Zero calibration method for power-assisted steering system of pilotless automobile and steering system

Abstract

The invention relates to a zero calibration method for a power-assisted steering system of a pilotless automobile and the steering system, and belongs to the field of power-assisted steering systems of automobiles. The zero calibration method for the steering power-assisted system of the pilotless automobile performs zero calibration, and the zero calibration comprises the following steps: driving an axle to rotate from one of a left limit and a right limit to the other so as to enable a magnetic ring on a piston of a power-assisted oil cylinder to move along a set direction; the magnetic induction sensor is arranged at a set position of a cylinder barrel of the boosting oil cylinder; the position, where the corresponding magnetic ring is located, of the cylinder barrel during conduction is determined as the zero position of the power-assisted steering system; the set position is that before an automobile leaves a factory and after an axle and a steering wheel are adjusted and centered, the magnetic induction sensor moves to the position corresponding to the cylinder barrel in the direction opposite to the set direction when the magnetic induction sensor is conducted. According to the invention, zero calibration is carried out by conducting the magnetic induction sensor and the magnetic ring, after zero drift occurs, the zero can be sensitively corrected, and the calibration precision is high.

Description

Technical Field

[0001] The present application relates to the technical field of automobile power steering systems, and in particular to a zero-position calibration method for a power steering system of an unmanned vehicle and a steering system. Background Art

[0002] Autonomous driving is the future trend, and ADAS (Advanced Driver Assistance System) is the only way for cars to achieve autonomous driving. Before performing ADAS calibration, the longitudinal centerline of the vehicle is usually calibrated.

[0003] In the related technology, two or more travel switches are installed on the steering knuckle of the axle to detect whether the steering wheel is in the neutral position, left turn, or right turn. The detected steering signal is used to control the centering reversing valve to switch the working position, so that the steering cylinder is connected to the centering oil circuit, and then the steering wheel is driven to rotate in the direction opposite to the steering state to achieve centering.

[0004] Because the travel switch is located on the same steering knuckle and is very close to the rotation axis, the accuracy of the centering signal is heavily dependent on the accuracy of the travel switch. After a period of use, the travel switch is prone to zero position drift, resulting in inaccurate reference datum of the vehicle's longitudinal centerline, requiring recalibration of the zero position. Summary of the invention

[0005] The embodiment of the present application provides a zero position calibration method and a steering system for an unmanned vehicle, so as to solve the defect in the related art that the travel switch is prone to zero position drift, resulting in inaccurate reference datum of the longitudinal centerline of the vehicle, requiring recalibration of the zero position, and the operation is very cumbersome and inefficient.

[0006] First aspect

[0007] The present application provides a method for zero-position calibration of a power steering system of an unmanned vehicle, wherein the zero-position calibration is performed, and the zero-position calibration comprises the following steps:

[0008] Driving the axle to rotate from one of the left limit and the right limit to the other, so that the magnetic ring on the piston of the booster oil cylinder moves along a set direction until it is connected with the magnetic induction sensor installed at a set position of the cylinder barrel of the booster oil cylinder;

[0009] The position of the corresponding magnetic ring on the cylinder barrel when the conduction is on is determined as the zero position of the power steering system;

[0010] The set position is: before the car rolls off the assembly line and leaves the factory, after the axle and the steering wheel are adjusted and aligned, the magnetic induction sensor moves in the opposite direction of the set direction to the position corresponding to the cylinder when it is turned on.

[0011] By adopting the above technical solution: by driving the axle to rotate from one of the left limit and the right limit to the other, the magnetic ring on the piston of the power-assisted oil cylinder moves along the set direction until it is connected with the magnetic induction sensor installed at the set position of the cylinder barrel of the power-assisted oil cylinder. At this time, zero-position calibration is realized, that is, the position of the corresponding magnetic ring on the cylinder barrel when connected is determined as the zero position of the power-assisted steering system, and the set position is the position determined after the axle and the steering wheel are adjusted and aligned before the car rolls off the assembly line and leaves the factory. The automatic zero-position calibration of the steering system is simple to operate and has high calibration accuracy.

