Device and method for controlling a steering wheel actuator of a steering system for creating a steering feel, vehicle comprising the device
The method and device for controlling steering wheel actuators in steering systems address the complexity of torque feedback by using actual and target steering speeds to determine actuating torque, improving steering feel and stability while providing haptic feedback.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- ROBERT BOSCH GMBH
- Filing Date
- 2025-10-13
- Publication Date
- 2026-05-21
AI Technical Summary
Existing steering systems face challenges in achieving a controlled steering feel with complex torque feedback control, requiring expert intervention and often resulting in dynamic and stability issues.
A method and device for controlling a steering wheel actuator that uses actual and target steering speeds to determine actuating torque, employing PI or PID controllers with adjustable parameters, and functions to adjust steering feel based on vehicle speed and steering angle, providing haptic feedback.
This approach simplifies torque control, reduces dynamic and stability problems, and enhances the driver's perception of vehicle movement and road conditions through precise steering feel generation.
Smart Images
Figure EP2025079392_21052026_PF_FP_ABST
Abstract
Description
[0001] R.410081
[0002] - 1 -
[0003] Description
[0004] title
[0005] Device and method for controlling a steering wheel actuator of a steering system to generate a steering feel, the device comprising a vehicle
[0006] State of the art
[0007] The invention relates to a device and a method for controlling a steering wheel actuator of a steering system to generate a steering feel and a vehicle comprising the device.
[0008] In steering systems with controlled steering feel, i.e., torque feedback, the controlled variable is the steering torque. With this torque control, an applicable target steering torque is generated, compared with the actual steering torque measured by a torque sensor, and any deviation between the target and actual steering torque is corrected.
[0009] Alternative control concepts for a controlled steering feel are based on the steering angle or regulate the steering feel in a cascade based on steering angle and hand torque.
[0010] A controlled steering feel can be provided in both an electric steering system (EPS steering system) and a steer-by-wire (SbW) steering system with feedback actuators.
[0011] A torque sensor is required for torque control. Controller design can be very demanding and time-consuming until a good compromise between dynamics and stability is found. The application of the often very complex steering feel functions for generating the target hand torque must be carried out by an expert with extensive experience. R.410081
[0012] - 2 -
[0013] Disclosure of the invention
[0014] The method for controlling a steering wheel actuator of a steering system to generate a steering feel according to claim 1 provides that an actual steering speed and a target steering speed are provided for steering speed control of the steering system. Depending on a deviation between the actual steering speed and the target steering speed, an actuating torque for the steering wheel actuator is determined, and the steering wheel actuator is controlled to adjust the actuating torque. In steering speed control, the target steering speed is not precisely regulated. The deviation and the resulting actuating torque for the steering wheel actuator generate the desired steering feel. Since the target steering speed does not need to be precisely regulated, fewer dynamic and stability problems occur.
[0015] The method, for example, involves determining the actuating torque using a controller, depending on the deviation and on controller parameters, in particular where the controller has a PI or PID controller architecture. Other controller architectures are also conceivable. The controller parameters are steering feel parameters.
[0016] For example, the integral (I) component is intended to be constant or limited depending on the actual steering speed. For example, the proportional (P) component is intended to be determined depending on the actual steering speed. For example, the actuating torque is intended to be limited depending on the actual steering speed.
[0017] The procedure provides, for example, that an operating parameter of a vehicle comprising the steering system, in particular a vehicle speed, is detected, and the control is influenced depending on the detected operating parameter.
[0018] For example, it is provided that the I-component is limited depending on the size of the operation. For example, it is provided that the P-component is limited depending on R.410081.
[0019] - 3 -
[0020] The operating size is determined. For example, it is intended that the actuating torque will be limited depending on the operating size.
[0021] It can be provided that a rack force is supplied to a rack of the steering system, in particular measured or calculated from steering system parameters or determined model-based from vehicle parameters, especially the vehicle speed and a steering angle of the steering system, wherein a vehicle speed is supplied, wherein the target steering speed is determined by means of a first function, wherein the first function determines the target steering speed for returning the rack force to the force zero point of the steering system as a function of the rack force and the vehicle speed. Depending on the rack force used, a driver of the vehicle receives haptic feedback about vehicle movement, driving condition and road surface excitations via the steering feel. The first function returns to the force zero point.
[0022] Especially at low vehicle speeds, this force zero point is reached much earlier than an angle zero point of the steering system and thus earlier than the straight-ahead position of the steering.
[0023] It can be provided that a steering angle of the steering system and a vehicle speed are supplied, whereby the target steering speed is determined by a second function. This second function determines the target steering speed for returning the steering angle to an angular zero point of the steering system for straight-ahead driving, depending on the steering angle and the vehicle speed. The second function returns to the angular zero point, i.e., to straight-ahead driving.
