Commercial vehicle electric control power steering system and control method

Abstract

The application provides a kind of commercial vehicle electric control power steering system and control method, comprising: upper steering column is connected with steering wheel;Electromagnetic clutch is arranged between upper steering column and lower steering column, for controlling the mechanical connection and decoupling between upper steering column and lower steering column;Return and road feeling motor is installed on upper steering column, for providing steering return torque and road feeling feedback;Electro-hydraulic steering assist mechanism is connected with lower steering column, for providing steering assist of wheel;Steering link is connected with electro-hydraulic steering assist mechanism and wheel, for transmitting steering torque to wheel;Control unit is used for controlling the engagement and separation of electromagnetic clutch according to vehicle driving state and driving mode, and controlling the working state of return and road feeling motor and electro-hydraulic steering assist mechanism.The scheme of the application improves the safety and reliability of vehicle driving.

Description

Technical Field

[0001] This invention relates to the field of vehicle control technology, and in particular to an electronic power steering system and control method for commercial vehicles. Background Technology

[0002] In recent years, chassis domain control technology has become the development direction of vehicle chassis control, and the first step is to achieve coordination between the braking and steering systems. In the implementation of some steering-assisted braking functions, such as braking on split-road surfaces, the system needs to automatically control the steering angle to help maintain directional stability. However, since commercial vehicles still use the steering assist device of the Electro-Hydraulic Power Steering (EHPS) system, there is a rigid connection between the steering system and the steering wheel. When the system automatically executes steering actions, it causes the steering wheel to rotate, which may lead to driver misjudgment and misoperation, or even injury to the driver, thus causing inconvenience to the development and design of steering-assisted braking functions.

[0003] In some exemplary technologies, a fully decoupled steer-by-wire hydraulic steering system is used, which solves the problems of high motor noise and inability to achieve the full decoupling of steering required by intelligent vehicles in traditional EPS. It avoids the impact on the steering wheel when the steering system works automatically, but it cannot achieve mechanical connection, and the safety is difficult to guarantee when the electronic control system fails.

[0004] In other exemplary technologies, an electro-hydraulic hybrid steering system is employed, retaining the valve structure of a traditional hydraulic power steering system while adding an electric power steering module. This achieves electro-hydraulic decoupling, allowing the electric power steering torque and hydraulic power steering torque to be distributed in any ratio. However, it cannot decouple the impact on the steering wheel during active control.

[0005] Therefore, the main problem with the above structure is that in the chassis domain control system, when the steering system needs to actively rotate to assist the braking system, it will cause the steering wheel to rotate, which may lead to driver misjudgment and thus affect the control effect. Some fully decoupled steering systems eliminate the mechanical connection between the steering wheel and the steering gear, which can solve the problem of the steering wheel being affected during active steering. However, because the mechanical connection is eliminated, safety cannot be guaranteed in the event of electronic control system failure. Therefore, the safety and reliability of vehicles driven using existing technologies are relatively poor. Summary of the Invention

[0006] This invention provides an electronic power steering system and control method for commercial vehicles, which addresses the shortcomings of poor safety and reliability in vehicle driving in existing technologies.

[0007] This invention provides an electronic power steering system for commercial vehicles, comprising: a steering wheel, an upper steering column, a return and road feel motor, an electromagnetic clutch, a lower steering column, an electro-hydraulic power steering mechanism, steering linkages, wheels, and a control unit;

[0008] The upper steering column is connected to the steering wheel;

[0009] The electromagnetic clutch is disposed between the upper steering column and the lower steering column. The electromagnetic clutch is used to control the mechanical connection and decoupling between the upper steering column and the lower steering column. When the electromagnetic clutch is engaged, the mechanical connection between the upper steering column and the lower steering column is maintained. When the electromagnetic clutch is disengaged, the decoupling between the upper steering column and the lower steering column is maintained.

[0010] The return and road feel motor is mounted on the upper steering column and is used to provide steering return torque and road feel feedback.

[0011] The electro-hydraulic power steering mechanism is connected to the lower steering column, and the electro-hydraulic power steering mechanism is used to provide assistance in steering the wheels;

[0012] The steering linkage is connected to the electro-hydraulic power steering mechanism and the wheel, and the steering linkage is used to transmit steering torque to the wheel;

[0013] The control unit is connected to the electromagnetic clutch, the return-to-center and road feel motor, and the electro-hydraulic power steering mechanism. The control unit is used to control the engagement and disengagement of the electromagnetic clutch according to the vehicle driving status and driving mode, and to control the working status of the return-to-center and road feel motor and the electro-hydraulic power steering mechanism.

[0014] According to the commercial vehicle electronic power steering system provided by the present invention, the driving modes include: driver driving mode, active control mode, chassis domain control mode, driver takeover mode, and system electronic control failure mode;

[0015] In driver driving mode, the control unit is used to control the engagement of the electromagnetic clutch and the mechanical connection between the upper steering column and the lower steering column, so that the driver's steering torque is transmitted to the lower steering column through the mechanical connection; the electro-hydraulic power steering mechanism is used to provide assistance.

[0016] In active control mode, the control unit is used to control the disengagement of the electromagnetic clutch and cut off the mechanical connection between the upper steering column and the lower steering column; the electro-hydraulic power steering mechanism is used to independently control the steering of the wheels; the return and road feel motor is used to provide road feel feedback.

[0017] In chassis domain control mode, the control unit is used to control the electromagnetic clutch to disengage and cut off the mechanical connection between the upper steering column and the lower steering column when a split road surface condition is detected; the electro-hydraulic power steering mechanism is used to actively adjust the steering angle of the wheels according to the vehicle driving status to maintain vehicle directional stability.

[0018] In driver-in-control mode, the control unit is used to control the electromagnetic clutch to switch from a disengaged state to an engaged state when it detects that the driver actively turns the steering wheel and the steering wheel angle exceeds a set threshold, thereby restoring the mechanical connection between the upper steering column and the lower steering column so that the driver's steering torque is transmitted to the lower steering column through the mechanical connection; the electro-hydraulic power steering mechanism is used to provide assistance according to the driver's operating intention, achieve the driver's target angle, and ensure a smooth switch from the active control mode or the chassis domain control mode to the driver driving mode;

[0019] In the electronic failure mode, the electromagnetic clutch automatically remains engaged under the action of the mechanical spring mechanism to maintain the mechanical connection between the upper steering column and the lower steering column, so that the driver's steering torque is transmitted to the lower steering column through the mechanical connection; the electro-hydraulic power steering mechanism is used to provide basic hydraulic assistance to ensure emergency steering capability.

[0020] According to the commercial vehicle electric power steering system provided by the present invention, in the active control mode, the chassis domain control mode and the driver takeover mode, the return-to-center and road feel motor is used to provide road feel feedback and assist the driver's steering operation, and provide necessary steering torque support.

[0021] In the driver's driving mode and the electronic control system failure mode, the return and road feel motors stop working, and the steering system maintains basic functions through mechanical connection and hydraulic power assistance.

[0022] According to the commercial vehicle electronic power steering system provided by the present invention, the commercial vehicle electronic power steering system further includes a steering angle sensor;

[0023] The steering angle sensor is used to monitor the steering angle of the upper steering column in real time and feed back the steering angle of the upper steering column to the control unit;

[0024] The control unit is also used to determine the driver's intention to take over and the switching of control modes based on the steering angle of the upper steering column.

[0025] According to the commercial vehicle electric power steering system provided by the present invention, when the control unit controls the engagement and disengagement of the electromagnetic clutch based on the vehicle's driving state and driving mode, it is specifically used for:

[0026] In the active control mode, the chassis domain control mode, or the driver takeover mode, an electronic control signal is output to the electromagnetic clutch; and in the driver driving mode, no electronic control signal is output to the electromagnetic clutch.

[0027] The electromagnetic clutch is specifically used for:

[0028] If an electronic control signal is received from the control unit, the system responds to the signal by being in a disengaged state to disconnect the mechanical connection between the upper steering column and the lower steering column; otherwise, it is in an engaged state to maintain the mechanical connection between the upper steering column and the lower steering column through its own spring mechanism; in the electronic control failure mode, the engaged state is automatically maintained under the action of the mechanical spring mechanism.

[0029] The present invention also provides a control method for an electric power steering system for commercial vehicles, which is applied to an electric power steering system for commercial vehicles. The system includes: a steering wheel, an upper steering column, a return and road feel motor, an electromagnetic clutch, a lower steering column, an electro-hydraulic power steering mechanism, steering linkages, wheels, and a control unit.

[0030] The method includes:

[0031] The control unit determines the vehicle's driving status and driving mode;

[0032] The control unit controls the engagement and disengagement of the electromagnetic clutch according to the vehicle's driving status and driving mode, and controls the working status of the return-to-center and road feel motor and the electro-hydraulic power steering mechanism.

[0033] The upper steering column is connected to the steering wheel;

[0034] The electromagnetic clutch is disposed between the upper steering column and the lower steering column. The electromagnetic clutch is used to control the mechanical connection and decoupling between the upper steering column and the lower steering column. When the electromagnetic clutch is engaged, the mechanical connection between the upper steering column and the lower steering column is maintained. When the electromagnetic clutch is disengaged, the decoupling between the upper steering column and the lower steering column is maintained.

