Steering control device and steering control method

Abstract

The invention relates to a steering control device and a steering control method. A steering control device (40) executes an input dependent variable calculation process, a coordination process, an operation process, a target value setting process, and a reflection process. The input dependent variable calculation process is a process for calculating a value of an input dependent variable in accordance with an intention of a driver for steering. The coordination process is a process in which the value of the input dependent variable and the external request value are input and the value of the target steering angle variable is output. The operation process is a process in which the value of the target steering angle variable is input and the actuator is operated. The target value setting process is a process in which the value of the target steering angle variable output by the coordination process is input and the target yaw rate is output. The reflection process is a process for reflecting an operation amount of feedback control in which a target yaw rate is a target value of the control amount to a steering angle operation performed by the operation process.

Description

Technical Field

[0001] This invention relates to a steering control device and a steering control method. Background Technology

[0002] Patent Document 1 describes a device for suppressing the deviation of a vehicle's driving direction based on the difference between a standard yaw rate corresponding to the steering wheel angle and a detected value of the yaw rate.

[0003] Patent Document 2 describes a device for controlling a motor that steers the steering wheels based on a coordinated steering command value that takes into account both the manual steering command value corresponding to the steering operation performed by the driver and the automatic steering command value.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2021-14221

[0005] Patent Document 2: Japanese Patent Application Publication No. 2020-168918

[0006] As mentioned above, when the steering wheels are turned based on the coordinated steering control command value, there is a concern that the deviation in the driving direction cannot be adequately suppressed when using the standard yaw rate set according to the steering control angle. Summary of the Invention

[0007] In one embodiment of the present invention, a steering control device is provided. The steering control device is configured to perform input-dependent variable calculation processing, coordination processing, operation processing, target value setting processing, and response processing. The input-dependent variable calculation processing is a process that calculates the value of an input-dependent variable based on the steering intention expressed by the driver's operation of an input unit. The input-dependent variable is a variable representing the steering angle of the vehicle's steering wheels corresponding to the steering intention. The coordination processing is a process that takes the value of the input-dependent variable and an external request value as input and outputs the value of a target steering angle variable. The target steering angle variable is a target value for the steering angle. The external request value is a variable representing a requested value for the steering angle, independent of the steering intention. The operation processing is a process that takes the value of the target steering angle variable as input and operates an actuator. The actuator is configured to apply power to the steering wheels to steer them. The target value setting processing is a process that takes the value of the target steering angle variable output from the coordination processing as input and outputs a target yaw rate. The above-mentioned feedback processing is a process that reflects the operation quantity of the feedback control, whereby the yaw rate is the control quantity and the target yaw rate is the target value of the control quantity, to the operation of the steering angle performed by the above-mentioned operation processing. It is a process that is performed when at least the value obtained by substituting the value obtained by overlapping the value of the above-mentioned input dependent variable with the value of the above-mentioned external request value into the target steering angle variable output by the above-mentioned coordination processing.

[0008] In other embodiments of the present invention, a steering control method is provided. The steering control method includes steps of performing input-dependent variable calculation processing, coordination processing, operation processing, target value setting processing, and response processing. The input-dependent variable calculation processing is a process of calculating the value of an input-dependent variable based on the steering intention expressed by the driver's operation of an input unit. The input-dependent variable is a variable representing the steering angle of the vehicle's steering wheels corresponding to the steering intention. The coordination processing is a process of taking the value of the input-dependent variable and an external request value as input and outputting the value of a target steering angle variable. The target steering angle variable is a target value for the steering angle. The external request value is a variable representing a requested value for the steering angle, independent of the steering intention. The operation processing is a process of taking the value of the target steering angle variable as input and operating an actuator. The actuator is configured to apply power to the steering wheels to steer them. The target value setting processing is a process of taking the value of the target steering angle variable output from the coordination processing as input and outputting a target yaw rate. The above-mentioned feedback processing is a process that reflects the operation quantity of the feedback control, whereby the yaw rate is the control quantity and the target yaw rate is the target value of the control quantity, to the operation of the steering angle performed by the above-mentioned operation processing. It is a process that is performed when at least the value obtained by substituting the value obtained by overlapping the value of the above-mentioned input dependent variable with the value of the above-mentioned external request value into the target steering angle variable output by the above-mentioned coordination processing. Attached Figure Description

[0009] Figure 1 This is a diagram showing the structure of the steering control system according to the first embodiment.

[0010] Figure 2 It means Figure 1 A block diagram of the processes performed by the steering control device in the system.

[0011] Figure 3 This is a diagram showing the structure of the steering control system according to the second embodiment.

[0012] Figure 4 It means Figure 3 A block diagram of the processes performed by the steering control device in the system.

[0013] Figure 5 This is a block diagram illustrating the processing performed by the steering control device in the third embodiment. Detailed Implementation

[0014] <First Implementation>

[0015] The first embodiment will now be described with reference to the accompanying drawings.