[0012] In some embodiments, the axle is driven to rotate from a left limit to a right limit; the set direction is from right to left along the cylinder.

[0013] By adopting the above technical solution: when the axle rotates slowly from the left limit to the right limit, the magnetic ring slowly approaches the magnetic induction sensor from the right side to the left, and stops after conduction. At this time, the position of the magnetic ring on the piston of the power-assisted cylinder and the guide tube of the magnetic induction sensor on the cylinder barrel of the power-assisted cylinder is determined as the zero position of the power-assisted system.

[0014] In some embodiments, the axle is driven to rotate from the right limit to the left limit; the set direction is from left to right along the cylinder.

[0015] By adopting the above technical solution: when the axle rotates slowly from the right limit to the left limit, the magnetic ring slowly approaches the magnetic induction sensor from the left side to the right side of the magnetic induction sensor, and stops after conduction. At this time, the position of the magnetic ring on the piston of the power-assisted cylinder and the guide tube of the magnetic induction sensor on the cylinder barrel of the power-assisted cylinder is determined as the zero position of the power-assisted system.

[0016] In some embodiments, zero calibration is performed periodically.

[0017] By adopting the above technical solution: periodic zero-position calibration can timely detect and correct these deviations, prevent error accumulation, and ensure long-term stable operation of the equipment.

[0018] In some embodiments, before performing zero-position calibration, the method further includes: determining whether a calibration instruction is received; if so, performing zero-position calibration, otherwise, not performing zero-position calibration.

[0019] By adopting the above technical solution: by judging whether the calibration instruction is received to control whether the zero-position calibration is performed, intelligent warning of faults can be carried out, and errors can be calibrated accurately and quickly to ensure travel safety.

[0020] In some embodiments, the length of the lower arm to which the power-assisting cylinder is connected is configured such that the left-right stroke of the power-assisting cylinder is ±225 mm.

[0021] By adopting the above technical solution: a longer lower arm may cause the cylinder to produce a larger displacement under a smaller angle change, while a shorter lower arm may require a larger angle change to achieve the same displacement, which helps to ensure the accuracy of the steering system, optimize the driving experience, improve safety and adapt to different driving needs.

[0022] In some embodiments, the length of the steering drop arm to which the electro-hydraulic steering machine is connected is configured such that the steering angle of the electro-hydraulic steering machine reaches ±780°.

[0023] By adopting the above technical solution: the turning angle range means that the electro-hydraulic steering gear can provide great steering flexibility. The larger turning angle range also means that when a large-angle steering is required, the driver can reduce the number of turns, thereby improving driving convenience and efficiency.

[0024] Second aspect

[0025] The embodiment of the present application provides a zero-position calibrated steering system, which includes:

[0026] The axle is provided with a lower arm, a cylinder support and an upper arm;

[0027] An electro-hydraulic steering gear connected to a steering drop arm;

[0028] A steering straight tie rod, the two ends of which are respectively connected to the upper arm and the steering drop arm;

[0029] A booster oil cylinder, whose two ends are respectively connected to the lower arm and the oil cylinder support, a magnetic ring is arranged on the piston of the booster oil cylinder, and a magnetic induction sensor is arranged at a set position of the cylinder barrel of the booster oil cylinder;

[0030] And, the set position is: before the car rolls off the assembly line and leaves the factory, after the axle and the steering wheel are adjusted and aligned, the magnetic induction sensor moves in the opposite direction of the set direction to the position corresponding to the cylinder when it is turned on.

[0031] By adopting the above technical solution: the steering system achieves zero position calibration through the coordinated use of the axle, lower arm, cylinder support, upper arm, electro-hydraulic steering gear, steering straight tie rod and power cylinder, so as to achieve limited vehicle rotation.

