Control method, control system and computer readable medium for vehicle steer-by-wire

Abstract

The application relates to a control method, a control system and a computer readable medium for vehicle steer-by-wire. The control method comprises: obtaining an operating torque of a steering wheel; obtaining a target torque value output to a steering gear according to the operating torque and a transmission ratio; and outputting the target torque; wherein, when the vehicle speed is below a first speed, the target torque is a product of the operating torque and a first transmission ratio A1; when the vehicle speed is between the first speed and a second speed, the target torque is a product of the operating torque and a second transmission ratio A2; when the vehicle speed is above the second speed, the target torque is a product of the operating torque and a third transmission ratio A3; wherein, the relationship among the first transmission ratio A1, the second transmission ratio A2 and the third transmission ratio A3 is a transmission ratio of a planetary gear mechanism: A1=1+alpha; A2=alpha; A3=1+1 / alpha; wherein, alpha is greater than 1.

Description

TECHNICAL FIELD

[0001] The present application relates to a control method, a control system and a computer readable medium for vehicle steering-by-wire. BACKGROUND

[0002] Steering-by-wire (SBW) is different from traditional automobile steering systems, such as hydraulic power steering (HPS), electrical hydraulic power steering (EHPS), and electric power steering (EPS). SBW cancels the mechanical connection between the steering wheel and the steering actuator, such as the steering shaft that mechanically connects the steering wheel and the steering actuator.

[0003] A SBW system generally includes a steering wheel module, a steering module, and a control unit. The steering wheel module generally includes a steering wheel, sensors, a reducer, and a motor, and is mainly used to sense the steering angle and torque of the steering wheel operated by the driver and transmit them to the control unit, and receive the road feel information sent by the control unit and output the simulated road feel feedback to the steering wheel through the motor and the reducer. The steering module generally includes a steering execution motor, a reducer, a rack and pinion steering gear, and a steering angle sensor, which controls the steering execution motor to control the steering of the wheels by receiving the steering signal output by the control unit, and the steering angle sensor outputs the execution to the control unit.

[0004] SBW cancels the mechanical connection between the steering wheel and the steering actuator, has variable transmission ratio, and can avoid the shortcomings of slow rotation at low speed and too sensitive rotation at high speed, and even vehicle instability.

[0005] However, the inventors have found that the current variable transmission ratio algorithm of SBW is relatively complex, which is not conducive to the rapid response of SBW.

[0006] Therefore, there is a need in the art for a control method, a control system and a computer readable medium for vehicle steering-by-wire to solve the defect of complex algorithm of SBW in the prior art. SUMMARY

[0007] The technical problem to be solved by the present application is to provide a control method for SBW with simple steps and easy execution, to improve the response speed of SBW and reduce the requirement of processor computing power for SBW.

[0008] The control method of the vehicle steer-by-wire according to the first aspect of the present application comprises: obtaining an operation torque of a steering wheel; obtaining a target torque value output to a steering gear according to the operation torque and a transmission ratio; outputting the target torque; wherein, corresponding to a vehicle speed below a first speed, the target torque is a product of the operation torque and a first transmission ratio A1; corresponding to a vehicle speed between the first speed and a second speed, the target torque is a product of the operation torque and a second transmission ratio A2; corresponding to a vehicle speed above the second speed, the target torque is a product of the operation torque and a third transmission ratio A3; wherein, the relationship between the first transmission ratio A1, the second transmission ratio A2 and the third transmission ratio A3 is a transmission ratio of a planetary gear mechanism: A1 = 1 + a; A2 = a; A3 = 1 + 1 / a; wherein, a is greater than 1.

[0009] In some embodiments, the first speed is 30 km / h and the second speed is 100 km / h.

[0010] In some embodiments, the a is 1 < a < 60.

[0011] According to the second aspect of the present application, a computer readable medium has a computer program, which, when executed by a processor, implements the steps of the control method of the vehicle steer-by-wire according to the first aspect.

[0012] According to the third aspect of the present application, a control system of a vehicle steer-by-wire comprises: a steering wheel control module comprising a steering wheel sensor for sensing a steering intention, wherein the steering intention comprises an operation torque and a steering angle of the steering wheel being operated; a steering control module comprising a steering actuator acting on a steering wheel and electronically controlled according to a steering requirement, the steering actuator being capable of outputting a torque to a steering gear; a control unit capable of receiving an input signal of the steering wheel sensor and outputting a signal to the steering actuator, the control unit comprising: a memory for storing instructions executable by a processor; and the processor for executing the instructions to implement the steps of any one of claims.