[0016] "Prerequisite Structure"

[0017] like Figure 1 As shown, the steering control device 10 includes a steering wheel 12. The steering wheel 12 is an input unit for the driver to input steering intentions. The steering wheel 12 is connected to a transmission shaft 14. Therefore, if the steering wheel 12 rotates, the transmission shaft 14 rotates as a unit. The rotational power of the transmission shaft 14 is transmitted to the steering shaft 16. The steering shaft 16 runs along the vehicle width direction (…). Figure 1 It extends in the left and right direction. Steering wheels 20 are connected to both ends of the steering shaft 16 via steering tie rods 18.

[0018] The transmission shaft 14 is configured to intersect with the steering shaft 16. Meshing teeth are formed on both the transmission shaft 14 and the steering shaft 16. Furthermore, through the meshing of these teeth, power can be transmitted from the transmission shaft 14 to the steering shaft 16. That is, the rotational power of the transmission shaft 14 is converted into axial displacement power towards the steering shaft 16. This axial displacement towards the steering shaft 16 is transmitted to the steering wheel 20 via the steering tie rod 18. As a result, the steering angle of the steering wheel 20 is changed. Furthermore, the steering angle is the rotation angle of the tire.

[0019] Additionally, the steering control device 10 includes an auxiliary motor 30. The auxiliary motor 30 generates a force, or auxiliary force, to assist steering operations performed by the driver. The rotational power of the auxiliary motor 30 is applied to the drive shaft 34. Meshing teeth are formed on the drive shaft 34 and the steering shaft 16. Furthermore, through the meshing of these teeth, power can be transmitted from the drive shaft 34 to the steering shaft 16. That is, the rotational power of the drive shaft 34 is converted into axial displacement power towards the steering shaft 16. Thus, the rotational power of the auxiliary motor 30 is converted into axial displacement power towards the steering shaft 16 via the drive shaft 34. Specifically, the auxiliary motor 30, as an example, is a three-phase brushless motor. Furthermore, the output voltage of the inverter 32 is applied to the terminals of the auxiliary motor 30.

[0020] The steering control device 40 controls the control quantity of the steering control device 10, which is the controlled object. To control the control quantity, the steering control device 40 refers to the steering torque Th input to the steering wheel 12. The steering torque Th is detected by the torque sensor 50. The torque sensor 50 is a sensor that detects the steering torque Th based on the degree of torsion of the torsion bar 52, which is part of the transmission shaft 14. Additionally, the steering control device 40 refers to the vehicle speed V detected by the vehicle speed sensor 54. Furthermore, the steering control device 40 refers to the rotation angle θa of the auxiliary motor 30 detected by the rotation angle sensor 56. Finally, the steering control device 40 refers to the currents iu, iv, and iw flowing in the auxiliary motor 30.

[0021] The steering control device 40 includes a PU 42 and a storage device 44. The PU 42 is a software processing device such as a CPU, GPU, or TPU. The storage device 44 includes an electrically erasable and rewritable non-volatile memory or a disk medium. The steering control program 44a is stored in the storage device 44. The steering control device 40 executes the steering control program 44a stored in the storage device 44 through the PU 42 to control the control quantities.

[0022] The steering control unit 40 can communicate with the ADASECU 70. The ADASECU 70 performs steering assistance processing based on objects outside the vehicle. The ADASECU 70 obtains information about objects outside the vehicle by acquiring image data Do, which represents an image of the area in front of the vehicle, captured by the camera 80. Here, objects outside the vehicle are not limited to vehicles in front, guardrails, or other objects above the road surface, but also include white lines, etc. The ADASECU 70 determines whether to perform assistance processing based on whether steering assistance is required, as indicated by input operations to the user interface 82.

[0023] ADASECU70 includes PU72 and storage device 74. PU72 executes the auxiliary program 74a stored in storage device 74 to perform auxiliary steering control processing.

[0024] "Processing performed by the steering control device 40"

[0025] exist Figure 2 The diagram shows the processing performed by the steering control device 40. Figure 2 The processing shown is achieved by PU42 executing steering control program 44a, for example, at a predetermined cycle.

[0026] The target steering torque setting process M10 calculates the target value of the steering torque Th, i.e., the target steering torque Th*, based on the axial force Taf. The axial force Taf is the force applied to the steering shaft 16. However, the axial force Taf is converted into the torque transmitted to the shaft 14. Furthermore, the target steering torque setting process M10 includes a process that sets the target steering torque Th* to a different value based on the vehicle speed V, even if the axial force Taf is the same. This setting aims to provide the driver with the optimal steering feel corresponding to the vehicle speed V.