[0032] In some embodiments, the length of the lower arm is configured so that the left and right stroke of the power-assisting cylinder is ±225 mm.

[0033] By adopting the above technical solution: the left and right stroke of the power cylinder determines the maximum angle that the wheel can turn, that is, the steering range of the vehicle. The length of the lower arm is configured so that the stroke of the power cylinder reaches ±225mm, which can ensure that the vehicle can easily complete large-angle steering when driving at low speed, thereby improving the vehicle's flexibility and passability.

[0034] In some embodiments, the length of the steering drop arm is configured to allow the steering angle of the electro-hydraulic steering machine to reach ±780°.

[0035] By adopting the above technical solution: the turning angle of the electro-hydraulic steering gear directly determines the turning range of the steering wheel. The steering arm length is configured so that the turning angle of the electro-hydraulic steering gear reaches ±780°, which can ensure that the driver can easily achieve full-range steering of the wheels when turning the steering wheel, meeting the steering needs in various driving scenarios.

[0036] The beneficial effects of the technical solution provided by this application include:

[0037] The embodiment of the present application provides a method for zero-position calibration of a power steering system of an unmanned vehicle, and the zero-position calibration is performed. The zero-position calibration includes the following steps: driving the axle to rotate from one of the left limit and the right limit to the other, so that the magnetic ring on the piston of the power-assisting oil cylinder moves along the set direction until the magnetic induction sensor installed at the set position of the cylinder barrel of the power-assisting oil cylinder is turned on; the position of the corresponding magnetic ring on the cylinder barrel when turned on is determined as the zero position of the power-assisting system; the set position is: before the car is off the assembly line and shipped out of the factory, after the axle and the steering wheel are adjusted and aligned, the magnetic induction sensor moves in the opposite direction of the set direction to the position corresponding to the cylinder barrel when turned on. Therefore, by moving the magnetic ring on the piston of the power-assisting oil cylinder along the set direction until the magnetic induction sensor installed at the set position of the cylinder barrel of the power-assisting oil cylinder is turned on, it is ensured that the movement can be stopped at the moment the magnetic induction sensor is turned on, which is conducive to the accurate positioning of the magnetic ring position, that is, the accurate positioning of the center position of the axle, and improving the consistency of zero-position calibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 A schematic diagram of the overall structure of the steering system provided in an embodiment of the present application;

[0040] Figure 2 Schematic diagram of the magnetic induction sensor and magnetic ring provided in the embodiment of the present application.

[0041] Reference numerals:

[0042] 1. Power cylinder; 10. Cylinder support; 11. Piston; 12. Cylinder barrel; 2. Magnetic induction sensor; 3. Magnetic ring; 4. Axle; 40. Upper arm; 41. Lower arm; 5. Adjustment hoop; 6. Electro-hydraulic steering gear; 7. Steering drop arm; 8. Steering straight tie rod; 9. Steering tie rod; DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0044] The embodiment of the present application provides a zero position calibration method and a steering system for an unmanned vehicle steering power system, which can solve the problem that the travel switch is prone to zero position drift, resulting in inaccurate reference datum of the longitudinal centerline of the vehicle, requiring recalibration of the zero position, and the operation is very cumbersome and inefficient.

[0045] Example 1

[0046] See also Figure 1 to Figure 2 As shown, an embodiment of the present application provides a method for zero-position calibration of a power steering system of an unmanned vehicle for performing zero-position calibration. First, the zero position of a vehicle power steering system refers to a reference position to which the steering wheel and steering mechanism should automatically return when there is no external force acting on the power steering system. This position is preset to ensure the accuracy and stability of the steering system. In a power steering system, accurate calibration of the zero position is crucial to the normal driving and safety of the vehicle. In case of position deviation due to manufacturing, assembly errors or long-term use, calibration of the zero position can ensure that the vehicle can perform precise steering operations according to the driver's intentions.

