Steering device and method for operating steering device

Abstract

To provide a method for operating a steering device, a steering device, and a vehicle, which avoid failure of the steering device.SOLUTION: A steering device 102 comprises: a rack 106; an electric motor 108 that adjusts the position of the rack 106; a first control circuit 110 that drives and controls the electric motor 108 depending on the deviation 116 of an actual position 118 of the rack 106 from a target position 120 of the rack 106; a second control circuit 112 that drives and controls the electric motor 108 depending on the deviation 116 of the actual position 118 from the target position 120; and a device 114 that switches from driving and controlling the electric motor 108 by the first control circuit 110 to driving and controlling the electric motor 108 by the second control circuit 112.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] Conventional technology The present invention relates to a steering arrangement and a method for operating a steering arrangement. Summary of the Invention [Problem to be solved by the invention]

[0002] Disclosure of the Invention By means of the steering device and method according to the independent claims, failures of the steering device are avoided, thereby meeting high demands on control precision or the requirements of ASIL D. [Means for solving the problem]

[0003] The steering device comprises a rack, an electric motor for adjusting the position of the rack, a first control circuit for controlling the electric motor depending on a deviation of an actual position of the rack from a target position of the rack, a second control circuit for controlling the electric motor depending on a deviation of the actual position from the target position, and a device for switching from controlling the electric motor by the first control circuit to controlling the electric motor by the second control circuit depending on a deviation of the actual value from a target value, wherein the device is configured to switch from controlling the electric motor by the first control circuit to controlling the electric motor by the second control circuit depending on a deviation of the actual value from a target value, wherein the actual value is the actual position of the rack and the target value is the target position of the rack, or the actual value is a derivative of the actual position of the rack and the target value is determined depending on a difference between the actual position of the rack and the target position.

[0004] The device can be configured to monitor the deviation of the actual value from the target value and to switch from controlling the drive of the electric motor by the first control circuit to controlling the drive of the electric motor by the second control circuit depending on the deviation of the actual value from the target value.

[0005] The device can be configured to compare the deviation of the actual value from the setpoint value with a limit value and to switch over from controlling the electric motor with the first control circuit to controlling the electric motor with the second control circuit if the deviation of the actual value from the setpoint value is greater than the limit value, which means that the device is configured to recognize the need for switching over particularly well.

[0006] The device can be configured to determine the limit value depending on the deviation of the actual value from the setpoint value, which means that the device is configured to adjust the limit value to the deviation of the actual value from the setpoint value.

[0007] The device can be configured to determine limit values ​​that become more localized as the deviation of the actual value from the target value increases, meaning that the device is configured to adjust the limit values ​​more sensitively as the deviation of the actual value from the target value increases.

[0008] The device can be configured to determine both a limit value for a positive deviation of the actual value from the target value and a limit value for a negative deviation of the actual value from the target value, which limit values ​​can be the same or different from each other, which means that the device is configured to adjust asymmetric boundaries.

[0009] A vehicle equipped with a steering device can also be configured.

[0010] A method for operating a steering device includes the steering device comprising: a rack; an electric motor for adjusting the position of the rack; a first control circuit for controlling the electric motor depending on a deviation of an actual position of the rack from a target position of the rack; and a second control circuit for controlling the electric motor depending on the deviation of the actual position from the target position, wherein switching from controlling the electric motor by the first control circuit to controlling the electric motor by the second control circuit is performed depending on the deviation of the actual position from the target position, wherein the actual value is the actual position of the rack and the target value is the target position of the rack, or the actual value is a derivative of the actual value of the rack, and the target value is determined depending on a difference between the actual position and the target position of the rack.

[0011] The method can be configured such that the deviation of the actual value from the setpoint value is monitored and a switchover from controlling the electric motor by the first control circuit to controlling the electric motor by the second control circuit takes place depending on the deviation of the actual value from the setpoint value, so that the need for a switchover is particularly well recognized.

[0012] The method can be configured such that the deviation of the actual value from the target value is compared with a limit value, and if the deviation of the actual value from the target value is greater than the limit value, a switchover from controlling the drive of the electric motor by the first control circuit to controlling the drive of the electric motor by the second control circuit is performed.

[0013] The method can be configured so that the limit value is determined depending on the deviation of the actual value from the setpoint value, whereby the limit value is adapted to the deviation of the actual value from the setpoint value.

[0014] The method can be configured such that the limit value is determined more localized as the deviation of the actual value from the target value increases, meaning that the limit value is set more sensitively as the deviation of the actual value from the target value increases.

[0015] The method can be configured to determine a limit for a positive deviation of the actual value from the target value and a limit for a negative deviation of the actual value from the target value, which may be the same or different, thereby setting asymmetric limits.

