Steering system and disengagement method for use in test drives of autonomous vehicles

Abstract

The invention is a steering system for use in test drives of an automated vehicle, comprising a manual steering device configured to manually steer the vehicle, a steering axle (30) attached to the manual steering device, and a direct drive motor (35) controllably influencing torque on the steering axle (30), wherein the direct drive motor (35) has a rotational axis (37) coaxial with the steering axle (30). The steering system is characterized in that it has at least two predetermined states characterizing different driving conditions, wherein each predetermined state has at least one predetermined disengagement limit, and that it further comprises a controller assembly operable based on a control parameter, configured to detect an actual predetermined state of the vehicle, and that the controller assembly initiates disengagement of the direct drive motor (35) if a case of reaching at least one predetermined disengagement limit corresponding to the actual predetermined state, based on a difference between a specified value of the control parameter and an actual value of the control parameter. The invention also relates to a disengagement method, and a data processing system, a computer program product and a computer readable medium for performing the method.

Description

Technical Field

[0001] This invention relates to a steering system for use in test driving of an autonomous vehicle. The invention also relates to a disengagement method, as well as a data processing system, computer program product, and computer-readable medium for implementing the method. Background Technology

[0002] People are seeking a more relaxed and enjoyable driving experience; therefore, various solutions for assisting drivers in maneuvering vehicles are known in this technological field. Vehicles with automatic self-driving capabilities are also known, that is, vehicles capable of driving themselves with little or no user intervention.

[0003] US2003 / 0221898A1 discloses a motor-driven steering controller adapted to reduce steering torque during counter-steering operations. The EPS motor is configured to steer the front wheels via reduction gears, a rack, and a pinion, thereby reducing the force required by the operator to operate the steering wheel and thus assisting the operator in driving the vehicle. Instead of being directly attached to the steering wheel shaft, the motor is connected via gears, which requires additional moving parts that are prone to wear and failure.

[0004] The document calculates and executes the steering torque required for counter-steering assistance; however, in cases of incorrect calculation, the operator could overtake the steering. It does not disclose methods to ensure safe overtaking.

[0005] US2006 / 0015228A1 discloses a method and system for handling steering dead zone in mobile machinery such as agricultural vehicles. The method includes an operator manually measuring a dead zone value, which is then used in a controller to compensate for the dead zone, thereby mitigating undesirable effects associated with it. The system includes a reversible electric motor, allowing the steering wheel to be turned clockwise or counterclockwise. Current calibration of the electric motor ensures the steering wheel turns without generating excessive torque, allowing for user-controlled overdrive. The motor is not directly driven, therefore additional gears are required to transmit the motor's torque to the steering wheel.

[0006] US2006 / 0195238A1 discloses a method and system for implementing automated vehicle control with parameter-driven disengagement, wherein the vehicle is an agricultural vehicle, such as a tractor or harvester. The vehicle is automatically guided along a predetermined route, and if predetermined parameters are exceeded, the automatic steering commands are suspended until a new engagement signal is received. The predetermined parameters for the system may be a minimum vehicle speed, a maximum vehicle speed, an approach angle between the vehicle and the route vector, a cross-track error limit, vehicle braking, signals from a seat switch or timeout sensor, excessive tilting or rolling of the vehicle, excessive acceleration, etc., or manual over-control by the user. The vehicle preferably employs a gearless electric motor.

[0007] EP1972482A2 discloses a steering drive system, preferably for industrial trucks. This steering drive system includes a steering drive unit with a motor that drives an adjusting wheel via a driveshaft when the motor is activated. This application discloses a solution for steering via wires, wherein a brushless electric motor is connected to the steering system. When the adjusting wheel is driven by the motor, the driver or operator can feel the direct connection between the steering mechanism and the adjusting wheel.

[0008] US2012 / 0130596A1 discloses a vehicle guidance system for agricultural vehicles, guiding them along a predetermined path to ensure efficient use of fuel or agricultural materials. The vehicle includes a steering wheel assembly having a steering wheel and a hub, wherein the hub is connected to a steering shaft and a drive assembly for direct drive of the steering wheel assembly. The axis of the drive assembly is coaxial with the steering wheel assembly. This application does not disclose a torque limit that the drive assembly cannot exceed, and therefore does not ensure that the driver can take over control of the vehicle at any time when necessary, for example, to avoid an accident.

[0009] US2014 / 0214275A1 discloses a steering controller for precision agriculture. This steering controller can rotate the steering axle of a vehicle to guide the vehicle along a desired path. A hub can be coupled to the steering axle of the vehicle, and a motor can rotate the steering axle by rotating the hub. The vehicle is preferably an agricultural vehicle, and its steering system is typically a hydraulic-based system. An operator can take control of the vehicle by rotating a steering wheel; however, the application does not disclose how this is made possible.

[0010] US2016 / 0334790A1 discloses an automated vehicle modification system. It employs a steering motor to apply torque to the steering column, wherein the steering motor can be an electric motor such as a brushed or brushless motor, and it interfaces with the steering column via pulleys or gears. The system can detect user input and allow the user to take control of the vehicle; it can even deduce the direction of the torque applied by the user.

[0011] Given the known methods, there is a need for a steering system that can be used to test autonomous vehicles under various traffic conditions and driving situations, and that allows for user or driver intervention in the event of unexpected or dangerous situations during testing. There is also a need for a steering system that allows the user to disengage and take control during testing, especially in cases where the vehicle's automatic steering malfunctions or has problems. Summary of the Invention

[0012] The main objective of this invention is to provide a steering system for use in testing autonomous vehicles that minimizes the drawbacks of existing technologies.

[0013] The term “autonomous vehicle” means any vehicle that can operate at least partially without human driver intervention, such as a self-driving vehicle, a semi-autonomous vehicle with self-driving or automatic driving capabilities, wherein the self-driving or automatic driving capabilities may be limited to certain road or environmental conditions or driving situations (such as automatic parking), or any conventional vehicle equipped with devices for enabling the automatic driving of the vehicle (such as a vehicle with a driving robot).

[0014] In the near future, transportation is expected to be fully automated through the use of autonomous vehicles, which can operate even without any human intervention. However, such vehicles need to be tested to ensure the safety of users, passengers, transported goods, the vehicles themselves, and any other people, vehicles, or objects along the autonomous vehicle's route. For example, redundant hardware and software solutions are needed to meet the necessary safety requirements. The software responsible for the vehicle's autonomous driving must be safe and should be prepared for safe handling of the vehicle in any possible environment, vehicle, and traffic conditions, including rare and unexpected events.

[0015] Some vehicles are designed with semi-autonomous solutions, meaning that the vehicle can drive itself automatically under certain conditions, but requires human driver intervention in dangerous or unexpected situations.

[0016] To ensure safe operation and compliance with safety regulations, autonomous vehicles and the software responsible for driving them require comprehensive testing. This testing needs to cover a wide range of driving scenarios that may occur during actual use of the vehicle, including driving in traffic and on public roads.

[0017] The purpose of this invention is to provide a steering system that allows for safe testing of automated vehicles under traffic conditions and various driving situations, and also allows for vehicle testing of different levels of automation, even fully automated vehicles.

[0018] A major problem with autonomous vehicles is that most of their self-driving functions are designed for use only under specific conditions (e.g., on highways, in urban areas, in specific weather conditions, in darkness, or at night), and therefore suffer from "fragility." Fragility refers to the phenomenon where the vehicle's autonomous driving functions work well under their intended conditions, but the system requires human intervention to handle situations the software wasn't designed to handle. This presents a challenge for human drivers: they need to recognize when automation is malfunctioning and understand why. Studies of human factors have shown that humans are slow to detect problems with automation, and even when they do, they are slow to understand them. When automation malfunctions, the unexpected shift requiring driver intervention or restoration of manual control of the vehicle can occur abruptly, and the driver may not be prepared to take over. Therefore, another object of the present invention is to provide a steering system that allows for safe disengagement and overtaking, even under various driving conditions and traffic situations.

[0019] Another object of the present invention is to provide a disengagement method that allows the driver or user to take over control of the vehicle.

[0020] Furthermore, the object of the present invention is to provide a data processing system comprising means for performing the steps of the method, a non-transitory computer program product for implementing the steps of the method according to the present invention on one or more computers, and a non-transitory computer-readable medium comprising instructions for performing the steps of the method on one or more computers.

[0021] The object of the present invention can be achieved by the steering system according to claim 1. The object of the present invention can also be achieved by the method according to claim 10, the data processing system according to claim 12, the non-transitory computer program product according to claim 13, and the non-transitory computer-readable medium according to claim 14. Preferred embodiments of the present invention are defined in the dependent claims.

[0022] Compared with existing methods, the main advantage of the steering system according to the present invention is that it allows for testing of autonomous vehicles under various driving conditions, even at different levels of automation, and thus helps to prevent autonomous vehicles from malfunctioning and malfunctioning.

[0023] Another advantage of the steering system according to the invention is that it can be used by trained safety drivers as well as any driver, because the steering system can operate like any conventional steering system, thus requiring no special skills to drive the test vehicle. Optionally, the steering system according to the invention can also operate without a driver, for example, for testing robotaxi company vehicles on public roads or, more preferably, in closed areas where other vehicles are not allowed to enter during testing.

[0024] Furthermore, the steering system according to the invention can also be used to train test drivers. Training may include driving a test vehicle equipped with the steering system according to the invention, or the steering system according to the invention may be installed on a test bench or any other simulated environment to provide realistic training to test drivers in a safe and reliable testing environment.

[0025] The steering system designed according to the present invention can be implemented in fully automated vehicles without a manual steering device such as a steering wheel or lever, and in certain situations, it can also be implemented in vehicles with a manual steering device, i.e., semi-automatic vehicles or vehicles with automatic driving functions. In the first case, adding a manual steering device allows for more sophisticated testing of automated vehicles in a safe manner, i.e., if unexpected or malfunctioning behavior of the vehicle is detected, a human driver can intervene, so the vehicle can be tested not only on closed tracks but also on ordinary roads under real traffic conditions. In the latter case, the steering system can be mounted on an existing vehicle steering axle.