[0035] The return and road feel motor is mounted on the upper steering column and is used to provide steering return torque and road feel feedback.

[0036] The electro-hydraulic power steering mechanism is connected to the lower steering column, and the electro-hydraulic power steering mechanism is used to provide assistance in steering the wheels;

[0037] The steering linkage is connected to the electro-hydraulic power steering mechanism and the wheel, and the steering linkage is used to transmit steering torque to the wheel.

[0038] According to the control method of the electronic power steering system for commercial vehicles provided by the present invention, the driving modes include: driver driving mode, active control mode, chassis domain control mode, driver takeover mode, and system electronic control failure mode.

[0039] The control unit controls the engagement and disengagement of the electromagnetic clutch according to the vehicle's driving status and driving mode, and controls the operating status of the return-to-center and road feel motor and the electro-hydraulic power steering mechanism, including:

[0040] In driver driving mode, the control unit controls the engagement of the electromagnetic clutch and the mechanical connection between the upper steering column and the lower steering column, so that the driver's steering torque is transmitted to the lower steering column through the mechanical connection; the electro-hydraulic power steering mechanism provides assistance.

[0041] In active control mode, the control unit controls the electromagnetic clutch to disengage, cutting off the mechanical connection between the upper steering column and the lower steering column; the electro-hydraulic power steering mechanism independently controls the steering of the wheels; the return and road feel motor provides road feel feedback.

[0042] In chassis domain control mode, when the control unit detects a split road surface condition, it controls the electromagnetic clutch to disengage and cuts off the mechanical connection between the upper steering column and the lower steering column; the electro-hydraulic power steering mechanism actively adjusts the steering angle of the wheels according to the vehicle's driving status to maintain vehicle directional stability.

[0043] In driver-in-control mode, when the control unit detects that the driver actively turns the steering wheel and the steering wheel angle exceeds a set threshold, it controls the electromagnetic clutch to switch from a disengaged state to an engaged state, restoring the mechanical connection between the upper steering column and the lower steering column, so that the driver's steering torque is transmitted to the lower steering column through the mechanical connection; the electro-hydraulic power steering mechanism provides assistance according to the driver's operating intention to achieve the driver's target angle, and ensures a smooth switch from the active control mode or the chassis domain control mode to the driver driving mode;

[0044] In the electronic failure mode, the electromagnetic clutch automatically remains engaged under the action of the mechanical spring mechanism to maintain the mechanical connection between the upper steering column and the lower steering column, so that the driver's steering torque is transmitted to the lower steering column through the mechanical connection; the electro-hydraulic power steering mechanism provides basic hydraulic assistance to ensure emergency steering capability.

[0045] According to the control method for an electronic power steering system for commercial vehicles provided by the present invention, the method further includes:

[0046] In active control mode, chassis domain control mode and driver takeover mode, the return and road feel motors provide road feel feedback and assist the driver's steering operation, providing necessary steering torque support.

[0047] In the driver's driving mode and the electronic control system failure mode, the return and road feel motors stop working, and the steering system maintains basic functions through mechanical connection and hydraulic power assistance.

[0048] According to the control method of the commercial vehicle electronic power steering system provided by the present invention, the commercial vehicle electronic power steering system further includes a steering angle sensor;

[0049] The method further includes:

[0050] The steering angle sensor monitors the steering angle of the upper steering column in real time and feeds back the steering angle of the upper steering column to the control unit.

[0051] The control unit determines the driver's intention to take over and the switching of control modes based on the steering angle of the upper steering column.

[0052] According to the control method of the commercial vehicle electric power steering system provided by the present invention, the control unit controls the engagement and disengagement of the electromagnetic clutch according to the vehicle driving state and driving mode, including:

[0053] In the active control mode, chassis domain control mode, or driver takeover mode, the control unit outputs an electronic control signal to the electromagnetic clutch;

[0054] In the driver's driving mode or the electronic control failure mode, the control unit does not output electronic control signals to the electromagnetic clutch;

[0055] If the electromagnetic clutch receives an electronic control signal output by the control unit, the electromagnetic clutch responds to the electronic control signal and is in a disengaged state to cut off the mechanical connection between the upper steering column and the lower steering column.

[0056] Otherwise, the electromagnetic clutch is engaged to maintain the mechanical connection between the upper steering column and the lower steering column through its own spring mechanism.

[0057] In the electronic failure mode, the electromagnetic clutch automatically maintains engagement under the action of the mechanical spring mechanism.

[0058] The commercial vehicle electronic power steering system and control method provided by this invention achieves a steering system function that, by setting an electromagnetic clutch between the upper and lower steering columns and installing a return-to-center and road-feed motor in the upper steering column, maintains the mechanical connection between the steering wheel and steering gear to improve safety when the driver actively operates the steering system, while decoupling from the steering wheel when the electronic control system actively controls the steering, thus avoiding affecting the driver's judgment and feel. Therefore, the solution of this invention improves the safety and reliability of vehicle driving. Attached Figure Description

[0059] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0060] Figure 1 This is a schematic diagram of the structure of the electronic power steering system for commercial vehicles provided by the present invention.

[0061] Figure 2 This is a flowchart illustrating the control method of the commercial vehicle electronic power steering system provided by the present invention. Detailed Implementation

[0062] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0063] It should be noted that the brief descriptions of terms in this application are only for the convenience of understanding the embodiments described below, and are not intended to limit the embodiments of this application. Unless otherwise stated, these terms should be understood in their ordinary and common meaning.

[0064] The terms "comprising" and "having," and any variations thereof, used in the specification, claims, and accompanying drawings of this application, are intended to be omniscient but not exclusive. For example, a product or device comprising a series of components is not necessarily limited to those explicitly listed, but may include other components not explicitly listed or inherent to such product or device. The term "element" as used in this application refers to any known or subsequently developed hardware, software, firmware, artificial intelligence, fuzzy logic, or combination of hardware and / or software code capable of performing the functions associated with that element.

[0065] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0066] Currently, commercial vehicles equipped with steer-by-wire systems typically employ the EHPS (Electronic Power Steering System) approach. This system features a rigid connection between the steering wheel, steering column, and steering gear; meaning that steering wheel rotation drives steering gear rotation, and wheel return to center or the power steering mechanism's response to external control also causes steering wheel rotation. The main problem with this structure is that in chassis domain control systems, when the steering system needs to actively rotate to assist the braking system, it causes steering wheel rotation, potentially leading to driver misjudgment and affecting control effectiveness. While some fully decoupled steering systems eliminate the mechanical connection between the steering wheel and steering gear, resolving the issue of steering wheel interference during active steering, the elimination of this mechanical connection compromises safety in the event of electronic control system failure.

[0067] Therefore, the safety and reliability of driving vehicles using existing technologies are relatively poor.

[0068] To address the aforementioned technical problems, this invention proposes the following technical concept: an electromagnetic clutch is installed between the upper and lower steering columns, and a return-to-center and road-sensing motor is installed on the upper steering column. This achieves a steering system function that can maintain the mechanical connection between the steering wheel and the steering gear to improve safety when the driver actively operates the system, while also decoupling from the steering wheel when the electronic control system actively controls the steering to avoid affecting the driver's judgment and feeling, thereby improving the safety and stability of vehicle driving.

[0069] The technical solution of this application and how it solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The following is a combination of... Figure 1 The present invention describes an electronically controlled power steering system for commercial vehicles.

[0070] Figure 1 This is a schematic diagram of the electronic power steering system for commercial vehicles provided by the present invention, as shown below. Figure 1As shown, the system includes: a steering wheel 1, an upper steering column 2, a return and road feel motor 3, an electromagnetic clutch 4, a lower steering column 5, an electro-hydraulic power steering mechanism 6, steering linkages 7, wheels 8, and a control unit 9.

[0071] The upper steering column 2 is connected to the steering wheel 1.

[0072] An electromagnetic clutch 4 is disposed between the upper steering column 2 and the lower steering column 5. The electromagnetic clutch 4 is used to control the mechanical connection and decoupling between the upper steering column 2 and the lower steering column 5. When the electromagnetic clutch 4 is engaged, the mechanical connection between the upper steering column 2 and the lower steering column 5 is maintained. When the electromagnetic clutch 4 is disengaged, the decoupling between the upper steering column 2 and the lower steering column 5 is maintained.

[0073] The return and road feel motor 3 is mounted on the upper steering column 2. The return and road feel motor 3 is used to provide steering return torque and road feel feedback.

[0074] The electro-hydraulic power steering mechanism 6 is connected to the lower steering column 5 and is used to provide steering assistance to the wheels 8.

[0075] The steering link 7 is connected to the electro-hydraulic power steering mechanism 6 and the wheel 8. The steering link 7 is used to transmit steering torque to the wheel 8.