[0016] Further advantageous embodiments can be seen from the following description and the drawings, in which: [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic diagram showing a vehicle equipped with a steering device. [Figure 2] FIG. 2 illustrates an exemplary first control circuit for a steering device. [Figure 3] FIG. 2 illustrates an exemplary second control circuit for a steering device. [Figure 4] 4 is a flow chart showing steps of a method for operating a steering device. DETAILED DESCRIPTION OF THE INVENTION

[0018] 1 is a schematic representation of a vehicle 100 having a steering arrangement 102. The steering arrangement 102 is configured to steer steered wheels 104 of the vehicle 100.

[0019] The steering system 102 includes a rack 106 configured to steer the steered wheels 104 .

[0020] The steering device 102 includes an electric motor 108 that adjusts the position of a rack 106 .

[0021] The steering device 102 includes a first control circuit 110 that controls the drive of the electric motor 108. The steering device 102 includes a second control circuit 112 that controls the drive of the electric motor 108. The steering device 102 includes a device 114 that switches from control of the drive of the electric motor 108 by the first control circuit 110 to control of the drive of the electric motor 108 by the second control circuit 112.

[0022] The first control circuit 110 is configured to drive and control the electric motor 108 depending on a deviation 116 of an actual position 118 of the rack 106 from a target position 120 of the rack 106 .

[0023] The second control circuit 112 is configured to drive and control the electric motor 108 depending on the deviation 116 of the actual position 118 of the rack 106 from the target position 120 of the rack 106 .

[0024] The device 114 is configured to switch from controlling the drive of the electric motor 108 by the first control circuit 110 to controlling the drive of the electric motor 108 by the second control circuit 112 depending on the deviation 116' of the actual value from the target value.

[0025] In one example, the actual value is the actual position 118 of the rack 106 and the target value is the target position 120 of the rack 106 .

[0026] In one example, the actual value is a derivative of the actual position 118 of the rack 106 and the target value is determined depending on the difference between the actual position 118 and the target position 120 .

[0027] The steering system 102 includes, in this example, a calculation device 122 configured to determine the deviation 116 of the actual position 118 from the target position 120 .

[0028] In one example, the computing device 122 is configured to determine the deviation 116 of the actual position 118 from the target position 120 by forming a difference between the actual position 118 and the target position 120 .

[0029] In one example, the computing device 122 is configured to determine the deviation 116' of the actual value from the target value.

[0030] In one example, the actual value is the actual position 118 of the rack 106 and the target value is the target position 120 of the rack 106 .

[0031] In one example, the actual value is a derivative of the actual position 118 of the rack 106 and the target value is determined depending on the difference between the actual position and the target position 120 of the rack 106 .

[0032] The device 114 is configured to monitor the deviation 116' of the actual value from the target value and, depending on the deviation 116', switch from controlling the drive of the electric motor 108 by the first control circuit 110 to controlling the drive of the electric motor 108 by the second control circuit 112.

[0033] In this example, the device 114 includes a switch 124 configured to switch from controlling the drive of the electric motor 108 by the first control circuit 110 to controlling the drive of the electric motor 108 by the second control circuit 112 depending on a switching signal 126.

[0034] In this example, the device 114 includes a monitoring device 128 configured to monitor a deviation 116' of the actual value from a target value and, depending on the deviation 116', determine a switchover signal 126 for switching from driving control of the electric motor 108 by the first control circuit 110 to driving control of the electric motor 108 by the second control circuit 112.

[0035] The device 114, in this example the monitoring device 128, can be configured to compare the deviation 116' of the actual value from the target value with a limit value and, if the deviation 116' of the actual value from the target value is greater than the limit value, to switch from controlling the drive of the electric motor 108 by the first control circuit 110 to controlling the drive of the electric motor 108 by the second control circuit 112.

[0036] The device 114, in this example the monitoring device 128, can be configured to determine a limit value depending on the deviation 116' of the actual value from the target value.

[0037] The device 114, in this example the monitoring device 128, can be configured to determine a limit value based on a difference between the actual position 118 and the target position 120 determined depending on the calculation device 122.

[0038] The device 114, in this example the monitoring device 128, can be configured to determine more localized limits as the deviation 116' of the actual value from the target value increases.

[0039] The device 114, in this example the monitoring device 128, can be configured to determine, with respect to the deviation 116' of the actual value from the target value, both a limit value for a positive deviation 116' of the actual value from the target value and a limit value for a negative deviation 116' of the actual value from the target value.

[0040] For example, the limit value for a positive deviation 116' of the actual value is configured to be different from the limit value for a negative deviation 116' of the actual value. The limit values ​​are configured in this example so that the speed of the rack 106 is within the acceptable range as long as the deviation 116' of the actual value from the target value is within the acceptable range. The limit values ​​are configured in this example so that the device 114 is configured to switch if the speed of the rack 106 is outside the acceptable range.