[0026] The steering system according to the invention can be used for professional and comprehensive testing of the quality of autonomous vehicles, or one or more of the autonomous or self-driving functions or characteristics of a vehicle.

[0027] The steering system designed according to the present invention can be configured to test technologies at different levels of automation, preferably from level 1 to level 5. Level 5 automation does not require a human driver; however, for the purpose of developing and fine-tuning the autonomous driving software, it is preferable that the test vehicle has an interface for manual steering, such as a steering wheel, joystick, or any mechanism that can provide safe manual driving input during testing. Even if the software responsible for autonomous driving has some faults or errors, or if unexpected situations occur during test driving, this manual intervention by the driver can ensure the safety of the vehicle and its environment.

[0028] For example, Level 1 automation requires the driver to physically operate the vehicle at all times (but not necessarily simultaneously) with their hands and / or feet. An example of Level 1 automation is adaptive cruise control, which helps the driver maintain a safe distance from other vehicles. Level 2 automation requires the driver to monitor the road and be ready to take over control at any time, preferably for short periods. An example of Level 2 automation is automatic parking. In the case of Level 3 automation, the driver is expected to have occasional control, but with sufficiently comfortable transition times. An example of a Level 3 vehicle is one that allows people to cruise on highways, preferably including driving on and off ramps, without any driver intervention. At Level 4, the driver should provide destination or navigation input, but is not expected to be able to take over control at any time during the journey. Currently, there are no Level 4 vehicles on the market; however, a Level 4 vehicle should be able to complete the entire journey from origin to destination without any driver input or intervention. Levels 1 through 4 of automation all require the driver to monitor the autonomous vehicle to behave as expected and to intervene (restore control) if the autonomous vehicle cannot handle the situation.

[0029] It has been recognized that superior dynamic performance and a comfortable driving experience can be achieved by directly mounting a drive motor on the steering axle of a vehicle, because a direct drive motor adds only a very small amount of inertia to the steering system that is imperceptible to the driver, thus providing a typical driving experience. Furthermore, since the direct drive motor can directly drive the vehicle, precise control of steering position and speed can be achieved, eliminating the need for additional transmission systems or gears, pulleys, gear assemblies, etc. Without an additional transmission system or gears, there is a expectation of no backlash or wear, which improves the reliability of the steering system according to the invention. In addition, it reduces the number of moving parts within the steering system, which also contributes to more reliable operation. The reduced number of moving parts improves the energy efficiency of the steering system because losses from intermediate mechanical components can be eliminated, and fewer parts apply reduced weight to the steering column, allowing for easier and more precise driving. All of these factors combined result in a smaller eco-friendly steering system footprint.

[0030] Another advantage of the steering system according to the invention is its compact size, with small axial dimensions and large bores, which allows the steering system to be installed in a variety of vehicles for testing purposes.

[0031] The steering system with a direct drive motor according to the present invention has a high torque-to-inertia ratio and a high torque-to-mass ratio, low torque ripple or cogging, and high torque even at low speeds.

[0032] Furthermore, due to the fewer components in the direct drive and steering system, the steering system according to the invention exhibits low noise and low self-excited vibration levels. The fewer components also reduce the need for and frequency of maintenance.

[0033] In some embodiments, the steering system is implemented with relatively large air gaps between the components of the steering system, which reduces cooling requirements and also results in relatively high shock resistance and adaptability to dirty environments.

[0034] The steering system according to the invention can therefore be used in the testing of any autonomous vehicle. Attached Figure Description

[0035] Preferred embodiments of the present invention are described below with reference to the following drawings, in which...

[0036] Figure 1 This is a schematic diagram of the cross-section of a traditional electric steering drive layout.

[0037] Figure 2 This is a schematic cross-sectional view of a preferred steering system with a direct-drive motor according to the present invention.

[0038] Figure 3 This is a side view of a preferred embodiment of the steering system according to the present invention.

[0039] Figure 4 It is based on Figure 3 A cross-section of a preferred embodiment of the steering system.

[0040] Figure 5 This is a schematic overview diagram of a preferred steering system according to the present invention and its connection with other vehicle components.

[0041] Figure 6 This is an example architecture of the steering system according to the present invention.

[0042] Figure 7 This is an example architecture of a steering system according to the invention, included in a simulated environment.

[0043] Figure 8 The illustration shows a schematic diagram of the estimated detachment event.

[0044] Figure 9 This is a diagram illustrating the disengagement and engagement events based on the current signal of a direct-drive motor.

[0045] Figure 10 This is a diagram illustrating the effect of state changes when there are no bridging states between them.

[0046] Figure 11 It is a diagram illustrating the effect of state changes that bridge the gap between states.

[0047] Figure 12 These are illustrations of two different predetermined states with a bridging state, and the typical deceleration limit in each state is associated with torque.

[0048] Figure 13 The diagram illustrates three different predetermined states with bridging states between them, and the typical deceleration limit for each state is associated with torque.

[0049] Figure 14 The diagram illustrates four different predetermined states with bridging states between them, and the typical de-limiting relationship for each state is associated with torque.

[0050] Figure 15 This is a diagram illustrating the effect of speed bumps on vertical acceleration signals.

[0051] Figure 16 This is a graph showing the relationship between the torque of the direct drive motor and the EPAS auxiliary torque under different predetermined conditions.

[0052] Figure 17 A diagram illustrating the various uses of the steering system according to the invention, and the relationships between those uses. Detailed Implementation

[0053] This invention relates to a steering system for use in testing autonomous vehicles. The steering system according to the invention includes a manual steering device configured to manually steer the vehicle, thus allowing the driver or user to take over control of the steering system or the vehicle, thereby avoiding accidents or dangerous situations and ensuring the safety of the vehicle under test and its environment, including other vehicles, objects, passengers, etc. The manual steering device is preferably a steering wheel, a lever, or any other handle that can be used to manually steer the vehicle.

[0054] The steering system according to the invention further includes a steering axle attached to a manual steering device, and a direct drive motor controllably influencing the torque on the steering axle, wherein the direct drive motor has a rotation axis coaxial with the steering axle. The direct drive motor is preferably a permanent magnet synchronous motor, such as a brushless DC motor.

[0055] The steering system according to the invention has at least two predetermined states characterizing different driving conditions, wherein the driving conditions preferably include at least one of the following: parking maneuver, traffic jam, urban driving, suburban driving, low-speed driving, high-speed driving, emergency maneuver, and closed-road driving. Preferably, the predetermined states are determined based on at least one state parameter, wherein the at least one state parameter is the vehicle's speed, lateral acceleration, yaw rate, and / or longitudinal acceleration.

[0056] Each predetermined state has at least one predetermined disengagement limit, and exceeding the predetermined disengagement limit preferably initiates disengagement of the direct drive motor. Preferably, in the event of disengagement, the vehicle's driver or user is informed and requested to take over control of the vehicle.

[0057] The steering system according to the invention also includes a controller component operable based on control parameters. The control parameters are preferably the position of the manual steering mechanism, the torque on the manual steering mechanism, the force on the manual steering mechanism, the speed of the manual steering mechanism, or the current of the direct drive motor.

[0058] The controller assembly is configured to detect the actual predetermined state of the vehicle, and includes a motion controller, a motor drive unit, and a feedback device. The motion controller is configured to generate a command including a predetermined value of a control parameter to be achieved. The motor drive unit is configured to supply power to the direct drive motor based on the command received from the motion controller, and the feedback device is configured to monitor the actual value of the control parameter and determine the difference between the predetermined value of the control parameter according to the command and the actual value of the control parameter. The feedback device is further configured to initiate disengagement of the direct drive motor if at least one predetermined disengagement limit corresponding to the actual predetermined state is reached based on the difference.

[0059] The motion controller preferably includes a high-level controller and a low-level controller, wherein the high-level controller preferably generates a motion profile including specified values ​​of control parameters for directly driving the motor, and the low-level controller receives the motion profile and generates a command including specified values ​​of control parameters to be achieved.

[0060] The controller assembly preferably also includes a wire drive unit arranged between the high-level controller and the low-level controller for converting the motion profile generated by the high-level controller into a signal that can be received by the low-level controller.

[0061] The steering system according to the invention preferably has an intermediate bridging state between two predetermined states, providing a smooth transition between the disengagement restrictions of the two predetermined states.

[0062] Preferred embodiments of the steering system according to the present invention will be combined below. Figures 1 to 17 To describe in more detail.

[0063] Figure 1 This is a schematic cross-sectional view of a conventional electric steering drive arrangement, which includes a steering axle 10 driven by a motor 15, wherein the motor 15 is attached to the steering axle 10 via a drive gear 12 and a reduction gearbox 14. At least one bearing 11 is preferably arranged around the steering axle 10. The steering axle 10 is rotatable about a first axis 17, and the motor 15 is rotatable about a second axis 18. In situations such as... Figure 1In conventional motor drive arrangements, the first axis 17 and the second axis 18 are not coincident and are not coaxial, thus requiring the drive gear 12 to be raised. Preferably, an angle sensor 13 is attached to the motor 15 to measure the rotation of the motor 15, which can be used to indicate the position of the steering wheel attached to the steering axle 10 for manual steering. The angle sensor 13 also typically rotates about the second axis 18. If the motor 15 is a brushless DC motor (BLDC motor), it is preferably equipped with a commutation encoder 16 to generate a commutation signal for commutating the brushless DC motor. The commutation encoder 16 is also preferably arranged to rotate about the second axis 18, which is the axis of the motor 15.