[0076] The control unit 9 is connected to the electromagnetic clutch 4, the return and road feel motor 3, and the electro-hydraulic power steering mechanism 6. The control unit 9 is used to control the engagement and disengagement of the electromagnetic clutch 4 according to the vehicle driving status and driving mode, and to control the working status of the return and road feel motor 3 and the electro-hydraulic power steering mechanism 6.

[0077] In this embodiment, the driving modes include: driver driving mode, active control mode, chassis domain control mode, driver takeover mode, and system electronic control failure mode.

[0078] The steering wheel 1 is the component directly operated by the driver. Specifically, in driver-controlled mode, the driver controls the vehicle's steering by turning the steering wheel 1. In active control mode and chassis domain control mode, the steering wheel 1 is decoupled from the steering system, but the driver can still perceive road feedback through the steering wheel 1. In driver-take-over mode, the driver takes over vehicle control by turning the steering wheel 1, and the system responds to the driver's operating intentions.

[0079] The upper steering column 2 is connected to the steering wheel 1 and is connected to the lower steering column 5 via an electromagnetic clutch 4. Specifically, when the electromagnetic clutch 4 is engaged, the upper steering column 2 and the lower steering column 5 are mechanically connected, and the driver's steering intention can be transmitted to the steering mechanism through mechanical transmission. When the electromagnetic clutch 4 is disengaged, the upper steering column 2 and the lower steering column 5 are decoupled, and the steering system independently controls the steering of the wheels 8.

[0080] The return-center and road feel motor 3 is mounted on the upper steering column 2 to provide steering return torque and road feel feedback. Specifically, in active control mode and chassis domain control mode, the return-center and road feel motor 3 provides road feel feedback to enhance the driver's driving experience. In driver-in-control mode, the return-center and road feel motor 3 assists the driver's steering operation, providing necessary steering torque support. In driver-driven mode and electronic control failure mode, the return-center and road feel motor 3 stops working, and the steering system relies on mechanical connection and hydraulic power assistance to maintain basic functions.

[0081] The electromagnetic clutch 4 is positioned between the upper and lower steering columns to control their mechanical connection and decoupling. Specifically, in driver-driven mode and electronic control failure mode, the electromagnetic clutch 4 engages, mechanically connecting the upper steering column 2 and lower steering column 5, allowing the driver's steering intention to be mechanically transmitted to the steering mechanism. In active control mode and chassis domain control mode, the electromagnetic clutch 4 disengages, decoupling the upper steering column 2 and lower steering column 5, allowing the steering system to independently control wheel steering. In electronic control failure mode, the electromagnetic clutch 4 automatically remains engaged under the action of a mechanical spring mechanism, ensuring mechanical connection.

[0082] The lower steering column 5 is connected to the electro-hydraulic power steering mechanism 6 and is used to transmit steering torque to the steering mechanism. Specifically, when the electromagnetic clutch 4 is engaged, the lower steering column 5 receives steering torque from the upper steering column 2 and transmits it to the electro-hydraulic power steering mechanism 6. When the electromagnetic clutch 4 is disengaged, the lower steering column 5 independently receives control signals from the electro-hydraulic power steering mechanism 6 to achieve steering of the wheels 8.

[0083] The electro-hydraulic power steering mechanism 6 is connected to the lower steering column 5 and provides steering assistance to the wheels. Specifically, in driver-driven mode, the electro-hydraulic power steering mechanism 6 provides assistance according to the driver's steering intention, helping the driver easily control the steering of the wheels 8. In active control mode and chassis domain control mode, the electro-hydraulic power steering mechanism 6 independently controls the steering angle of the wheels 8 according to the instructions of the control unit. In driver-take-over mode, the electro-hydraulic power steering mechanism 6 provides assistance according to the driver's operating intention to achieve the driver's target angle. In electronic control failure mode, the electro-hydraulic power steering mechanism 6 continues to provide basic hydraulic assistance to ensure emergency steering capability.

[0084] The steering link 7 connects the electro-hydraulic power steering mechanism 6 and the wheel 8, and is used to transmit steering torque to the wheel. Specifically, the steering link 7 transmits the steering torque of the electro-hydraulic power steering mechanism 6 to the wheel, thereby realizing the steering action of the wheel.

[0085] Among them, wheel 8 receives steering torque to achieve vehicle steering. Wheel 8 adjusts steering angle according to the steering torque transmitted by steering link 7 to achieve vehicle steering control.

[0086] The control unit 9 controls the engagement and disengagement of the electromagnetic clutch 4, as well as the operation of the return-to-center and road feel motor 3 and the electro-hydraulic power steering mechanism 6, based on the vehicle's driving status and driving mode. Specifically, in driver-driven mode, the control unit 9 engages the electromagnetic clutch 4, and the driver's steering intention is mechanically transmitted to the steering mechanism, with the electro-hydraulic power steering mechanism 6 providing assistance. In active control mode, the control unit 9 disengages the electromagnetic clutch 4, and the electro-hydraulic power steering mechanism 6 independently controls the steering of the wheels 8, with the return-to-center and road feel motor 3 providing road feel feedback. In chassis domain control mode, when the control unit 4 detects a split-road surface, it disengages the electromagnetic clutch 4, and the electro-hydraulic power steering mechanism 6 actively adjusts the steering angle of the wheels 8 to maintain vehicle directional stability. In driver-in-control mode, when the control unit 9 detects that the driver actively turns the steering wheel and the angle exceeds a set threshold, it engages the electromagnetic clutch 4, and the electro-hydraulic power steering mechanism 6 provides assistance according to the driver's operating intention to achieve the driver's target angle. In electronic control failure mode, the electromagnetic clutch 4 automatically remains engaged under the action of a mechanical spring mechanism, and the electro-hydraulic power steering mechanism 6 provides basic hydraulic assistance to ensure emergency steering capability.

[0087] In summary, the electronic power steering system for commercial vehicles achieves flexible switching between multiple driving modes through the coordinated work of its various components, thereby improving driving safety, driving experience, and system intelligence. The control unit dynamically adjusts the state of the electromagnetic clutch and the output of the power steering mechanism according to different driving modes and vehicle operating conditions, ensuring optimal steering performance under various operating conditions.

[0088] It is understood that this embodiment achieves a steering system function that can maintain the mechanical connection between the steering wheel and the steering gear to improve safety when the driver actively operates the steering system, and can decouple from the steering wheel when the electronic control system actively controls the steering system to avoid affecting the driver's judgment and feeling, thereby improving the accuracy and reliability of vehicle driving.

[0089] Optionally, in some possible implementations, the above driving modes include: driver driving mode, active control mode, chassis domain control mode, driver takeover mode, and system electronic control failure mode.

[0090] In driver driving mode, control unit 9 is used to control the engagement of electromagnetic clutch 4 and the mechanical connection between upper steering column 2 and lower steering column 5 so that the driver's steering torque is transmitted to lower steering column 5 through mechanical connection; electro-hydraulic power steering mechanism 6 is used to provide assistance.

[0091] In active control mode, control unit 9 is used to control the disengagement of electromagnetic clutch 4, cutting off the mechanical connection between upper steering column 2 and lower steering column 5; electro-hydraulic power steering mechanism 6 is used to independently control the steering of wheel 8; return and road feel motor 3 is used to provide road feel feedback.

[0092] In chassis domain control mode, control unit 9 is used to control electromagnetic clutch 4 to disengage and cut off the mechanical connection between upper steering column 2 and lower steering column 5 when a split road condition is detected; electro-hydraulic power steering mechanism 6 is used to actively adjust the steering angle of wheel 8 according to the vehicle driving status to maintain vehicle directional stability.

[0093] In driver takeover mode, control unit 9 is used to control electromagnetic clutch 4 to switch from disengaged state to engaged state when it detects that the driver actively turns steering wheel 1 and the steering angle of steering wheel 1 exceeds a set threshold, thereby restoring the mechanical connection between upper steering column 2 and lower steering column 5 so that the driver's steering torque is transmitted to lower steering column 5 through mechanical connection; electro-hydraulic power steering mechanism 6 is used to provide assistance according to the driver's operating intention, achieve the driver's target angle, and ensure a smooth switch from active control mode or chassis domain control mode to driver driving mode.

[0094] In the electronic failure mode, the electromagnetic clutch 4 automatically remains engaged under the action of the mechanical spring mechanism to maintain the mechanical connection between the upper steering column 2 and the lower steering column 5, so that the driver's steering torque can be transmitted to the lower steering column 5 through the mechanical connection; the electro-hydraulic power steering mechanism 6 is used to provide basic hydraulic assistance to ensure emergency steering capability.

[0095] The driver driving mode refers to the mode in which the driver directly controls the vehicle's steering through the steering wheel. For example, application scenarios for the driver driving mode include: daily driving, where the driver has full control over the vehicle's steering, or when non-autonomous driving or driver assistance functions are enabled.

[0096] Specifically, in driver driving mode, the electromagnetic clutch 4 is engaged, maintaining the mechanical connection between the upper and lower steering columns through its own spring mechanism. When the driver turns the steering wheel 1, the steering torque is transmitted through the upper steering column 2 to the electromagnetic clutch 4, and then to the lower steering column 5. After detecting the driver's steering intention, the electro-hydraulic power steering mechanism 6 provides hydraulic assistance to help the wheels 8 steer. In this mode, the return-to-center and road feel motor 3 mainly provides road feel feedback, enhancing the driver's perception of the steering.

