of the settings;

[0020] Figure 5 is a diagram schematically showing an example of a reference EPS model used in a command value setting unit;

[0021] Figure 6 is a block diagram showing the configuration of a reaction angle control unit;

[0022] Figure 7 is a block diagram showing the configuration of a rotation angle control unit;

[0023] Figure 8A is the first weight W md Figure 1 shows an example of a setup for Figure 8B is the second weight W ad Figure 1 shows an example of the setup;

[0024] Figure 9 is a diagram schematically showing the configuration of a steering system according to a second embodiment of the present invention;

[0025] Figure 10 is a block diagram showing the electrical configuration of the reaction ECU and the rotation ECU;

[0026] Figure 11 is a diagram schematically illustrating the operation of the second setting unit;

[0027] Figure 12 is a flowchart illustrating an example of a routine of a second setting process performed by a second setting unit; and

[0028] Figure 13 is a flowchart illustrating a modified example of the routine of the second setting process performed by the second setting unit. DETAILED DESCRIPTION

[0029] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0030] (1) First embodiment

[0031] The following will describe an overview of the configuration of the steering system 1 according to the first embodiment. Figure 1 As shown, a steering system 1 includes a steering wheel 2 as a steering member for steering a vehicle, a turning mechanism 4 for turning a turning wheel 3, and a steering shaft 5 connected to the steering wheel 2. Here, there is no mechanical connection between the steering shaft 5 and the turning mechanism 4 for transmitting movement such as torque or rotational motion.

[0032] The steering shaft 5 includes a first shaft 7, one end of which is connected to the steering wheel 2; a torsion bar 8, one end of which is connected to the other end of the first shaft 7; and a second shaft 9, one end of which is connected to the other end of the torsion bar 8. A torque sensor 11 is provided near the torsion bar 8. The torque sensor 11 detects the steering torque (torsion bar torque) T applied to the steering wheel 2 based on the relative rotational displacement between the first shaft 7 and the second shaft 9. d In this embodiment, the steering torque T detected by the torque sensor 11 is d : The torque for steering left is detected as a positive value, the torque for steering right is detected as a negative value, and the steering torque T d The size of increases as its absolute value increases.

[0033] A reaction motor 13 that controls the rotational angle of the second shaft 9 (hereinafter also referred to as the "steering wheel angle") is connected to the second shaft 9 via a speed reducer 12. The reaction motor 13 is an electric motor that applies a reaction torque to the second shaft 9. The speed reducer 12 is composed of a worm gear mechanism including a worm shaft (not shown) integrally rotatably connected to the output shaft of the reaction motor 13 and a worm gear (not shown) engaged with the worm shaft and integrally rotatably connected to the second shaft 9. A rotation angle sensor 14 that detects the rotational angle of the reaction motor 13 is provided in the reaction motor 13.

[0034] The rotating mechanism 4 is composed of a rack and pinion mechanism including a pinion shaft 15 and a rack shaft 16. The rotating wheel 3 is connected to the end of the rack shaft 16 via a pull rod 17 and a joint lever arm (not shown). The pinion shaft 15 is connected to the output shaft of the rotating motor 19 via a reducer 18. The reducer 18 is composed of a worm gear mechanism including a worm shaft (not shown) integrally rotatably connected to the output shaft of the rotating motor 19 and a worm wheel (not shown) engaged with the worm shaft and integrally rotatably connected to the pinion shaft 15. The pinion 15A is connected to the end of the pinion shaft 15. A rotation angle sensor 20 that detects the rotation angle of the rotating motor 19 is provided in the rotating motor 19.

[0035] In the following description, the reduction ratio (gear ratio) of the speed reducer 12 is represented by N1, and the reduction ratio of the speed reducer 18 is represented by N2. The reduction ratio is defined as the angular velocity ω of the worm and worm wheel. wg and the angular velocity ω of the worm gear ww The ratio of ω wg / ω ww The rack shaft 16 extends straight in the vehicle width direction. A rack 16A, which meshes with the pinion 15A, is formed in the rack shaft 16. When the rotary motor 19 rotates, its rotational force is transmitted to the pinion shaft 15 via the speed reducer 18. The rotation of the pinion shaft 15 is converted into axial movement of the rack shaft 16 by the rack and pinion mechanism. This causes the rotary wheel 3 to rotate.

[0036] The vehicle includes a charge-coupled device (CCD) camera 25 that images the road ahead of the vehicle in the direction of travel (i.e., captures an image of the road ahead of the vehicle), a global positioning system (GPS) 26 that detects the vehicle's position, a radar 27 that detects the shape of the road or obstacles, and a map information memory 28 that stores map information. A first mode switch 121, a second mode switch 122, and a third mode switch 123 for manually switching the steering mode are also installed in the vehicle.

[0037] As will be described later, the steering modes include a manual steering mode in which steering is performed by manual drive, an automatic steering mode in which steering is performed by automatic drive, and a cooperative steering mode in which steering can be performed based on both manual drive and automatic drive. The CCD camera 25, GPS 26, radar 27, and map information memory 28 are connected to a main electronic control unit (ECU) 201 that performs drive support control or automatic drive control. The main ECU 201 performs surrounding environment recognition, host vehicle position estimation, route planning, etc. based on information obtained from the CCD camera 25, GPS 26, and radar 27, as well as map information obtained from the map information memory 28, and determines control target values ​​for the steering or drive actuators.

[0038] In this embodiment, the main ECU 201 sets the rotational automatic steering angle command value for automatic steering to the automatic steering angle command value θ adac In this embodiment, the automatic steering control is, for example, a control for causing the vehicle to travel along a target trajectory. The automatic steering angle command value θ adac Is the target value of the steering angle for automatically driving the vehicle along the target trajectory. Setting such an automatic steering angle command value θ adac The process is widely known, and a detailed description thereof will be omitted herein.

[0039] The main ECU 201 generates mode setting signals S1, S2, and S3 based on the operation of the mode switches 121, 122, and 123. Specifically, when the driver turns on the first mode switch 121, the main ECU 201 outputs the cooperative steering mode setting signal S1 to set the steering mode to the cooperative steering mode. When the driver turns on the second mode switch 122, the main ECU 201 outputs the automatic steering mode setting signal S2 to set the steering mode to the automatic steering mode. When the driver turns on the third mode switch 123, the main ECU 201 outputs the manual steering mode setting signal S3 to set the steering mode to the manual steering mode.

[0040] In this embodiment, when the second shaft 9 is rotated in the left steering direction by the reaction motor 13, or when the turning wheel 3 is rotated in the left steering direction by the turning motor 19, the automatic steering angle command value θ adac and the assist torque command value T which will be described later. ac and the manual steering angle command value θ mdac On the other hand, when the second shaft 9 is rotated in the right steering direction by the reaction motor 13, or when the turning wheel 3 is rotated in the right steering direction by the turning motor 19, these command values ​​θ adac 、T ac and θ mdac In this embodiment, the automatic steering angle command value θadac is set to the rotation angle of the pinion shaft 15, and the manual steering angle command value θ mdac is set as the rotation angle of the second axis 9.

[0041] The automatic steering angle command value θ set by the main ECU 201 adac Mode setting signals S1, S2, S3 generated by the main ECU 201 are supplied to the reaction ECU 202 and the rotation ECU 203 via the vehicle network. The reaction ECU 202 controls the reaction motor 13, and the rotation ECU 203 controls the rotation motor 19.

[0042] The steering torque T detected by the torque sensor 11 d The output signal of the rotation angle sensor 20 and the rotation angle sensor 14 are input to the reaction ECU 202. The reaction ECU 202 controls the reaction motor 13 based on the input signal and information input from the main ECU 201. The output signal of the rotation angle sensor 20 is input to the rotation ECU 203. The rotation ECU 203 controls the rotation motor 19 based on the output signal of the rotation angle sensor 20, the information provided from the reaction ECU 202, and the information provided from the main ECU 201. The electrical configuration of the reaction ECU 202 and the rotation ECU 203 will be described below. The reaction ECU 202 will be described first. As Figure 2 As shown, the reaction ECU 202 includes a microcomputer 40, a drive circuit (inverter circuit) 31 that is controlled by the microcomputer 40 and supplies power to the reaction motor 13, and a circuit for detecting the current flowing in the reaction motor 13 (hereinafter referred to as "motor current I rm ”) current detection circuit 32.