[0064] and Figure 1 on the contrary, Figure 2 A cross-section of a steering system according to the invention is shown. The steering system includes a steering axle 20 rotatable about a first axis 27 and a direct drive motor 25 rotatable about the first axis 27 of the steering axle 20. Preferably, the steering system also includes at least one bearing 21 surrounding the steering axle 20. Preferably, the steering system also includes an angle sensor 23 attached to the steering axle 20 via a gear 22, and the angle sensor 23 is rotatable about a second axis 28, which is preferably arranged parallel to the first axis 27 of the steering axle 20 and the direct drive motor 25.

[0065] The following provides an example of an implementation of a steering system according to the present invention. The steering system according to this example includes the following hardware components:

[0066] A brushless DC motor (BLDC motor), which serves as a direct drive motor 25, features passive cooling and an aluminum alloy housing, preferably 7075 aluminum alloy (AA7075).

[0067] An absolute multi-turn encoder with optical scanning as an angle sensor 23, which is capable of precise position measurement, even for positions exceeding 360°.

[0068] High-performance servo driver, ideally with 18A continuous RMS current and 36A peak RMS current.

[0069] A temperature sensor is used to monitor the temperature of the windings of the rotor of the direct-drive motor 25.

[0070] A boost converter (preferably with specifications of 12V / 48V and 50A) is used to supply power to the direct drive motor 25, and

[0071] Steering axle 20, preferably the original (OEM) steering column of the vehicle to be tested.

[0072] Figure 3 and Figure 4 A preferred embodiment of the steering system according to the present invention is shown, wherein Figure 3 It is a side view of the steering system and Figure 4 This is a cross-sectional view of the steering system.

[0073] according to Figure 3 and Figure 4 The steering system includes a direct drive motor 35 having a stator 35a, a rotor 35b, and a motor shaft 35c, wherein the direct drive motor 35 is rotatable about an axis 37. The motor shaft 35c is arranged around a steering axle 30 such that the axis 37 of the motor shaft 35c is coaxial with the axis of the steering axle 30, i.e., both the steering axle 30 and the motor shaft 35c are rotatable about the axis 37. Preferably, the steering axle 30 is the original steering column of the vehicle to be used for test driving.

[0074] The direct drive motor 35 is preferably disposed within the motor housing 36. To provide a sufficiently strong contact between the stator 35a of the direct drive motor 35 and the motor housing 36, an adhesive method is used, preferably in the form of a special adhesive. The same adhesive method can be applied between the rotor 35b and the motor shaft 35c. The motor housing 36 of the direct drive motor 35 is preferably secured to the steering axle 30 using the original bolt holes of the steering axle 30.

[0075] Preferably, one or more first bearings 31 are arranged around the motor shaft 35c, according to Figure 3 and Figure 4 In the preferred embodiment shown, the direct drive motor 35 has two first bearings 31 arranged in respective bearing housings 38 and 48.

[0076] The direct drive motor 35, due to its compact size, has low inertia; therefore, if the controller assembly controlling it has been finely tuned or calibrated, it can precisely turn the steering wheel attached to the steering axle 30 to the desired position. As another advantage, the compact size of the direct drive motor 35 does not impose excessive additional weight on the steering axle 30. As a result, the steering system according to the invention is highly responsive and maintains sufficient power. Preferably, a temperature sensor is arranged in the steering system to monitor the winding temperature of the rotor 35b.

[0077] The steering system preferably uses 48VDC current, thus requiring a motor drive unit to supply power to the direct drive motor 35. The motor drive unit is preferably integrated into the vehicle, for example, into the vehicle's trunk, and may include a battery and / or a boost converter.

[0078] The motor shaft 35c is preferably connected to the steering axle 30 via a clutch 40, and the clutch 40 is preferably connected to the motor shaft 35c via a first bracket 41.

[0079] As an extension of the steering axle 30, the steering system according to the invention may include an inner pillar 32 and an outer pillar 34, which are arranged coaxially with each other and with the axis 37 of the steering axle 30. A second bearing 49a may be arranged between the inner pillar 32 and the outer pillar 34. Additional bearings, such as a third bearing 49b, may be arranged around the steering axle 30.

[0080] Angle sensor 33, preferably an absolute rotary encoder, is directly mounted to the steering axle 30. Using the angle sensor 33 according to this preferred embodiment, the steering system according to the invention can obtain the actual steering angle position even after power failure due to the design capabilities of the angle sensor 33. For diagnostic purposes, two angle sensors 33 can be added to measure the difference between the steering axle 30 and the rotor 35b. The redundancy of the steering system according to the invention can also be increased by using dual windings for the direct drive motor 35.

[0081] according to Figure 3 and Figure 4 In a preferred embodiment, the steering axle 30 and the angle sensor 33 are connected via pulleys 42, 44 and a drive belt 43.

[0082] The steering system may also include means for securing the various components of the steering system to each other or to structural components of the vehicle. For example, a coupling 39 can be used to secure the position of the outer column 34 relative to the direct drive motor 35. A second bracket 45 can be used to secure the position of the motor housing 36 of the direct drive motor 35 relative to the steering axle 30. Furthermore, a third bracket 46 can be used to connect the direct drive motor 35 to the vehicle, i.e., to the vehicle chassis. A fourth bracket 47 can be used to mount the steering system as a whole to the vehicle chassis.

[0083] Figure 5 This is a schematic diagram of a steering system according to the present invention, showing the steering system and its connections to other parts of the vehicle. Figure 5A preferred embodiment of the steering system includes a steering axle 50 attached to a steering wheel 52, which allows the vehicle to be manually driven by a human driver 54. A direct drive motor 55 is gearlessly arranged on the steering axle 50, wherein the axis of rotation of the direct drive motor 55 is coaxial with the axis of rotation of the steering axle 50. Figure 5 The steering system also includes an angle sensor 53 for determining the exact position of the steering wheel 52.

[0084] Both the direct drive motor 55 and the angle sensor 53 are connected to a controller assembly 56, which receives feedback position signals from the angle sensor 53 and sends commands to the direct drive motor 55 to steer the vehicle. Preferably, the command includes a target current value to be achieved for the direct drive motor 55. The controller assembly 56 can be connected to an external network 57, such as the Internet, cloud, or database, to receive further information about the vehicle's steering.

[0085] To steer the vehicle, the steering axle 50 needs to be connected to the vehicle's wheels 60. According to... Figure 5 The steering axle 50 and the wheel 60 are connected via an intermediate shaft 51 having a torque sensor 59. For example, the torque sensor 59 can be implemented as a torsion bar. The wheel 60 and the torque sensor 59 are preferably attached to a rack and pinion 61, which transmits the steering torque applied to the steering axle 50 to the wheel 60.

[0086] Furthermore, the device 63 for electric assisted steering (EPAS) can also be connected to the rack and pinion 61 via gear 62 to further assist the steering of the wheels 60. The device 63 for electric assisted steering preferably receives signals from the electric control unit (ECU) 58.

[0087] Figure 6 A preferred configuration 600 of the steering system according to the invention is shown. Dashed boxes indicate various locations within the vehicle where components of the steering system and associated components are located. Possible locations include the driver's seat 610, the passenger seat 620, the trunk 630, the center console 640, and the steering column 650.

[0088] A device for manual steering of the vehicle is arranged at the driver's seat 610, preferably a steering wheel 611 connected to the steering axle 601. The steering wheel 611 can apply torque to the steering axle 601 to steer the vehicle.

[0089] A controller assembly is preferably located below the passenger seat 620, and is connected to elements of the steering column 650. A power supply 632 is preferably located in the vehicle's trunk 630. A main battery 631 is also located in the vehicle's trunk 630. Preferably, both the main battery 631 and the power supply 632 are connected to an emergency stop device 641, which is preferably implemented as a button located in the center console 640 for easy access.

[0090] A direct drive motor 655 is disposed at the steering column 650, which is connected to the steering axle 601 via a clutch 651, preferably an anti-slip clutch. In this arrangement, the direct drive motor 655 can apply torque to the steering axle 601 to steer the vehicle. The direct drive motor 655 is preferably thermally coupled to a temperature sensor 652. The steering column 650 also includes a steering angle sensor 653, which is in mechanical contact with the steering axle 601.

[0091] The direct drive motor 655 is preferably connected to the controller assembly 621 to receive control signals, and the controller assembly 621 is further connected to the temperature sensor 652 to monitor the temperature of the direct drive motor 655, and to the steering angle sensor 653 to receive information about the rotational position of the steering axle 601.

[0092] The steering axle 601 can also be connected to the vehicle's servo motor 602, preferably the vehicle's original servo motor 602. Like the direct drive motor 655 and the steering wheel 611, the servo motor 602 can also apply torque to the steering axle 601.

[0093] Figure 7 An exemplary architecture of the steering system according to the invention, including in a simulated environment, is shown because testing of autonomous vehicles is not limited to road testing. The steering system according to the invention can also be used for simulation testing, in which the steering system is mounted on a test bench, preferably a HIL (hardware-in-the-loop) test bench, and the driver can interact with the steering system in a manner similar to that during test driving.

[0094] Test benches, especially HIL test benches, can allow the following tests:

[0095] - Robustness testing of the steering system's controller components.

[0096] - Robustness testing of the mechanical structure of the direct drive motor 75

[0097] - By using devices for manual steering, such as the steering wheel 71, and actuators, such as the pedals 76, test the overdrive function and possible driver intervention.

[0098] - Before implementing the complete steering system in a real vehicle, test the complete steering system, and

[0099] - Test the new firmware, i.e., the hardware or software component, before a planned update.

[0100] As can be seen from the above, the test bench allows for the testing and fine-tuning of the hardware components of the steering system according to the invention, including testing the reliability and durability of the hardware components before the steering system is integrated into a vehicle. Furthermore, the test bench equipped with the steering system can also be used for testing and validating subsystems or the entire steering system. The test bench equipped with the steering system according to the invention can also be used to train test drivers who then participate in real-vehicle testing. In-loop testing also allows for the simulation of various driving scenarios.