[0097] In practical applications, in driver-only mode, the driver has full control over vehicle steering. The electromagnetic clutch 4 is engaged, maintaining the mechanical connection between the upper steering column 2 and the lower steering column 5. The steering wheel 1 remains mechanically connected to the steering system. In this mode, the driver's steering torque is transmitted to the lower steering column 5 via the electromagnetic clutch 4, which, with the assistance of the electro-hydraulic power steering mechanism 6, steers the wheels. The return-to-center and road feel motor 3 is typically not engaged; the steering system primarily relies on mechanical connections and hydraulic power steering.

[0098] Active control mode refers to the mode in which the vehicle's autonomous driving or driver assistance system actively controls the steering of the wheels. For example, application scenarios for active control mode include: when autonomous driving functions are enabled (such as lane keeping assist, automatic parking, etc.); and when the system needs to automatically adjust the steering angle to maintain vehicle stability or perform specific driving tasks.

[0099] Specifically, in active control mode, when the autonomous driving or assisted driving system issues a steering request, the electromagnetic clutch 4 disengages the upper steering column 2 and the lower steering column 5, cutting off the mechanical connection. The electro-hydraulic power steering mechanism 6 independently controls the steering angle of the wheels 8 according to system instructions, realizing autonomous driving or assisted driving functions. Because the electromagnetic clutch 4 is disengaged, the steering wheel 1 will not rotate with the wheels, avoiding interference with the driver. In this mode, the return-to-center and road feel motor 3 mainly provides road feel feedback or simulates steering resistance to enhance the driver's perception.

[0100] In practical applications, under active control mode, the autonomous driving system controls the steering of the wheels. When the autonomous driving or assisted driving system issues a steering request, the control unit 9 controls the electromagnetic clutch 4 to disengage and controls the electro-hydraulic power steering mechanism 6 to steer the wheels 8. At this time, because the upper steering column 2 and the lower steering column 5 are decoupled, the steering wheel 1 will not rotate, thus avoiding interference with the driver's decision-making and preventing injury to the driver caused by the rotation of the steering wheel 1.

[0101] Chassis domain control mode refers to a mode in which the vehicle chassis control system actively adjusts the steering angle based on the vehicle's driving status. For example, application scenarios for chassis domain control mode include: when the vehicle is driving on complex road surfaces (such as split-road surfaces or slippery surfaces); and when the system needs to actively intervene in the steering to maintain vehicle directional stability.

[0102] Specifically, in chassis domain control mode, when the system detects a split-road surface condition, control unit 9 controls the electromagnetic clutch 4 to disengage, thereby separating the upper steering column 2 and the lower steering column 5. The electro-hydraulic power steering mechanism 6, according to the instructions of the chassis domain control system, actively controls the wheels 8 to deflect at a certain angle towards the side with high traction (during driving) or low traction (during braking), maintaining vehicle directional stability. The steering angle sensor monitors the steering angle of the upper steering column 2 in real time, providing feedback to the system. In this mode, the return-to-center and road feel motor 3 provides auxiliary steering torque or road feel feedback, enhancing system stability.

[0103] In practical applications, under chassis domain control mode, the chassis control system actively adjusts the steering angle. When accelerating or braking on a split-road surface (i.e., one side of the left and right wheels is at high attachment and the other side is at low attachment), the vehicle will yaw due to the difference in braking / driving force on both sides. When the system detects a split-road surface, if the driver does not perform steering correction, the chassis domain controller intervenes. First, it disengages the electromagnetic clutch 4, and then actively controls the power steering mechanism 6 to deflect a certain angle towards the high attachment side (during driving) or the low attachment side (during braking). (The deflection angle is determined based on the actual vehicle's driving acceleration or braking intensity, according to actual vehicle testing and calibration.) This allows the steering system to automatically maintain directional stability with the assistance of the steering system, without requiring manual correction from the driver, thus reducing the demands on the driver's driving skills.

[0104] In this context, driver takeover mode refers to a mode in which, in active control mode or chassis domain control mode, the driver actively intervenes in steering operations, and the system switches control from the autonomous driving or chassis domain control system to the driver. For example, application scenarios for driver takeover mode include: when the driver needs to take over vehicle control (such as when the autonomous driving system is about to disengage or the driver actively intervenes); and when the driver turns the steering wheel beyond a set threshold.

[0105] Specifically, in driver-in-control mode, the steering angle sensor monitors the driver's intentions in real time. The electro-hydraulic power steering mechanism 6 adjusts the wheel steering according to the driver's target angle to ensure a smooth transition. The return-to-center and road-feed motor 3 assists the driver's operation, enhancing the driving experience.

[0106] In practical applications, in driver-take-off mode, the driver actively intervenes in steering, and the system smoothly switches control. For example, during active control mode, when the angle sensor detects that the upper steering column 2 has rotated beyond a certain angle under driver control, the system prioritizes the driver's target angle and uses the electro-hydraulic power steering mechanism 6 to achieve that target angle. Furthermore, during the transition from active control mode to chassis domain control mode, the output angle of the electro-hydraulic power steering mechanism 6 is smoothed to prevent large abrupt changes.

[0107] Among them, the system electronic control failure mode refers to the mode in which the steering system switches to mechanical backup mode when the electronic control system fails, ensuring that the vehicle still has basic steering ability. For example, the application scenarios of the system electronic control failure mode include: when the electronic control system malfunctions or fails; when the system detects the loss or abnormality of electronic control signals.

[0108] Specifically, in the system's electronic control failure mode, when the electronic control system fails, the electromagnetic clutch 4 automatically engages under the action of the mechanical spring mechanism, maintaining the mechanical connection between the upper steering column 2 and the lower steering column 5. The electro-hydraulic power steering mechanism 6 continues to provide basic hydraulic assistance, ensuring that the driver can manually control the steering of the wheels 8 via the steering wheel 1. The return-to-center and road feel motor 3 ceases operation, and the steering system relies on the mechanical connection and hydraulic assistance to maintain basic functions.

[0109] In practical applications, when the electronic control system fails, the steering system switches to mechanical backup mode to ensure emergency steering capability. The electromagnetic clutch 4 remains engaged under the action of the mechanical system, maintaining the mechanical connection between the upper steering column 2 and the lower steering column 5. The system still possesses basic mechanical and hydraulic power assist capabilities to ensure safety in the event of electronic control system failure.

[0110] In this implementation, the driver-centric driving mode provides direct mechanical connection and assistance, enhancing the driving experience. The active control mode supports autonomous driving functions, reduces driver interference, and provides road feel feedback. The chassis domain control mode adapts to complex road surfaces, dynamically adjusting the steering angle to improve driving stability. The driver takeover mode responds quickly to driver input, ensuring a smooth transition and improving driving safety. The system electronic control failure mode provides mechanical backup and emergency steering capabilities, ensuring system reliability. These modes not only meet the needs of different driving scenarios but also significantly improve the steering performance and safety of commercial vehicles through intelligent control.

[0111] Optionally, in some possible implementations, in active control mode, chassis domain control mode and driver takeover mode, the return and road feel motor 3 is used to provide road feel feedback and assist the driver's steering operation, providing necessary steering torque support; in driver driving mode and electronic control system failure mode, the return and road feel motor 3 stops working, and the steering system maintains basic functions through mechanical connection and hydraulic power assistance.

[0112] Understandably, on the one hand, the return-center and road feel motor 3 provides road feel feedback in active control mode, chassis domain control mode, and driver takeover mode, which enhances the driving experience, reduces misoperation, and ensures a smooth transition between modes in driver takeover mode. Specifically, in autonomous driving or chassis domain control mode, the steering wheel 1 is decoupled from the steering system, but the return-center and road feel motor 3 can still provide simulated road feel feedback. This allows the driver to feel a certain amount of steering resistance, enhancing their perception of the vehicle's status and improving the driving experience. Road feel feedback helps the driver better judge the vehicle's driving status, especially in complex road conditions or autonomous driving mode. This feedback reduces misoperation caused by a lack of road feel, improving driving safety. In driver takeover mode, the return-center and road feel motor 3 assists the driver's steering operation, providing necessary steering torque support. This ensures a smooth transition from autonomous driving or chassis domain control mode to driver driving mode, avoiding abrupt changes caused by mode switching, and further improving driving stability and safety.

[0113] On the other hand, the return-center and road feel motor 3 assists the driver's steering operations in active control mode, chassis domain control mode, and driver takeover mode, reducing driving difficulty and improving system response speed. Specifically, in complex conditions (such as split-level roads or slippery roads), the auxiliary steering torque provided by the return-center and road feel motor 3 helps the driver control the wheel steering more easily, reducing driving difficulty. Especially in emergency situations, it can quickly respond to the driver's operating intentions and maintain vehicle stability. The return-center and road feel motor 3 can quickly provide steering torque support, enhancing the system's response speed and ensuring that the steering system's actions are more precise and timely in autonomous driving or chassis domain control modes.