[0027] The steering operation quantity calculation process M12 is a process that calculates the steering operation quantity Ts*, which is the control quantity of the steering torque Th. The steering operation quantity calculation process M12 includes a process that calculates the steering torque Th as the control quantity and the target steering torque Th* as the target value of the control quantity, i.e., a feedback control operation quantity, and calculates the steering operation quantity Ts* based on this operation quantity. The steering operation quantity calculation process M12 can also include a process that further includes a process that calculates the target steering torque Th* as the target value of the control quantity, i.e., an open-loop control operation quantity, and calculates the steering operation quantity Ts* based on this operation quantity. The operation quantity used for feedback control, for example, when both the steering torque Th and the target steering torque Th* are positive, and when the steering torque Th is greater than the target steering torque Th*, becomes the amount used to increase the absolute value of the requested torque for the auxiliary motor 30. Furthermore, the steering operation quantity Ts*, as an example, becomes the amount converted into the torque applied to the transmission shaft 14.

[0028] The axial force calculation process M14 calculates the axial force Taf by adding the steering torque Th to the steering operation amount Ts*. Furthermore, the steering torque Th is the torque applied to the transmission shaft 14, so in this embodiment, the axial force Taf is the value of converting the force applied axially along the steering shaft 16 into the torque applied to the transmission shaft 14.

[0029] The standard model operation processing M16 is a process that takes the axial force Taf as input and outputs the target value of the steering equivalent angle θp, i.e., the target steering equivalent angle θp0*. Specifically, the standard model operation processing M16 uses a formula that replaces the steering equivalent angle θp in the model expression expressed by the following formula (c1) with the target steering equivalent angle θp0* and outputs the target steering equivalent angle θp0*.

[0030]

[0031] The model represented by the above formula (c1) is a model that models the value represented by the steering equivalent angle θp when a torque equal to the axial force Taf is input to the transmission shaft 14. The steering equivalent angle θp is a variable representing the steering angle of the steering wheel 20. The steering equivalent angle θp is positively correlated with the steering angle. The steering equivalent angle θp can also be, for example, the rotation angle of the transmission shaft 14.

[0032] In the above formula (c1), the viscosity coefficient C is a coefficient modeled after considering the friction of the steering control device 10. Additionally, the inertia coefficient J is a coefficient modeled after considering the inertia of the steering control device 10. Furthermore, the elasticity coefficient K is a coefficient modeled after considering the specifications of the suspension and wheel alignment of the vehicle on which the steering control device 10 is mounted. This model may not accurately represent the actual steering control device 10 or the vehicle on which it is mounted. This model can also be a standard model designed to set the behavior in response to an input steering angle as ideal behavior. When using a standard model, the steering feel can be adjusted through the design of the standard model.

[0033] The coordination process M18 is a process that takes the target steering equivalent angle θp0* as input and the auxiliary correction amount Δθp as output, and outputs the target steering equivalent angle θpa*. In the case of steering assistance processing performed by the ADASECU70, the auxiliary correction amount Δθp is a correction amount to the target steering equivalent angle θp0* output from the ADASECU70. The assistance processing can also be, for example, a process used to prevent the vehicle from leaving its lane. In this case, the auxiliary correction amount Δθp is an amount used to fine-tune the target steering equivalent angle θp0* for the purpose of preventing lane departure.

[0034] In detail, the coordination process M18 includes a gain multiplication process M18a and an addition process M18b. The gain multiplication process M18a outputs the value obtained by multiplying the auxiliary correction amount Δθp by the gain G. The addition process M18b substitutes the value obtained by multiplying the target steering equivalent angle θp0* by the gain G into the target steering equivalent angle θpa*. When the auxiliary process begins, PU72 increases the gain G from "0" towards "1". Conversely, when the auxiliary process ends, PU72 decreases the gain G from "1" towards "0".

[0035] The target yaw rate setting process M20 is a process that takes the target steering equivalent angle θpa* and vehicle speed V as inputs and the target yaw rate yr* as output. The target yaw rate yr* is the yaw rate yr assuming that the vehicle is traveling on a flat road surface unaffected by airflow, with the steering angle being the target steering equivalent angle θpa* and the vehicle speed being V.

[0036] PU42 aligns the sign of the target yaw rate yr* with the sign of the target steering equivalent angle θpa*. PU42 adjusts the target yaw rate yr* according to the vehicle speed V when the absolute value of the target yaw rate yr* at a high vehicle speed V is greater than or equal to the absolute value of the target yaw rate yr* at a low vehicle speed V. PU42 also adjusts the target yaw rate yr* according to the target steering equivalent angle θpa* when the absolute value of the target yaw rate yr* at a high vehicle speed V is greater than or equal to the absolute value of the target yaw rate yr* at a low vehicle speed V.

[0037] Furthermore, in the statement "satisfying the condition of setting B when A is large to B when A is hour and changing B according to A," "when A is large" and "when A is hour" refer to their relative size relationship when comparing the two. For example, "when A is large" corresponds to "when A is the first value," and "when A is small" corresponds to "when A is the second value, which is less than the first value." Moreover, the above statement means that, by setting the first value and the second value, B when A is the first value is greater than B when A is the second value.