[0043] The microcomputer 40 includes a CPU and memory (e.g., ROM and RAM), and functions as a plurality of functional processing units by executing predetermined programs. In other words, the microcomputer 40 functions as an example of a "control unit" in the present invention by executing the predetermined programs. The plurality of functional processing units include a manual steering angle command value setting unit 41, a hands-on / off determination unit 42, a switching unit 43, a reaction combined angle command value calculation unit 44, a reaction angle control unit 45, a first weighting unit 46, a second weighting unit 47, and a third weighting unit 48. The reaction angle control unit 45 is an example of a "reaction force control unit" in the present invention.

[0044] The first weighting unit 46 weights the steering torque T detected by the torque sensor 11 according to the mode setting signal input to the first weighting unit 46. dSpecifically, first, when one of the mode setting signals S1, S2, and S3 is input to the first weighting unit 46, the first weighting unit 46 sets the first weight W according to the current steering mode and the input mode setting signal. md Then, the first weighting unit 46 adds the steering torque T d Multiply by the first weight W md Then, the first weighting unit 46 adds the multiplied value W md ·T d As the steering torque T subjected to the first weighting process d ' is supplied to the manual steering angle command value setting unit 41.

[0045] The manual steering angle command value setting unit 41 is provided to set the steering angle corresponding to the operation of the steering wheel 2 (more accurately, the rotation angle of the second shaft 9) as the manual steering angle command value θ when the driver operates the steering wheel 2. mdac The manual steering angle command value setting unit 41 uses the steering torque T subjected to the first weighting process. d 'To set the manual steering angle command value θ mdac The details of the manual steering angle command value setting unit 41 will be described later. The manual steering angle command value θ set by the manual steering angle command value setting unit 41 is mdac Provided to the second weighting unit 47.

[0046] The second weighting unit 47 weights the manual steering angle command value θ set by the manual steering angle command value setting unit 41 according to the mode setting signal input to the second weighting unit 47. mdac The second weighting process is performed. Specifically, when one of the mode setting signals S1, S2, and S3 is input to the second weighting unit 47, the second weighting unit 47 sets the first weight W according to the current steering mode and the input mode setting signal. md Then, the second weighting unit 47 weights the manual steering angle command value θ mdac Multiply by the first weight W md Then, the second weighting unit 47 adds the multiplied value W md ·θ mdac As the manual steering angle command value θ subjected to the second weighting process mdac ' is provided to the reaction combined angle command value calculation unit 44.

[0047] The hands-on / hands-off determination unit 42 determines whether the driver is gripping the steering wheel 2 (hands-on) or not gripping the steering wheel 2 (hands-off). As the hand-on / hands-off determination unit 42, a unit that determines hands-on / hands-off based on an output signal from a touch sensor provided in the steering wheel 2, a unit that determines hands-on / hands-off based on an image captured by a camera provided in the vehicle, or the like can be used. As long as it can determine hands-on / hands-off, a unit having a configuration other than the aforementioned configuration can be used as the hand-on / hands-off determination unit 42. A hand-on / hands-off determination signal output from the hand-on / hands-off determination unit 42 is supplied to the switching unit 43.

[0048] When the hands-on / hands-off determination unit 42 determines that the driver is holding the steering wheel 2, the switching unit 43 sets the automatic steering angle command value θ set by the main ECU 201 to adac As the reaction automatic steering angle command value θ rtac is supplied to the third weighting unit 48. On the other hand, when the hands-on / hands-off determination unit 42 determines that the driver does not grip the steering wheel 2, the switching unit 43 sets 0 as the reaction automatic steering angle command value θ rtac Provided to the third weighting unit 48.

[0049] The third weighting unit 48 adjusts the reaction automatic steering angle command value θ supplied from the switching unit 43 according to the mode setting signal input to the third weighting unit 48. rtac The third weighting process is performed. Specifically, when one of the mode setting signals S1, S2, and S3 is input to the third weighting unit 48, the third weighting unit 48 sets the second weight W according to the current steering mode and the input mode setting signal. ad Then, the third weighting unit 48 weights the reaction automatic steering angle command value θ rtac Multiply by the second weight W ad Then, the third weighting unit 48 adds the multiplied value W ad ·θ rtac As the reaction automatic steering angle command value θ subjected to the third weighting process rtac ' is provided to the reaction combined angle command value calculation unit 44.

[0050] The reaction combined angle command value calculation unit 44 calculates the reaction automatic steering angle command value θ subjected to the third weighting process supplied from the third weighting unit 48 by rtac ' and the manual steering angle command value θ subjected to the second weighting process supplied from the second weighting unit 47 mdac 'Add to calculate the reaction combined angle command value θ rcmd The first weight W set by the first weighting unit 46 and the second weighting unit 47 will be described later. md and the second weight W set by the third weighting unit 48 addetails.

[0051] The reaction angle control unit 45 is based on the reaction combined angle command value θ rcmd To control the angle of the reaction motor 13. More specifically, the reaction angle control unit 45 controls the driving circuit 31 so that the steering angle θ rt (The rotation angle of the second shaft 9) approaches the reaction combined angle command value θ rcmd The details of the reaction angle control unit 45 will be described later. The rotation ECU 203 will be described below. The rotation ECU 203 includes: a microcomputer 80, a drive circuit (inverter circuit) 71 that is controlled by the microcomputer 80 and supplies power to the rotation motor 19, and a circuit for detecting the current flowing in the rotation motor 19 (hereinafter referred to as "motor current I sm ”) current detection circuit 72.

[0052] The microcomputer 80 includes a CPU and memory (e.g., ROM and RAM), and functions as a plurality of functional processing units by executing predetermined programs. The plurality of functional processing units include a rotational combined angle command value calculation unit 81, a rotational angle control unit 82, and a fourth weighting unit 83. The rotational angle control unit 82 is an example of a "rotational angle control unit" in the present invention.

[0053] The fourth weighting unit 83 adjusts the automatic steering angle command value θ supplied from the main ECU 201 according to the mode setting signal input to the fourth weighting unit 83. adac Execute the fourth weighting process. Specifically, when one of the mode setting signals S1, S2, and S3 is input to the fourth weighting unit 83, the fourth weighting unit 83 first sets the second weight W according to the current steering mode and the input mode setting signal. ad Then, the fourth weighting unit 83 calculates the automatic steering angle command value θ adac Multiply by the second weight W ad Then, the fourth weighting unit 83 adds the multiplied value W ad ·θ adac As the automatic steering angle command value θ subjected to the fourth weighting process adac ' is provided to the rotation combination angle command value calculation unit 81.

[0054] The rotation combined angle command value calculation unit 81 calculates the manual steering angle command value θ subjected to the second weighting process supplied from the second weighting unit 47 in the reaction ECU 202 by mdac ' and the automatic steering angle command value θ subjected to the fourth weighting process supplied from the fourth weighting unit 83 adac 'Add to calculate the rotation combined angle command value θ scmd The second weight W set by the fourth weighting unit 83 will be described later. addetails.

[0055] The rotation angle control unit 82 is based on the rotation combined angle command value θ scmd To control the angle of the rotation motor 19. More specifically, the rotation angle control unit 82 controls the driving circuit 71 so that the rotation angle θ sp (The rotation angle of the pinion shaft 15) approaches the rotation combined angle command value θ scmd The details of the rotation angle control unit 82 will be described later. Figure 2 In the configuration shown, the first weighting unit 46 and the second weighting unit 47 are examples of the "first weighting unit" or the "third weighting unit" in the present invention, and the third weighting unit 48 and the fourth weighting unit 83 are examples of the "second weighting unit" or the "fourth weighting unit" in the present invention. The mode setting signals S1, S2, and S3 are examples of the "predetermined first information," "predetermined second information," "predetermined third information," or "predetermined fourth information" in the present invention. The configuration of the manual steering angle command value setting unit 41 will be described below. Figure 3 As shown, the manual steering angle command value setting unit 41 includes an assist torque command value setting unit 51 and a command value setting unit 52 .