[0114] On the other hand, the return-to-center and road-feed motor 3 ceases operation in both driver-driven mode and electronic control system failure mode. In driver-driven mode, the return-to-center and road-feed motor 3 stops operating, and the steering system relies entirely on mechanical connections and hydraulic power assist to maintain basic functions. This preserves the reliability and directness of traditional steering systems, ensuring that the driver can directly control the vehicle through the mechanical system in non-autonomous driving mode. In electronic control system failure mode, the return-to-center and road-feed motor 3 stops operating, and the steering system relies on mechanical connections and hydraulic power assist to maintain basic functions. This design ensures that the vehicle still possesses emergency steering capabilities in the event of a complete failure of the electronic control system, allowing the driver to manually control the vehicle through the mechanical system, reducing safety risks caused by system malfunctions. By stopping the operation of the return-to-center and road-feed motor 3 in electronic control failure mode, the system relies on mechanical backup to maintain basic functions, improving system reliability and safety.

[0115] In this embodiment, in active control mode, chassis domain control mode, and driver takeover mode, the return-center and road feel motor 3 provides road feel feedback and assists the driver's steering operation, providing necessary steering torque support. In driver driving mode and electronic control system failure mode, the return-center and road feel motor 3 stops working, and the steering system maintains basic functions through mechanical connection and hydraulic assistance. This embodiment not only improves the intelligence level of the commercial vehicle's electronic power steering system, but also significantly improves the system's safety and driving experience through dynamic adjustment capabilities.

[0116] Optionally, in one possible implementation, the above-mentioned commercial vehicle electronic power steering system further includes a steering angle sensor;

[0117] The steering angle sensor is used to monitor the steering angle of the upper steering column 2 in real time and feed back the steering angle of the upper steering column 2 to the control unit 9;

[0118] The control unit 9 is also used to determine the driver's intention to take over and switch control modes based on the steering angle of the upper steering column 2.

[0119] Specifically, in chassis domain control mode, the steering angle sensor monitors the steering angle of the upper steering column 2 in real time and provides feedback to the system.

[0120] Specifically, in driver-in-control mode, the steering angle sensor monitors the driver's intentions in real time. The electro-hydraulic power steering mechanism 6 adjusts the wheel steering according to the driver's target angle to ensure a smooth transition. The return-to-center and road-feed motor 3 assists the driver's operation, enhancing the driving experience.

[0121] In this embodiment, the steering angle sensor can monitor the steering angle of the upper steering column in real time and feed the data back to the control unit 9. This real-time monitoring capability enables the system to accurately perceive the rotation state of the steering wheel, providing accurate data support for subsequent control decisions. By monitoring the steering angle in real time, the system can respond promptly to the driver's operating intentions, reducing control errors caused by data delays or inaccuracies, thereby improving the overall reliability of the system. Accordingly, when the steering angle sensor detects that the driver actively turns the steering wheel 1 and the angle exceeds a set threshold, the control unit 9 can quickly determine the driver's intention to take over vehicle control. This rapid response capability ensures that the system can smoothly and promptly return control to the driver at critical moments. In autonomous driving or chassis domain control mode, the driver may need to take over vehicle control at any time. The introduction of the steering angle sensor enables the system to detect the driver's intention to take over in a timely manner, avoiding safety risks caused by system delays, thereby significantly improving driving safety.

[0122] Optionally, in one possible implementation, when the control unit 9 is used to control the engagement and disengagement of the electromagnetic clutch according to the vehicle's driving state and driving mode, it is specifically used for:

[0123] In active control mode, chassis domain control mode, or driver takeover mode, an electronic control signal is output to the electromagnetic clutch 4; and in driver driving mode, no electronic control signal is output to the electromagnetic clutch 4.

[0124] Electromagnetic clutch 4, specifically used for:

[0125] If an electronic control signal is received from the control unit 9, the system responds to the signal by being in a disengaged state to disconnect the mechanical connection between the upper steering column 2 and the lower steering column 5; otherwise, it is in an engaged state to maintain the mechanical connection between the upper steering column 2 and the lower steering column 5 through its own spring mechanism; in the electronic control failure mode, the engaged state is automatically maintained under the action of the mechanical spring mechanism.

[0126] It should be noted that in the electronic control failure mode, even if the control unit 9 completely fails, it cannot output control signals. The electromagnetic clutch 4 is automatically maintained in the engaged state by a mechanical spring mechanism, ensuring the mechanical connection between the upper steering column 2 and the lower steering column 5. This design ensures emergency steering capability and significantly improves the reliability and safety of the system.

[0127] In this embodiment, on the one hand, the control unit 9 precisely controls the engagement and disengagement of the electromagnetic clutch 4 by outputting electronic control signals. The system can quickly switch operating modes according to different driving needs, reducing driving risks caused by inaccurate mode switching and improving system reliability and safety. On the other hand, in the event of electronic control system failure, the electromagnetic clutch 4 can automatically maintain engagement under the action of a mechanical spring mechanism. This design ensures that even if the electronic control system completely fails, the vehicle can still maintain basic steering function through mechanical connection. Furthermore, in driver-in-control mode, the control unit 9 can quickly output electronic control signals to disengage the electromagnetic clutch 4, ensuring that the driver's operation can be immediately transmitted to the steering system. This rapid response capability improves driving safety, especially in emergency situations. Moreover, during mode switching, the response of the electromagnetic clutch 4 ensures a smooth transition of the steering system, avoiding abrupt changes caused by mode switching and improving driving comfort. Finally, the engagement and disengagement state of the electromagnetic clutch 4 is dynamically adjusted according to the driving mode, enabling the system to adapt to various driving scenarios, from autonomous driving to manual driving, improving the system's adaptability and flexibility. Therefore, this embodiment not only improves system performance but also provides strong support for the development of autonomous and intelligent driving technologies.

[0128] In the commercial vehicle electronic power steering system provided in this embodiment, the upper steering column 2 is connected to the steering wheel 1; the electromagnetic clutch 4 is disposed between the upper steering column 2 and the lower steering column 5, and is used to control the mechanical connection and decoupling between the upper steering column 2 and the lower steering column 5; when the electromagnetic clutch 4 is engaged, the mechanical connection between the upper steering column 2 and the lower steering column 5 is maintained; when the electromagnetic clutch 4 is disengaged, the decoupling between the upper steering column 2 and the lower steering column 5 is achieved; the return-center and road feel motor 3 is mounted on the upper steering column 2, and is used to provide steering return torque and road feel feedback; the electro-hydraulic power steering mechanism 6 is connected to the lower steering column 5, and is used to provide wheel steering assistance; the steering linkage 7 is connected to the electro-hydraulic power steering mechanism 6 and the wheel 8, and is used to transmit steering torque to the wheel 8; the control unit 9 is connected to the electromagnetic clutch 4, the return-center and road feel motor 3, and the electro-hydraulic power steering mechanism 6, and is used to control the engagement and disengagement of the electromagnetic clutch 4 according to the vehicle driving state and driving mode, and to control the working state of the return-center and road feel motor 3 and the electro-hydraulic power steering mechanism 6. The solution in this embodiment, by incorporating an electromagnetic clutch between the upper and lower steering columns and a return-to-center and road-sensing motor in the upper steering column, achieves a steering system function that maintains a mechanical connection between the steering wheel and steering gear to improve safety during driver-operated steering, while simultaneously decoupling from the steering wheel when the electronic control system actively controls the steering, thus avoiding interference with the driver's judgment and feel. Therefore, the solution of this invention improves the safety and reliability of vehicle driving.

[0129] In some embodiments, the present invention also provides a control method for an electric power steering system for commercial vehicles. The control method is applied to an electric power steering system for commercial vehicles, the system including: a steering wheel 1, an upper steering column 2, a return and road feel motor 3, an electromagnetic clutch 4, a lower steering column 5, an electro-hydraulic power steering mechanism 6, a steering linkage 7, wheels 8, and a control unit 9.

[0130] Figure 2 This is a flowchart illustrating the control method for the electronic power steering system for commercial vehicles provided by the present invention, as shown below. Figure 2 As shown, the method includes steps 201 and 202.

[0131] Step 201: Control unit 1 determines the vehicle's driving status and driving mode.

[0132] Step 202: Control unit 2 controls the engagement and disengagement of electromagnetic clutch 4 according to vehicle driving status and driving mode, and controls the working status of return-to-center and road feel motor 3 and electro-hydraulic power steering mechanism 6.

[0133] The upper steering column 2 is connected to the steering wheel 1.

[0134] An electromagnetic clutch 4 is disposed between the upper steering column 2 and the lower steering column 5. The electromagnetic clutch 4 is used to control the mechanical connection and decoupling between the upper steering column 2 and the lower steering column 5. When the electromagnetic clutch 4 is engaged, the mechanical connection between the upper steering column 2 and the lower steering column 5 is maintained. When the electromagnetic clutch 4 is disengaged, the decoupling between the upper steering column 2 and the lower steering column 5 is maintained.