[0013] In some embodiments, the steering actuator comprises an electric motor, and the control unit further comprises a pulse width modulation circuit and a driving circuit, and the steps implemented by the processor according to the instructions further comprise: the pulse width modulation circuit sends a pulse width modulation signal to the driving circuit to provide a driving signal for driving the steering actuator, and judges whether the output torque of the steering actuator is the target torque.

[0014] In some embodiments, the electric motor is a brushless direct current motor.

[0015] In some embodiments, the control unit has a first bus port, the steering wheel control module has a second bus port, and the steering control module has a third bus port. The control unit communicates with the steering wheel control module through the bus between the first bus port and the second bus port, so that the control unit acquires the operating torque sensed by the steering wheel sensor. The control unit communicates with the steering control module through the bus between the first bus port and the third bus port, so that the steering actuator acquires the value of the target torque.

[0016] In some embodiments, the bus communication is CAN bus communication or CAN FD bus communication.

[0017] In some embodiments, the steering wheel sensor includes a non-contact inductive position sensor. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to make the above objectives, features and advantages of the present application more apparent, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings, in which:

[0019] Figure 1 is a flowchart of a control method of vehicle steer-by-wire according to an embodiment of the present application;

[0020] Figure 2 is a structural schematic block diagram of a control system of vehicle steer-by-wire according to an embodiment of the present application;

[0021] Figure 3 is a structural schematic block diagram of a control system of vehicle steer-by-wire according to another embodiment of the present application.

[0022] REFERENCE SIGNS

[0023] 100 - control system of steer-by-wire;

[0024] 1 - steering wheel control module, 11 - steering wheel sensor, 12 - second bus port;

[0025] 2 - steering control module, 21 - steering actuator, 22 - steering gear, 23 - third bus port;

[0026] 3 - control unit, 31 - memory, 32 - processor, 33 - pulse width modulation circuit, 34 - drive circuit, 35 - first bus port. DETAILED DESCRIPTION

[0027] The present application is described in detail below with reference to the accompanying drawings and specific embodiments. Note that the aspects described below with reference to the accompanying drawings and specific embodiments are only exemplary and should not be understood as limiting the scope of protection of the present application in any way.

[0028] The following description is presented to enable any person skilled in the art to practice the application and is provided in the context of particular embodiments. Various modifications to the embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to a wide range of embodiments. Thus, the present application is not intended to be limited to the embodiments presented, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. In the following detailed description, numerous specific details are set forth in order to provide a more thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced without necessarily being limited to these specific details. In other instances, well-known structures and devices are shown in block diagram form, rather than in detail, in order to avoid obscuring the present application.

[0029] The reader's attention is directed to all papers and documents which are filed concurrently with this specification and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference. All the features disclosed in this specification, (including any accompanying claims, abstract, and drawings) can be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed in this specification is one example only of a generic series of equivalent or similar features. It is understood that the use of a flow diagram illustrates the operation of a system in accordance with embodiments of the present application. It is understood that the operations of the flow diagram can not necessarily be performed in the order shown. Other operations can be added or some operations can be performed in parallel. It is also understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms "connected" and "coupled" and variations thereof are used broadly and encompass both direct and indirect connections and couplings. Further, "connected" and "coupled" and variations thereof are used broadly and encompass connections and couplings where one or more intervening components are present. In addition, any reference to claimifying an element means that the element is claimed in one or more claims of the disclosure.

[0030] Reference is first made to Figure 1 In some embodiments, the control method of the vehicle steer-by-wire includes:

[0031] Step S100: obtaining an operation torque of a steering wheel;

[0032] Step S200: obtaining a target torque value output to a steering gear according to the operation torque and a transmission ratio;

[0033] Step S300: outputting the target torque obtained in S200 to perform steering.

[0034] For the ratio of the target torque to the operating torque, embodiments employ the transmission ratio of the planetary gear mechanism corresponding to the variable transmission ratio for different speed stages, i.e.:

[0035] Corresponding to the vehicle speed below the first speed, the target torque is the product of the operating torque and the first transmission ratio A1;

[0036] Corresponding to the vehicle speed between the first speed and the second speed, the target torque is the product of the operating torque and the second transmission ratio A2;

[0037] Corresponding to the vehicle speed above the second speed, the target torque is the product of the operating torque and the third transmission ratio A3;

[0038] Wherein, the relationship between the first transmission ratio A1, the second transmission ratio A2, and the third transmission ratio A3 is the transmission ratio of the planetary gear mechanism:

[0039] A1 = 1 + a;

[0040] A2 = a;

[0041] A3 = 1 + 1 / a; wherein a is greater than 1.