[0101] The driver or user can interact with a junction such as the steering wheel 71 or any other device for manual steering, and one or more actuators such as the pedal 76. The steering wheel 71 is connected to a steering axle 70, which is equipped with a direct drive motor 75. The direct drive motor 75 is controlled by a controller assembly including a wire drive unit 74. The wire drive unit 74 is preferably connected to the pedal 76.

[0102] To provide a realistic scenario, the test architecture includes a vehicle ECU (electronic control unit) simulator 77 and an EPAS (electric power steering) simulator 73. The EPAS simulator 73 is used to generate simulated power steering 72 on the steering axle 70.

[0103] To generate input parameters for the controller component, a simulation computer 78 is used, which has simulation software 79a and virtual sensors 79b. The simulation computer 78 preferably provides the controller component with virtual sensor data, traffic scenarios, and a vehicle model. The controller component is capable of operating in this simulation environment and can receive signals and data from the simulation computer 78 and the vehicle ECU simulator 77, and can issue commands to the direct drive motor 75 and the pedal 76. The commands are preferably translated by the wire drive unit 74 for the direct drive motor 75 and the pedal 76. The EPAS simulator 73 preferably also uses simulation data and inputs from the simulation computer 78.

[0104] The characteristics of detachment will be discussed in detail below.

[0105] As discussed above, the steering system according to the invention has at least two predetermined states characterizing different driving conditions, such as parking and urban driving. Each predetermined state has at least one predetermined disengagement limit to maintain the safe operation of the vehicle under test.

[0106] Disengagement is an action in which autonomous driving should cease and manual control of the vehicle is necessary for safety reasons. Predetermined disengagement limits can be hardware restrictions or other predetermined thresholds that may indicate the vehicle's behavior is becoming unstable or that autonomous driving has become dangerous, for example, due to an error.

[0107] When the deviance limit is reached or exceeded, manual overriding of the autonomous driving system is preferable to ensure the safety of test personnel, passengers in the test vehicle, the vehicle itself, and any other persons, vehicles, or objects along the planned route of the test vehicle.

[0108] It has been recognized that different driving situations require different exit restrictions to ensure safe testing and reduce the possibility of unnecessary human intervention. Different driving situations serve as the basis for predetermined states.

[0109] The predetermined state is preferably determined based on at least one state parameter, such as the vehicle's speed (see point a below), lateral acceleration, yaw rate, and / or longitudinal acceleration. In addition to the state parameters, the parameters listed below at points b)-f) can also be used as a basis for determining the predetermined state characteristics of the vehicle at a given point in time, i.e., what the actual predetermined state of the vehicle is.

[0110] a) Vehicle speed. Detecting vehicle speed is a crucial factor in characterizing the necessity of disengagement actions, therefore, vehicle speed monitoring is preferred. Monitoring vehicle speed also allows for speed-based steering control (i.e., speed-dependent vehicle control). Vehicle speed can be derived from a displayed vehicle speed, emitted by the ABS brake pads and transmitted via the CAN bus. Other methods can also be used to determine vehicle speed, such as striking Hall effect sensors attached to the vehicle's wheels and receiving analog signals corresponding to the wheel clicks. Auxiliary speedometers for determining vehicle speed are also commercially known and available. Preferably, multiple methods can be used simultaneously to achieve redundant speed measurements. The safety level of the speed signal preferably corresponds to ASIL-D level for optimal safety, thus redundant speed signal sensing is desirable.

[0111] b) Reference Position or Torque. In a steering system with a high-level controller and a low-level controller, the high-level controller sends a motion curve, or reference signal, to the low-level controller. This motion curve includes specified values ​​for control parameters, such as the target position or target torque to be achieved. The high-level controller calculates the acceleration required to reach this target value and warns the driver to take over control of the automated driving system if the calculated acceleration exceeds a safety limit, indicating unexpected or erroneous behavior of the vehicle or the automated driving software. The warning can be sent in the form of visual and / or audible signals. In the event of such a warning, the low-level controller preferably continues to control the vehicle within its low-level limit to ensure vehicle safety. This prevents the target value from increasing too rapidly.

[0112] c) Steering wheel or steering axle speed. The steering wheel or steering axle speed is preferably calculated using the vehicle's steering position sensor or the position sensor of the direct drive motor. The vehicle's steering position sensor or the direct drive motor's position sensor is preferably an angle sensor. For safety and redundancy, both the steering position sensor and the direct drive motor's position sensor can be used. The maximum steering wheel speed is preferably limited to a disengagement limit that cannot be exceeded; otherwise, the low-level controller immediately warns the driver and disengages the automatic steering function. Preferably, at least one steering angle sensor is attached to the steering axle. More preferably, at least two steering angle sensors are attached to the steering axle, one to the direct drive motor, and the other is originally installed in the vehicle (built-in steering wheel position sensor). As mentioned above, redundant signals are preferably used for safety reasons.

[0113] d) Target position of the steering wheel or steering axle. Preferably, the target position of the steering wheel or steering axle is also monitored, primarily by a position sensor of the direct drive motor, preferably with high accuracy (±0.05-0.1°). Secondly, a built-in steering wheel position sensor can also be used to monitor the target position of the steering wheel, but it typically has lower accuracy, so using a built-in steering wheel position sensor is preferably only an alternative.

[0114] e) Steering probability estimation. The automatic software preferably calculates the target position or target torque value via a high-level controller and a low-level controller and sends it to the direct drive motor. If the request from the high-level controller is ignored by the low-level controller because reaching the estimated position or torque would exceed the target value for disengagement, the steering system according to the invention preferably notifies the driver before disengagement occurs, thus allowing the driver time to perform necessary safety maneuvers. Figure 8 An example is shown where the vehicle is expected to exceed the exit limit in a curve.

[0115] f) Current of the direct-drive motor. The low-level controller converts the output current of the direct-drive motor into torque. More than one disengagement limit can be defined related to the current of the direct-drive motor. For example, a hardware limit that cannot be exceeded, otherwise disengagement will occur when it does. In addition to the hard limit (i.e., the limit that cannot be exceeded), a soft limit can also be defined as the disengagement limit. The soft limit can preferably exceed, for example, a certain time. In the case of a soft limit, disengagement will only occur if the time exceeding the limit is longer than the limit, or if the cumulative value of the parameter exceeds the limit value. Figure 9 Example effects are shown when different takeoff limits associated with the current of a direct-drive motor are reached and / or exceeded.

[0116] One or more of the parameters mentioned above can be used to determine which predetermined state the vehicle belongs to at a given point in time. For example, the vehicle's speed can be the sole determining factor; in other cases, combinations of other parameters can be used.

[0117] As mentioned above, Figure 8 This illustrates a disengagement maneuver based on an estimate of the likelihood of steering, i.e., whether a safe steering is possible under specified target parameters, or whether a future disengagement is anticipated.

[0118] The autonomous driving software of vehicle 80 typically includes a route planning unit, which perceives a road model 84 within a certain distance. Based on the road model 84, an absolute steering torque 83 can be calculated, which is required to keep vehicle 80 on road 85 even if road 85 is curved. As vehicle 80 approaches curve 86, the torque required to drive vehicle 80 along road 85 increases. The anticipated future torque can be calculated by estimation unit 81, preferably by steering probability estimator, and compared with departure limit 82, which is related to steering torque. If the torque estimate indicates that at a later point in time, i.e., when vehicle 80 is in curve 86, departure limit 82 is expected to be exceeded, a warning 87 can be sent to the driver of vehicle 80, who can then resume manual control before entering curve 86. In addition to the torque acting on the steering wheel, other parameters can be calculated based on predetermined departure limits.

[0119] Figure 9 This is a diagram illustrating the disconnection event based on the current signal 90 of the direct drive motor. The current signal 90 constitutes the output current value of the direct drive motor and is shown as a function of time. In the low-level controller, the output current of the direct drive motor is converted into torque acting on the steering axle. Similar to the reference... Figure 8The torque discussed, and the predetermined disengagement limit, can also be associated with the output current of the direct drive motor. For the output current, the predetermined disengagement limit can be a hardware limit 91 (a hard limit that cannot be exceeded) and / or a current threshold 92 (a soft limit that can be exceeded under certain conditions). The hardware limit 91 is preferably determined by the hardware of the direct drive motor, and because the hardware limit 91 is a hard limit, disengagement occurs when the hardware limit 91 is reached (see [link to relevant documentation]). Figure 9 The break-off point 93 will occur. According to Figure 9 For example, the hardware limit 91 for the output current is set to 30A (Amperes), so once the actual value of the output current at the disconnection point 93 reaches the 30A limit of hardware limit 91, disconnection occurs. When the output current returns to below the predetermined disconnection limit, i.e., below hardware limit 91 and current threshold 92, the automatic drive can be reactivated (see reactivation point 94).

[0120] The current threshold 92 is a soft limit, so it can be exceeded, for example, by a predetermined time interval. If the current signal 90 exceeds the current threshold 92, a timer is preferably started, and the timer runs as long as the current signal 90 exceeds the current threshold 92. If the time interval measured by the timer is shorter than the predetermined time interval, disconnection will not occur (see point 95 where disconnection does not occur). Figure 9 Another case is shown in which the current signal 90 exceeds the current threshold 92 for a longer time interval, so the disconnection occurs at the disconnection point 96.

[0121] In the case of soft limiting, alternatively, the cumulative over-limit signal can be measured based on the time interval measured by a timer and the output current value exceeding the current threshold 92. The cumulative over-limit signal can be calculated as the integral value of the current signal 90 exceeding the current threshold 92, i.e., the area represented by the stripes. In addition to integration, other methods can be used to approximate the represented area. For example, the sum of the output current values ​​can be multiplied by the time interval measured by the timer.

[0122] When a disengagement action is initiated, such as due to exceeding the disengagement limit or a serious, irreversible error, a signal is sent to the human driver to take over control of the vehicle, and a driver handover window is activated. During the driver handover window, the steering system and automatic software continue to drive the vehicle until the human driver takes over control, or until the driver handover window expires. The human driver can take over control by manually steering the vehicle or by using an activation lever or any other indication that the driver has taken over control. If the driver handover window expires without the human driver taking over control, safety maneuvers are activated.