[0056] The assist torque command value setting unit 51 sets an assist torque command value T t as a target value of the assist torque required for manual operation. ac The assist torque command value setting unit 51 calculates the assist torque command value based on the steering torque T subjected to the first weighting process. d 'To set the assist torque command value T ac . Figure 4 The response to the steering torque T d 'Assist torque command value T ac Setting example. When the steering torque T d ' is a positive value, the auxiliary torque command value T ac is positive, and when the steering torque T d 'When it is a negative value, the auxiliary torque command value T ac Auxiliary torque command value T ac is set so that T ac The absolute value of the steering torque T d ' increases with the increase of its absolute value.

[0057] The assist torque command value setting unit 51 can set the steering torque T d 'Multiply by a preset constant to calculate the assist torque command value T ac In this embodiment, the command value setting unit 52 uses the reference EPS model to set the manual steering angle command value θ mdac . Figure 5is a diagram schematically showing an example of a reference EPS model used for the command value setting unit 52 .

[0058] The reference EPS model is a single inertial model including the lower column. Figure 5 J c is the inertia of the lower column, θ c is the rotation angle of the lower column, and T d is the steering torque. d , torque N from the electric motor (auxiliary motor) c ·T m and road surface load torque T r1 Applied to the lower column. N c is the reduction ratio of the speed reducer provided in the transmission path between the assist motor and the lower column, and T m The motor torque generated by the assist motor. Road surface load torque T r1 It is expressed by equation (1) using the spring constant k and the viscous damping coefficient c.

[0059] T r1 =-k·θ c -c(dθ c / dt)...(1)

[0060] In this embodiment, the spring constant k and the viscous damping coefficient c are set to predetermined values ​​calculated in advance through experiments, analysis, etc. The motion equation of the reference EPS model is expressed by equation (2).

[0061] J c ·d 2 θ c / dt 2 =T d +N c ·T m -k·θ c -c(dθ c / dt)...(2)

[0062] The command value setting unit 52 calculates the steering torque T d 'Substitute T d The assist torque command value T set by the assist torque command value setting unit 51 ac Substitute N c ·T m And solve the differential equation of formula (2) to calculate the rotation angle θ of the lower column c Then, the command value setting unit 52 sets the rotation angle θ of the lower column obtained c Set to the manual steering angle command value θ mdac The configuration of the reaction angle control unit 45 will be described below. Figure 6 As shown, the reaction angle control unit 45 generates a reaction angle command value θ based on the reaction combined angle command value θ. rcmd The reaction angle control unit 45 includes an angle difference calculation unit 61, a PD control unit 62, a current command value calculation unit 63, a current difference calculation unit 64, a PID control unit 65, a PWM control unit 66, a rotation angle calculation unit 67, and a reduction ratio divider unit 68.

[0063] The rotation angle calculation unit 67 calculates the rotor rotation angle θ of the reaction motor 13 based on the output signal of the rotation angle sensor 14. rm The reduction ratio divider 68 divides the rotor rotation angle θ calculated by the rotation angle calculation unit 67 by rm Divide by the reduction ratio N1 of the reducer 12 to obtain the rotor rotation angle θ rm Converted into the rotation angle of the second shaft 9 (actual steering angle) θ rt The angle difference calculation unit 61 calculates the reaction combined angle command value θ rcmd and the actual steering angle θ rt The difference Δθ r (=θ rcmd -θ rt ).

[0064] The PD control unit 62 calculates the angle difference Δθ calculated by the angle difference calculation unit 61. r A proportional differential operation (PD operation) is performed to calculate the torque command value T of the reaction motor 13. rcmd The current command value calculation unit 63 calculates the torque command value T calculated by the PD control unit 62 by rcmd Divide by the torque constant K of the reaction motor 13 r To calculate the current command value I rcmd .

[0065] The current difference calculation unit 64 calculates the current command value I obtained by the current command value calculation unit 63. rcmd The motor current I detected by the current detection circuit 32 rm The difference ΔI r (=I rcmd -I rm PID control unit 65 calculates the current difference ΔI calculated by current difference calculation unit 64. r Proportional-integral-derivative calculation (PID calculation) is performed to generate a motor current I for flowing through the reaction motor 13. rm Approaching current command value I rcmdThe PWM control unit 66 generates a PWM control signal having a duty ratio (duty factor) corresponding to the drive command value, and supplies the generated PWM control signal to the drive circuit 31. Therefore, the power corresponding to the drive command value is supplied to the reaction motor 13. The configuration of the rotation angle control unit 82 will be described below. Figure 7 As shown, the rotation angle control unit 82 is based on the rotation combined angle command value θ scmd The drive circuit 71 controls the rotation of the motor 19. The rotation angle control unit 82 includes an angle difference calculation unit 91, a PD control unit 92, a current command value calculation unit 93, a current difference calculation unit 94, a PID control unit 95, a PWM control unit 96, a rotation angle calculation unit 97, and a reduction ratio divider unit 98.

[0066] The rotation angle calculation unit 97 calculates the rotor rotation angle θ of the rotary motor 19 based on the output signal of the rotation angle sensor 20. sm The reduction ratio divider 98 divides the rotor rotation angle θ calculated by the rotation angle calculation unit 97 by sm Divide by the reduction ratio N2 of the reducer 18 to obtain the rotor rotation angle θ sm Converted to the rotation angle (actual rotation angle) θ of the pinion shaft 15 sp The angle difference calculation unit 91 calculates the rotation combined angle command value θ scmd and the actual rotation angle θ sp The difference Δθ s (=θ scmd -θ sp ).

[0067] The PD control unit 92 calculates the angle difference Δθ calculated by the angle difference calculation unit 91. s A proportional differential operation (PD operation) is performed to calculate a torque command value T for rotating the motor 19. scmd The current command value calculation unit 93 calculates the torque command value T calculated by the PD control unit 92 by scmd Divide by the torque constant K of the rotary motor 19 s To calculate the current command value I scmd .

[0068] The current difference calculation unit 94 calculates the current command value I obtained by the current command value calculation unit 93. scmd The motor current I detected by the current detection circuit 72 sm The difference ΔI s (=I scmd -I sm PID control unit 95 calculates the current difference ΔI calculated by current difference calculation unit 94. sProportional-integral-derivative operation (PID operation) is performed to generate a motor current I for flowing through the rotary motor 19. sm Approaching current command value I scmd The PWM control unit 96 generates a PWM control signal having a duty ratio (duty factor) corresponding to the drive command value, and supplies the generated PWM control signal to the drive circuit 71. Thus, the power corresponding to the drive command value is supplied to the rotation motor 19. The operation will be described below. The automatic steering mode is based only on the automatic steering angle command value (rotation automatic steering angle command value) θ. adac The steering mode controls the rotation motor 19. The manual steering mode is based only on the manual steering angle command value θ mdac The cooperative steering mode is based on the automatic steering angle command value θ adac and the manual steering angle command value θ mdac The rotation combined angle command value θ calculated by the two scmd To control the steering mode of the rotary motor 19. The cooperative steering mode will be described below. Figure 2 When the steering mode is set to cooperative steering mode, the first weight W md and the second weight W ad Set to 1.0. Therefore, the first weighting process (=T d ) steering torque T d ' becomes equal to the steering torque T d , and undergoes the second weighting process (=W md ·θ mdac ) manual steering angle command value θ mdac ' becomes equal to the steering torque T d Calculated manual steering angle command value θ mdac . Subjected to the fourth weighting process (=W ad ·θ adac ) of the automatic steering angle command value θ adac ' becomes equal to the automatic steering angle command value θ set by the main ECU 201 adac .