[0135] The return and road feel motor 3 is mounted on the upper steering column 2. The return and road feel motor 3 is used to provide steering return torque and road feel feedback.

[0136] The electro-hydraulic power steering mechanism 6 is connected to the lower steering column 5 and is used to provide steering assistance to the wheels 8.

[0137] The steering link 7 is connected to the electro-hydraulic power steering mechanism 6 and the wheel 8. The steering link 7 is used to transmit steering torque to the wheel 8.

[0138] In this embodiment, the driving modes include: driver driving mode, active control mode, chassis domain control mode, driver takeover mode, and system electronic control failure mode.

[0139] The steering wheel 1 is the component directly operated by the driver. Specifically, in driver-controlled mode, the driver controls the vehicle's steering by turning the steering wheel 1. In active control mode and chassis domain control mode, the steering wheel 1 is decoupled from the steering system, but the driver can still perceive road feedback through the steering wheel 1. In driver-take-over mode, the driver takes over vehicle control by turning the steering wheel 1, and the system responds to the driver's operating intentions.

[0140] The upper steering column 2 is connected to the steering wheel 1 and is connected to the lower steering column 5 via an electromagnetic clutch 4. Specifically, when the electromagnetic clutch 4 is engaged, the upper steering column 2 and the lower steering column 5 are mechanically connected, and the driver's steering intention can be transmitted to the steering mechanism through mechanical transmission. When the electromagnetic clutch 4 is disengaged, the upper steering column 2 and the lower steering column 5 are decoupled, and the steering system independently controls the steering of the wheels 8.

[0141] The return-center and road feel motor 3 is mounted on the upper steering column 2 to provide steering return torque and road feel feedback. Specifically, in active control mode and chassis domain control mode, the return-center and road feel motor 3 provides road feel feedback to enhance the driver's driving experience. In driver-in-control mode, the return-center and road feel motor 3 assists the driver's steering operation, providing necessary steering torque support. In driver-driven mode and electronic control failure mode, the return-center and road feel motor 3 stops working, and the steering system relies on mechanical connection and hydraulic power assistance to maintain basic functions.

[0142] The electromagnetic clutch 4 is positioned between the upper and lower steering columns to control their mechanical connection and decoupling. Specifically, in driver-driven mode and electronic control failure mode, the electromagnetic clutch 4 engages, mechanically connecting the upper steering column 2 and lower steering column 5, allowing the driver's steering intention to be mechanically transmitted to the steering mechanism. In active control mode and chassis domain control mode, the electromagnetic clutch 4 disengages, decoupling the upper steering column 2 and lower steering column 5, allowing the steering system to independently control wheel steering. In electronic control failure mode, the electromagnetic clutch 4 automatically remains engaged under the action of a mechanical spring mechanism, ensuring mechanical connection.

[0143] The lower steering column 5 is connected to the electro-hydraulic power steering mechanism 6 and is used to transmit steering torque to the steering mechanism. Specifically, when the electromagnetic clutch 4 is engaged, the lower steering column 5 receives steering torque from the upper steering column 2 and transmits it to the electro-hydraulic power steering mechanism 6. When the electromagnetic clutch 4 is disengaged, the lower steering column 5 independently receives control signals from the electro-hydraulic power steering mechanism 6 to achieve steering of the wheels 8.

[0144] The electro-hydraulic power steering mechanism 6 is connected to the lower steering column 5 and provides steering assistance to the wheels. Specifically, in driver-driven mode, the electro-hydraulic power steering mechanism 6 provides assistance according to the driver's steering intention, helping the driver easily control the steering of the wheels 8. In active control mode and chassis domain control mode, the electro-hydraulic power steering mechanism 6 independently controls the steering angle of the wheels 8 according to the instructions of the control unit. In driver-take-over mode, the electro-hydraulic power steering mechanism 6 provides assistance according to the driver's operating intention to achieve the driver's target angle. In electronic control failure mode, the electro-hydraulic power steering mechanism 6 continues to provide basic hydraulic assistance to ensure emergency steering capability.

[0145] The steering link 7 connects the electro-hydraulic power steering mechanism 6 and the wheel 8, and is used to transmit steering torque to the wheel. Specifically, the steering link 7 transmits the steering torque of the electro-hydraulic power steering mechanism 6 to the wheel, thereby realizing the steering action of the wheel.

[0146] Among them, wheel 8 receives steering torque to achieve vehicle steering. Wheel 8 adjusts steering angle according to the steering torque transmitted by steering link 7 to achieve vehicle steering control.

[0147] The control unit 9 controls the engagement and disengagement of the electromagnetic clutch 4, as well as the operation of the return-to-center and road feel motor 3 and the electro-hydraulic power steering mechanism 6, based on the vehicle's driving status and driving mode. Specifically, in driver-driven mode, the control unit 9 engages the electromagnetic clutch 4, and the driver's steering intention is mechanically transmitted to the steering mechanism, with the electro-hydraulic power steering mechanism 6 providing assistance. In active control mode, the control unit 9 disengages the electromagnetic clutch 4, and the electro-hydraulic power steering mechanism 6 independently controls the steering of the wheels 8, with the return-to-center and road feel motor 3 providing road feel feedback. In chassis domain control mode, when the control unit 4 detects a split-road surface, it disengages the electromagnetic clutch 4, and the electro-hydraulic power steering mechanism 6 actively adjusts the steering angle of the wheels 8 to maintain vehicle directional stability. In driver-in-control mode, when the control unit 9 detects that the driver actively turns the steering wheel and the angle exceeds a set threshold, it engages the electromagnetic clutch 4, and the electro-hydraulic power steering mechanism 6 provides assistance according to the driver's operating intention to achieve the driver's target angle. In electronic control failure mode, the electromagnetic clutch 4 automatically remains engaged under the action of a mechanical spring mechanism, and the electro-hydraulic power steering mechanism 6 provides basic hydraulic assistance to ensure emergency steering capability.

[0148] In summary, the electronic power steering system for commercial vehicles achieves flexible switching between multiple driving modes through the coordinated work of its various components, thereby improving driving safety, driving experience, and system intelligence. The control unit dynamically adjusts the state of the electromagnetic clutch and the output of the power steering mechanism according to different driving modes and vehicle operating conditions, ensuring optimal steering performance under various operating conditions.

[0149] It is understood that this embodiment achieves a steering system function that can maintain the mechanical connection between the steering wheel and the steering gear to improve safety when the driver actively operates the steering system, and can decouple from the steering wheel when the electronic control system actively controls the steering system to avoid affecting the driver's judgment and feeling, thereby improving the accuracy and reliability of vehicle driving.

[0150] Optionally, in some implementations, the driving modes include: driver driving mode, active control mode, chassis domain control mode, driver takeover mode, and system electronic control failure mode.

[0151] Step 202 above includes:

[0152] In driver driving mode, control unit 9 controls the engagement of electromagnetic clutch 4, mechanically connecting upper steering column 2 and lower steering column 5, so that the driver's steering torque is transmitted to lower steering column 5 through mechanical connection; electro-hydraulic power steering mechanism 6 provides assistance.

[0153] In active control mode, control unit 9 controls electromagnetic clutch 4 to disengage, cutting off the mechanical connection between upper steering column 2 and lower steering column 5; electro-hydraulic power steering mechanism 6 independently controls the steering of wheel 8; return and road feel motor 3 provides road feel feedback.

[0154] In chassis domain control mode, when the control unit 9 detects a split road surface condition, it controls the electromagnetic clutch 4 to disengage, cutting off the mechanical connection between the upper steering column 2 and the lower steering column 5; the electro-hydraulic power steering mechanism 6 actively adjusts the steering angle of the wheels 8 according to the vehicle's driving status to maintain vehicle directional stability.

[0155] In driver takeover mode, when the control unit 9 detects that the driver actively turns the steering wheel 1 and the steering wheel 1 turns an angle exceeding a set threshold, it controls the electromagnetic clutch 4 to switch from disengaged to engaged state, restoring the mechanical connection between the upper steering column 2 and the lower steering column 5, so that the driver's steering torque is transmitted to the lower steering column 5 through the mechanical connection; the electro-hydraulic power steering mechanism 6 provides assistance according to the driver's operating intention, achieves the driver's target angle, and ensures a smooth switch from active control mode or chassis domain control mode to driver driving mode.

[0156] In the electronic failure mode, the electromagnetic clutch 4 automatically remains engaged under the action of the mechanical spring mechanism to maintain the mechanical connection between the upper steering column 2 and the lower steering column 5, so that the driver's steering torque can be transmitted to the lower steering column 5 through the mechanical connection; the electro-hydraulic power steering mechanism 6 is used to provide basic hydraulic assistance to ensure emergency steering capability.

[0157] In this implementation, the driver-centric driving mode provides direct mechanical connection and assistance, enhancing the driving experience. The active control mode supports autonomous driving functions, reduces driver interference, and provides road feel feedback. The chassis domain control mode adapts to complex road surfaces, dynamically adjusting the steering angle to improve driving stability. The driver takeover mode responds quickly to driver input, ensuring a smooth transition and improving driving safety. The system electronic control failure mode provides mechanical backup and emergency steering capabilities, ensuring system reliability. These modes not only meet the needs of different driving scenarios but also significantly improve the steering performance and safety of commercial vehicles through intelligent control.