[0123] If a serious error occurs and the steering system and automatic software can no longer reliably control the vehicle, safety maneuvers should be initiated immediately without opening the driver handover window. Even in this situation, a signal should be sent to the human driver to take over control of the vehicle as quickly as possible. In this case, a stronger and more obvious signal is preferable.

[0124] Safe maneuvering is preferably implemented as a lower-level safety function on the drive-by-wire controller. During safe maneuvering, if steering is engaged by an Advanced Driver Assistance System (ADAS), the previously received steering request is retained, and acceleration requests are not accepted. However, if a braking request is activated at an inappropriate time, the braking request is retained. If braking is not actuated at an inappropriate time, but ADAS is controlling the brakes, a slight deceleration is requested to slow the vehicle down during safe maneuvering.

[0125] At any time, when the human driver initiates driver overdrive or presses the activation lever, safety controls cease and the human driver takes manual control of the vehicle.

[0126] As an example, when safety maneuvers begin, maintain the final steering angle position and reduce the vehicle's longitudinal speed until the vehicle comes to a stop.

[0127] In another example, when safety controls are activated, the vehicle is instructed to find a parking position, slow down, and stop. Preferably, the vehicle's hazard lights are activated.

[0128] The predetermined state can be based on different operating environments that occur during vehicle driving. Such predetermined states could be, for example, driving on a highway, driving in the city, driving in the suburbs, parking, driving on a closed track, etc. Different predetermined states may require different disengagement restrictions based on the characteristics of each driving situation. The decision to determine the actual predetermined state of the vehicle can be made based on one or more of the parameters a)-f) above. The decision can be made based on only one parameter, such as the vehicle's speed, or based on a combination of the parameters above.

[0129] For example, a decision about the actual predetermined state of the vehicle can be made by a decision-making unit, which preferably has inputs such as the vehicle's speed and information from an external inertial measurement unit (IMU), such as lateral acceleration, yaw rate, and / or longitudinal acceleration.

[0130] Preferably, the decision-making unit receives map data of the vehicle's environment (such as SD or HD map data), which is preferably fused with the vehicle's high-precision location data (such as real-time motion location (RTK) or GPS data) and / or visual data. The visual data is preferably obtained from a camera and may include information based on traffic signs (such as speed limits), which can improve the reliability of the decision. The decision-making unit may implement a specific neural network or any other machine learning algorithm trained to determine the actual state of the vehicle, so that changes in the vehicle's state can also be detected.

[0131] Including additional parameters in the decision can improve the accuracy and reliability of the decision, thus reducing the possibility of misclassification of the vehicle's intended state. Optionally, the following parameters and measurements may be further included in the decision and can serve as the basis for determining whether the vehicle is off-limits.

[0132] Most vehicles are equipped with torque sensors (TSU sensors), such as torsion bars, that measure the vehicle's torque. By monitoring the signals from the torque sensors, the decision-making unit receives feedback from the torque applied by the human driver. During test driving, the human driver and the direct drive motor can apply torque to the steering axle. In fully autonomous driving, even if the human driver does not apply any force to the steering wheel or any other manual steering mechanism, the vehicle typically detects the torque applied by the direct drive motor as driver input. In situations where disengagement is possible, it is preferable to know that the human driver, the direct drive motor, or both are applying torque to the steering axle. An additional logic layer can be added to determine whether the human driver, the direct drive motor, or both are applying torque to the steering axle. This additional logic layer can obtain input from the torque sensor to aid in decision-making.

[0133] Information about the speed of the steering axle (also known as rack speed) emanating from the vehicle's servo drive can improve the robustness of the decision-making unit. The maximum permissible speed limit for the servo drive can also be a disengagement limit, where the controller warns the human driver and disengages the direct drive motor from the steering system.

[0134] Any type of mechanical, acoustic, and / or optical sensor (i.e., strain sensor) can be attached to or around the steering wheel. Disengagement can be initiated based on signals from the strain sensor. For example, if a loud shout (e.g., "STOP") is detected by the steering system when a certain decibel limit is exceeded, it can trigger immediate disengagement of lateral control. This will allow for the safety of vehicle passengers, such as by initiating emergency braking and safe parking of the vehicle, and can be used in fully automated vehicles without a steering wheel or other manual driving mechanisms.

[0135] Preferably, each test vehicle is equipped with an external IMU sensor for autonomous driving. The IMU sensor can monitor the vehicle's pitch, roll, and / or yaw, and is therefore also useful for identifying external noise, speed bumps, and stones, which on the one hand momentarily increase the torque required from the direct drive motor, but on the other hand do not pose any danger. Events such as hitting a stone or speed bump should not be the cause of disengagement; therefore, inputting signals from one or more IMU sensors into the decision-making unit can reduce the risk of unnecessary disengagement. Figure 15 The effect of speed fluctuations on the torque signal is shown.

[0136] The steering system according to the invention has at least two different predetermined states. Several examples of typical predetermined states will be described in detail below. Figure 12 , 13 14 also shows preferred embodiments of the steering system having two, three, and four predetermined states, respectively.

[0137] One possible driving scenario for autonomous vehicles is driving on a closed track. Closed tracks are commonly used for testing autonomous vehicles because public transportation is not available on them, allowing testing to be conducted in a safe and stable environment. While driving on a closed track, all departure restrictions can be disabled, and the vehicle's true self-driving capabilities can be tested. This testing can be performed even without a human driver inside the vehicle. Even if departure restrictions are disabled or set to unattainable values, a human driver can remain in the vehicle and, with the aid of a manual steering mechanism (e.g., a steering wheel) according to the steering system of the invention, take over the automatic operation of the vehicle, thereby maintaining its safety in the event of unexpected software errors.

[0138] In a closed-track driving environment, vehicle manufacturers or testers can equip their test vehicles, and even their fully automated driverless vehicles, with the steering system according to the invention for their test days. This allows for the testing of features such as lane keeping assist, emergency overtaking, accident avoidance, and other automated driving characteristics. A human driver can supervise the testing from inside the vehicle and intervene in the event of an emergency to prevent accidents and potential vehicle damage.

[0139] Another pre-defined state can be the parking state, which may include driving in a parking lot. When parked or operating a vehicle in a parking lot, the vehicle speed is relatively low, typically between 0-15 km / h; however, greater torque may be required to navigate the vehicle. In this state, the risk level is relatively low, partly due to the lower speed, and the human driver should be able to easily overtake the steering system and manually steer the vehicle. Peak torque can be in the range of ±10 Nm, preferably ±8 Nm or ±6 Nm. Peak torque can depend on various factors such as longitudinal forces, lateral forces, linear damping, inertial effects, lift, friction, etc. The average torque required from a direct drive motor is typically higher than 4 Nm.

[0140] Another pre-defined state could be urban driving, which could include driving in traffic jams. In urban areas, such as cities and towns, the maximum speed is typically limited to 50 km / h; however, specific speed limits are stipulated by national laws and regulations. Driving in urban areas therefore corresponds to moderate-speed movement; however, unexpected situations may occur more frequently than in parked areas, such as due to pedestrians. Urban environments can also include various road conditions and routes, such as steep streets, roundabouts, and streets with sharp turns or curves. Even in urban environments, emergency braking should be possible, therefore the speed range for urban driving should be between 0 km / h and 50 km / h. As the vehicle moves at moderate speeds in urban environments, the power assist can provide sufficient torque for the direct-drive motor to operate smoothly. Human drivers, especially trained test drivers, have sufficient reaction time to overtake without deviating from their lanes. Hands-on operation is not a necessary use case, but it is recommended. During AEB (Automatic Emergency Braking) activation, the autonomous driving software must keep the vehicle within its lane, and the steering system should handle situations at intersections and roundabouts.

[0141] Moving to suburban areas can further restrict or even restrict vehicle speeds. Speed ​​limits in suburban areas are generally higher than in urban areas, so vehicle speeds in suburban areas are typically around 50-70 km / h. Within this speed range, existing steering assist systems generally offer the highest performance, meaning the steering wheel can be rotated at its maximum possible speed without restrictions. Within this speed range, such rapid steering wheel movement can lead to lane departure, thus requiring a high level of attention and the ability to intervene quickly to control the vehicle. Therefore, if no restrictions are imposed on the steering system, the human driver must be prepared to take over control of the vehicle at any time. Consequently, the human driver is expected to keep their hands on the steering wheel or any other device used for manual steering. In manual driving situations, the human driver's reaction time is significantly reduced.

[0142] In suburban areas, where roads have more than one lane and vehicles are driven at speeds of 50-70 km / h, human drivers have more time to execute successful overtaking maneuvers, or, in the event of a disengagement, more time to take over control of the vehicle. Under suburban driving conditions, the average torque required from the direct-drive motor during testing was in the range of approximately ±3-6 Nm.

[0143] Driving on highways can also serve as a basis for a predetermined state. In contrast to the aforementioned predetermined state, on highways, vehicles are permitted to drive at higher speeds than on other types of roads, and the maximum permissible speed typically depends on national traffic regulations. The typical maximum speed is 130 km / h; however, some countries, such as Germany, also have highways without speed limits. Therefore, vehicles are expected to drive at high speeds in an environment where other vehicles are also moving at high speeds. The possible speed range is between 0 km / h and 130 km / h. The speed range used for highway driving must also include lower speeds, even 0 km / h in extreme cases, because autonomous vehicles should also be able to perform AEB (Automatic Emergency Braking) on ​​highways. This means that the steering system must be active and able to react when the vehicle in front of the test vehicle comes to a complete stop. The steering system according to the invention can handle sharp turns, such as at overpasses or intersections. The steering system can also guide vehicles on sloping curves on highways.

