A working method of an EPS system auxiliary function and a vehicle four-wheel positioning method

Abstract

The application discloses a working method of an auxiliary function of an EPS system, and comprises the following steps: when a whole vehicle power supply is powered on and an engine is in an off state, the vehicle control system detects that a torsion bar bears a torque, and the EPS system outputs a power assistance so that the EPS system drives a output shaft to rotate to release the torque borne by the torsion bar. The application further discloses a vehicle four-wheel positioning method, and comprises the following steps: fixing a steering wheel and positioning four wheels of the vehicle, releasing the torque of the torsion bar by using the above method while positioning the four wheels, and releasing the fixing of the steering wheel until the four-wheel positioning of the vehicle is completed. When the application detects that the torsion bar bears the torque, the EPS system outputs the power assistance to release the torque of the torsion bar, avoids that the torsion bar with the torque drives the steering wheel to rotate to cause the steering wheel to be not straight, and simultaneously avoids that the exhaust gas emitted by the engine and the noise generated by the engine cause pollution without starting the engine, and energy waste can be avoided.

Description

Technical Field

[0001] This invention relates to the field of vehicle steering wheel return technology, and more specifically, to a method for operating an EPS system auxiliary function and a method for vehicle four-wheel alignment. Background Technology

[0002] The vehicle's EPS system, which stands for Electrical Power Steering, is an electric power steering system. Its main function is to provide assistance to the steering system when the user turns the steering wheel, enabling the wheels to turn. For example... Figure 2 As shown, the EPS system 1 includes an input shaft 11, an output shaft 13, and a torsion bar 12 disposed between the input shaft 11 and the output shaft 13. The input shaft 11 is connected to the spindle 3 of the steering wheel 2, thereby inputting the rotation action of the steering wheel 2 to the EPS system 1. The output shaft 13 is connected to the wheel 8, thereby the EPS system 1 outputting the rotation action to the wheel 8.

[0003] In the automobile manufacturing process, four-wheel alignment is a crucial step in ensuring vehicle driving safety and performance. For example... Figure 1 and Figure 2 As shown, the vehicle's four-wheel alignment parameters are currently adjusted mainly by adjusting the length of the steering tie rod 6. During the four-wheel alignment parameter adjustment process when the vehicle is off the production line, the wheels 8 are located on the drum. Under the action of the drum, the wheels 8 are constantly rotating forward. Adjusting the length of the steering tie rod 6 causes the wheels 8 to rotate left and right around the front strut 7. Under the reaction force of the wheels 8, the steering tie rod 6 drives the steering intermediate shaft 4 to rotate through the steering gear 5 and applies a torque to the EPS system 1 through the steering intermediate shaft 4. However, since the steering wheel 2 is fixed at this time, this torque is borne by the torsion bar 12 in the EPS system 1.

[0004] If the steering wheel is immediately released after the four-wheel alignment parameters are adjusted, the torque borne by the torsion bar will be released immediately, causing the steering wheel to rotate. Currently, the EPS system requires the engine to be ignited and the torsion bar in the EPS system to bear torque. If the EPS system is used to release torque, the engine exhaust will be directly emitted onto the production line, causing significant pollution to the working environment of the operators and affecting their physical and mental health. Furthermore, having the engine ignited will result in unnecessary energy waste, which is neither energy-efficient nor environmentally friendly. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies, such as the torque of the torsion bar in the EPS system causing the steering wheel to rotate and become misaligned when the steering wheel is released after the four-wheel alignment of the vehicle, and the pollution of the working environment caused by starting the engine to make the EPS system work to release the torque and eliminate the misalignment of the steering wheel. This invention provides a working method for the auxiliary function of the EPS system and a method for four-wheel alignment of the vehicle.