[0069] In the case where the hands-on / hands-off determination unit 42 determines that the driver is holding the steering wheel 2, the third weighting process (=W ad ·θ rtac ) of the reaction automatic steering angle command value θ rtac ' becomes equal to the automatic steering angle command value θ adac Therefore, in this case, by setting the manual steering angle command value θ mdac and the automatic steering angle command value θ set by the main ECU 201 adac Add to calculate the reaction combined angle command value θrcmd , and based on the reaction force combined angle command value θ rcmd To control the reaction motor 13. By setting the manual steering angle command value θ mdac and the automatic steering angle command value θ adac Add to calculate the rotation angle command value θ scmd , and based on the rotation combined angle command value θ scmd To control the rotation motor 19.

[0070] Therefore, even during automatic steering control, since the driver's intention is immediately reflected in the turning motor 19 and the reaction motor 13, it is possible to achieve coordinated control in which steering control (turning control and reaction control (steering wheel angle control)) is performed primarily by the automatic steering control without switching between manual steering control and automatic steering control. Since switching between manual steering control and automatic steering control can be performed seamlessly, the driver does not feel uncomfortable when operating manually.

[0071] On the other hand, in the case where the hands-on / hands-off determination unit 42 determines that the driver is not holding the steering wheel 2, zero is set as the reaction automatic steering angle command value θ rtac ' is provided to the third weighting unit 48. Therefore, in this case, based on the manual steering angle command value θ mdac and the automatic steering angle command value θ adac The rotation combined angle command value θ obtained by adding scmd to control the rotation motor 19, and based on the manual steering angle command value θ mdac The reaction combined angle command value θ rcmd To control the reaction motor 13. In this case, since the manual steering angle command value θ mdac ' is almost zero, so the steering wheel 2 is fixed to the neutral position during the automatic steering. Therefore, it is possible to avoid a situation where the steering wheel 2 is rotated by the automatic steering and the driver touches the steering wheel 2 when the driver is not holding the steering wheel 2. The automatic steering mode will be described below. When the steering mode is set to the automatic steering mode, the first weight W is set to md Set to zero and the second weight W ad Set to 1.0. Therefore, the first weighting process (=W md ·T d ) steering torque T d ' and the manual steering angle command value θ subjected to the second weighting process mdac ' is zero. Therefore, based only on the automatic steering angle command value θ adac To control the rotation motor 19, and based on the rotation automatic steering angle command value θ rtacTo control the reaction motor 13. The manual steering mode will be described below. In the case where the steering mode is set to the manual steering mode, the first weight W md Set to 1.0 and the second weight W ad Set to zero. Therefore, it undergoes the third weighting process (=W ad ·θ rtac ) of the reaction automatic steering angle command value θ rtac ' and undergo the fourth weighting process (=W ad ·θ adac ) of the automatic steering angle command value θ adac ' is zero. Therefore, based only on the manual steering angle command value θ mdac To control the rotation motor 19, and based on the manual steering angle command value θ mdac To control the reaction motor 13.

[0072] That is, the reaction ECU 202 and the rotation ECU 203 can switch the steering mode between the cooperative steering mode, the automatic steering mode and the manual steering mode by the driver's operation of the mode switches 121, 122 and 123. The weight W will be described below. md and W ad Example of a setting. Figure 8A and Figure 8B The first weight W when switching the steering mode is shown in FIG. md and the second weight W ad Example of a setting. Figure 8A , a time point t2 after a predetermined time T has passed since the time point (time point t1) of the input mode setting signal S1, S2 or S3 is reached, and the first weight W is indicated by the broken line L1. md The state gradually increases from 0 to 1.0, and the first weight W is indicated by the broken line L2 md The state gradually decreases from 1.0 to 0.

[0073] exist Figure 8B In the example, from time point t1 to time point t2, the second weight W is indicated by the broken line L3. ad The second weight W gradually increases from 0 to 1.0, as indicated by the broken line L4. ad The state gradually decreases from 1.0 to 0. Therefore, due to the first weighting process (=W md ·T d ) steering torque T d The absolute value of ' and undergo the second weighting process (=W md ·θ mdac ) manual steering angle command value θ mdac ', and undergo the third weighting process (=W ad ·θ rtac) of the reaction automatic steering angle command value θ rtac The absolute value of ' and undergo the fourth weighting process (=W ad ·θ adac ) of the automatic steering angle command value θ adac The absolute value of ' gradually increases or decreases, so that the switching between the steering modes is smoothly performed.

[0074] Switch the first weight W between 0 and 1.0 md and the second weight W ad The required time period T is set to a predetermined value calculated in advance through experiments, analysis, etc. The first weight W is switched between 0 and 1.0. md The time required T can be set to switch the second weight W between 0 and 1.0 ad The time T required is different. The first weight W md and the second weight W ad Can be set to ramp up or down non-linearly (rather than linearly).

[0075] In the first embodiment, when the mode switch 121, 122 or 123 is operated without changing the steering mode, it is assumed that the operation is invalid. In the first embodiment, when one of the mode switches 121, 122 and 123 is operated within a time period until a predetermined time period T has passed after each mode switch 121, 122 or 123 has been operated, it is assumed that the operation is invalid. A modified example of the first embodiment will be described below. The automatic steering mode setting signal S2 or the manual steering mode setting signal S3 can be generated depending on whether the driver holds the steering wheel 2. Specifically, the hands-on / hands-off determination unit 42 outputs the manual steering mode setting signal S3 when the state in which the driver does not hold the steering wheel 2 (released state) is changed to the state in which the driver holds the steering wheel 2 (held state). On the other hand, the hands-on / hands-off determination unit 42 outputs the automatic steering mode setting signal S2 when the held state is changed to the released state.

[0076] In this case, regarding the switch between the automatic steering mode and the manual steering mode, the driver can switch the operating mode between an operation mode performed based on the hands-on / hands-off determination unit 42 and an operation mode performed based on the second mode switch 122 and the third mode switch 123. In the first embodiment, the first to fourth weighting units 46, 47, 48, and 83 are provided. A first configuration can be adopted in which the first weighting unit 46, the third weighting unit 48, and the fourth weighting unit 83 are provided and the second weighting unit 47 is omitted. A second configuration can be adopted in which the second weighting unit 47, the third weighting unit 48, and the fourth weighting unit 83 are provided and the first weighting unit 46 is omitted. In the first configuration, the first weighting unit 46 is an example of the "first weighting unit" or the "third weighting unit" in the present invention. In the second configuration, the second weighting unit 47 is an example of the "first weighting unit" or the "third weighting unit" in the present invention.

[0077] A third configuration may be adopted in which only the first weighting unit 46 is provided and the second to fourth weighting units 47, 48, and 83 are omitted, a fourth configuration may be adopted in which only the second weighting unit 47 is provided and the first weighting unit 46, the third weighting unit 48, and the fourth weighting unit 83 are omitted, or a fifth configuration may be adopted in which the first weighting unit 46 and the second weighting unit 47 are provided and the third weighting unit 48 and the fourth weighting unit 83 are omitted. In this case, when the steering mode is set to the automatic steering mode, by setting the first weighting unit W md Set to zero to automatically adjust the steering angle based on the command value θ adac To control the rotation motor 19.

[0078] In the third configuration, the first weighting unit 46 is an example of the "first weighting unit" or the "third weighting unit" in the present invention. In the fourth configuration, the second weighting unit 47 is an example of the "first weighting unit" or the "third weighting unit" in the present invention. In the fifth configuration, the first weighting unit 46 and the second weighting unit 47 are examples of the "first weighting unit" or the "third weighting unit" in the present invention.

[0079] A sixth configuration may be employed in which the third weighting unit 48 and the fourth weighting unit 83 are provided and the first weighting unit 46 and the second weighting unit 47 are omitted. In this case, in the case where the steering mode is set to the manual steering mode, by setting the second weight W ad Set to zero to enable the steering to be controlled based on the manual steering angle command value θ mdac To control the rotation motor 19.

[0080] Second embodiment

[0081] A schematic configuration of a steering system 1A according to a second embodiment will be described below. Figure 91A is a diagram schematically showing the configuration of a steering system 1A according to a second embodiment. Figure 9 In the above reference Figure 1 The components described will be used in conjunction with Figure 1 The same reference numerals are used to represent the same figures in FIG.