[0144] In normal operation, even in the event of emergency braking, a vehicle should maintain its lane on a highway. Based on artificial intelligence or sensor data from radar, vision sensors, lidar, etc., and using predictive models, test vehicles can perform lane changes even in emergency situations to avoid accidents. Lane changes can be performed automatically or by human driver intervention. Before performing a lane change maneuver, the target lane must be checked by sensors and the driver.

[0145] When performing tests to analyze a vehicle's lane-keeping capabilities, for a single lane change, a slight left or right turn (approximately ±15°) is necessary with quick and precise positioning to achieve optimal comfort for the human driver and passengers. For two-lane changes, more dynamic maneuvering is required.

[0146] When driving on a highway, the peak torque of the direct-drive motor in the steering system is not very high, typically around 7 Nm. This torque resistance can be easily overcome by a human driver. If a human driver wishes to take over control of the test vehicle while driving on a highway, the steering wheel must be turned very carefully and smoothly to avoid entering another lane. Due to the higher speeds on highways, extra caution must be taken to avoid applying excessive force or torque to the steering wheel to prevent unexpected lane changes.

[0147] In such a scenario, where the steering system malfunctions and the driver does not wish to steer the vehicle, the driver must overcome the torque of the steering system. If the driver needs to use more than 10 Nm of torque to overtake the steering system and initiate a disengagement maneuver, the test vehicle may attempt a lane change during this process.

[0148] A direct-drive motor can use an average torque of up to 2-3 Nm for lane keeping and single lane changes. In this case, insufficient torque, such as less than 1.1 Nm, will not turn the vehicle. This, along with friction in the steering system, will cause angular and lateral errors, which can be avoided by providing torque above the average value. This phenomenon can also affect other intended states.

[0149] In the exemplary state of highway driving, the following restrictions apply. If the vehicle's speed exceeds 100 ms between 25 m / s and 37.5 m / s, the vehicle is considered to be in a highway driving state. Disengagement restrictions related to highway driving states may be as follows:

[0150] The vehicle's yaw rate must not exceed ±0.11 rad / s for more than 100 ms.

[0151] The lateral acceleration of the vehicle must not exceed ±4.2 m / s². 2 More than 100ms

[0152] The steering wheel position must not exceed ±0.262 rad for more than 100 ms.

[0153] The steering wheel torque must not exceed ±5 Nm for more than 100 ms, and

[0154] The steering wheel torque manually applied to the steering wheel must not exceed ±2.5 Nm for more than 100 ms.

[0155] Exceeding any of the above limits will result in disengagement, and the human driver will need to take over control of the vehicle.

[0156] Another possible pre-defined state could be an emergency maneuvering state. This state should cover a speed range from 0 km / h to, for example, 130 km / h or 200 km / h, the maximum speed typically allowed on highways. An emergency state corresponds to an emergency situation where even rapid and sharp turns are anticipated, thus avoiding an accident. The torque applied by the direct-drive motor of the steering system can be within the range of ±10 Nm.

[0157] Different predetermined states typically have different disengagement limits. Therefore, in such cases, when the vehicle state changes, the disengagement limits also change drastically, leading to unstable vehicle operation or sudden disengagement due to exceeding the disengagement limits of the new state.

[0158] To avoid issues related to state changes, intermediate bridging states can be introduced between different predetermined states, allowing for a smooth transition away from the constraints of predetermined states.

[0159] The controller component can use decision-making units, such as neural networks, to detect and determine the appropriate actual predetermined stage of the vehicle based on available data, such as the actual values ​​of control parameters. In this case, when a change in the actual predetermined stage is detected, a bridging command can be generated to apply a bridging function, allowing for a smooth transition away from the predetermined state. If there is a malfunction in the vehicle's control, or if the bridging command cannot be delivered within a certain timeframe, the steering system preferably warns the human driver and relinquishes control.

[0160] The decision-making unit of the steering system needs to determine possible predetermined states and their changes, and should apply intermediate bridging states between the predetermined states. Preferably, the decision-making unit should be able to identify situations such as traffic jams on highways. If the decision-making unit limits the situation to an emergency, it can immediately switch from a predetermined highway driving phase to an urban driving state including traffic jams. In this case, the controller components can preferably steer the vehicle using the maximum possible speed limit.

[0161] For example, bridging states can be applied between the following states: parking state and urban driving state, urban driving state and suburban driving state, and suburban driving state and highway driving state. Figure 10 and Figure 11 The effect of changing the vehicle state in both bridging and non-bridging states is shown.

[0162] Figure 10A force is applied where no bridging state is used in the steering system. According to the example, firstly, the vehicle is driven at a lower speed, such as urban or suburban speed (e.g., 40 km / h indicated by the first road sign 108), which allows for a higher applied torque 100. Subsequently, the vehicle travels along curve 107 onto a road with a higher speed limit (e.g., 110 km / h indicated by the second road sign 109). Due to the change in vehicle speed, the actual predetermined state of the vehicle also changes from the first state corresponding to urban or suburban driving to a second state corresponding to highway driving, for example at t1. With the change in the actual predetermined state, the applicable disengagement limit also changes, i.e., from the first disengagement limit 101 corresponding to the first state to the second disengagement limit 102 corresponding to the second state. Figure 12 In the example shown, the first departure limit 101 in the first state is higher than the second departure limit 102 in the second state because, as has been shown on highways, large applied torque can lead to undesirable lane changes, which must be avoided. Figure 10 As can be seen, the change in state occurs after curve 107, therefore the torque 100 applied to the steering system has decreased to below the levels of the two disengagement limits 101 and 102. Therefore, in this situation, disengagement does not occur at points 103 and 104, regardless of whether bridging is present or absent.

[0163] on the contrary, Figure 11 An example is given where a vehicle is driving in curve 117, and a state change occurs during curve 117 (at t3). In this example, the speed limit is lower in the first section of curve 117 (e.g., 40 km / h as indicated by the first road sign 118), and then higher in the second section of curve 117 (e.g., 90 km / h as indicated by the second road sign 119). In this case, when the vehicle enters the second state, the torque 110 applied to the steering system is higher than the second disengagement limit 112 of the second state. This will cause an immediate disengagement in the middle of curve 117, i.e., at disengagement point 114, which would be dangerous if the human driver does not take immediate action to take control of the vehicle. This situation could even lead to deviation from the road or lane. This sudden disengagement can be avoided by a bridging state, which allows for a smooth transition of the disengagement limit. The bridging state preferably includes a bridging function 115, which connects the bridging start point 113 and the bridging end point 116, defining the transition between the disengagement limits 111 and 112 of each state. It can be seen that the bridging function 115 defines a smooth transition between the first disengagement limit 111 and the second disengagement limit 112 by extending the transition time. Therefore, the torque 110 can be kept below the bridging function 115, and thus no disengagement occurs.

[0164] The bridging function can be any monotonic function that connects the states free from constraints 111 and 112. For example, the bridging function 115 can be a linear function or a nonlinear function.

[0165] Figure 12 An example of a steering system according to the invention is given, which has two predetermined states corresponding to different driving conditions. Figure 12 The driving conditions include a first state 120 corresponding to low-speed driving, which preferably includes parking and driving in urban environments. Since the typical speed limit in urban areas is 50 km / h, the typical speed of the vehicle is in the range of approximately 0-50 km / h. The torque to be applied to the steering axle is typically in the range of ±8-10 Nm, because particularly in parking situations, low speeds are typical, but the vehicle is expected to even make sharp turns, requiring a greater torque to be applied to the steering axle. The disengagement limit related to the applied torque can preferably be set to ±10 Nm. In other embodiments of the steering system according to the invention, the first state 120 can also be divided into another state, namely, a divided state with one side corresponding to parking and the other side corresponding to urban driving, just as... Figure 14 middle.

[0166] Figure 12 The second state 122 corresponds to another driving situation, such as high-speed driving, covering scenarios of driving in suburban areas with a typical driving speed of about 50-70 km / h, driving on main roads with a typical driving speed of about 70-90 km / h, and driving on highways or motor vehicle lanes with a typical driving speed in the range of about 90-200 km / h. Preferably, in the second state 122, the vehicle typically moves at a speed in the range of about 50-200 km / h. In other embodiments of the steering system according to the invention, the second state 122 can also be divided into more states, just like... Figure 13 and Figure 14 middle.

[0167] In the second state 122, the vehicle speed is relatively higher compared to the first state 120, and a smaller torque is expected to be applied to the steering axle. At high speeds, excessive torque may lead to unintentional lane changes, which should be avoided. In the second state 122, the expected torque range is ±3-6 Nm; therefore, the departure limit can preferably be set to ±4 Nm or ±6 Nm.

[0168] As with Figure 11 The related discussion suggests that a bridging state 121 can be introduced to smoothly transition the deconstraint between states 120 and 122. According to... Figure 12 A bridging state 121 is introduced between the first state 120 and the second state 122.

[0169] Preferably, according to Figure 12 The steering system also includes an emergency mode (not shown) to handle emergency situations. The emergency mode preferably covers a speed range of 0-200 km / h and has a torque range equivalent to the first mode 120, and preferably has a disengagement limit of ±10 Nm.

[0170] Figure 13 An example of a steering system according to the invention is given, which has three predetermined states corresponding to different driving conditions. Figure 13 The driving conditions include a first state 130 corresponding to a parking situation (parking state), where the vehicle's normal speed is in the range of approximately 0-5 km / h, and the torque to be applied to the steering axle is typically in the range of ±10 Nm, because low speed is normal in the parking situation, but the vehicle is expected to even make sharp turns, which requires greater torque on the steering axle. The disengagement limit related to the applied torque can preferably be set to ±10 Nm.

[0171] Figure 13 The second state 132 corresponds to another driving situation, such as driving in an urban environment (urban driving state). In an urban environment, the vehicle typically moves at a speed in the range of approximately 5-50 km / h, as urban areas usually have a speed limit of approximately 50 km / h. In urban driving state, compared to the parking state, a smaller torque is expected to be applied to the steering axle; however, sharp turns are also expected. Therefore, in urban driving state, the expected torque range is ±8 Nm; thus, the release limit can be set to ±8 Nm.