[0024] It may be possible to implement a third function that dampens the target steering speed, whereby this third function dampens the target steering speed depending on the actual steering speed and the vehicle speed. This allows the damping sensation to be specifically adjusted for the driver.
[0025] It may be provided that a target steering speed is determined using each of the functions, with the target steering speed for R.410081
[0026] - 4 -
[0027] The control is determined by summing the target steering speeds provided by the individual functions.
[0028] A device for controlling a steering wheel actuator of a steering system to generate a steering feel provides that the device is designed to perform the procedure.
[0029] A vehicle may be provided that includes the device and the steering system.
[0030] Further embodiments can be found in the following description and the drawing. The drawing shows:
[0031] Fig. 1 shows a vehicle with a steering system and a device for controlling a steering wheel actuator of the steering system to generate steering feel; Fig. 2 shows a block diagram of an exemplary controller structure for control; Fig. 3 shows a block diagram of an exemplary first function for control; Fig. 4 shows a block diagram of an exemplary second function for control; Fig. 5 shows a block diagram of an exemplary third function for control; Fig. 6 shows a block diagram of an exemplary controller encompassing the functions.
[0032] Fig. 7 shows a flowchart with steps of a procedure for controlling the steering wheel actuator of the steering system to generate the steering feel.
[0033] Figure 1 shows a schematic representation of a vehicle 100 with a steering system 102.
[0034] The steering system 102 comprises a steering wheel 104 and a steering wheel actuator 106 for generating a steering feel at the steering wheel 104.
[0035] A controlled steering feel can be provided in both an electric steering system (EPS steering system) and a steer-by-wire (SbW) steering system with feedback actuators.
[0036] The steering system 102 in the example includes a rack 108, with which a steering angle around an angle zero point for straight-ahead driving of the vehicle 100 and R.410081
[0037] - 5 -
[0038] a force zero point of a rack force occurring on the rack 110 is adjustable.
[0039] The vehicle 100 includes a device 110 for controlling the steering wheel actuator 106 to generate the steering feel.
[0040] In the example, the device 110 is designed to measure the rack force, or to calculate it from steering-internal parameters of the steering system 102, or to determine it from vehicle parameters using a model.
[0041] The device 110 is designed to measure an actual steering speed or to calculate it from steering-internal parameters of the steering system 102.
[0042] The device 110 is configured to control the steering actuator 106. The device 110 is configured to determine an actuating torque for controlling the steering actuator 106 and to actuate the steering actuator 106 with this actuating torque.
[0043] The device 110 is designed to detect a vehicle speed or, in particular, to receive it via a data bus in the vehicle 100, preferably from another control unit of the vehicle 100.
[0044] Figure 2 shows a block diagram of an exemplary controller structure of a controller 200 for controlling the steering actuator 106.
[0045] The exemplary controller structure includes a P-component 202, an I-component 204 and a D-component 206.
[0046] The controller 200 is designed to determine the actuating torque 208 depending on the actual steering speed 210, a target steering speed 212 and the vehicle speed 214.
[0047] The controller 200 includes a comparator 216 for determining a deviation 218 between the actual steering speed 210 and the target steering speed 212. R.410081
[0048] - 6 -
[0049] The controller 200 includes an adder 220 for determining the sum of the output variables from the P-component 202, the I-component 204 and the D-component 206.
[0050] The proportional (P) component 202 is configured to determine the output variable 222 of the proportional (P) component 202 as a product of the deviation 218 with a controller parameter P and with the weighted value of the target steering speed 212 and the weighted value of the vehicle speed 214. In this example, the controller parameters of the proportional (P) component 202 define whether and, if so, with what weight the target steering speed 212 and / or the vehicle speed 214 are included in the product. The weight as a controller parameter for the target steering speed 212 is, for example, defined by a characteristic curve as a function of the target steering speed 212. The weight as a controller parameter for the vehicle speed 214 is, for example, defined by a characteristic curve as a function of the vehicle speed 214. It may also be possible to determine the proportional (P) component as a function of the actual steering speed 210.
[0051] The vehicle speed 214 is an example of an operating parameter of the vehicle 100. It may be provided that the P-component is determined depending on another operating parameter of the vehicle 100 or the steering system 102.
[0052] The I-component 204 is configured to determine the output variable 224 of the I-component 204 as a function of a controller parameter I. In the example, the controller parameter I is multiplied by the deviation 218. For instance, the deviation 218, multiplied by the parameter C, is added to each preceding value of the output variable 224.
[0053] For example, it is intended that the I-component will be limited, in particular, to be constant or dependent on the actual steering speed.
[0054] For example, the integral component is limited depending on the operating size. For example, the actuating torque is limited depending on the operating size. R.410081
[0055] - 7 -
[0056] The D-component 206 is configured to determine the output variable 226 of the D-component 206 as a function of a controller parameter D. For example, a change in the deviation 218 is multiplied by the controller parameter D.