[0038] Taking the target yaw rate setting process M20 as an example, it can also be a process in which the target yaw rate yr* is mapped by PU42 while the storage device 44 stores the mapping data. The mapping data is data in which the target steering equivalent angle θpa* and the vehicle speed V are input variables and the target yaw rate yr* is the output variable.

[0039] Furthermore, the mapping data is a set of discrete values ​​of input variables and corresponding values ​​of output variables. Additionally, the mapping operation can be performed by setting the value of the corresponding output variable of the mapping data as the result if any one of the input variable values ​​matches the input variable value of the mapping data. Alternatively, if none of the input variable values ​​match the input variable values ​​of the mapping data, the mapping operation can be performed by setting the result to the value obtained through interpolation of the multiple output variables contained in the mapping data. Alternatively, the mapping operation can also be performed by setting the result to the output variable of the mapping data corresponding to the most recent value among the multiple input variable values ​​contained in the mapping data, even if none of the input variable values ​​match the input variable values ​​of the mapping data.

[0040] Deviation calculation processing M22 is used to calculate the deviation between the target yaw rate yr* and the yaw rate yr.

[0041] The yaw rate feedback processing M24 is a process where the output value of the deviation calculation processing M22 is used as input and the yaw rate correction Δθc is used as output. The yaw rate correction Δθc is the operational variable of the feedback control, where the yaw rate yr is the control variable and the target yaw rate yr* is the target value of the control variable. The yaw rate correction Δθc can also be the output value of the proportional component corresponding to the output value of the deviation calculation processing M22. Alternatively, the yaw rate correction Δθc can be the sum of the output values ​​of the proportional component and the integral component corresponding to the output value of the deviation calculation processing M22. However, the feedback control used to calculate the yaw rate correction Δθc is not limited to classical control.

[0042] The target steering equivalent angle setting process M26 is to substitute the value obtained by adding the yaw rate correction amount Δθc to the target steering equivalent angle θpa* into the target steering equivalent angle θp*.

[0043] The steering angle calculation process M30 is a process that takes the rotation angle θa of the auxiliary motor 30 as input and the steering equivalent angle θp as output. The steering angle calculation process M30 includes a process of accumulating the rotation angle θa. In this accumulation process, the steering equivalent angle when the vehicle is moving forward is set to "0".

[0044] The angle operation quantity calculation process M32 is a process that takes the steering equivalent angle θp and the target steering equivalent angle θp* as inputs and the auxiliary torque Ta* as output. The auxiliary torque Ta* is the operation quantity for control, where the steering equivalent angle θp is the control quantity. The angle operation quantity calculation process M32 calculates the auxiliary torque Ta* based on the operation quantity calculated when the steering equivalent angle θp is the control quantity and the target steering equivalent angle θp* is the target value of the control quantity (i.e., feedback control). Alternatively, the angle operation quantity calculation process M32 can also calculate the auxiliary torque Ta* based on the operation quantity calculated when the target steering equivalent angle θp* is the target value of the control quantity (i.e., open-loop control).

[0045] The auxiliary operation processing M34 is a process that outputs an operation signal MS to the inverter 32 to control the torque of the auxiliary motor 30 based on the auxiliary torque Ta*. Furthermore, the operation signal MS actually becomes the operation signal for each branch and arm of the inverter 32.

[0046] <The function and effects of this implementation method>

[0047] The PU42 of the steering control unit 40 calculates the target steering equivalent angle θp0* based on the steering torque Th input to the transmission shaft 14. The PU72 of the ADASECU 70 calculates the auxiliary correction amount Δθp for assisting steering based on the image data Do. The PU42 sets the target yaw rate yr* based on the value of the target steering equivalent angle θp0* corrected by the auxiliary correction amount Δθp, i.e., the target steering equivalent angle θpa*. The PU42 sets the final target steering equivalent angle θp* by correcting the target steering equivalent angle θpa* with an operational amount Δθc, i.e., a yaw rate correction amount, to make the yaw rate yr close to the target yaw rate yr*. Furthermore, the PU42 performs control to make the steering equivalent angle θp close to the target steering equivalent angle θp*.

[0048] Here, the target steering equivalent angle θp* is a value that has been corrected for the target steering equivalent angle θpa* using the yaw rate correction amount Δθc. The yaw rate correction amount Δθc is an operational amount used to bring the yaw rate yr closer to the target yaw rate yr*. Moreover, the target yaw rate yr* is the yaw rate that is expected to be achievable under the driving conditions of satisfying the target steering equivalent angle θpa* and vehicle speed V on a flat road surface without being affected by airflow or other factors. Therefore, the reasons why the yaw rate yr deviates from the target yaw rate yr* are due to crosswinds blowing towards the vehicle, road surface disturbances such as road slope and road steps, and vehicle aging and deterioration.