[0042] It can be understood that the transmission ratio of the planetary gear mechanism introduced above is similar to the meaning commonly defined in the art, i.e. satisfying the planetary gear mechanism motion characteristic equation:

[0043] n1 + an2 = (1 + a)n3, n1 is the sun gear rotation speed, n2 is the gear ring rotation speed, n3 is the planetary carrier rotation speed, and a is the gear ring teeth number ÷ sun gear teeth number, so the transmission ratio of the planetary gear mechanism theoretically has the following six values:

[0044] A. The gear ring is fixed, the sun gear is driven, and the planetary carrier is passive, i.e. n2 = 0, at this time the transmission ratio is n1 / n3 = 1 + a;

[0045] B. The gear ring is fixed, the planetary carrier is driven, and the sun gear is passive, i.e. n2 = 0, at this time the transmission ratio is n3 / n1 = 1 / (1 + a);

[0046] C. The sun gear is fixed, the gear ring is driven, and the planetary carrier is passive, i.e. n1 = 0, at this time the transmission ratio is n2 / n3 = 1 + 1 / a;

[0047] D. The sun gear is fixed, the planetary carrier is driven, and the gear ring is passive, i.e. n1 = 0, at this time the transmission ratio is n3 / n2 = a / (a + 1);

[0048] E. The planetary carrier is fixed, the sun gear is driven, and the gear ring is passive, i.e. n3 = 0, at this time the transmission ratio is -n1 / n2 = -a;

[0049] F. The planetary carrier is fixed, the ring gear is driven, and the sun gear is passive, i.e. n3=0, and the transmission ratio is -n2 / n1=-1 / α.

[0050] It can be understood that the transmission ratio of the planetary gear mechanism is described herein only to explain the basis of the variable transmission ratio between the target torque and the operating torque in the steer-by-wire control method in the above embodiments, and does not mean that a planetary gear mechanism is arranged between the steering wheel and the steering actuator. Therefore, for the transmission ratios of E and F in the above embodiments, since they are not truly connected by a planetary gear mechanism, and there is no reverse gear, the absolute values of E and F can be taken. For the planetary gear transmission ratio, α is greater than 1, and in addition, A1>A2>A3 needs to be ensured. In addition, the inventors have found that A1, A2, and A3 generally need to be greater than 1 to ensure basic steering functions, and therefore, according to the planetary gear transmission ratio formula and the above requirements, A1=1+α, A2=α, and A3=1+1 / α are selected. Generally, 1<α<60 is the simulation test data of a conventional passenger vehicle, but according to different vehicle models of different vehicle manufacturers, different steering wheel feel and requirements are required, and the value of α can be adjusted accordingly to meet the above-mentioned A1>A2>A3.

[0051] In some embodiments, the first speed is 30 km / h, and the second speed is 100 km / h, i.e. when the corresponding vehicle speed is below 30 km / h, the target torque is the product of the operating torque and A1, when the corresponding vehicle speed is between 30 km / h and 100 km / h, the target torque is the product of the operating torque and A2, and when the corresponding vehicle speed is above 100 km / h, the target torque is the product of the operating torque and A3. The first speed and the second speed adopt the above values, which have good universality. However, it can be understood that the values of the first speed and the second speed are not limited to the above description, and other values can be defined, and corresponding adjustments can be made according to different vehicle models of different vehicle manufacturers.

[0052] The above embodiments have the beneficial effects that, first, the above embodiments ensure the basic advantages of steer-by-wire, i.e. at low vehicle speed, the target torque output to the wheels has a large multiple increase from the steering wheel torque, reducing the required steering wheel torque and reducing the number of steering wheel turns; at high vehicle speed, the target torque output to the wheels has a large decrease from the steering wheel torque, resulting in the need to turn the steering wheel by a large angle to change direction, reducing the disadvantage of the steering wheel being uncontrollable, a small turn resulting in lateral movement, improving safety, stability and reliability. At medium vehicle speed, similarly, the target torque output to the wheels has a certain degree of decrease from the steering wheel torque, resulting in the need to turn the steering wheel by a moderate angle to change direction, reducing the disadvantage of the steering wheel being uncontrollable, improving the comfort of the driver's driving. Furthermore, the inventors have found that using the transmission ratio of the planetary gear mechanism as the transmission ratio of steer-by-wire, on the basis of realizing the above advantages of steer-by-wire, the control logic and the corresponding programming algorithm are relatively simple to implement, and have good reliability in actual operation, and because the algorithm is simple, the response speed is fast in actual operation, and the requirement for processor computing power is also relatively low, which is conducive to reducing the cost of the corresponding control unit.