[0047] In this application, the zero position calibration includes the following steps: driving the axle 4 to rotate from one of the left limit and the right limit to the other, so that the magnetic ring 3 on the piston 11 of the power-assisting oil cylinder 1 moves along the set direction until it is connected with the magnetic induction sensor 2 installed at the set position of the cylinder 12 of the power-assisting oil cylinder 1; by determining the position of the corresponding magnetic ring 3 on the cylinder 12 when it is connected as the zero position of the power-assisting system; this position represents the initial state of the power-assisting system when there is no external force. Through the use of the power-assisting oil cylinder 1, the magnetic induction sensor 2 and the magnetic ring 3, the power-assisting system of the driverless car can obtain an accurate and reliable initial position reference, providing a solid foundation for subsequent automatic driving control. This method not only improves the accuracy and response speed of the steering system, but also enhances the safety and stability of the whole vehicle.

[0048] The setting position of the cylinder 12 of the power cylinder 1 is: before the car rolls off the assembly line and leaves the factory, it is usually necessary to do a four-wheel alignment to adjust the centering of each axle 4 and the steering wheel. That is, after the axle 4 and the steering wheel are adjusted to the center, the magnetic induction sensor 2 moves in the opposite direction of the set direction to the position corresponding to the cylinder 12 when the magnetic ring 3 is turned on.

[0049] In this application, when the axle 4 is driven to rotate from the left limit to the right limit, the set direction is from right to left along the cylinder 12. In this process, the axle 4 slowly rotates from the left limit to the right limit, and the piston 11 of the booster cylinder 1 will move accordingly, that is, the magnetic ring 3 on the piston 11 of the booster cylinder 1 will also move along the set direction.

[0050] The specific movement process of the magnetic ring 3 on the piston 11 of the power-boosting cylinder 1 is as follows: first, before calibration, the steering gear is controlled so that the axle 4 is located at the left limit, the piston 11 of the power-boosting cylinder 1 is at the right limit of the cylinder 12, and the magnetic ring 3 is located on the right side of the magnetic induction sensor 2 when viewed from the front to the back of the vehicle; when the axle 4 slowly rotates from the left limit to the right limit, the magnetic ring 3 slowly approaches the magnetic induction sensor 2 from the right side to the left of the magnetic induction sensor 2, and stops after conduction. At this time, the magnetic ring 3 on the piston 11 of the power-boosting cylinder 1 and the guide tube position of the magnetic induction sensor 2 on the cylinder 12 of the power-boosting cylinder 1 are determined as the zero position of the power-boosting system.

[0051] In the adjustment mode of driving the axle 4 to rotate from the left limit to the right limit, the set position of the cylinder 12 of the power-assisted cylinder 1 is before the car rolls off the production line and leaves the factory. After the axle 4 and the steering wheel are adjusted and aligned, the fixed position of the magnetic induction sensor 2 on the cylinder 12 is manually adjusted, as follows: the axle 4 and the steering wheel are aligned, the position of the piston 11 of the power-assisted cylinder 1 is usually in the middle position of the cylinder 12, and the magnetic induction sensor 2 is slowly approached to the position of the piston 11 of the power-assisted cylinder 1 from the left side of the cylinder 12 of the power-assisted cylinder 1 until the magnetic induction sensor 2 is turned on and stops immediately, and then the magnetic induction sensor 2 is fixed. At this time, the fixed position where the magnetic induction sensor 2 and the magnetic ring 3 are turned on is the zero position of the power steering system.

[0052] In the present application, when the axle 4 is driven to rotate from the right limit to the left limit, the set direction is from left to right along the cylinder 12. In this process, the axle 4 slowly rotates from the right limit to the left limit, and the piston 11 of the booster cylinder 1 will move accordingly, that is, the magnetic ring 3 on the piston 11 of the booster cylinder 1 will also move along the set direction.