[0082] The steering system 1A according to the second embodiment differs from the steering system 1 according to the first embodiment in the following five points. The first difference is that the interior camera 29 that images the driver (i.e., captures his image) is connected to the main ECU 201A. The second difference is that in addition to the automatic steering angle command value θ adac In addition to the mode setting signals S1, S2, and S3, the alertness α and the manual steering request TOR (take-over request) are supplied from the main ECU 201A to the steering ECU 203A.

[0083] The third difference is that the steering torque T detected by the torque sensor 11 is d is provided to the reaction ECU 202A and the rotation ECU 203A. The fourth difference is that the automatic steering angle command value θ adac The mode setting signals S1, S2 and S3 are not provided from the main ECU 201A to the reactive ECU 202A. The fifth difference is that the automatic stop request S stop The signal is supplied from the rotation ECU 203A to the main ECU 201A.

[0084] The main ECU 201A determines the driver's alertness α based on the image of the driver captured by the interior camera 29. In this embodiment, the alertness α has a value equal to or greater than 0 and equal to or less than 1. The alertness α is 0 when the driver is asleep, and is 1 when the driver's eyes are fully open. The main ECU 201A may use another method to determine the driver's alertness α.

[0085] When a situation requiring switching the steering mode to the manual steering mode is detected during control in the automatic steering mode, the main ECU 201A generates a manual steering request TOR to the driver through audio, screen display, etc. at a point a first predetermined time or a first predetermined distance before the point of the situation. The situation requiring switching the steering mode to the manual steering mode during control in the automatic steering mode is, for example, a situation in which the vehicle moves from an automatic driving possible road section where automatic driving is possible to an automatic driving impossible road section where automatic driving is not possible.

[0086] As will be described later, the automatic stop request S may be provided from the rotation ECU 203A to the main ECU 201A. stopThe automatic stop request is used to cause the main ECU 201A to generate an automatic steering angle command value for moving the vehicle and stopping it at a predetermined stop position. The electrical configurations of the reaction ECU 202A and the rotation ECU 203A will be described below. Figure 10 2 is a block diagram showing the electrical configuration of the reaction ECU 202A and the rotation ECU 203A. Figure 10 In the above reference Figure 2 The components described will be used in conjunction with Figure 2 The reaction ECU 202A will be described below. Figure 10 The reaction ECU 202A according to the second embodiment differs from the reaction ECU 202 according to the first embodiment in the configuration of the plurality of functional processing units of the microcomputer 40. The plurality of functional processing units include a manual steering angle command value setting unit 41, a hands-on / hands-off determination unit 42, a switching unit 43, a reaction combined angle command value calculation unit 44, a reaction angle control unit 45, a first weighted sum multiplier unit 101, a second weighted sum multiplier unit 102, and a third weighted sum multiplier unit 103. The reaction angle control unit 45 is an example of a "reaction force control unit" in the present invention.

[0087] The first weighted sum multiplier unit 101 converts the steering torque T detected by the torque sensor 11 into th Multiplied by the first weight W set by the weight setting unit 110 provided in the rotation ECU 203A md Then, the first weighted sum multiplier unit 101 adds the multiplied value W md ·T d The steering torque Td′ is supplied to the manual steering angle command value setting unit 41 as a result of being subjected to the first weighting and multiplication. md Has a value equal to or greater than 0 and equal to or less than 1.

[0088] The manual steering angle command value setting unit 41 is provided to set the steering angle corresponding to the operation of the steering wheel 2 (more accurately, the rotation angle of the second shaft 9) as the manual steering angle command value θ when the driver operates the steering wheel 2. mdac The manual steering angle command value setting unit 41 uses the steering torque T subjected to the first weighted sum multiplication. th 'To set the manual steering angle command value θ mdac The configuration of the manual steering angle command value setting unit 41 is similar to that of the manual steering angle command value setting unit 41 according to the first embodiment (refer to Figure 3 ) are the same, so the description thereof will be omitted. The manual steering angle command value θ set by the manual steering angle command value setting unit 41 is mdacProvided to the second weighted sum multiplier unit 102.

[0089] The second weighted sum multiplier unit 102 converts the manual steering angle command value θ mdac Multiplied by the first weight W set by the weight setting unit 110 md Then, the second weighted sum multiplier unit 102 adds the multiplied value W md ·θ mdac As the manual steering angle command value θ subjected to the first weighted sum multiplication mdac ' is supplied to the reaction combined angle command value calculation unit 44. In the case where the hands-on / hands-off determination unit 42 determines that the driver is holding the steering wheel 2, the switching unit 43 sets the automatic steering angle command value θ set by the main ECU 201A to adac As the reaction automatic steering angle command value θ rtac is supplied to the third weighted sum multiplier unit 103. On the other hand, in the case where the hands-on / hands-off determination unit 42 determines that the driver is not holding the steering wheel 2, the switching unit 43 sets zero as the reaction automatic steering angle command value θ rtac Provided to the third weighted sum multiplier unit 103.

[0090] The third weighted sum multiplier unit 103 converts the reaction automatic steering angle command value θ rtac Multiplied by the second weight W set by the weight setting unit 110 ad Then, the third weighted sum multiplier unit 103 adds the multiplied value W ad ·θ rtac As the reaction automatic steering angle command value θ subjected to the second weighted sum multiplication rtac 'Provided to the reaction combination angle command value calculation unit 44. The second weight W ad has a value equal to or greater than 0 and equal to or less than 1. The reaction combined angle command value calculation unit 44 performs the second weighted sum multiplication (=W ad ·θ rtac ) of the reaction automatic steering angle command value θ rtac ' and the first weighted sum multiplication (=W md ·θ mdac ) manual steering angle command value θ mdac 'Add to calculate the reaction combined angle command value θ rcmd .

[0091] The reaction angle control unit 45 is based on the reaction combined angle command value θ rcmd The reaction angle control unit 45 is configured similarly to the reaction angle control unit 45 according to the first embodiment (see Figure 6 ) are the same, so the description thereof is omitted. The following will describe the rotation ECU 203A. Figure 10 The rotation ECU 203A according to the second embodiment differs from the rotation ECU 203 according to the first embodiment in the configuration of the plurality of functional processing units of the microcomputer 80. The plurality of functional processing units include a rotation combined angle command value calculation unit 81, a rotation angle control unit 82, a fourth weighted sum multiplier unit 104, and a weight setting unit 110. The rotation angle control unit 82 is an example of the "rotation angle control unit" of the present invention.

[0092] The fourth weighted sum multiplier unit 104 converts the automatic steering angle command value θ adac Multiplied by the second weight W set by the weight setting unit 110 ad Then, the fourth weighted sum multiplier unit 104 adds the multiplied value W ad ·θ adac As the automatic steering angle command value θ subjected to the second weighted sum multiplication adac ' is supplied to the rotational combination angle command value calculation unit 81. The rotational combination angle command value calculation unit 81 subjects the value supplied from the second weighted sum multiplier unit 102 of the reaction ECU 202 to the first weighted sum multiplication (=W md ·θ mdac ) manual steering angle command value θ mdac ' and the second weighted sum multiplication (=W supplied from the fourth weighted sum multiplier unit 104 ad ·θ adac ) of the automatic steering angle command value θ adac 'Add to calculate the rotation combined angle command value θ scmd .

[0093] The rotation angle control unit 82 is based on the rotation combined angle command value θ scmd The configuration of the rotation angle control unit 82 is similar to that of the rotation angle control unit 82 according to the first embodiment (see Figure 7 ) are the same, so the description thereof is omitted. In this embodiment, the first weighting and multiplier unit 101, the second weighting and multiplier unit 102 and the weight setting unit 110 are examples of the “first weighting unit” or the “third weighting unit” in the present invention, and the third weighting and multiplier unit 103, the fourth weighting and multiplier unit 104 and the weight setting unit 110 are examples of the “second weighting unit” or the “fourth weighting unit” in the present invention. The weight setting unit 110 will be described below. The weight setting unit 110 is based on the mode setting signals S1, S2, S3 provided from the main ECU 201A, the manual steering request TOR, the driver's alertness α and the steering torque T detected by the torque sensor 11.d To set the first weight W md and the second weight W ad .exist Figure 10 In the configuration shown, the mode setting signals S1, S2 and S3, the manual steering request TOR, the driver's alertness α and the steering torque T d It is an example of “predetermined first information”, “predetermined second information”, “predetermined third information” or “predetermined fourth information” in the present invention.