[0053] Reference Figure 2 As introduced above, in some embodiments, the control system 100 of the vehicle steer-by-wire can include a steering wheel control module 1, a steering control module 2 and a control unit 3.

[0054] The steering wheel control module 1 includes a steering wheel sensor 11 for sensing the steering intention, wherein the steering intention includes the steering torque and the steering angle of the steering wheel being operated. Preferably, the steering wheel sensor 11 can include contactless inductive position sensors, , but not limited thereto, which can accurately and reliably detect the torque and angle of the steering wheel and convert them into electronic signals for transmission.

[0055] The steering control module 2 includes a steering actuator 21 acting on the steering wheel and electronically controlled according to the steering requirement, which can output a target torque to the steering actuator 22. The steering actuator 21 can generally be a combination of a motor and a reducer, and the motor can be a brushless DC motor, for example, which has a long system life and stable operation, but is not limited thereto, for example, a brush motor can also be used. The steering actuator 22 can be an actuator such as a rack and pinion.

[0056] The control unit 3, capable of receiving the input signal of the steering wheel sensor 11 and outputting the signal to the steering actuator 21, comprises: a memory 31 for storing instructions executable by a processor; and a processor 32 for executing the instructions to implement the steps of the control method as described in the above embodiments. The control unit 3 can be in the form of a micro-control unit (MCU), which has a similar meaning as the common meaning in the art, for example, the common form of MCU is a single-chip microcomputer, which integrates the central processing unit (CPU) with a proper reduction in frequency and specifications, and the memory, timer, and peripheral interfaces such as USB, A / D conversion, UART, PLC, DMA, etc. on a single chip to form a chip-level computer for different application scenarios to make different combinations of control.

[0057] With reference to Figure 3 As shown, preferably, in some embodiments, the circuit structure of the control unit 3 for controlling the output of the steering actuator 21 to reach the target torque can be that the control unit 3 further comprises a pulse width modulation circuit 33 and a driving circuit 34, and the instructions executed by the processor 32 further comprise: the pulse width modulation circuit 33 sends a pulse width modulation (PWM) signal to the driving circuit 34, the driving circuit 34 can be in the form of a gate drive unit (GDU) to provide a driving signal for driving the steering actuator 21, and it is determined whether the output torque of the steering actuator 21 is the target torque, for example, according to the current of the motor in combination with the numerical relationship between the target torque and the operating torque as described above, if the target torque is not reached, the pulse width modulation signal is continuously adjusted until the target torque is reached.

[0058] With reference to Figure 3As shown, the communication between the control unit 3 and the steering wheel control module 1 and the steering control module 2 can be bus communication, for example, CAN bus or CAN FD bus communication. Here, the CAN bus and CAN FD bus communication have similar meanings as in the art, i.e., Controller Area Network (CAN), a serial communication protocol bus for real-time applications, the CAN protocol is used for communication between various different elements in the vehicle, instead of the power wiring harness. The characteristics of the CAN protocol include serial data communication with integrity, providing real-time support, high transmission rate, and having addressing and error detection capabilities. The CAN FD (CAN with Flexible Data rate) bus communication is similar to the CAN, but the CAN FD has a faster speed and a further expanded data field length compared with the CAN. The specific bus communication structure can be that the control unit 3 has a first bus port 35, the steering wheel control module 1 has a second bus port 12, and the steering control module 2 has a third bus port 23. The control unit 3 and the steering wheel control module 1 communicate through the bus between the first bus port 35 and the second bus port 12, so that the control unit 3 obtains the operating torque sensed by the steering wheel sensor 11. The control unit 3 and the steering control module 2 communicate through the bus between the first bus port 35 and the third bus port 23, so that the steering actuator 21 obtains the value of the target torque. The use of bus communication has the beneficial effect of further reducing the power wiring harness and further simplifying the structure of the system, as described above.

[0059] In addition, it should be noted that the memory 31 and the processor 32 in the above description are not limited to a specific memory or processor. In some cases, the memory 31 and the processor 32 can have a distributed structure, for example, they can include a memory and a processor located at the vehicle end and the background cloud end respectively, and the vehicle end and the background cloud end together implement the above-mentioned control method of steer-by-wire. Furthermore, in the embodiment using the distributed structure, the specific execution terminal of each step can be adjusted according to the actual situation, and the specific scheme of each step implemented in a specific terminal should not be improperly limited to the protection scope of the present application.

[0060] Another aspect of the present application also provides a computer readable medium having a computer program, which, when executed by a processor, implements the steps of the control method of steer-by-wire of a vehicle as described in any one or more of the above embodiments. For details, please refer to the above description, which will not be repeated here.