[0006] The objective of this invention can be achieved using the following technical solutions:

[0007] A method for operating an auxiliary function of an EPS system includes the following steps:

[0008] When the vehicle power supply is on and the engine is off, and the vehicle control system detects the torque on the torsion bar of the electric power steering system, the vehicle control system activates the EPS system auxiliary function, causing the EPS system to output power assistance. This causes the EPS system to drive the output shaft to rotate, thereby releasing the torque on the torsion bar. When the vehicle control system detects that the torque on the torsion bar has been released, the vehicle control system stops the EPS system from outputting power assistance.

[0009] According to the aforementioned technical means, the vehicle's EPS system includes a torque sensor for detecting the torque of the torsion bar, or a torque sensor is installed at the torsion bar, and the torque sensor is electrically connected to the vehicle control system. If, during four-wheel alignment, the inner tie rod of the steering tie rod moves, causing a force to be applied to the torsion bar, the torsion bar deforms and generates torque. Therefore, when the vehicle control system detects torque on the torsion bar of the EPS system, it activates the EPS system's auxiliary function even when the engine is not running. The EPS output assists in rotating the output shaft, thereby moving the inner tie rod and eliminating the torque generated by the movement of the inner tie rod, preventing the steering wheel from becoming misaligned after the steering wheel is released. Simultaneously, since this invention allows the EPS system to be activated before the engine is started, it avoids pollution of the workers' working environment by engine exhaust and noise, and also avoids energy waste caused by engine starting.

[0010] Furthermore, the assistance output by the EPS system auxiliary function is 20%-50% of the normal assistance output of the EPS system.

[0011] Based on the aforementioned technical means, normal EPS system assistance refers to the assistance output by the EPS system when assisting steering during vehicle movement. The EPS system is powered by the vehicle's battery, which is charged by the alternator driven by the engine while it is running. Since the engine is not running, it cannot charge the vehicle's battery. To prevent the driver from excessively operating the EPS in this situation, potentially causing the vehicle to lose power, and because the EPS system's assistance function is only intended to release the torque of the torsion bar and to save energy, the EPS system's assistance function only provides partial assistance. This also serves to alert staff that such operation is abnormal.

[0012] Furthermore, the assistance output by the EPS system auxiliary function is 30% of the normal assistance output of the EPS system.

[0013] A method for four-wheel alignment of a vehicle includes the following steps:

[0014] S1: Fix the steering wheel to limit its rotation. Since the steering wheel is fixedly connected to the spindle, the input shaft of the EPS system is also fixedly connected to the spindle, thus fixing the input shaft as well. At the same time, the vehicle is four-wheel aligned when the vehicle power is on and the engine is off.

[0015] S2: During the four-wheel alignment process, the inner tie rod of the steering tie rod is rotated to drive the outer tie rod of the steering tie rod to move axially, thereby causing the wheel to rotate around the front strut. If the vehicle control system detects that the torsion bar of the EPS system is bearing torque, the vehicle control system activates the EPS system auxiliary function, causing the EPS system to output power assistance, which causes the output shaft to rotate and release the torque of the torsion bar. When the vehicle control system detects that the torque borne by the torsion bar has been released, the vehicle control system stops the EPS system from outputting power assistance.

[0016] S3: Repeat step S2 until the wheels are adjusted to the target position, thus completing the four-wheel alignment of the vehicle;

[0017] S4: After completing the four-wheel alignment of the vehicle, release the steering wheel from the lock.

[0018] According to the aforementioned technical means, the spindle is fixedly connected to the steering wheel, and the spindle is connected to the input shaft of the EPS system via a spline. In the EPS system, the input shaft is fixedly connected to a torsion bar, and the torsion bar is fixedly connected to the output shaft. When the movements of the spindle and the output shaft are asynchronous, the torsion bar will bear torque. At the same time, the output shaft of the EPS system is connected to the wheels through components such as the steering tie rod, steering gear, and steering intermediate shaft. Since the steering wheel is fixed, the spindle is also fixed.