[0041] In this example, the first control circuit 110 is configured to determine a first target motor torque 130 depending on the deviation 116 of the actual position 118 from the target position 120 to drive and control the electric motor 108.

[0042] The second control circuit 112 is configured in this example to determine a second target motor torque 132 depending on the deviation 116 of the actual position 118 from the target position 120 for driving and controlling the electric motor 108.

[0043] In this example, the electric motor 108 is driven by either a first target motor torque 130 or a second target motor torque 132 depending on the position of the switch 124 .

[0044] 2 shows an exemplary first control circuit 110. The first control circuit 110 is configured, for example, to control a first target motor torque 130 via a first torque control circuit 206 depending on a deviation 202 of an actual value 134 from a target value 204. The first torque control circuit 206 is a PID control circuit in this example. The first control circuit 110 and the second control circuit 112 differ from each other. The first control circuit 110 and the second control circuit 112 preferably differ from each other in that the errors in the first control circuit 110 and the second control circuit 112 are not equal, resulting in a motor torque having an error.

[0045] In this example, the first control circuit 110 is configured to determine the target value 204 depending on the deviation 116 of the actual position 118 from the target position 120. In this example, the first control circuit 110 is configured to determine the target value 204 from a characteristic curve 208 that associates the target value 204 with the deviation 116. Here, the characteristic curve 208 can be configured to be selected from a family of characteristic curves 210 depending on the deviation 116 of the actual position 118 from the target position 120.

[0046] 3 illustrates an exemplary second control circuit 112. The second control circuit 112 is configured, for example, to control a second target motor torque 132 depending on the deviation 116 of the actual position 118 from the target position 120 via a second torque control circuit 302, which in this example is a PID control circuit.

[0047] FIG. 4 illustrates steps in a method for operating the steering device 102.

[0048] The method includes step 402 .

[0049] In step 402 , the electric motor 108 is controlled by the first control circuit 110 depending on the deviation 116 of the actual position 118 from the target position 120 .

[0050] The method includes step 404 .

[0051] In step 404, it is determined whether or not a switch should be made from controlling the drive of the electric motor 108 by the first control circuit 110 to controlling the drive of the electric motor 108 by the second control circuit 112 408.

[0052] If it is determined that a switch should be made from controlling the drive of the electric motor 108 by the first control circuit 110 to controlling the drive of the electric motor 108 by the second control circuit 112 408, step 406 is executed. If it is not determined that a switch should be made, step 402 is executed.

[0053] For example, the deviation 116' of the actual value from the target value is monitored.

[0054] For example, the deviation 116' of the actual value from the target value is compared with a limit value, and if the deviation 116' of the actual value from the target value is greater than the limit value, it is determined that a switch should be made from controlling the drive of the electric motor 108 by the first control circuit 110 to controlling the drive of the electric motor 108 by the second control circuit 112.

[0055] It can be configured to determine the limit value depending on the deviation 116' of the actual value from the target value. As the deviation 116' of the actual value from the target value increases, it can be configured to determine a more localized limit value.

[0056] The limit value can be configured to be determined depending on the deviation 116 of the actual position 118 of the rack 106 from the target position 120 of the rack 106. As the deviation 116 between the actual position 118 of the rack 106 and the target position 120 of the rack 106 increases, a more localized limit value can be determined.

[0057] In one example, for the deviation 116' of the actual value from the target value, both a limit value for a positive deviation 116' of the actual value from the target value and a limit value for a negative deviation 116' of the actual value from the target value are determined, where the limit values ​​are different, which means that asymmetric limit values ​​are used.

[0058] The limit value can be configured in this example so that the speed of the rack 106 is within the acceptable range as long as the deviation 116' of the actual value from the target value is within the limit value, meaning that a switchover occurs if the speed of the rack 106 falls outside the acceptable range.

[0059] In step 406 , a switch is made from controlling the drive of the electric motor 108 by the first control circuit 110 to controlling the drive of the electric motor 108 by the second control circuit 112 408 .

[0060] This can mean that the deviation 116' of the actual value from the setpoint value is monitored and, depending on the deviation 116', particularly more localized limit values ​​are determined.

[0061] This means that the deviation 116' of the actual value from the target value is monitored and, depending on the deviation 116' of the actual value from the target value, a switchover can be made from controlling the drive of the electric motor 108 by the first control circuit 110 to controlling the drive of the electric motor 108 by the second control circuit 112.

[0062] This means that the deviation 116' of the actual value from the target value is monitored and can be configured to switch over if the deviation 116' of the actual value from the target value is positive and greater than the limit value for a positive deviation, or if the deviation 116' of the actual value from the target value is negative and greater in absolute value than the limit value for a negative deviation 116' of the actual value from the target value.