[0053] The specific movement process of the magnetic ring 3 on the piston 11 of the power-boosting cylinder 1 is as follows: first, before calibration, the steering gear is controlled so that the axle 4 is located at the right limit, the piston 11 of the power-boosting cylinder 1 is at the left limit of the cylinder 12, and the magnetic ring 3 is located on the left side of the magnetic induction sensor 2 when viewed from the front to the back of the vehicle; when the axle 4 slowly rotates from the right limit to the left limit, the magnetic ring 3 slowly approaches the magnetic induction sensor 2 from the left side to the right of the magnetic induction sensor 2, and stops after conduction. At this time, the magnetic ring 3 on the piston 11 of the power-boosting cylinder 1 and the guide tube position of the magnetic induction sensor 2 on the cylinder 12 of the power-boosting cylinder 1 are determined as the zero position of the power-boosting system.

[0054] In the adjustment mode of driving the axle 4 to rotate from the right limit to the left limit, the set position of the cylinder 12 of the power-steering cylinder 1 is before the car rolls off the production line and leaves the factory. After the axle 4 and the steering wheel are adjusted and aligned, the fixed position of the magnetic induction sensor 2 on the cylinder 12 is manually adjusted, as follows: the axle 4 and the steering wheel are aligned, the position of the piston 11 of the power-steering cylinder 1 is usually in the middle position of the cylinder 12, and the magnetic induction sensor 2 is slowly approached to the position of the piston 11 of the power-steering cylinder 1 from the right side of the cylinder 12 of the power-steering cylinder 1 until the magnetic induction sensor 2 is turned on and stops immediately, and then the magnetic induction sensor 2 is fixed. At this time, the fixed position where the magnetic induction sensor 2 and the magnetic ring 3 are turned on is the zero position of the power steering system.

[0055] Regardless of whether the axle 4 is driven to rotate from the left limit to the right limit, or from the right limit to the left limit, the movement direction of the magnetic ring 3 on the piston 11 of the power cylinder 1 is relative to the movement direction of the magnetic induction sensor 2 manually calibrated for the first time. This relative movement relationship maintains consistency, ensuring that the magnetic induction sensor 2 is sensed and conductive when it is at the same distance from the magnetic ring 3, greatly improving the repeatability of the magnetic induction sensor 2 and the consistency of the zero position calibration.

[0056] In the present application, when manually calibrating the position of the magnetic induction sensor 2, after determining the fixed position of the magnetic induction sensor 2 on the cylinder 12, it is necessary to fix the magnetic induction sensor 2. The specific method includes connecting an adjusting band 5 to the cylinder 12 of the power-assisted oil cylinder 1, and the magnetic induction sensor 2 is connected to the adjusting band 5. When the magnetic induction sensor 2 is slowly approached to the position of the piston 11 of the power-assisted oil cylinder 1 from the right side of the cylinder 12 of the power-assisted oil cylinder 1, until the magnetic induction sensor 2 is turned on and stops immediately, the adjusting band 5 is tightened to effectively fix the magnetic induction sensor 2. The structure is simple and reliable.

[0057] In this application, after completing the automatic calibration of the magnetic induction sensor 2 and the magnetic ring 3, it is also necessary to periodically perform zero-position calibration to avoid the situation where the zero-position offset is not corrected in time due to various reasons. After long-term operation or multiple operations, the actual position of the device may be slightly offset due to various factors. Regular zero-position calibration can detect and correct these offsets in time, prevent error accumulation, and ensure the long-term stable operation of the equipment.

[0058] In this application, when the vehicle is started or under certain conditions, such as when the ignition switch is turned on, the power steering system will perform a self-check to check whether the sensors, actuators and other components are working properly. After the self-check is completed, the system will check whether a calibration instruction is received from the vehicle control unit or other related modules. This instruction may be triggered by the driver through a button or touch screen on the vehicle dashboard, or it may be automatically issued by the vehicle's fault diagnosis system after detecting a specific fault code. Therefore, before performing zero-position calibration, it also includes: determining whether a calibration instruction has been received; if so, after receiving the calibration instruction, the system will check whether the vehicle is in a state suitable for calibration, and then perform zero-position calibration, otherwise, no zero-position calibration is performed.