[0158] Optionally, in some possible implementations, the above method further includes:

[0159] In active control mode, chassis domain control mode and driver takeover mode, the return and road feel motor 3 provides road feel feedback and assists the driver's steering operation, providing necessary steering torque support;

[0160] In driver driving mode and electronic control system failure mode, the return and road feel motor 3 stops working, and the steering system maintains basic functions through mechanical connection and hydraulic power assistance.

[0161] In this embodiment, in active control mode, chassis domain control mode, and driver takeover mode, the return-center and road feel motor 3 provides road feel feedback and assists the driver's steering operation, providing necessary steering torque support. In driver driving mode and electronic control system failure mode, the return-center and road feel motor 3 stops working, and the steering system maintains basic functions through mechanical connection and hydraulic assistance. This embodiment not only improves the intelligence level of the commercial vehicle's electronic power steering system, but also significantly improves the system's safety and driving experience through dynamic adjustment capabilities.

[0162] Optionally, in one possible implementation, the above-mentioned commercial vehicle electronic power steering system further includes a steering angle sensor;

[0163] The above methods also include:

[0164] The steering angle sensor monitors the steering angle of the upper steering column 2 in real time and feeds back the steering angle of the upper steering column 2 to the control unit 9;

[0165] The control unit 9 determines the driver's intention to take over and the switching of control modes based on the steering angle of the upper steering column 2.

[0166] In this embodiment, the steering angle sensor can monitor the steering angle of the upper steering column in real time and feed the data back to the control unit 9. This real-time monitoring capability enables the system to accurately perceive the rotation state of the steering wheel, providing accurate data support for subsequent control decisions. By monitoring the steering angle in real time, the system can respond promptly to the driver's operating intentions, reducing control errors caused by data delays or inaccuracies, thereby improving the overall reliability of the system. Accordingly, when the steering angle sensor detects that the driver actively turns the steering wheel 1 and the angle exceeds a set threshold, the control unit 9 can quickly determine the driver's intention to take over vehicle control. This rapid response capability ensures that the system can smoothly and promptly return control to the driver at critical moments. In autonomous driving or chassis domain control mode, the driver may need to take over vehicle control at any time. The introduction of the steering angle sensor enables the system to detect the driver's intention to take over in a timely manner, avoiding safety risks caused by system delays, thereby significantly improving driving safety.

[0167] Optionally, in one possible implementation, in step 202 above, the control unit 9 controls the engagement and disengagement of the electromagnetic clutch according to the vehicle's driving state and driving mode, including:

[0168] In active control mode, chassis domain control mode or driver takeover mode, control unit 9 outputs electronic control signal to electromagnetic clutch 4;

[0169] In driver driving mode, control unit 9 does not output electronic control signals to electromagnetic clutch 4.

[0170] If the electromagnetic clutch 4 receives the electronic control signal output by the control unit 9, it responds to the electronic control signal and is in the disengaged state to cut off the mechanical connection between the upper steering column 2 and the lower steering column 5.

[0171] Otherwise, the electromagnetic clutch 4 is engaged to maintain the mechanical connection between the upper steering column 2 and the lower steering column 5 through its own spring mechanism.

[0172] In the electronic control failure mode, the electromagnetic clutch 4 automatically maintains the engaged state under the action of the mechanical spring mechanism.

[0173] It should be noted that in the electronic control failure mode, even if the control unit 9 completely fails, it cannot output control signals. The electromagnetic clutch 4 is automatically maintained in the engaged state by a mechanical spring mechanism, ensuring the mechanical connection between the upper steering column 2 and the lower steering column 5. This design ensures emergency steering capability and significantly improves the reliability and safety of the system.

[0174] In this embodiment, on the one hand, the control unit 9 precisely controls the engagement and disengagement of the electromagnetic clutch 4 by outputting electronic control signals. The system can quickly switch operating modes according to different driving needs, reducing driving risks caused by inaccurate mode switching and improving system reliability and safety. On the other hand, in the event of electronic control system failure, the electromagnetic clutch 4 can automatically maintain engagement under the action of a mechanical spring mechanism. This design ensures that even if the electronic control system completely fails, the vehicle can still maintain basic steering function through mechanical connection. Furthermore, in driver-in-control mode, the control unit 9 can quickly output electronic control signals to disengage the electromagnetic clutch 4, ensuring that the driver's operation can be immediately transmitted to the steering system. This rapid response capability improves driving safety, especially in emergency situations. Moreover, during mode switching, the response of the electromagnetic clutch 4 ensures a smooth transition of the steering system, avoiding abrupt changes caused by mode switching and improving driving comfort. Finally, the engagement and disengagement state of the electromagnetic clutch 4 is dynamically adjusted according to the driving mode, enabling the system to adapt to various driving scenarios, from autonomous driving to manual driving, improving the system's adaptability and flexibility. Therefore, this embodiment not only improves system performance but also provides strong support for the development of autonomous and intelligent driving technologies.

[0175] In the commercial vehicle electronic power steering system provided in this embodiment, the upper steering column 2 is connected to the steering wheel 1; the electromagnetic clutch 4 is disposed between the upper steering column 2 and the lower steering column 5, and is used to control the mechanical connection and decoupling between the upper steering column 2 and the lower steering column 5; when the electromagnetic clutch 4 is engaged, the mechanical connection between the upper steering column 2 and the lower steering column 5 is maintained; when the electromagnetic clutch 4 is disengaged, the decoupling between the upper steering column 2 and the lower steering column 5 is achieved; the return-center and road feel motor 3 is mounted on the upper steering column 2, and is used to provide steering return torque and road feel feedback; the electro-hydraulic power steering mechanism 6 is connected to the lower steering column 5, and is used to provide wheel steering assistance; the steering linkage 7 is connected to the electro-hydraulic power steering mechanism 6 and the wheel 8, and is used to transmit steering torque to the wheel 8; the control unit 9 is connected to the electromagnetic clutch 4, the return-center and road feel motor 3, and the electro-hydraulic power steering mechanism 6, and is used to control the engagement and disengagement of the electromagnetic clutch 4 according to the vehicle driving state and driving mode, and to control the working state of the return-center and road feel motor 3 and the electro-hydraulic power steering mechanism 6. The solution in this embodiment, by incorporating an electromagnetic clutch between the upper and lower steering columns and a return-to-center and road-sensing motor in the upper steering column, achieves a steering system function that maintains a mechanical connection between the steering wheel and steering gear to improve safety during driver-operated steering, while simultaneously decoupling from the steering wheel when the electronic control system actively controls the steering, thus avoiding interference with the driver's judgment and feel. Therefore, the solution of this invention improves the safety and reliability of vehicle driving.

[0176] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0177] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0178] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A commercial vehicle electronic power steering system, characterized in that, include: Steering wheel, upper steering column, return and road feel motor, electromagnetic clutch, lower steering column, electro-hydraulic power steering mechanism, steering linkage, wheels, and control unit; The upper steering column is connected to the steering wheel; The electromagnetic clutch is disposed between the upper steering column and the lower steering column. The electromagnetic clutch is used to control the mechanical connection and decoupling between the upper steering column and the lower steering column. When the electromagnetic clutch is engaged, the upper steering column and the lower steering column are mechanically connected. When the electromagnetic clutch is disengaged, the upper steering column and the lower steering column are decoupled. The return and road feel motor is mounted on the upper steering column and is used to provide steering return torque and road feel feedback. The electro-hydraulic power steering mechanism is connected to the lower steering column, and the electro-hydraulic power steering mechanism is used to provide assistance in steering the wheels; The steering linkage is connected to the electro-hydraulic power steering mechanism and the wheel, and the steering linkage is used to transmit steering torque to the wheel; The control unit is connected to the electromagnetic clutch, the return-center and road feel motor, and the electro-hydraulic power steering mechanism. The control unit is used to control the engagement and disengagement of the electromagnetic clutch according to the vehicle driving status and driving mode, and to control the working status of the return-center and road feel motor and the electro-hydraulic power steering mechanism. The driving modes include: chassis domain control mode, driver takeover mode, and system electronic control failure mode; In chassis domain control mode, the control unit is used to control the electromagnetic clutch to disengage and cut off the mechanical connection between the upper steering column and the lower steering column when a split road surface condition is detected; the electro-hydraulic power steering mechanism is used to actively adjust the steering angle of the wheels according to the vehicle driving status to maintain vehicle directional stability. In driver-in-control mode, the control unit is used to control the electromagnetic clutch to switch from a disengaged state to an engaged state when it detects that the driver actively turns the steering wheel and the steering wheel angle exceeds a set threshold, thereby restoring the mechanical connection between the upper steering column and the lower steering column so that the driver's steering torque is transmitted to the lower steering column through the mechanical connection; the electro-hydraulic power steering mechanism is used to provide assistance according to the driver's operating intention, achieve the driver's target angle, and ensure a smooth switch from active control mode or chassis domain control mode to driver driving mode; In the system's electronic control failure mode, the electromagnetic clutch automatically remains engaged under the action of the mechanical spring mechanism to maintain the mechanical connection between the upper steering column and the lower steering column, so that the driver's steering torque can be transmitted to the lower steering column through the mechanical connection; the electro-hydraulic power steering mechanism is used to provide basic hydraulic assistance to ensure emergency steering capability. The chassis domain control mode refers to the mode in which the vehicle chassis control system actively adjusts the steering angle according to the vehicle's driving status; the driver takeover mode refers to the mode in which, under active control mode or chassis domain control mode, the driver actively intervenes in the steering operation, switching control from the automatic driving system or chassis domain control system to the driver; the system electronic control failure mode refers to the mode in which, when the electronic control system fails, the steering system switches to mechanical backup mode to ensure that the vehicle still has basic steering capabilities.