[0094] Automatic steering mode is in the first weight W md is 0 and the second weight W ad When the steering mode is greater than 0, it is based only on the automatic steering angle command value θ adac To control the steering mode of the rotation motor 19. The manual steering mode is in the first weight W md Greater than 0 and the second weight W ad The steering mode is 0 and is based only on the manual steering angle command value θ mdac To control the steering mode of the rotary motor 19. The cooperative steering mode is in the first weight W md Greater than 0 and the second weight W ad The steering mode is greater than 0 and is based on considering the automatic steering angle command value θ adac and the manual steering angle command value θ mdac The combined rotation angle command value (cooperative steering command value) θ calculated by the two scmd To control the steering mode of the rotary motor 19.

[0095] The weight setting unit 110 includes a first setting unit 111 and a second setting unit 112. The first setting unit 111 sets the first weight W based on the mode setting signals S1, S2, S3 supplied from the main ECU 201A. md and the second weight W ad The first setting unit 111 is an example of a “switching unit” in the present invention. The second setting unit 112 sets the steering torque T detected by the torque sensor 11 based on the manual steering request TOR supplied from the main ECU 201A and the driver's alertness α. d To set the first weight W md and the second weight W ad The first setting unit 111 will be described below. When the cooperative steering mode setting signal S1 is input, the first setting unit 111 sets the first weight W md and the second weight W ad When the automatic steering mode setting signal S2 is input, the first setting unit 111 sets the first weight W md Set to 0, and the second weight W adWhen the manual steering mode setting signal S3 is input, the first setting unit 111 sets the first weight W md Set to 1, the second weight W ad Set to 0.

[0096] The first setting unit 111 can be configured to set the first weight W md Gradually increase the first weight W when changing from 0 to 1 md , and in the first weight W md Gradually reduce the first weight W when changing from 1 to 0 md Similarly, the first setting unit 111 can set the second weight W ad Gradually increase the second weight W when changing from 0 to 1 ad , and in the second weight W ad Gradually reduce the second weight W when changing from 1 to 0 ad The second setting unit 112 will be described below. Figure 11 An outline of the operation of the second setting unit 112 is described. In the following description, the manual steering request TOR is also referred to as TOR for short.

[0097] exist Figure 11 In the example, the area E1 represents a portion of the autonomous driving possible area, and the area E2 represents a portion of the autonomous driving impossible area. Figure 11 When driving on the right side of the vehicle, the boundary B between area E1 and area E2 is the point where "the steering mode is switched to the manual steering mode under the control of the automatic steering mode" occurs (hereinafter referred to as the "predetermined manual steering switching point B").

[0098] When the main ECU 201A detects that the vehicle 200 is approaching the predetermined manual steering switching point B based on the information acquired from the CCD camera 25, the GPS 26, and the radar 27 and the map information, it generates a TOR at a point a first predetermined time T1 or a first predetermined distance L1 before the vehicle 200 reaches the predetermined manual steering switching point B. In this example, the TOR is generated when the vehicle 200 reaches the predetermined manual steering switching point B. Figure 11 At point A in FIG, the main ECU 201A generates TOR.

[0099] Upon receiving the TOR, the second setting unit 112 basically sets the first weight W mdis set to 1. Thus, the steering mode is switched from the automatic steering mode to the cooperative steering mode. In the case where the driver's steering (i.e., steering performed by the driver) is detected at or before a second predetermined time T2 or a second predetermined distance L2 before the vehicle 200 reaches the predetermined manual steering switching point B and then the vehicle 200 reaches the predetermined manual steering switching point B, the second setting unit 112 sets the second weight W ad is set to 0. Thus, the steering mode is switched from the cooperative steering mode to the manual steering mode. In this case, for example, the vehicle 200 moves along Figure 11 Travel along the route indicated by the solid line R1.

[0100] A point a second predetermined time T2 or a second predetermined distance L2 before the point at which the vehicle reaches the predetermined manual steering switching point B is shown as Figure 11 In the following description, a time period required after the vehicle 200 reaches point A until the vehicle 200 reaches point C is defined as a third predetermined time T3, and a distance from point A to point C is defined as a third predetermined distance L3. On the other hand, in a case where the driver's steering is not detected at or before the second predetermined time T2 or the second predetermined distance L2 before the vehicle 200 reaches the predetermined manual steering switching point B, the second setting unit 112 sets the automatic stop request S stop Sent to the main ECU 201A. Upon receiving the automatic stop request S stop When the main ECU 201A calculates a route along which the vehicle 200 moves and stops at a road shoulder or the like, and generates an automatic steering angle command value θ for automatically steering the vehicle 200 along the route. adac In this case, the vehicle 200 is traveling along Figure 11 The vehicle travels and stops along the route indicated by the dotted line R2.

[0101] In this embodiment, upon receiving the TOR, the second setting unit 112 monitors the driver's alertness α transmitted from the main ECU 201A, and maintains the first weight W after receiving the TOR. md is 0 until the driver's alertness α becomes equal to or greater than a predetermined first threshold α th1 The driver's alertness α becomes equal to or greater than the first threshold α at or before a second predetermined time T2 or a second predetermined distance L2 before the vehicle 200 reaches the predetermined manual steering switching point B. th1 When the second setting unit 112 sets the first weight W md Set to 1. This switches the steering mode from autonomous steering mode to cooperative steering mode.

[0102] On the other hand, the driver's alertness α does not become equal to or greater than the first threshold α at or before the second predetermined time T2 or the second predetermined distance L2 before the vehicle 200 reaches the predetermined manual steering switching point B. th1 When the second setting unit 112 automatically stops requesting S stop In this case, as described above, the vehicle 200 automatically turns so that the vehicle moves and stops at a road shoulder or the like.

[0103] Figure 12 2 is a flowchart showing an example of a routine of the weight setting process executed by the second setting unit 112. In the case where the TOR is received from the main ECU 201A (step S1: YES), the second setting unit 112 determines whether the driver's alertness α sent from the main ECU 201A is equal to or greater than a predetermined first threshold α. th1 (Step S2).

[0104] When the driver's alertness α is equal to or greater than the first threshold α th1 In the case of (step S2: yes), the second setting unit 112 determines that the driver can drive normally, and sets the first weight W md Set to 1 (step S3). Thus, the steering mode is switched from the automatic steering mode to the cooperative steering mode. In this embodiment, the first threshold α th1 Corresponding to the “predetermined threshold” in the present invention.

[0105] Next, the second setting unit 112 determines whether the driver has operated the steering wheel (step S4). In this embodiment, for example, whether the driver has operated the steering wheel is determined based on the temporal change in the steering torque Td detected by the torque sensor 11. Another method may be used to determine whether the driver has operated the steering wheel. If it is determined that the driver has operated the steering wheel (step S4: Yes), the second setting unit 112 determines whether a first predetermined time T1 has elapsed after receiving the TOR in step S1 (step S5).

[0106] When the first predetermined time T1 has not passed after receiving the TOR (step S5: No), the second setting unit 112 returns the routine to step S2. When it is determined in step S5 that the first predetermined time T1 has passed after receiving the TOR (step S5: Yes), the second setting unit 112 sets the second weight W ad The weight setting process is then ended by the second setting unit 112. Thus, the steering mode is switched from the cooperative steering mode to the manual steering mode.

[0107] If it is determined in step S4 that the driver has not operated the steering wheel (step S4: No), the second setting unit 112 determines whether a third predetermined time T3 has elapsed after receiving the TOR in step S1 (step S7). In other words, the second setting unit 112 determines whether the current time is the second predetermined time T2 before the time when the vehicle reaches the predetermined manual steering switching point B (i.e., whether the second predetermined time T2 before the time when the vehicle reaches the predetermined manual steering switching point B has already been reached).