[0059] In the present application, the length of the lower arm 41 connected to the power-assisting cylinder 1 is configured so that the left and right stroke of the power-assisting cylinder 1 is ±225mm. The stroke of the power-assisting cylinder 1 directly determines the distance it can push or pull. The stroke of ±225mm means that when the cylinder is at its maximum extension and maximum contraction, its piston 11 rod can move 225mm outward or inward respectively. The length of the lower arm 41 is closely related to the stroke of the power-assisting cylinder 1. By adjusting the length of the lower arm 41, the movement effect of the cylinder under a specific stroke can be changed. Specifically, a longer lower arm 41 may cause the cylinder to produce a larger displacement under a smaller angle change, while a shorter lower arm 41 may require a larger angle change to achieve the same displacement, which helps to ensure the accuracy of the steering system, optimize the driving experience, improve safety, and adapt to different driving needs.

[0060] In addition, the length of the steering arm 7 connected to the electro-hydraulic steering gear 6 is configured so that the turning angle of the electro-hydraulic steering gear 6 reaches ±780°. The turning angle range of ±780° means that the electro-hydraulic steering gear 6 can provide great steering flexibility. The larger turning angle range also means that when a large-angle steering is required, the driver can reduce the number of turns, thereby improving the convenience and efficiency of driving. It is important to ensure the stability of the vehicle during the steering process by accurately controlling the turning angle range of the electro-hydraulic steering gear 6, and to make the steering system respond more quickly and accurately by configuring the reasonable length of the steering arm 7, which helps to reduce the roll and swing during the steering process. During the zero-position calibration process of the steering system, ensuring that the turning angle of the electro-hydraulic steering gear 6 reaches the preset range can avoid the problem of vehicle driving direction deviation caused by steering system deviation, thereby improving the driving safety of the vehicle.

[0061] The implementation principle of the embodiment of the present application is as follows: before the car rolls off the assembly line and leaves the factory, the axle 4 and the steering wheel are aligned, the position of the piston 11 of the power-steering cylinder 1 is usually in the middle position of the cylinder barrel 12, and the magnetic induction sensor 2 is slowly approached to the position of the piston 11 of the power-steering cylinder 1 from the left side of the cylinder barrel 12 of the power-steering cylinder 1 until the magnetic induction sensor 2 is turned on and stops immediately, at this time the magnetic induction sensor 2 is fixed, and the position where the magnetic induction sensor 2 and the magnetic ring 3 are turned on and fixed is the zero position of the power steering system. Then, after driving for a while, the vehicle axle 4 is driven to rotate from one of the left limit and the right limit to the other, so that the magnetic ring 3 on the piston 11 of the power-assisting cylinder 1 moves along the set direction until it is connected with the magnetic induction sensor 2 installed at the set position of the cylinder 12 of the power-assisting cylinder 1; the position of the corresponding magnetic ring 3 on the cylinder 12 when connected is determined as the zero position of the power-assisting system; this position represents the initial state of the power-assisting system when there is no external force. Through the use of the power-assisting cylinder 1, the magnetic induction sensor 2 and the magnetic ring 3, the power-assisting system of the driverless car can obtain an accurate and reliable initial position reference, providing a solid foundation for subsequent automatic driving control.

[0062] Example 2

[0063] In some alternative embodiments, see Figure 1 and Figure 2 The embodiment of the present application provides a zero-position calibrated steering system, which includes: an axle 4, an electro-hydraulic steering gear 6, a steering straight tie rod 8 and a power cylinder 1, wherein the axle 4 is provided with a lower section arm 41, a cylinder support 10, and an upper section arm 40, and the electro-hydraulic steering gear 6 is connected to a steering vertical arm 7; the two ends of the steering straight tie rod 8 are respectively connected to the upper section arm 40 and the steering vertical arm 7; the two ends of the power cylinder 1 are respectively connected to the lower section arm 41 and the cylinder support 10, a magnetic ring 3 is provided on the piston 11 of the power cylinder 1, and a magnetic induction sensor 2 is provided at the set position of the cylinder barrel 12 of the power cylinder 1.