[0049] The assist correction amount Δθp output by ADASECU70 does not assume the aforementioned crosswinds, road surface disturbances, vehicle aging and deterioration, etc. Therefore, even if the assist correction amount Δθp is calculated to suppress lane departure, without the use of the yaw rate correction amount Δθc, the vehicle may still leave the lane due to crosswinds and other factors.

[0050] In contrast, the PU42 can achieve steering control as a purpose by employing a yaw rate correction Δθc.

[0051] In particular, PU42 inputs the target steering equivalent angle θpa* output from coordination processing M18 into the target yaw rate setting processing M20. In other words, in addition to the correction based on the yaw rate correction amount Δθc, PU42 also sets the target yaw rate yr* based on the value of the downstream variable used to calculate the target steering equivalent angle θp*. Therefore, compared to substituting upstream variable values ​​such as the target steering equivalent angle θp0* into the target yaw rate setting processing M20, the target yaw rate yr* can be set to a more appropriate value to achieve the desired steering control.

[0052] Based on the above-described embodiment, the following functions and effects can also be obtained.

[0053] (1-1) In this embodiment, the yaw rate yr is used as the operating quantity of the feedback control as the correction quantity for correcting the target steering equivalent angle θpa*. Thus, the feedback control with the yaw rate yr as the control quantity can be quickly reflected in the steering equivalent angle θp.

[0054] <Second Implementation>

[0055] Hereinafter, the second embodiment will be described with reference to the accompanying drawings and focusing on the differences from the first embodiment.

[0056] "Prerequisite Structure"

[0057] exist Figure 3 The structure of the steering control system of this embodiment is shown in the diagram. Furthermore, in... Figure 3 For convenience, the following is a summary of the text. Figure 1 The components shown are labeled with the same reference numerals.

[0058] like Figure 3 As shown, in the steering control device 10, the transmission shaft 14 separates the input shaft 14a, which is connected to the steering wheel 12, and the output shaft 14b, which engages with the steering shaft 16. Furthermore, in this embodiment, the output shaft 14b is not actually required. However, it is provided for the convenience of the following explanation.

[0059] A reaction force motor 90 is provided on the input shaft 14a. The reaction force motor 90 is a motor used to apply torque, i.e., reaction force, to the steering wheel 12 in the opposite direction to the torque input by the driver. As an example, the reaction force motor 90 is a three-phase brushless motor. In addition, the output voltage of the inverter 92 is applied to the terminals of the reaction force motor 90.

[0060] The torque of the steering motor 100 is applied to the steering shaft 16 via the drive shaft 34. The steering motor 100, as an example, is a three-phase brushless motor. Furthermore, the output voltage of the inverter 102 is applied to the terminals of the steering motor 100.

[0061] The steering control device 40 uses the steering control device 10 as the controlled object. The steering control device 40 operates the inverter 92 to control the control quantity of the controlled object, i.e., the reaction force. Additionally, the steering control device 40 operates the inverter 102 to control the control quantity of the controlled object, i.e., the steering angle of the steering wheel 20.

[0062] For controlling the reaction force, which is a control quantity, the steering control device 40 refers to the rotation angle θs of the reaction force motor 90 detected by the rotation angle sensor 110. Furthermore, for controlling the reaction force, the steering control device 40 refers to the currents ius, ivs, and iws flowing into the reaction force motor 90. Additionally, for controlling the steering angle, which is a control quantity, the steering control device 40 refers to the rotation angle θt of the steering motor 100 detected by the rotation angle sensor 112. Furthermore, for controlling the steering angle, the steering control device 40 refers to the currents iut, ivt, and iwt flowing in the steering motor 100.

[0063] "Processing performed by the steering control device 40"

[0064] exist Figure 4 The diagram shows the processing performed by the steering control device 40. In other words, Figure 4 This illustrates the processing performed by the steering control device 40 when the power transmission from the steering wheel 12 to the steering wheel 20 is cut off. Furthermore, in Figure 4 For convenience, the following is a summary of the text. Figure 2 The processes shown are labeled with the same reference numerals.

[0065] like Figure 4 As shown, the standard model operation processing M16 is the process of replacing the target steering equivalent angle θp0* and outputting the target steering control angle θh*.

[0066] The steering angle calculation process M40 is a process that takes the rotation angle θs as input and the steering angle θh as output. The steering angle calculation process M40 includes a process for accumulating the rotation angle θs. Furthermore, in this accumulation process, the steering angle θh is set to zero in the neutral position.

[0067] The target reaction torque calculation process M42 is a process that takes the steering angle θh and the target steering angle θh* as inputs and the target reaction torque Tr* as output. The target reaction torque calculation process M42 calculates the target reaction torque Tr* based on the input of the steering angle θh as the control variable and the target steering angle θh* as the target value of the control variable (i.e., the operation variable of feedback control). Alternatively, the target reaction torque calculation process M42 can also calculate the target reaction torque Tr* based on the input of the target steering torque Th* as the target value of the control variable (i.e., the operation variable of open-loop control).