[0108] When the third predetermined time T3 has not passed after receiving the TOR (step S7: No), the second setting unit 112 returns the routine to step S4. When it is determined in step S7 that the third predetermined time T3 has passed after receiving the TOR (step S7: Yes), the second setting unit 112 automatically stops the request S stop This is sent to the main ECU 201A (step S8), and then the weight setting process is ended. In this case, as described above, the vehicle 200 automatically turns so that the vehicle 200 moves and stops at the road shoulder.

[0109] When it is determined in step S2 that the driver's alertness α is less than the first threshold α th1 In the case of (step S2: No), the second setting unit 112 determines that the driver cannot drive normally, and sets the first weight W md is set to zero (step S9). Then, the second setting unit 112 determines whether a third predetermined time T3 has elapsed after the TOR is received in step S1 (step S10).

[0110] When the third predetermined time T3 has not elapsed after receiving the TOR (step S10: No), the second setting unit 112 returns the routine to step S2. When it is determined in step S10 that the third predetermined time T3 has elapsed after receiving the TOR (step S10: Yes), the second setting unit 112 notifies the main ECU 201A of the automatic stop request S3. stop (Step S8), and then the weight setting process is ended. Thus, as described above, the vehicle is guided by the automatic steering and stops at the road shoulder or the like.

[0111] exist Figure 12 In the weight setting process shown, the driver's alertness α is equal to or greater than the first threshold α at or before a point where the third predetermined time T3 has passed after the second setting unit 112 has received the TOR. th1Under certain conditions, the steering mode switches from automatic steering mode to cooperative steering mode. Therefore, manual steering can be performed simultaneously with automatic steering. Thus, the driver can prepare for manual driving before switching the steering mode to manual steering mode at a predetermined manual steering switching point B.

[0112] On the other hand, since the driver's alertness α becomes equal to or greater than the first threshold α after receiving the TOR th1 Only automatic steering is possible before, so when the driver cannot drive normally, can forbid to carry out manual steering.When passing the 3rd predetermined time T3 under the state that the driver cannot drive normally, can guide and stop the vehicle in safe position by automatic steering.

[0113] The driver's alertness α becomes equal to or greater than the first threshold α at or before a point where a third predetermined time T3 has passed after receiving the TOR. th1 However, in the case where the driver's steering is not detected at or before a point where the third predetermined time T3 has elapsed after the TOR is received, the vehicle can be guided and stopped at a safe position by automatic steering. Figure 12 The process of step S2, step S9 and step S10 in the above method can be omitted. Figure 12 In the case where a TOR is received in step S1 of the routine, the second setting unit 112 causes the routine to proceed to step S3. In this case, when a TOR is received, the steering mode is unconditionally set to the cooperative steering mode.

[0114] Figure 13 2 is a flowchart showing a modified example of the weight setting process performed by the second setting unit 112. In the case where TOR is received from the main ECU 201A (step S21: YES), the second setting unit 112 sets the first weight W based on the driver's alertness α sent from the main ECU 201A. md (Step S22).

[0115] The second setting unit 112 sets the first weight W md , so that the first weight W md As the alertness α increases, the second setting unit 112 may set the alertness α to the first weight W md Or it can be based on a predetermined relational expression W md =F(α) to set the first weight W md When the first weight W is set in step S22 md When the first weight W is greater than 0, the steering mode is set to cooperative steering mode. md The minimum value of the alertness α when it is greater than 0 is defined as the second threshold α th2When the second threshold value α in this modified example is th2 Corresponding to the “predetermined threshold” in the present invention.

[0116] The first weight W set in step S22 can be md The minimum value of is set to a predetermined value greater than 0 and less than 1. In this case, when TOR is received, the steering mode is unconditionally set to the cooperative steering mode. Then, the second setting unit 112 determines whether the driver has operated the steering wheel (step S23). In this embodiment, based on the steering torque T detected by the torque sensor 11, d The time change of θ is used to determine whether the driver has operated the steering wheel.

[0117] In the case where it is determined that the driver has operated the steering wheel (step S23: YES), the second setting unit 112 determines whether the first predetermined time T1 has passed after receiving the TOR in step S21 (step S24). In the case where the first predetermined time T1 has not passed after receiving the TOR (step S24: NO), the second setting unit 112 returns the routine to step S22. Therefore, the first weight W is reset based on the driver's alertness α. md , and then execute the processing of step S23 and subsequent steps again.

[0118] In the case where it is determined in step S24 that the first predetermined time T1 has elapsed after the TOR is received (step S24: YES), the second setting unit 112 sets the second weight W ad is set to zero (step S25). Then, the second setting unit 112 ends the weight setting process. Thus, the steering mode is switched from the collaborative steering mode to the manual steering mode. When it is determined in step S23 that the driver has not operated the steering wheel (step S23: No), the second setting unit 112 determines whether a third predetermined time T3 has passed after receiving the TOR in step S21 (step S26). In other words, the second setting unit 112 determines whether the current time point is a time point of the second predetermined time T2 before the time point when the vehicle reaches the predetermined manual steering switching point B (that is, whether the time point of the second predetermined time T2 before the time point when the vehicle reaches the predetermined manual steering switching point B has been reached).

[0119] In the case that the third predetermined time T3 has not elapsed after receiving the TOR (step S26: NO), the second setting unit 112 returns the routine to step S22. Therefore, the first weight W is reset based on the driver's alertness α. md , and then the processing of step S23 and the subsequent steps are executed again. When it is determined in step S26 that the third predetermined time T3 has passed after receiving the TOR (step S26: YES), the second setting unit 112 automatically stops the request Sstop This is sent to the main ECU 201A (step S27), and the weight setting process is ended. In this case, as described above, the vehicle 200 moves by automatic steering and stops at a road shoulder or the like.

[0120] exist Figure 13 In the weight setting process shown, when the second setting unit 112 receives TOR, the first weight W is set based on the driver's alertness α sent from the main ECU 201. md Then, in the first weight W md When the alertness α is greater than 0 (when the alertness α is equal to or greater than the second threshold α th2 (When the steering mode is set to the cooperative steering mode.) Therefore, manual steering can be performed while the automatic steering is being performed. Therefore, similar to the above embodiment, the driver can prepare for manual driving before switching the steering mode to the manual steering mode at the predetermined manual steering switching point B.

[0121] In this modified example, when the driver's alertness α is relatively low, the first weight W md is set to a relatively small value, and thus the manual steering-to-rotation combined angle command value (cooperative steering command value) θ can be reduced. scmd On the other hand, when the driver's alertness α is relatively high, the first weight W md is set to a relatively large value, and thus the manual steering-to-rotation combined angle command value (cooperative steering command value) θ can be increased. scmd Therefore, in this modified example, cooperative steering suitable for the driver's alertness α can be performed.

[0122] In this modified example, when the driver's steering is not detected at or before a point at which the third predetermined time T3 has elapsed after the TOR is received, the vehicle can be guided and stopped at a safe position by automatic steering.

[0123] Other Modification Examples of the Second Embodiment

[0124] exist Figure 12 Step S5 and Figure 13 In step S24, the second setting unit 112 determines whether the first predetermined time T1 has passed after receiving the TOR, but may determine whether the vehicle has reached the predetermined manual steering switching point B (see Figure 11 ).

[0125] exist Figure 12 Steps S7 and S10 and Figure 13In step S26, the second setting unit 112 determines whether the third predetermined time T3 has passed after the TOR is received, that is, whether the current time point is the time point of the second predetermined time T2 before the time point when the vehicle reaches the predetermined manual steering switching point B (that is, whether the time point of the second predetermined time T2 before the time point when the vehicle reaches the predetermined manual steering switching point B has been reached). However, the second setting unit 112 may determine whether the vehicle has already reached the vehicle position A (see Figure 11 ) after the third predetermined distance L3 point C (ie, whether the vehicle has reached the predetermined manual steering switching point B before the second predetermined distance L2 point).