[0064] The axle 4 is an important part of the vehicle chassis, which carries the weight of the vehicle and transmits the driving force and braking force of the wheels. In this steering system, multiple components related to the steering system are installed on the axle 4, such as the lower arm 41, the cylinder support 10 and the upper arm 40, which work together to achieve the steering of the wheels. The electro-hydraulic steering machine 6 is one of the core components of the steering system. It generates hydraulic energy by driving the hydraulic pump through an electric motor, and then provides power for the booster cylinder 1. The electro-hydraulic steering machine 6 is also connected to the steering vertical arm 7, which is a key part of the mechanical transmission and converts the rotational motion of the steering machine into the left and right swing of the wheel. The steering straight tie rod 8 is a rigid rod connecting the upper arm 40 and the steering vertical arm 7. Its main function is to transmit the movement of the steering vertical arm 7 to the upper arm 40, thereby driving the steering of the wheel. The design of the steering straight tie rod 8 needs to ensure that the transmitted force and movement are accurate and reliable. The booster cylinder 1 is an actuator of the hydraulic power steering system. It is installed on the axle 4, one end of which is connected to the lower arm 41 and the other end is connected to the cylinder support 10. There is a piston 11 inside the power-assisted oil cylinder 1, and a magnetic ring 3 is arranged on the piston 11 to detect the position of the piston 11. When hydraulic energy acts on the piston 11, it pushes the piston 11 to move, and then drives the wheel to steer through the connecting rod mechanism. The magnetic induction sensor 2 is installed on the cylinder 12 of the power-assisted oil cylinder 1, and its set position corresponds to the magnetic ring 3 on the piston 11. When the piston 11 moves in the cylinder 12, the magnetic ring 3 will move accordingly, thereby changing the magnetic field around the magnetic induction sensor 2. The sensor accurately measures the position of the piston 11 by detecting this change in the magnetic field, thereby realizing position feedback and closed-loop control of the steering system.

[0065] In addition, the zero-calibrated steering system also includes a steering tie rod 9, a rod connecting the upper arm 40 and the lower arm 41, whose main function is to achieve synchronous steering of the two wheels and adjust the toe to ensure the stability and controllability of the vehicle during driving.

[0066] In this application, the set position is: slowly move the magnetic induction sensor 2 close to the piston 11 of the power-steering cylinder 1 from the left side of the cylinder barrel 12 of the power-steering cylinder 1 until the magnetic induction sensor 2 is turned on and stops immediately. At this time, fix the magnetic induction sensor 2. At this time, the position where the magnetic induction sensor 2 and the magnetic ring 3 are turned on and fixed is the zero position of the power-steering system.

[0067] Conversely, the magnetic induction sensor 2 can also be slowly moved from the right side of the cylinder barrel 12 of the power-assisted oil cylinder 1 to the position of the piston 11 of the power-assisted oil cylinder 1. It should be noted that during manual calibration and automatic calibration, the magnetic ring 3 and the magnetic induction sensor 2 are in relative motion directions.

[0068] In the present application, the length of the lower arm 41 is configured so that the left and right stroke of the power-assisting cylinder 1 is ±225 mm; the length of the steering arm 7 is configured so that the turning angle of the electro-hydraulic steering gear 6 reaches ±780°. The left and right stroke of the power-assisting cylinder 1 determines the maximum angle that the wheel can rotate, that is, the steering range of the vehicle. Configuring the length of the lower arm 41 so that the stroke of the power-assisting cylinder 1 reaches ±225 mm can ensure that the vehicle can easily complete large-angle steering when driving at low speeds, thereby improving the flexibility and passability of the vehicle; the turning angle of the electro-hydraulic steering gear 6 directly determines the turning range of the steering wheel. Configuring the length of the steering arm 7 so that the turning angle of the electro-hydraulic steering gear 6 reaches ±780° can ensure that the driver can easily achieve all-round steering of the wheels when turning the steering wheel, thereby meeting the steering requirements in various driving scenarios.