[0068] The steering operation signal generation process M44 operates the inverter 92 by inputting a target reaction torque Tr*. The steering operation signal generation process M44 includes a process for calculating the control quantity, where the torque of the reaction motor 90 is the control quantity and the target reaction torque Tr* is the target value of the control quantity. The calculation of the control quantity refers to the rotation angle θs and the currents ius, ivs, and iws. Furthermore, the steering operation signal generation process M44 includes a process for operating the inverter 92 based on this control quantity. Figure 4 The document describes the operation signal MSs of inverter 92. Furthermore, the operation signal MSs is actually an individual operation signal for each switching element of inverter 92.

[0069] The target steering equivalent angle calculation and processing M50 is a process that takes the steering angle θh and vehicle speed V as inputs and the target steering equivalent angle θp0* as output. PU42 adjusts the target steering equivalent angle θp0* based on the steering angle θh when the absolute value of the steering angle θh is large, provided that the absolute value of the target steering equivalent angle θp0* is greater than the absolute value of the target steering equivalent angle θp0* when the absolute value of the steering angle θh is small.

[0070] The angle calculation and processing M30 is a process where the rotation angle θt of the steering motor 100 is used as the input instead of the rotation angle θa, and the equivalent steering angle θp is the output.

[0071] The angle operation calculation and processing M32 is a process that takes the steering equivalent angle θp and the target steering equivalent angle θp* as inputs and the target steering torque Tt* as the output instead of the auxiliary torque Ta*.

[0072] The steering operation signal generation process M34a operates the inverter 102 by inputting a target steering torque Tt*. The steering operation signal generation process M34a can also be a process that calculates the torque of the steering motor 100 as a control quantity, and converts the target steering torque Tt* into a value representing the torque of the steering motor 100, which is the target value of the control quantity, i.e., the control operation quantity. The calculation of the operation quantity refers to the rotation angle θt and the currents iut, ivt, and iwt. Furthermore, the steering operation signal generation process M34a includes the process of operating the inverter 102 based on this operation quantity. Figure 5 The document records the operation signal MSt of inverter 102. Furthermore, the operation signal MSt is actually an individual operation signal for each switching element of inverter 102.

[0073] <The function and effects of the second embodiment>

[0074] PU42 calculates the target steering equivalent angle θp0* based on the steering angle θh. PU72 of ADASECU70 calculates the auxiliary correction amount Δθp for assisted steering based on the image data Do. PU42 sets the target yaw rate yr* based on the value of the target steering equivalent angle θp0* corrected by the auxiliary correction amount Δθp, i.e., the target steering equivalent angle θpa*. PU42 sets the final target steering equivalent angle θp* by correcting the target steering equivalent angle θpa* with an operational amount Δθc, i.e., a yaw rate correction amount, to make the yaw rate yr close to the target yaw rate yr*. Furthermore, PU42 controls the steering wheel 20 to make its steering angle close to the target steering equivalent angle θp*.

[0075] Therefore, according to this embodiment, the same effect as the first embodiment described above is achieved.

[0076] <Third Implementation Method>

[0077] Hereinafter, the third embodiment will be described with reference to the accompanying drawings and focusing on the differences from the second embodiment.

[0078] exist Figure 5 The diagram shows the processing performed by the steering control device 40. In other words, Figure 5 This illustrates the processing performed by the steering control device 40 when the power transmission from the steering wheel 12 to the steering wheel 20 is cut off. Furthermore, in Figure 5 For convenience, the following is a summary of the text. Figure 4 The processes shown are labeled with the same reference numerals.

[0079] In this embodiment, the output of the coordination process M18 is the target steering equivalent angle θp*, which serves as the input to the yaw rate feedback process M24 and the angle operation amount calculation process M32. Furthermore, the yaw rate correction amount ΔTaf output by the yaw rate feedback process M24 is a correction amount for the axial force Taf. That is, the axial force calculation process M14 substitutes the value obtained by adding the steering torque Th to the steering operation amount Ts* into the axial force Taf0. The axial force correction process M60 substitutes the value obtained by adding the yaw rate correction amount ΔTaf to the axial force Taf0 into the axial force Taf, which serves as the input to the target steering torque setting process M10 and the standard model calculation process M16.

[0080] Therefore, the yaw rate yr, as the control quantity, is reflected in the target steering angle θh*. Thus, PU42 performs control to make the torque of the reaction motor 90 appropriate for the steering angle θh, while keeping the yaw rate yr close to the target yaw rate yr*. On the other hand, PU42 sets the target equivalent steering angle θp0* based on the steering angle θh. Therefore, the yaw rate yr, as the control quantity, is reflected in the target equivalent steering angle θp*.

[0081] <Other Implementation Methods>

[0082] Furthermore, this embodiment can be modified as follows. This embodiment and the following modifications can be combined with each other to implement them within the scope of technical non-contradiction.