2. The commercial vehicle electronic power steering system according to claim 1, characterized in that, The driving modes also include: driver driving mode and active control mode; In driver driving mode, the control unit is used to control the engagement of the electromagnetic clutch, and the upper steering column and the lower steering column are mechanically connected so that the driver's steering torque is transmitted to the lower steering column through the mechanical connection; the electro-hydraulic power steering mechanism is used to provide assistance. In active control mode, the control unit is used to control the disengagement of the electromagnetic clutch and cut off the mechanical connection between the upper steering column and the lower steering column; the electro-hydraulic power steering mechanism is used to independently control the steering of the wheels; and the return and road feel motor is used to provide road feel feedback.

3. The commercial vehicle electronic power steering system according to claim 2, characterized in that, In the active control mode, the chassis domain control mode, and the driver takeover mode, the return-to-center and road feel motors are used to provide road feel feedback and assist the driver's steering operation, providing necessary steering torque support. In the driver's driving mode and the electronic control system failure mode, the return and road feel motors stop working, and the steering system maintains basic functions through mechanical connection and hydraulic power assistance.

4. The commercial vehicle electronic power steering system according to claim 1, characterized in that, The commercial vehicle electronic power steering system also includes a steering angle sensor; The steering angle sensor is used to monitor the steering angle of the upper steering column in real time and feed back the steering angle of the upper steering column to the control unit; The control unit is also used to determine the driver's intention to take over and the switching of control modes based on the steering angle of the upper steering column.

5. The commercial vehicle electronic power steering system according to any one of claims 2-4, characterized in that, When the control unit controls the engagement and disengagement of the electromagnetic clutch according to the vehicle's driving status and driving mode, it is specifically used for: In the active control mode, the chassis domain control mode, or the driver takeover mode, an electronic control signal is output to the electromagnetic clutch; and in the driver driving mode, no electronic control signal is output to the electromagnetic clutch. The electromagnetic clutch is specifically used for: If an electronic control signal is received from the control unit, the system responds to the signal by being in a disengaged state to disconnect the mechanical connection between the upper steering column and the lower steering column; otherwise, it is in an engaged state to maintain the mechanical connection between the upper steering column and the lower steering column through its own spring mechanism. In the system's electrical control failure mode, the engagement state is automatically maintained under the action of the mechanical spring mechanism.

6. A control method for an electronic power steering system in a commercial vehicle, characterized in that, An electric power steering system for commercial vehicles is provided, comprising: a steering wheel, an upper steering column, a return and road feel motor, an electromagnetic clutch, a lower steering column, an electro-hydraulic power steering mechanism, steering linkages, wheels, and a control unit. The method includes: The control unit determines the vehicle's driving status and driving mode; The control unit controls the engagement and disengagement of the electromagnetic clutch according to the vehicle's driving status and driving mode, and controls the working status of the return-to-center and road feel motor and the electro-hydraulic power steering mechanism. The upper steering column is connected to the steering wheel; The electromagnetic clutch is disposed between the upper steering column and the lower steering column. The electromagnetic clutch is used to control the mechanical connection and decoupling between the upper steering column and the lower steering column. When the electromagnetic clutch is engaged, the upper steering column and the lower steering column are mechanically connected. When the electromagnetic clutch is disengaged, the upper steering column and the lower steering column are decoupled. The return and road feel motor is mounted on the upper steering column and is used to provide steering return torque and road feel feedback. The electro-hydraulic power steering mechanism is connected to the lower steering column, and the electro-hydraulic power steering mechanism is used to provide assistance in steering the wheels; The steering linkage is connected to the electro-hydraulic power steering mechanism and the wheel, and the steering linkage is used to transmit steering torque to the wheel; The driving modes include: chassis domain control mode, driver takeover mode, and system electronic control failure mode; the control unit controls the engagement and disengagement of the electromagnetic clutch according to the vehicle driving status and driving mode, and controls the working status of the return-to-center and road feel motor and the electro-hydraulic power steering mechanism, including: In chassis domain control mode, when the control unit detects a split road surface condition, it controls the electromagnetic clutch to disengage and cuts off the mechanical connection between the upper steering column and the lower steering column; the electro-hydraulic power steering mechanism actively adjusts the steering angle of the wheels according to the vehicle's driving status to maintain vehicle directional stability. In driver-in-control mode, when the control unit detects that the driver actively turns the steering wheel and the steering wheel angle exceeds a set threshold, it controls the electromagnetic clutch to switch from a disengaged state to an engaged state, restoring the mechanical connection between the upper steering column and the lower steering column, so that the driver's steering torque is transmitted to the lower steering column through the mechanical connection; the electro-hydraulic power steering mechanism provides assistance according to the driver's operating intention to achieve the driver's target angle, and ensures a smooth switch from active control mode or chassis domain control mode to driver driving mode; In the system's electronic control failure mode, the electromagnetic clutch automatically remains engaged under the action of the mechanical spring mechanism to maintain the mechanical connection between the upper steering column and the lower steering column, so that the driver's steering torque is transmitted to the lower steering column through the mechanical connection; the electro-hydraulic power steering mechanism provides basic hydraulic assistance to ensure emergency steering capability. The chassis domain control mode refers to the mode in which the vehicle chassis control system actively adjusts the steering angle according to the vehicle's driving status; the driver takeover mode refers to the mode in which, under active control mode or chassis domain control mode, the driver actively intervenes in the steering operation, switching control from the automatic driving system or chassis domain control system to the driver; the system electronic control failure mode refers to the mode in which, when the electronic control system fails, the steering system switches to mechanical backup mode to ensure that the vehicle still has basic steering capabilities.

7. The control method for the electronic power steering system of a commercial vehicle according to claim 6, characterized in that, The driving modes also include: driver driving mode and active control mode; The control unit controls the engagement and disengagement of the electromagnetic clutch according to the vehicle's driving status and driving mode, and controls the operating status of the return-to-center and road feel motor and the electro-hydraulic power steering mechanism, and also includes: In driver driving mode, the control unit controls the engagement of the electromagnetic clutch, and the upper steering column and the lower steering column are mechanically connected so that the driver's steering torque is transmitted to the lower steering column through the mechanical connection; the electro-hydraulic power steering mechanism provides assistance. In active control mode, the control unit controls the electromagnetic clutch to disengage, cutting off the mechanical connection between the upper steering column and the lower steering column; the electro-hydraulic power steering mechanism independently controls the steering of the wheels; and the return and road feel motor provides road feel feedback.

8. The control method for the electronic power steering system of a commercial vehicle according to claim 7, characterized in that, The method further includes: In active control mode, chassis domain control mode and driver takeover mode, the return and road feel motors provide road feel feedback and assist the driver's steering operation, providing necessary steering torque support. In the driver's driving mode and the electronic control system failure mode, the return and road feel motors stop working, and the steering system maintains basic functions through mechanical connection and hydraulic power assistance.

9. The control method for the electric power steering system of a commercial vehicle according to claim 7, characterized in that, The commercial vehicle electronic power steering system also includes a steering angle sensor; The method further includes: The steering angle sensor monitors the steering angle of the upper steering column in real time and feeds back the steering angle of the upper steering column to the control unit. The control unit determines the driver's intention to take over and the switching of control modes based on the steering angle of the upper steering column.

10. The control method for a commercial vehicle electronic power steering system according to any one of claims 7-9, characterized in that, The control unit controls the engagement and disengagement of the electromagnetic clutch according to the vehicle's driving status and driving mode, including: In the active control mode, chassis domain control mode, or driver takeover mode, the control unit outputs an electronic control signal to the electromagnetic clutch; In the driver's driving mode or the system's electronic control failure mode, the control unit does not output electronic control signals to the electromagnetic clutch; If the electromagnetic clutch receives an electronic control signal output by the control unit, the electromagnetic clutch responds to the electronic control signal and is in a disengaged state to cut off the mechanical connection between the upper steering column and the lower steering column. Otherwise, the electromagnetic clutch is engaged to maintain the mechanical connection between the upper steering column and the lower steering column through its own spring mechanism. In the system's electronic control failure mode, the electromagnetic clutch automatically maintains engagement under the action of the mechanical spring mechanism.

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