[0069] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0070] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0071] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for zero position calibration of a steering assist system of an unmanned vehicle, characterized in that: Perform zero position calibration, the zero position calibration comprises the following steps: Driving the axle (4) to rotate from one of the left limit and the right limit to the other, so that the magnetic ring (3) on the piston (11) of the booster oil cylinder (1) moves in a set direction until it is connected to the magnetic induction sensor (2) installed at a set position of the cylinder (12) of the booster oil cylinder (1); The position of the corresponding magnetic ring (3) on the cylinder (12) when the conduction is on is determined as the zero position of the power steering system; The set position is: before the car rolls off the production line and leaves the factory, after the axle (4) and the steering wheel are adjusted and aligned, the magnetic induction sensor (2) moves in the opposite direction of the set direction to the position corresponding to the cylinder (12) when it is turned on.

2. A method for zero-position calibration of a power steering system of an unmanned vehicle as claimed in claim 1, characterized in that: Driving the axle (4) to rotate from the left limit to the right limit; The setting direction is from right to left along the cylinder (12).

3. A method for zero-position calibration of a steering assist system of an unmanned vehicle as claimed in claim 1, characterized in that: Driving the axle (4) to rotate from the right limit to the left limit; The setting direction is from left to right along the cylinder (12).

4. A method for zero-position calibration of a steering assist system of an unmanned vehicle as claimed in claim 1, characterized in that: Perform zero calibration periodically.

5. The method for zero-position calibration of a power steering system of an unmanned vehicle as claimed in claim 1, characterized in that: Before performing zero position calibration, the method further includes: determining whether a calibration instruction is received; If yes, perform zero calibration, otherwise, do not perform zero calibration.

6. A method for zero-position calibration of a power steering system of an unmanned vehicle as claimed in claim 1, characterized in that: The length of the lower arm (41) connected to the power-assisting oil cylinder (1) is configured so that the left-right stroke of the power-assisting oil cylinder (1) is ±225 mm.

7. The steering system with zero position calibration as claimed in claim 1, characterized in that: The length of the steering drop arm (7) connected to the electro-hydraulic steering machine (6) is configured so that the steering angle of the electro-hydraulic steering machine (6) reaches ±780°.

8. A zero-calibrated steering system, characterized in that: It includes: A vehicle axle (4) on which a lower arm (41), a cylinder support (10) and an upper arm (40) are arranged; An electro-hydraulic steering machine (6) connected to a steering drop arm (7); A steering straight tie rod (8), two ends of which are respectively connected to the upper section arm (40) and the steering drop arm (7); A booster oil cylinder (1), the two ends of which are respectively connected to a lower arm (41) and an oil cylinder support (10); a magnetic ring (3) is arranged on a piston (11) of the booster oil cylinder (1); and a magnetic induction sensor (2) is arranged at a set position of a cylinder barrel (12) of the booster oil cylinder (1); Furthermore, the set position is: before the car rolls off the production line and leaves the factory, after the axle (4) and the steering wheel are adjusted and aligned, the magnetic induction sensor (2) moves in the opposite direction of the set direction to the position corresponding to the cylinder barrel (12) when it is turned on.

9. The zero-calibrated steering system according to claim 8, characterized in that: The length of the lower arm (41) is configured so that the left-right stroke of the power-assisting oil cylinder (1) is ±225 mm.

10. The zero-calibrated steering system according to claim 8, characterized in that: The length of the steering drop arm (7) is configured so that the turning angle of the electro-hydraulic steering machine (6) reaches ±780°.

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