[0019] During four-wheel alignment, the steering wheel is first secured with a fixture. Then, the inner tie rod is rotated. Since the outer tie rod is threaded onto the inner tie rod, rotating the inner tie rod is equivalent to pushing the outer tie rod out or retracting it. Rotating the inner tie rod causes the outer tie rod to move left or right, and also changes the overall length of the steering tie rod, thus adjusting it. The left and right movement of the outer tie rod causes the wheel to rotate left and right around the front strut. Simultaneously, the inner tie rod also moves left and right under the reaction force of the wheel, driving the steering intermediate shaft through the steering gear, which in turn drives the output shaft to rotate. Because the steering wheel is fixed, the input shaft is also fixed, and the torsion bar of the EPS system will be subjected to a torque due to deformation. If the torque of the torsion bar is not released, releasing the steering wheel will cause it to rotate, resulting in a misaligned steering wheel. The torque borne by the torsion bar can only be released by rotating either the input or output shaft. Therefore, in this invention, the torque is released simply by rotating the output shaft to rotate the wheel around the front strut, as long as the torsion bar bears the torque. This invention utilizes an EPS (Electric Power Steering) system with an auxiliary function. The vehicle control system detects the torque borne by the torsion bar of the EPS system and activates its auxiliary function, causing the EPS system to output power assist. The EPS system rotates its output shaft, which, through the steering intermediate shaft and steering gear, moves the inner steering tie rod, thereby releasing the torque caused by the movement of the inner tie rod. Once the vehicle control system detects that the torque borne by the torsion bar has been released, it stops the EPS system from outputting power assist. At this point, because the length of the tie rod has changed, the position of the wheels has also changed.

[0020] When the inner tie rod rotates, the wheel rotates left and right around the front strut, and before the torsion bar torque is released, the wheel's current posture is the intermediate posture. After the torsion bar torque is released, the force continues to be transmitted to the wheel, causing the wheel to rotate in the opposite direction. The wheel's posture has now rotated relative to the intermediate posture, so step S2 needs to be repeated until the torsion bar torque is released and the wheel rotation caused by the torque release is complete. At this point, the wheel's position is exactly the target position.

[0021] The above process eliminates the torque of the torsion bar during the adjustment of the four-wheel alignment parameters. This not only prevents the steering wheel from becoming misaligned after it is unsecured and rotated, but also improves the accuracy of the four-wheel alignment.

[0022] Furthermore, in step S2, by rotating the inner tie rod of the steering tie rod, the outer tie rod of the steering tie rod is driven to move axially, thereby causing the wheel to rotate around the front strut. At this time, under the reaction force of the wheel, the inner tie rod leaves the initial position and moves towards the position of the torsion bar, causing the torsion bar to bear torque. The vehicle control system activates the EPS system auxiliary function, causing the EPS system to output power assistance, causing the output shaft to rotate and drive the inner tie rod to move axially in the opposite direction to return to the initial position of the inner tie rod through the intermediate shaft and the steering gear, thereby releasing the torque of the torsion bar. The vehicle control system then stops the EPS system from outputting power assistance.

[0023] According to the aforementioned technical means, during the four-wheel alignment process, before each rotation of the inner tie rod, its initial position is as follows: Rotation of the inner tie rod causes the outer tie rod to move left and right, thereby causing the wheels to rotate left and right around the front strut. The inner tie rod also moves left and right under the reaction force of the wheels, and through the steering gear, it drives the steering intermediate shaft, which in turn drives the output shaft to rotate. Because the steering wheel is fixed, the input shaft is also fixed, causing the torsion bar to bear torque. The vehicle control system activates the EPS system's auxiliary function, causing the EPS system to output power assist. The EPS system rotates the output shaft, which drives the steering intermediate shaft and steering gear to move, thus causing the intermediate shaft and steering gear to move the inner tie rod back to its initial position. At this point, the torque generated by the deformation of the torsion bar has been released. Although the inner tie rod returns to its initial position, because the overall length of the steering tie rod has changed after the inner tie rod rotates, the wheel position after the torque of the torsion bar has been released is still different from the wheel position before the inner tie rod was rotated; that is, wheel alignment adjustment has been performed.