[0063] Then, step 408 is executed.

[0064] In step 408 , the electric motor 108 is controlled by the second control circuit 112 depending on the deviation 116 of the actual position 118 from the target position 120 .

Claims

1. A steering device (102), The steering device (102) comprises a rack (106), an electric motor (108) for adjusting the position of the rack (106), a first control circuit (110) for controlling the driving of the electric motor (108) depending on a deviation (116) of an actual position (118) of the rack (106) from a target position (120) of the rack (106), a second control circuit (112) for controlling the driving of the electric motor (108) depending on the deviation (116) of the target position (118) from the actual position (120), and a device (114) for switching from the driving control of the electric motor (108) by the first control circuit (110) to the driving control of the electric motor (108) by the second control circuit (112), The device (114) is configured to switch over from controlling the drive of the electric motor (108) by the first control circuit (110) to controlling the drive of the electric motor (108) by the second control circuit (112) depending on the deviation (116') of the actual value from the target value, wherein: the actual value is an actual position (118) of the rack (106), and the target value is a target position (120) of the rack (106); Or, the actual value is a derivative of the actual position (118) of the rack (106), and the target value is determined depending on the difference between the actual position (118) of the rack (106) and the target position (120). A steering device (102).

2. 2. The steering device (102) of claim 1, wherein the device (114) is configured to monitor a deviation (116') of the actual value from the target value and to switch over from controlling the drive of the electric motor (108) by the first control circuit (110) to controlling the drive of the electric motor (108) by the second control circuit (112) depending on the deviation (116') of the actual value from the target value.

3. 3. The steering device (102) of claim 2, wherein the device (114) is configured to compare a deviation (116') of the actual value from the target value with a limit value, and to switch over from controlling the drive of the electric motor (108) by the first control circuit (110) to controlling the drive of the electric motor (108) by the second control circuit (112) if the deviation (116') of the actual value from the target value is greater than the limit value.

4. 4. A steering arrangement (102) according to claim 3, wherein the arrangement (114) is configured to determine the limit value depending on the deviation (116') of the actual value from the target value.

5. 5. A steering device (102) according to claim 4, wherein the device (114) is configured to determine limit values ​​that become more localized as the deviation (116') of the actual value from the target value increases.

6. 6. The steering device (102) according to claim 3, wherein the device (114) is configured to determine, for a deviation (116') of the actual value from the target value, both a limit value for a positive deviation (116') of the actual value from the target value and a limit value for a negative deviation (116') of the actual value from the target value.

7. A vehicle (100) comprising a steering device (102) according to any one of claims 1 to 6.

8. A method of operating a steering device (102), comprising: The steering device (102) comprises a rack (106), an electric motor (108) that adjusts the position of the rack (106), a first control circuit (110) that drives and controls the electric motor (108) depending on a deviation (116) of an actual position (118) of the rack (106) from a target position (120) of the rack (106), and a second control circuit (112) that drives and controls the electric motor (108) depending on the deviation (116) of the target position (118) from the actual position (120). Depending on the deviation (116') of the actual value from the setpoint value, a switchover (404) is made from the drive control (402) of the electric motor (108) by the first control circuit (110) to the drive control (408) of the electric motor (108) by the second control circuit (112), wherein: the actual value is an actual position (118) of the rack (106), and the target value is a target position (120) of the rack (106); Or, the actual value is a derivative of the actual position (118) of the rack (106), and the target value is determined depending on the difference between the actual position and the target position (120) of the rack (106). A method characterized by:

9. 9. The method according to claim 8, further comprising monitoring (404) a deviation (116') of the actual value from the setpoint value, and switching (406) from controlling the drive of the electric motor (108) by the first control circuit (110) to controlling the drive of the electric motor (108) by the second control circuit (112) depending on the deviation (116') of the actual value from the setpoint value.

10. 10. The method of claim 9, further comprising comparing the deviation (116') of the actual value from the target value with a limit value (404), and switching over (406) from controlling the drive of the electric motor (108) by the first control circuit (110) to controlling the drive of the electric motor (108) by the second control circuit (112) if the deviation (116') of the actual value from the target value is greater than the limit value.

11. 11. The method of claim 10, wherein the limit value is determined (404) depending on the deviation (116') of the actual value from the target value.

12. 12. The method of claim 11, wherein a more localized limit value is determined (404) as the deviation (116') of the actual value from the target value increases.

13. 13. The method according to claim 10, wherein for a deviation (116') of the actual value from the target value, both a limit value for a positive deviation (116') of the actual value from the target value and a limit value for a negative deviation (116') of the actual value from the target value are determined (404).

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