[0126] In the second embodiment, the first to fourth weighted sum multiplier units 101, 102, 103, and 104 are provided. However, a configuration may be employed in which the first weighted sum multiplier unit 101, the third weighted sum multiplier unit 103, and the fourth weighted sum multiplier unit 104 are provided, and the second weighted sum multiplier unit 102 is omitted. Alternatively, a configuration may be employed in which the second weighted sum multiplier unit 102, the third weighted sum multiplier unit 103, and the fourth weighted sum multiplier unit 104 are provided, and the first weighted sum multiplier unit 101 is omitted.

[0127] In the former configuration, the first weighting and multiplier unit 101 and the weight setting unit 110 are examples of the "first weighting unit" or "third weighting unit" in the present invention. In the latter configuration, the second weighting and multiplier unit 102 and the weight setting unit 110 are examples of the "first weighting unit" or "third weighting unit" in the present invention. In the second embodiment, although the weight setting unit 110 is provided in the steering ECU 203A, the weight setting unit 110 may also be provided in the reaction ECU 202A. Although the first and second embodiments of the present invention have been described above, the present invention may be implemented in other forms.

[0128] In the first and second embodiments, the same automatic steering angle command value θ adac The main ECU 201 or the main ECU 201A is provided to the reaction ECU 202 or the reaction ECU 202A and the rotation ECU 203 or the rotation ECU 203A. However, the main ECU 201 or the main ECU 201A can separately set the automatic steering angle command value for the reaction motor 13 and the automatic steering angle command value for the rotation motor 19, and provide the set automatic steering angle command values ​​to the corresponding reaction ECU 202 or the reaction ECU 202A and the rotation ECU 203 or the rotation ECU 203A.

[0129] The present invention can also be applied to, for example, a steer-by-wire system employing a four-wheel steering system in which the front and rear wheels rotate independently. In this case, two rotation ECUs are provided for the front and rear wheels. The present invention can also be applied to a steer-by-wire system employing a four-wheel independent steering system in which the four wheels rotate independently. In this case, a rotation ECU is provided for each wheel.

[0130] Various modifications may be made to the above-described embodiments without departing from the scope of the present invention.

Claims

1. A steering system, characterized in that: include: Steering components; a rotating mechanism (4) mechanically decoupled from the steering member; a reaction motor (13) configured to apply a reaction torque to the steering member; a rotary motor (19) configured to drive the rotary mechanism (4); a steering torque detection unit configured to detect a steering torque applied to the steering member; as well as a control unit configured to control the driving of the reaction motor (13) and the rotation motor (19), Wherein, the control unit includes: a manual steering angle command value setting unit configured to set a manual steering angle command value based on the steering torque; a first weighting unit configured to perform weighting processing on the manual steering angle command value according to predetermined first information; a reaction combined angle command value calculation unit configured to calculate a reaction combined angle command value based on a reaction automatic steering angle command value and the manual steering angle command value weighted by the first weighting unit; a rotational combined angle command value calculation unit configured to calculate a rotational combined angle command value based on a rotational automatic steering angle command value and the manual steering angle command value weighted by the first weighting unit; a reaction force control unit configured to make the rotation angle of the reaction motor (13) consistent with the reaction combined angle command value; and A rotation angle control unit is configured to make the rotation angle of the rotation motor (19) consistent with the rotation combined angle command value.

2. The steering system according to claim 1, characterized in that Also includes: A switching unit is configured to switch the control mode of the reaction motor (13) and the rotary motor (19) to a manual steering mode based on a driver's operation.

3. A steering system, characterized in that: include: Steering components; a rotating mechanism (4) mechanically decoupled from the steering member; a reaction motor (13) configured to apply a reaction torque to the steering member; a rotary motor (19) configured to drive the rotary mechanism (4); a steering torque detection unit configured to detect a steering torque applied to the steering member; as well as a control unit configured to control the driving of the reaction motor (13) and the rotation motor (19), Wherein, the control unit includes: a manual steering angle command value setting unit configured to set a manual steering angle command value based on the steering torque; a second weighting unit configured to perform weighting processing on the reaction automatic steering angle command value and the rotational automatic steering angle command value according to predetermined second information; a reaction combined angle command value calculation unit configured to calculate a reaction combined angle command value based on the manual steering angle command value and the reaction automatic steering angle command value weighted by the second weighting unit; a rotational combined angle command value calculation unit configured to calculate a rotational combined angle command value based on the manual steering angle command value and the rotational automatic steering angle command value weighted by the second weighting unit; a reaction force control unit configured to make the rotation angle of the reaction motor (13) consistent with the reaction combined angle command value; and A rotation angle control unit is configured to make the rotation angle of the rotation motor (19) consistent with the rotation combined angle command value.

4. The steering system according to claim 3, characterized in that: Also includes: A switching unit is configured to switch the control mode of the reaction motor (13) and the rotary motor (19) to a manual steering mode based on a driver's operation.

5. A steering system, characterized in that: include: Steering components; a rotating mechanism (4) mechanically decoupled from the steering member; a reaction motor (13) configured to apply a reaction torque to the steering member; a rotary motor (19) configured to drive the rotary mechanism (4); a steering torque detection unit configured to detect a steering torque applied to the steering member; as well as a control unit configured to control the driving of the reaction motor (13) and the rotation motor (19), Wherein, the control unit includes: a manual steering angle command value setting unit configured to set a manual steering angle command value based on the steering torque; a third weighting unit configured to perform weighting processing on the manual steering angle command value according to predetermined third information, a fourth weighting unit configured to perform weighting processing on the reaction automatic steering angle command value and the rotational automatic steering angle command value according to predetermined fourth information, a reaction combined angle command value calculation unit configured to calculate a reaction combined angle command value based on the manual steering angle command value weighted by the third weighting unit and the reaction automatic steering angle command value weighted by the fourth weighting unit; a rotational combined angle command value calculation unit configured to calculate a rotational combined angle command value based on the manual steering angle command value weighted by the third weighting unit and the rotational automatic steering angle command value weighted by the fourth weighting unit; a reaction force control unit configured to make the rotation angle of the reaction motor (13) consistent with the reaction combined angle command value; and A rotation angle control unit is configured to make the rotation angle of the rotation motor (19) consistent with the rotation combined angle command value.

6. The steering system according to claim 5, characterized in that: The control unit comprises: an automatic steering mode in which the reaction motor (13) and the rotation motor (19) are controlled based on the reaction automatic steering angle command value and the rotation automatic steering angle command value; a manual steering mode in which the reaction motor (13) and the rotary motor (19) are controlled based on the manual steering angle command value; and a cooperative steering mode in which the reaction motor (13) and the rotation motor (19) are controlled based on the reaction automatic steering angle command value and the manual steering angle command value and a cooperative steering command value, the cooperative steering command value being the rotation combined angle command value calculated in consideration of the rotation automatic steering angle command value and the manual steering angle command value; and The control unit is configured to control the reaction motor (13) and the rotary motor (19) in the cooperative steering mode unconditionally or when a predetermined condition is satisfied, when a condition is detected during control in the automatic steering mode in which the automatic steering mode is to be switched to the manual steering mode and a manual steering request is output to the driver at a point a first predetermined time or a first predetermined distance before the point in which the condition is reached.

7. The steering system according to claim 6, characterized in that The control unit is configured to, when the manual steering request is output to the driver, weight the manual steering angle command value based on the driver's alertness using the third weighting unit, and control the reaction motor (13) and the rotary motor (19) in the cooperative steering mode using the weighted manual steering angle command value.

8. The steering system according to claim 6, characterized in that The predetermined condition is a condition that the driver's alertness is equal to or greater than a predetermined threshold.

9. The steering system according to claim 6, characterized in that: The control unit is configured to, after the manual steering request has been output, output an automatic stop request for generating an automatic steering angle command value for causing the vehicle to move and stop at a predetermined stop position when no steering performed by the driver is detected at or before a point a second predetermined time or a second predetermined distance before the point at which the condition is reached.

10. The steering system according to any one of claims 5 to 9, characterized in that Also includes: A switching unit is configured to switch the control mode of the reaction motor (13) and the rotary motor (19) to a manual steering mode based on a driver's operation.

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