[0024] The entire four-wheel alignment process is as follows: Rotate the inner tie rod → Move the outer tie rod left and right → Rotate the wheel around the front strut left and right → Move the inner tie rod left and right under the reaction force of the wheel and the outer tie rod → Rotate the steering intermediate shaft under the action of the inner tie rod through the steering gear → Rotate the output shaft under the drive of the steering intermediate shaft → The torsion bar bears the torque → The EPS system outputs power assist and drives the steering inner tie rod to move back to the initial position of the inner tie rod through the steering intermediate shaft and the steering gear. Repeat the above actions until the wheel rotates to the correct position.

[0025] Furthermore, it also includes the following steps:

[0026] After the four-wheel alignment is completed, before the vehicle leaves the production line, the vehicle control system disables the EPS system assistance function, so that the EPS system provides normal assistance when the user drives the car.

[0027] Based on the above technical means, this function is no longer needed after the vehicle rolls off the production line or reaches the user. Therefore, the EPS system needs to be in normal working condition. Thus, during the vehicle production process in the factory, the EPS system auxiliary function needs to be turned off after the four-wheel alignment is completed.

[0028] Furthermore, the following steps are also included between steps S3 and S4:

[0029] S4.1: Angle median calibration for the EPS system.

[0030] Furthermore, the EPS system auxiliary functions must be disabled simultaneously under the following conditions:

[0031] The EPS system has been configured for offline operation; the median angle of the EPS system has been calibrated.

[0032] Furthermore, the EPS system can also provide normal assistance when the following conditions are met simultaneously:

[0033] The vehicle is powered on; the vehicle control system detects engine ignition; the torsion bar in the EPS system is subjected to torque.

[0034] Based on the aforementioned technical means, in order to ensure that the driver can operate the steering wheel normally during the normal circulation and driving of the vehicle within the factory, the vehicle control system provides ordinary power steering in this situation after detecting engine ignition.

[0035] Furthermore, when fixing the steering wheel, a positioning fixture is used to lock the steering wheel.

[0036] Based on the aforementioned technical means, the positioning fixture can be a car anti-theft lock or other device that can restrict the rotation of the steering wheel, or the steering wheel lock that comes with the car can be used to lock the steering wheel.

[0037] The beneficial effects of this invention are:

[0038] (1) The present invention utilizes the EPS system to set the EPS system auxiliary function. The EPS system can be turned on when the engine is not running. When the torsion bar of the EPS system is detected to be subjected to torque, the EPS system outputs assistance to release the torque of the torsion bar, thereby preventing the torsion bar with torque from driving the steering wheel to rotate and causing the steering wheel to be misaligned. At the same time, the exhaust gas and noise generated by the engine can be avoided without starting the engine, and energy waste can be avoided.

[0039] (2) This invention utilizes the EPS system's auxiliary function. During four-wheel alignment, after rotating the wheels, the EPS system's auxiliary function is used to release the torque of the torsion bar. Then, the wheels are rotated again, and the torsion bar torque is released again. This cycle is repeated until the wheels are properly aligned. This achieves the simultaneous elimination of the torsion bar torque during the adjustment of the four-wheel alignment parameters, which not only avoids steering wheel misalignment after the four-wheel alignment parameters are adjusted, but also improves the accuracy of the four-wheel alignment.

[0040] (3) The EPS system auxiliary function output limit output avoids the driver's excessive operation of EPS, which may cause the whole vehicle to run out of power, and also saves energy.

[0041] (4) After the four-wheel alignment is completed, the EPS system auxiliary function needs to be turned off to ensure that the driver can operate the steering wheel normally during the normal circulation and driving of the vehicle in the factory, so that the EPS system is in normal working condition after the vehicle is off the production line or in the hands of the user. Attached Figure Description

[0042] Figure 1 A schematic diagram of the connection structure between the vehicle's steering wheel and wheels;

[0043] Figure 2 This is a schematic diagram of a steering tie rod.