[0057] Furthermore, it may be provided that the actuating torque 208 is limited depending on the actual steering speed 210.
[0058] Figure 3 shows a block diagram of an exemplary first function 300 for control. The first function 300 is configured to determine the target steering speed 212.
[0059] The first function 300 provides that the rack force 302 of the rack 108 of the steering system 102 and the vehicle speed 214 are provided.
[0060] The first function 300 is designed to determine the target steering speed 212 for resetting the rack force 302 to the force zero point of the steering system 102 as a function of the rack force 302 and the vehicle speed 214.
[0061] In the example, the magnitude of the rack force 302 is mapped to an input variable 306 for the first function 300 using a characteristic curve 304, and the target steering speed 212 is determined depending on the input variable 306 and depending on the vehicle speed 214.
[0062] Several characteristic curves 304 can be provided for different vehicle speeds 214, each assigned to a specific point of the vehicle speed 214. For example, the magnitude of the rack force 302 is mapped to the input variable 306 by characteristic curve 304, which is assigned to a specific point, i, of the vehicle speed 214.
[0063] Figure 4 shows a block diagram of an exemplary second function 400 for control. The second function 400 is configured to determine the target steering speed 212. R.410081
[0064] - 8 -
[0065] The second function 400 provides that the steering angle 402 of the steering system 102 and the vehicle speed 214 are provided.
[0066] The second function 400 is designed to determine the target steering speed 212 for resetting the steering angle 402 to the angle zero point of the steering system 102 for straight-ahead driving of the vehicle 100 as a function of the steering angle 402 and the vehicle speed 214.
[0067] In the example, the magnitude of the steering angle 402 is mapped to an input variable 406 for the second function 400 using a characteristic curve 404, and the target steering speed 212 is determined depending on the input variable 406 and depending on the vehicle speed 214.
[0068] Several characteristic curves 404 can be provided for different vehicle speeds 214, each assigned to a specific vehicle speed 214 reference point. For example, the magnitude of the steering angle 402 is mapped to the input variable 406 by characteristic curve 404, which is assigned to a specific vehicle speed 214 reference point.
[0069] Figure 5 shows a block diagram of an exemplary third function 500 for control.
[0070] The third function 500 is designed to dampen the target steering speed 212.
[0071] The third function 500 provides that the actual steering speed 210 of the steering system 102 and the vehicle speed 214 are provided.
[0072] The third function 500 is designed to dampen the target steering speed 212 depending on the actual steering speed 210 and the vehicle speed 214.
[0073] In the example, the magnitude of the actual steering speed 210 is mapped to an input variable 506 for the third function 500 using a characteristic curve 504, and the target steering speed 212 is determined depending on the input variable 506 and the vehicle speed 214. R.410081
[0074] - 9 -
[0075] Several characteristic curves 504 can be provided for different vehicle speeds 214, each assigned to a specific vehicle speed 214 reference point. For example, the magnitude of the actual steering speed 210 is mapped to the input variable 506 using characteristic curve 504, which is assigned to a specific vehicle speed 214 reference point.
[0076] The functions can be used individually. It is also possible to use two or all three functions in combination. For example, a target steering speed is determined for each function used, and the target steering speed for the control system is then determined by summing the target steering speeds provided by the individual functions.
[0077] Figure 6 shows a block diagram of an exemplary controller 600 comprising three functions. The controller 600 includes an adder 602 configured to sum the target steering speeds 212 provided by the individual functions to obtain the target steering speed 212' for the control system.
[0078] Figure 7 shows a flowchart with steps of a procedure for controlling the steering wheel actuator 106 of the steering system 102 to generate the steering feel.
[0079] The procedure includes step 702.
[0080] In step 702, the actual steering speed 210 and the target steering speed 212 are provided.
[0081] For example, the vehicle speed 214 and the rack force 302 are provided, and the target steering speed 212 is determined using the first function 300. The rack force 302 is, for example, measured, calculated from steering system parameters 102, or determined from vehicle parameters using a model. R.410081
[0082] - 10 -
[0083] For example, the steering angle 402 and the vehicle speed 214 are provided, and the target steering speed 212 is determined using the second function 400.
[0084] For example, the target steering speed 212 is dampened by means of the third function 500.
[0085] It may be provided that a target steering speed 212 is determined with at least two of the functions 300, 400, 500, and that the target steering speed 212 for the control is determined by summing the target steering speeds 212 provided by the individual functions 300, 400, 500.
[0086] The procedure includes step 704.
[0087] In step 704, the actuating torque 208 for the steering wheel actuator 106 is determined depending on the deviation 218 between the actual steering speed 210 and the target steering speed 212.