[0172] Figure 13 The third state 134 corresponds to driving at high speeds, such as in suburban areas with a typical driving speed of approximately 50-70 km / h; driving on main roads with a typical driving speed of approximately 70-90 km / h; and driving on highways or motor vehicle lanes, where the typical driving speed is in the range of approximately 90-200 km / h. In other embodiments of the steering system according to the invention, the third state 134 can also be divided into more states, as shown in... Figure 14 middle.

[0173] Considering the traffic regulations of different countries, different speed limits apply to State 134. For example, in some countries such as Germany, there are also highways without speed limits. Preferably, the speed limit for highway driving corresponds to the maximum permissible speed or possible maximum speed for vehicles on roads in a particular country. In highway driving situations, because highways tend to have fewer curves and fewer sharp turns, lower torque is expected during normal operation. For this reason, the torque release limit for highway driving is lower than that for urban driving or parking situations. As an example, the release limit in State 134 can be set to ±4 Nm.

[0174] As with Figure 11 The related discussion suggests that bridging states 131 and 133 can be introduced to smoothly transition the deconstraints between adjacent states 130, 132, and 134. According to... Figure 13 A first bridging state 131 is introduced between the first state 130 and the second state 132, and a second bridging state 133 is introduced between the second state 132 and the third state 134.

[0175] Preferably, according to Figure 13 The steering system also includes an emergency mode (not shown) to handle emergency situations. The emergency mode preferably covers a speed range of 0-200 km / h and has a torque range comparable to the first mode 130 (i.e., the parking mode), and preferably has a similar ±10 Nm disengagement limit.

[0176] Figure 14 For example, compared to Figure 12 and 13 The steering system has more predetermined states. Figure 14 Four distinct predetermined states (states 140, 142, 144, 146) are shown, with three bridging states 141, 143, 145 in between.

[0177] according to Figure 14 The steering system includes a parking state as a first state 140, wherein the characteristics of the first state 140 are similar to... Figure 13 The first state 130 is similar in characteristics, with a detour constraint of approximately ±9-10 Nm.

[0178] Figure 14 The second state 142 better corresponds to urban driving conditions, where the speed range is approximately 5-50 km / h. Figure 14 The second state 142 is characterized by Figure 13 The second state 132 is characterized by a release constraint of approximately ±7-8 Nm.

[0179] Exceeding 50km / h, according to Figure 14The steering system includes two additional predetermined states: a third state 144 corresponding to suburban driving and a fourth state 146 corresponding to highway driving. The third state 144 (suburban driving state) preferably covers a speed range of approximately 50-70 km / h, and the maximum allowable torque is preferably in the range of 3-6 Nm, thus the third state 144 has a disengagement limit of approximately ±6 Nm.

[0180] The fourth state 146 (highway driving state) preferably corresponds to a speed range of approximately 70–200 km / h. In cases where the speed limit on a highway is higher than 200 km / h, the fourth state 146 preferably also covers this higher speed range. However, for safety reasons, it is reasonable to limit the vehicle's maximum possible speed; that is, if the vehicle attempts to drive faster than the preset maximum speed limit, disengagement is initiated. As discussed above, in high-speed driving situations, even a relatively small amount of torque applied to the steering axle can lead to dangerous situations, including lane departure. For this reason, the maximum permissible torque is preferably in the range of 2–4 Nm, thus the fourth state 146 preferably has a disengagement limit of approximately ±4 Nm.

[0181] Three bridging states 141, 143, and 145 are arranged between different predetermined states 140, 142, 144, and 146. Each bridging state 141, 143, and 145 has a bridging function that defines a smooth, monotonic transition between the departure constraints of the different predetermined states 140, 142, 144, and 146. The bridging function can be a linear function or any other monotonic function, and different bridging states can have different bridging functions. In this case, when the difference between the departure constraints of the predetermined states 140, 142, 144, and 146 is large, the bridging function preferably corresponds to a longer time period, allowing for a longer and less steep transition, thereby reducing the probability of departure events occurring.

[0182] Preferably, according to Figure 14 The steering system also includes an emergency mode (not shown) to handle emergency situations. The emergency mode preferably covers a speed range of 0-200 km / h (i.e., the total permissible speed range) and has a torque range comparable to the first mode 140 (i.e., the parking mode), with similar disengagement limits of ±9-10 Nm.

[0183] In other preferred embodiments of the steering system according to the invention, the third state 144 and the fourth state 146 may correspond to different speed ranges. For example, the third state 144 may preferably correspond to a speed range of about 50-90 km / h, with a disengagement limit of about ±5-6 Nm, wherein the fourth state 146 may preferably correspond to a speed range of about 90-200 km / h, with a disengagement limit of about ±3-4 Nm.

[0184] Figure 15 The effect of a vehicle driving over a speed bump is shown. Due to its height, the speed bump 151 causes a change in the vehicle's vertical acceleration 150 (Z-acceleration), according to... Figure 15 This is the acceleration in the Z-axis direction. The deceleration bump 151 causes a characteristic change in the signal of the vertical acceleration 150, such as its... Figure 15 As shown in the graph. If it is decided that the unit receives a signal of vertical acceleration 150, it can be easily identified that the change in vertical acceleration 150 is a result of speed bump 151. Although crossing speed bump 151 will also cause an increase in torque, this should not be a reason for starting disengagement.

[0185] Figure 16 A graph showing the typical torque distribution between the direct drive motor and the EPAS auxiliary torque of the steering system according to the invention under different driving conditions is presented, where the X-axis shows the torque applied to the steering axle by the direct drive motor and the Y-axis shows the torque applied by the EPAS. The driving conditions include a first state 161 corresponding to parking, a second state 162 corresponding to urban or suburban driving, a third state 163 corresponding to highway driving, a fourth state 164 corresponding to urban or suburban driving, and a fifth state 165 corresponding to parking.

[0186] As can be seen, in state 163, corresponding to highway driving, almost no torque is required from the EPAS side, but the direct drive motor can provide all the torque needed for highway driving. The torque applied by the direct drive motor is also limited, i.e., within ±5 Nm. Conversely, in parked conditions, see states 161 and 165, both the direct drive motor and the EPAS require a higher level of torque (up to ±10 Nm).

[0187] Figure 17 This is a schematic diagram illustrating various applications (i.e., applications 181, 182, 183, 184, 185) of the steering system according to the invention. To allow the vehicle to perform fully automated driving on public roads, the following steps are preferably taken to ensure the safety of the vehicle, its passengers, transported goods, and other vehicles, people, and objects along the route of the automated vehicle.

[0188] As a first step 171, drivers can be trained on the test autonomous vehicle so that they can familiarize themselves with the task. First step 171 can be performed using any training and / or simulation environment; preferably, the steering system according to the invention can serve as an interface between the driver and the autonomous driving software, wherein the steering system is preferably attached to a test bench. Therefore, the first use 181 of the steering system according to the invention can be driver training. The first objective 191 of the first step is to have trained drivers familiar with the vehicle and steering system, thus enabling them to conduct test drives more safely than ordinary drivers.

[0189] As a second step 172 of the test, the vehicle may be equipped with a steering system according to the invention. Therefore, as a second use 182, the steering system according to the invention can be used to evaluate the steering system and its components without any autonomous driving software. The second step 172 allows testing of the steering system without the limiters typically introduced by autonomous driving software, thus allowing for the testing and estimation of hardware limitations, and the steering system can be operated with variable inputs. Therefore, the second objective 192 associated with the second step 172 is to determine the hardware limitations of the steering system according to the invention.

[0190] As a third step 173 of the test, the test can be performed using automated simulation software; therefore, as a third use 183, the steering system according to the invention can be used in a simulated driving environment (see...). Figure 7 In a simulated environment, the robustness of the steering system's automatic software and hardware can be tested. Furthermore, the effect of driver overdrive can also be tested using the steering system according to the invention. The third step 173 can also be used for further training of the test driver, because the simulated environment can also include and simulate driving restrictions, deceleration restrictions, and faults, so the test driver can learn how to react in such situations. Therefore, the third objective 193 associated with the third step 173 is to test the robustness of the hardware, software, and firmware; to continue training the test driver under similar real-world conditions; and also to allow for thorough testing of driver overdrive.

[0191] The fourth step 174 of the test can be a fine-tuning of the steering system, preferably via closed-track driving. Therefore, as a fourth use 184, the steering system according to the invention can be used for closed-track driving and for fine-tuning of the steering system's hardware and software. The fourth objective 194 associated with the fourth step 174 of the test defines a disengagement restriction for each predetermined state.

[0192] The fifth step 175 of the test can be conducted on public roads, wherein the steering system according to the invention is installed in a test vehicle, preferably provided by any manufacturer, as a fifth use 185 of the steering system according to the invention. A fifth objective 195 related to the fifth step 175 is the fully automated operation of the test vehicle. In this case, a human driver is preferably in the vehicle, alert and ready to take over control if necessary. The fifth step 175 of the test can focus on automated software; however, the steering system according to the invention ensures that even in emergency situations, a human driver can intervene and avoid any possible accidents.

[0193] The present invention also relates to a method for disengaging a direct drive motor of a steering system according to the invention from a manual steering device. The method includes the step of commanding the direct drive motor of the steering system to a predetermined value of control parameters, wherein the control parameters are preferably the position of the manual steering device, the torque of the manual steering device, the force on the manual steering device, the speed of the manual steering device, or the current of the drive motor.

[0194] The method also includes the steps of monitoring the actual values ​​of the control parameters and generating the difference between the specified values ​​of the control parameters and the actual values ​​of the control parameters.

[0195] The method also includes a step of initiating a disengagement based on the difference if at least one predetermined disengagement limit corresponding to the actual predetermined state is reached.

[0196] The present invention also relates to a data processing system comprising means for performing the method steps according to the present invention.