[0083] Regarding the calculation and processing of input dependency variables

[0084] exist Figure 2 In the illustrated process, although feedback control with steering torque Th as the control variable is used to calculate the target steering equivalent angle θp0* as the input dependent variable, it is not limited to this. For example, the target steering equivalent angle θp0* as the input dependent variable can also be calculated based solely on the operating quantity of open-loop control with steering torque Th as the control variable.

[0085] exist Figure 4 as well as Figure 5 In the illustrated process, the target steering equivalent angle θp0* is calculated as an input-dependent variable based on the steering angle θh, which represents the driver's intention to perform steering maneuvers, and the vehicle speed V, but this is not the only possible approach. For example, the target steering equivalent angle θp0* can also be calculated based on the target steering angle θh* and the vehicle speed V. In this case, the driver's intention to perform steering maneuvers is represented by the steering torque Th. Moreover, the target steering angle θh* is calculated using a process where the steering torque Th is the input and the target steering angle θh* is the output. Therefore, the target steering equivalent angle θp0* calculated using a process where the target steering angle θh* and the vehicle speed V are the inputs and the target steering equivalent angle θp0* is the output, and it is an input-dependent variable.

[0086] Regarding coordination and handling

[0087] The process, which uses information about objects outside the vehicle to assist in steering control as output, and inputs a dependent variable and outputs a target steering angle variable, is not limited to the process illustrated in the above embodiments. For example, the above process could also be a process that substitutes the weighted average of the output of the process assisting in steering control and the values ​​of the input dependent variables into the target steering angle variable.

[0088] The external request values ​​that become input to the coordination process are not limited to the output values ​​of processes that assist vehicle steering based on information about objects outside the vehicle. For example, they could also be corrections to the target steering equivalent angle θp0* based on wheel slip detection results.

[0089] Regarding operational procedures

[0090] The operation processing is not limited to the operation of the actuator based on the feedback control quantity of the steering equivalent angle θp as the control quantity. For example, it can also be the operation of the actuator based solely on the operation of the open-loop control quantity of the target steering equivalent angle θp* as the target value of the control quantity.

[0091] Regarding the setting of target values

[0092] The target value setting process is not limited to the process where the target steering equivalent angle θp* and vehicle speed V are inputs and the target yaw rate yr* is output. For example, when both the front and rear wheels of the vehicle can steer, the target values ​​of the steering equivalent angles of both the front and rear wheels and the vehicle speed V can also be input variables.

[0093] Regarding the handling of feedback

[0094] The process of reflecting the operated quantity of feedback control, with the yaw rate yr as the control quantity, to the reaction force, and reflecting the operated quantity to the actuator operation performed by the operation process via the value of the input dependent variable, is not limited to... Figure 5 The illustrated processing. This processing could, for example, be the correction of the elastic coefficient K in the normative model calculation processing M16 by using the yaw rate yr as the control variable in feedback control. Alternatively, this processing could, for example, be the correction of the target steering angle θh* by using the yaw rate yr as the control variable in feedback control.

[0095] Regarding ADASECU70

[0096] Data containing information about objects outside the vehicle is not limited to image data. For example, it could also be dot matrix data generated from reflected light from lasers illuminating the LiDAR in mutually different directions. Dot matrix data is a set of data representing the distance between the object reflecting the laser and the LiDAR, as well as the direction of illumination.

[0097] Regarding the steering control device

[0098] exist Figure 3 In the illustrated structure, the device for operating the reaction force motor 90 and the device for the steering motor 100 can also be considered as independent devices.

[0099] It can also be integrated into ADASECU70 and steering control device 40.

[0100] The steering control device is not limited to a device that includes a PU42 and a storage device 44 and performs software processing. For example, it may also include dedicated hardware circuitry such as an ASIC that performs at least a portion of the processing performed in the above embodiments. That is, the steering control device may also include a processing circuit having any of the structures of (a) to (c) below.

[0101] (a) A processing circuit having all the processing devices that perform the above processing according to the program, and a program storage device such as a storage device for storing the program.

[0102] (b) A processing circuit having a processing device and a program storage device for performing a portion of the above processing according to a program, and a dedicated hardware circuit for performing the remaining processing.

[0103] (c) A processing circuit that has all the dedicated hardware circuits to perform the above processing.

[0104] Here, there can be multiple software execution devices equipped with processing units and program storage units. In addition, there can also be multiple dedicated hardware circuits.

[0105] Regarding steering control methods

[0106] The entity that performs the various controls described above is not limited to the steering control device installed in the vehicle. For example, the driver's mobile terminal can also perform part of the above-mentioned processes.

[0107] Regarding the Input Department

[0108] The input unit for the driver to input steering intentions is not limited to the steering wheel 12. For example, it could also be a joystick.