[0088] The actuating torque 208 is determined, for example, with a controller depending on the deviation 218 and depending on the controller parameters.
[0089] In this example, the controller has a PI or PID controller architecture. The controller can be structured as described for the 200 or 600 controllers.
[0090] In one example, the integral component of the controller is limited, and this limit can depend on the actual steering speed of 210.
[0091] The proportional (P) component of the controller, e.g., the P gain, is determined in one example depending on the actual steering speed 210. For example, the P gain is determined from a characteristic curve of P gains versus the actual steering speed 210.
[0092] The actuating torque 208 is limited in an example depending on the actual steering speed 210, in particular to a limit value derived from R.410081
[0093] - 11 -
[0094] a characteristic curve of limit values is determined above the actual steering speed 210.
[0095] It may be stipulated that an operating parameter of the vehicle 100 is recorded. The operating parameter is, for example, the vehicle speed 214.
[0096] It may be provided that the regulation is influenced depending on the size of the business being assessed.
[0097] For example, the I-component is limited depending on the size of the operation, in particular to a limit value that is determined from a characteristic curve of limit values over the size of the operation.
[0098] For example, the proportional gain (P-component), and in particular the P-gain, is determined depending on the operating size. For instance, the P-gain is determined from a characteristic curve of P-gains versus the operating size.
[0099] For example, the actuating torque is limited depending on the operating size, in particular to a limit value that is determined from a characteristic curve of limit values over the operating size.
[0100] The procedure includes step 706.
[0101] In step 706, the steering wheel actuator 106 is controlled to set the actuating torque 208.
Claims
R.410081 - 12 - Claims 1. Method for controlling a steering wheel actuator (106) of a steering system (102) to generate a steering feel, characterized in that an actual steering speed (210) and a target steering speed (212) are provided for steering speed control of the steering system (102) (702), depending on a deviation (218) between the actual steering speed (210) and the target steering speed (212) an actuating torque (208) for the steering wheel actuator (106) is determined (704), and the steering wheel actuator (106) is controlled to set the actuating torque (706).
2. The method according to claim 1, characterized in that the actuating torque (208) is determined with a controller (200, 600) depending on the deviation (218) and depending on controller parameters (704), in particular wherein the controller has a PI or PID controller structure.
3. The method according to claim 2, characterized in that the I-component is limited in particular as constant or as dependent on the actual steering speed (210) (704), or that the P-component is determined as dependent on the actual steering speed (210) (704), or that the actuating torque (208) is limited as dependent on the actual steering speed (210) (704).
4. The method according to one of the preceding claims, characterized in that an operating parameter of a vehicle (100) comprising the steering system (102), in particular a vehicle speed (214), is detected and the control is influenced depending on the detected operating parameter (704).
5. The method according to claim 4, characterized in that the I-component is limited depending on the operating size (704), or that the P-component is determined depending on the operating size (704), or that the actuating torque is limited depending on the operating size (704). R.410081 - 13 - 6. The method according to one of the preceding claims, characterized in that a rack force (302) of a rack (108) of the steering system (102) is provided (702), in particular measured or calculated from steering-internal parameters of the steering system (102) or determined model-based from vehicle parameters, in particular the vehicle speed and a steering angle of the steering system (102), wherein a vehicle speed (214) is provided (702), wherein the target steering speed (212) is determined by means of a first function (300) (702), wherein the first function (300) determines the target steering speed for resetting the rack force (302) to the force zero point of the steering system (102) as a function of the rack force (302) and the vehicle speed (214).
7. The method according to one of the preceding claims, characterized in that a steering angle (402) of the steering system (102) and a vehicle speed (214) are provided (702), wherein the target steering speed (212) is determined by means of a second function (400) (702), wherein the second function (400) determines the target steering speed (212) for returning the steering angle (402) to an angle zero point of the steering system (102) for straight-ahead driving of the vehicle (100) as a function of the steering angle (402) and the vehicle speed (214).
8. The method according to one of the preceding claims, characterized in that the target steering speed (212) is damped by means of a third function (500) (702), wherein the third function (500) dampens the target steering speed (212) depending on the actual steering speed (210) and the vehicle speed (214).
9. The method according to claims 6 to 8, characterized in that a target steering speed (212) is determined by each of the functions (300, 400, 500) (702), wherein the target steering speed (212') for the control is determined by summing the target steering speeds (212) provided by the individual functions (300, 400, 500) (702).
10. Device (110) for controlling a steering wheel actuator (106) of a steering system (102) for generating a steering feel, thereby R.410081 - 14 - characterized in that the device (110) is configured to carry out the method according to any one of claims 1 to 9.
11. Vehicle (100), characterized in that the vehicle (100) comprises the device (110) according to claim 10 and a steering system (102).