[0197] Furthermore, the present invention also relates to a computer program product comprising instructions that, when executed by a computer, cause the computer to perform an embodiment of the method according to the present invention.

[0198] Computer program products can be executed by one or more computers.

[0199] Furthermore, the present invention also relates to a readable medium comprising instructions that, when executed by a computer, cause the computer to perform an embodiment of the method according to the present invention.

[0200] A computer-readable medium may be a single item or may include multiple individual items.

[0201] Of course, the present invention is not limited to the preferred embodiments described in detail above, but can have further variations, modifications, and developments within the scope of protection defined by the claims. Furthermore, all embodiments that can be defined by any combination of dependent claims are part of the present invention.

[0202] List of reference numerals

[0203] 10-steering axle

[0204] 11 bearings

[0205] 12 drive gears

[0206] 13 Angle Sensor

[0207] 14 Reduction Gearbox

[0208] 15 motors

[0209] 16-commutation encoder

[0210] 17 First Axis

[0211] 18 Second Axis

[0212] 20 steering axle

[0213] 21 bearing

[0214] 22 gears

[0215] 23 Angle Sensor

[0216] 25 direct drive motors

[0217] 27 First Axis

[0218] 28 Second Axis

[0219] 30 steering axle

[0220] 31 bearing

[0221] 32 inner columns

[0222] 33 Angle Sensor

[0223] 34 outer columns

[0224] 35 direct drive motor

[0225] 35a stator

[0226] 35b rotor

[0227] 35c motor shaft

[0228] 36 motor housing

[0229] 37 axis

[0230] 38 bearing housing

[0231] 39 Connecting parts

[0232] 40 clutch

[0233] 41 First stent

[0234] 42 pulleys

[0235] 43 transmission belt

[0236] 44 pulleys

[0237] 45 Second support

[0238] 46 Third support

[0239] 47 Fourth support

[0240] 48 bearing housing

[0241] 49a Second Bearing

[0242] 49b Third Bearing

[0243] 50 steering axle

[0244] 51 intermediate shaft

[0245] 52 Steering Wheel

[0246] 53 Angle Sensor

[0247] 54 human pilots

[0248] 55 direct drive motor

[0249] 56 controller components

[0250] 57 External Networks

[0251] 58 Electronic Control Units (ECUs)

[0252] 59 Torque Sensor

[0253] 60 wheels

[0254] 61 rack and pinion

[0255] 62 gears

[0256] 63 Electric Assisted Steering (EPAS)

[0257] 600 architecture

[0258] 601 Steering Axle

[0259] 602 Servo Motor

[0260] 610 Driver's Seat

[0261] 611 Steering Wheel

[0262] 620 Passenger Seats

[0263] 621 Controller Component

[0264] 630 trunk

[0265] 631 main battery

[0266] 632 power supply

[0267] 640 Center Console

[0268] 641 Device for emergency parking

[0269] 650 steering column

[0270] 651 Clutch

[0271] 652 Temperature Sensor

[0272] 653 Steering Angle Sensor

[0273] 655 direct drive motor

[0274] 70 steering axle

[0275] 71 Steering Wheel

[0276] 72 Simulation-Assisted Steering

[0277] 73EPAS (Electric Power Steering) Simulator

[0278] 74-wire drive unit

[0279] 75 direct drive motor

[0280] 76 pedals

[0281] 77ECU (Electronic Control Unit) Emulator

[0282] 78 Analog Computer

[0283] 79a simulation software

[0284] 79b Virtual Sensor

[0285] 80 vehicles

[0286] 81 estimation units

[0287] 82 Unrestricted

[0288] 83 Absolute Steering Torque

[0289] 84 road models

[0290] 85 Road

[0291] 86 bends

[0292] 87 Warning

[0293] 90 current signal

[0294] 91 Hardware Limitations

[0295] 92 current threshold

[0296] 93 breakaway point

[0297] 94 reactivation points

[0298] 95 points

[0299] 96 breakaway point

[0300] 100 torque

[0301] 101 First Detachment from Restriction

[0302] 102 Second Detachment

[0303] 103 points

[0304] 104 points

[0305] 107 Curves

[0306] 108 First Road Sign

[0307] 109 Second Road Sign

[0308] 110 Nm of torque

[0309] 111 First Detachment from Restriction

[0310] 112 Second Detachment

[0311] 113 Bridging Start Point

[0312] 114 Departure Point

[0313] 115 Bridging Functions

[0314] 116 Bridge to the End

[0315] 117 bends

[0316] 118 First Road Sign

[0317] 119 Second Road Sign

[0318] 120 First state

[0319] 121 First bridging state

[0320] 122 Second State

[0321] 130 First State

[0322] 131 First bridging state

[0323] 132 Second State

[0324] 133 Second Bridged State

[0325] 134 Third State

[0326] 140 First State

[0327] 141 First bridging state

[0328] 142 Second State

[0329] 143 Second Bridged State

[0330] 144 Third State

[0331] 145 Third Bridged State

[0332] 146 Fourth State

[0333] 150 vertical acceleration

[0334] 151 Speed ​​bump

[0335] 160 Nm of torque

[0336] 161 First State

[0337] 162 Second State

[0338] 163 Third State

[0339] 164 Fourth State

[0340] 165 Fifth State

[0341] 171 First Step

[0342] 172 Step Two

[0343] 173 Step 3

[0344] 174 Step Four

[0345] 175 Step 5

[0346] 181 Primary Use

[0347] 182 Secondary Use

[0348] 183 Third Use

[0349] 184 Fourth Use

[0350] 185 Fifth Use

[0351] 191 First Objective

[0352] 192 Second Objective

[0353] 193 Third Objective

[0354] 194 Fourth Objective

[0355] 195 Fifth Goal

Claims

1. A steering system for use in test driving of an autonomous vehicle, comprising: - Manual steering system, the manual steering system being configured for a manually steering vehicle. - Steering axles (20, 30, 50, 601, 70), said steering axles being attached to said manual steering device, and - Direct drive motors (25, 35, 55, 655, 75), which controllably affect the torque on the steering axles (20, 30, 50, 601, 70), wherein, The direct drive motors (25, 35, 55, 655, 75) have rotation axes (27, 37) coaxial with the steering axles (20, 30, 50, 601, 70). Its features are, The steering system has at least two predetermined states characterizing different driving conditions, wherein each predetermined state has at least one predetermined disengagement restriction (82, 101, 102, 111, 112), and The steering system further includes a controller component (56) operable based on control parameters, the controller component (56) being configured to detect the actual predetermined state of the vehicle, and the controller component (56) including - A motion controller that generates commands including specified values ​​of the control parameters to be achieved. - A motor drive unit, which supplies power to the direct drive motors (25, 35, 55, 655, 75) based on commands received from the motion controller, and - A feedback device for monitoring the actual value of the control parameter and determining the difference between the predetermined value of the control parameter and the actual value of the control parameter, and for initiating disengagement of the direct drive motor (25, 35, 55, 655, 75) under the following conditions: based on the difference, if at least one predetermined disengagement limit (82@, 101, 102, 111, 112) corresponding to the actual predetermined state is reached.

2. The system according to claim 1, characterized in that, The predetermined state is determined based on at least one state parameter.

3. The system according to claim 2, characterized in that, At least one state parameter is the vehicle’s speed, lateral acceleration, yaw rate, and / or longitudinal acceleration.

4. The system according to any one of claims 1 to 3, characterized in that, The predetermined state is further determined based on the driving situation, which includes at least one of the following: parking maneuver, traffic jam, urban driving, suburban driving, low-speed driving, high-speed driving, emergency maneuver, and closed-track driving.

5. The system according to any one of claims 1 to 4, characterized in that, The steering system has intermediate bridging states (121, 131, 133, 141, 143, 145) between two predetermined states, and provides a smooth transition between the disengagement restrictions (82, 101, 102, 111, 112) of the two predetermined states.

6. The system according to any one of claims 1 to 5, characterized in that, The control parameters are the position of the manual steering device, the torque of the manual steering device, the force on the manual steering device, the speed of the manual steering device, or the current of the direct drive motor (25, 35, 55, 655, 75).

7. The system according to any one of claims 1 to 6, characterized in that, The motion controller includes: - A high-level controller that generates motion profiles including predetermined values ​​of control parameters for the direct drive motors (25, 35, 55, 655, 75), and - A low-level controller, which receives the motion profile and generates a command that includes a specified value of the control parameter to be achieved.

8. The system according to claim 7, characterized in that, The controller assembly includes a wire drive unit (74) disposed between the high-level controller and the low-level controller for converting motion profiles generated by the high-level controller into signals receivable by the low-level controller.

9. The system according to any one of claims 1 to 8, characterized in that, The direct drive motors (25, 35, 55, 655, 75) are permanent magnet synchronous motors.

10. A method for disengaging a direct drive motor (25, 35, 55, 65, 75) from a manual steering device in a steering system according to claim 1, the method comprising the following steps: - Command the direct drive motors (25, 35, 55, 65, 75) of the steering system to reach the specified values ​​of the control parameters. - Monitor the actual values ​​of the control parameters. - Generate the difference between the specified value of the control parameter and the actual value of the control parameter, and - Disengagement is initiated under the following conditions: based on the difference, if at least one predetermined disengagement limit (82, 101, 102, 111, 112) corresponding to the actual predetermined state is reached.

11. The method according to claim 10, characterized in that, The control parameters are the position of the manual steering device, the torque of the manual steering device, the force on the manual steering device, the speed of the manual steering device, or the current of the direct drive motor (25, 35, 55, 655, 75).

12. A data processing system comprising means for performing the steps of the method according to any one of claims 10-11.

13. A non-transitory computer program product comprising instructions that, when executed by a computer, cause the computer to perform the method of any one of claims 10-11.

14. A non-transitory computer-readable medium comprising instructions that, when executed by a computer, cause the computer to perform the method of any one of claims 10-11.

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