[0061] In summary, the vehicle steer-by-wire control method, control system and computer readable medium have the following advantages, including but not limited to: the transmission ratio of the planetary gear mechanism is used as the transmission ratio of the steer-by-wire, the control logic and the corresponding programming algorithm are relatively simple, the reliability is good in actual operation, and the response speed is fast in actual operation due to the simple algorithm, and the requirement for processor operation capacity is also low, which is conducive to reducing the cost of the corresponding control unit.

[0062] The various illustrative logical blocks, and circuits described in connection with the embodiments disclosed herein can be implemented or performed with a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The general purpose processor can be a microprocessor, but in the alternative, the processor can be any conventional processor, controller, microcontroller, or state machine. A processor can also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0063] The steps of a method or algorithm described in connection with the embodiments disclosed herein can be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium can be integral to the processor. The processor and the storage medium can reside in an ASIC. The ASIC can reside in a user terminal. In the alternative, the processor and the storage medium can reside as discrete components in a user terminal.

[0064] In one or more exemplary embodiments, the functions described can be implemented in hardware, software, firmware, or any combination thereof. If implemented in software as a computer program product, the functions can be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media can be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0065] The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. However, it is to be understood that the scope of protection is not to be limited to the specific embodiments disclosed and that modifications are possible within the scope of the application.

Claims

1. A control method of a vehicle steer-by-wire, characterized by, The method comprises: acquiring an operation torque of a steering wheel; obtaining a value of a target torque output to a steering gear according to the operation torque and a transmission ratio; outputting the target torque; wherein, corresponding to a vehicle speed below a first speed, the target torque is a product of the operation torque and a first transmission ratio A1; corresponding to a vehicle speed between the first speed and a second speed, the target torque is a product of the operation torque and a second transmission ratio A2; corresponding to a vehicle speed above the second speed, the target torque is a product of the operation torque and a third transmission ratio A3; wherein, a relationship between the first transmission ratio A1, the second transmission ratio A2 and the third transmission ratio A3 is a transmission ratio of a planetary gear mechanism: A1＝1+α； A2＝α； A3＝1+1 / α； wherein, α is greater than 1.

2. The control method according to claim 1, characterized by, The first speed is 30 km / h, and the second speed is 100 km / h.

3. The control method according to claim 1, characterized by, The α is 1 < α < 60.

4. A computer readable medium having a computer program thereon, characterized in that, The program is executed by a processor to implement the control method of any one of claims 1-3.

5. A control system (100) for a vehicle steer-by-wire, characterized by The method comprises: a steering wheel control module (1) comprising a steering wheel sensor (11) for sensing a steering intention, wherein the steering intention comprises an operation torque of the steering wheel being operated, a steering angle; a steering control module (2) comprising a steering actuator (21) acting on a steering wheel and electronically controlled according to a steering requirement, the steering actuator (21) being capable of outputting a torque to a steering gear (22); a control unit (3) capable of receiving an input signal of the steering wheel sensor (11) and outputting a signal to the steering actuator (21), the control unit (3) comprising: a memory (31) for storing instructions executable by a processor; and the processor (32) for executing the instructions to implement the control method of any one of claims 1-3.

6. The control system (100) of claim 5, characterized in that The steering actuator (21) comprises a motor, and the control unit (3) further comprises a pulse width modulation circuit (33) and a driving circuit (34), and the processor (32) is configured to execute the instructions to implement the control method further comprising: The pulse width modulation circuit (33) sends a pulse width modulation signal to the driving circuit (34) to provide a driving signal for driving the steering actuator (21), and determines whether the output torque of the steering actuator (21) is the target torque.

7. The control system (100) of claim 6, characterized by The motor is a brushless direct current motor.

8. The control system (100) of claim 5, characterized in that, The control unit (3) has a first bus port (35), the steering wheel control module (1) has a second bus port (12), and the steering control module (2) has a third bus port (23), the control unit (3) and the steering wheel control module (1) communicate through the bus between the first bus port (35) and the second bus port (12) to enable the control unit (3) to acquire the operation torque sensed by the steering wheel sensor (11); and the control unit (3) and the steering control module (2) communicate through the bus between the first bus port (35) and the third bus port (23) to enable the steering actuator (21) to acquire the value of the target torque.

9. The control system (100) of claim 8, characterized in that The bus communication is CAN bus communication or CAN FD bus communication.

10. The control system (100) of claim 5, characterized in that, The steering wheel sensor (11) comprises contactless inductive position sensors (CIPOS).

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