[0109] "Regarding the disconnection state of power transmission"

[0110] The structure that achieves the disconnection of power transmission between the input unit for input steering torque and the steering wheel 20 is not limited to... Figure 4 The illustrated structure. For example, a clutch can also be provided between the input shaft 14a and the output shaft 14b.

[0111] Regarding the steering control system

[0112] As an actuator to steer the steering wheel 20, a component that has an auxiliary motor 30 or a steering motor 100 mounted coaxially on the steering shaft 16 may be used. Furthermore, a structure that transmits power from the auxiliary motor 30 or the steering motor 100 to the steering shaft 16 via a belt reducer using a ball screw mechanism may also be used.

[0113] Steering mechanisms capable of altering the relationship between the steering angle and the steering control angle are not limited to... Figure 3 As illustrated, a steering control device that cuts off the power transmission between the steering wheel 12 and the steering wheel 20. For example, a steering control device capable of changing the relationship between the steering angle and the steering control angle can also be constructed by making the gear capable of transmitting power between the steering wheel 12 and the steering wheel 20 a variable gear.

Claims

1. A steering control device, wherein, Its structure consists of input dependency variable calculation processing, coordination processing, operation processing, target value setting processing, and reflection processing. The above-described input-dependent variable calculation process calculates the values ​​of input-dependent variables based on the driver's intention to perform steering maneuvers as indicated by their operation of the input unit. The input-dependent variables mentioned above represent the steering angles of the vehicle's steering wheels corresponding to the aforementioned steering maneuvering intention. The above coordination process involves taking the values ​​of the input dependency variables and the external request values ​​as inputs, and taking the value of the target steering angle variable as the output. The target steering angle variable mentioned above is the target value of the steering angle. The aforementioned externally requested values ​​are variables representing requested values ​​for the steering angle, independent of the intent of the aforementioned steering maneuver. The above operation process involves taking the target steering angle variable as input and processing the actuator accordingly. The actuator described above is configured to apply the power to turn the steering wheel to the steering wheel. The above target value setting process takes the target steering angle variable output from the above coordination process as input and the target yaw rate as output. The above-mentioned feedback processing is a process that reflects the operation quantity of the feedback control, whereby the yaw rate is the control quantity and the target yaw rate is the target value of the control quantity, to the operation of the steering angle performed by the above-mentioned operation processing. It is a process that is performed when at least the value obtained by substituting the value obtained by overlapping the value of the above-mentioned input dependent variable with the value of the above-mentioned external request value into the target steering angle variable output by the above-mentioned coordination processing.

2. The steering control device according to claim 1, wherein, The above-mentioned response processing is the process of inputting the value of the target steering angle variable, which has been corrected by the above-mentioned operation amount, into the above-mentioned operation processing.

3. The steering control device according to claim 1, wherein, The system is configured to perform the following processes when the power transmission between the steering wheel and the input unit is cut off: input-dependent variable calculation, coordination, operation, target value setting, response, and reaction force setting. The aforementioned reaction force setting process is a process that sets a force to overcome the driver's operation of the input unit, i.e., a reaction force. The above-mentioned reaction processing includes reflecting the above-mentioned operation quantity to the above-mentioned reaction force, and reflecting the above-mentioned operation quantity to the operation of the above-mentioned steering angle performed by the above-mentioned operation processing via the value of the above-mentioned input-dependent variable.

4. The steering control device according to claim 1, wherein, The aforementioned external request value is the output value of the processing that assists in the steering operation of the vehicle based on information from outside the vehicle.

5. A steering control method, comprising: The process involves calculating and processing input dependency variables, coordinating and manipulating them, setting target values, and reflecting the results. The above-described input-dependent variable calculation process calculates the values ​​of input-dependent variables based on the driver's intention to perform steering maneuvers as indicated by their operation of the input unit. The input-dependent variables mentioned above represent the steering angles of the vehicle's steering wheels corresponding to the aforementioned steering maneuvering intention. The above coordination process involves taking the values ​​of the input dependency variables and the external request values ​​as inputs, and taking the value of the target steering angle variable as the output. The target steering angle variable mentioned above is the target value of the steering angle. The aforementioned externally requested values ​​are variables representing requested values ​​for the steering angle, independent of the intent of the aforementioned steering maneuver. The above operation process involves taking the target steering angle variable as input and processing the actuator accordingly. The actuator described above is configured to apply the power to turn the steering wheel to the steering wheel. The above target value setting process takes the target steering angle variable output from the above coordination process as input and the target yaw rate as output. The above-mentioned feedback processing is a process that reflects the operation quantity of the feedback control, whereby the yaw rate is the control quantity and the target yaw rate is the target value of the control quantity, to the operation of the steering angle performed by the above-mentioned operation processing. It is a process that is performed when at least the value obtained by substituting the value obtained by overlapping the value of the above-mentioned input dependent variable with the value of the above-mentioned external request value into the target steering angle variable output by the above-mentioned coordination processing.

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