[0044] Figure 3 This is a schematic diagram showing the connection relationship between the spindle, input shaft, torsion bar, and output shaft.

[0045] Figure 4 This is a schematic diagram illustrating the working principle of the auxiliary function of the EPS system of the present invention.

[0046] Figure 5 This is a schematic diagram of the vehicle four-wheel alignment method of the present invention;

[0047] Figure 6 This diagram illustrates the assist situation of the EPS system under different conditions according to the present invention.

[0048] Figure 7 This is a flowchart of the vehicle four-wheel alignment method of the present invention.

[0049] Among them, 1-EPS system, 11-input shaft, 12-torsion bar, 13-output shaft, 2-steering wheel, 3-spindle, 4-steering intermediate shaft, 5-steering gear, 6-steering tie rod, 61-inner tie rod, 62-outer tie rod, 7-front strut, 8-wheel. Detailed Implementation

[0050] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.

[0051] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0052] This embodiment proposes a working method for the auxiliary functions of an EPS system, such as... Figures 1 to 4 As shown, it includes the following steps:

[0053] When the vehicle power supply is on and the engine is off, when the vehicle control system detects that the torsion bar 12 of the EPS system 1 is bearing torque, the vehicle control system activates the auxiliary function of the EPS system 1, causing the EPS system 1 to output power assistance, which causes the EPS system 1 to drive the output shaft 13 to rotate, thereby releasing the torque borne by the torsion bar 12. When the vehicle control system detects that the torque borne by the torsion bar 12 of the vehicle control system has been released, the vehicle control system stops the EPS system 1 from outputting power assistance.

[0054] The vehicle's EPS system 1 includes a torque sensor for detecting the torque of the torsion bar 12, or a torque sensor is installed at the torsion bar 12, and the torque sensor is electrically connected to the vehicle control system. In this invention, when the vehicle is powered on and the engine is not running, if the inner tie rod 61 of the steering tie rod 6 moves during four-wheel alignment, causing a force to be applied to the torsion bar 12, the torsion bar 12 deforms and generates torque. Therefore, when the vehicle control system detects that the torsion bar 12 of the EPS system 1 is subjected to torque, the vehicle control system activates the EPS system 1 auxiliary function even when the engine is not running. The EPS output assists the rotation of the output shaft 13, thereby moving the inner tie rod 61 and eliminating the torque generated by the movement of the inner tie rod 61, preventing the steering wheel 2 from becoming misaligned after the fixing of the steering wheel 2 is removed. Simultaneously, since this invention can activate the EPS system 1 before the engine is started, it avoids pollution of the working environment by engine exhaust and noise, and also avoids energy waste caused by engine starting.

[0055] In this embodiment, the assistance output by the EPS system 1 when the auxiliary function is working is 30% of the normal assistance of the EPS system 1.

[0056] Normal power assist of EPS system 1 refers to the power assistance output by EPS system 1 when assisting steering during vehicle movement. EPS system 1 is powered by the vehicle's battery, which is charged by the alternator driven by the engine when it is running. Since the engine is not running, it cannot charge the vehicle's battery. To prevent the driver from excessively operating EPS in this situation, which could lead to a depletion of the vehicle's battery, and also to conserve energy, since the EPS system 1's assist function is only intended to release the torque of torsion bar 12, EPS system 1's assist function only provides partial assistance. This also serves to alert staff that such operation is abnormal.

[0057] Another implementation is provided in which the assist output of the EPS system 1 when the assist function is working is 20% of the normal assist of the EPS system 1.

[0058] Another implementation is provided in which the assist output of the EPS system 1 when the assist function is working is 50% of the normal assist of the EPS system 1.

[0059] Another implementation is provided in which the assist output of the EPS system 1 when the assist function is working is 40% of the normal assist of the EPS system 1.

[0060] This embodiment also proposes a vehicle four-wheel alignment method, such as... Figure 5 and Figure 7 As shown, it includes the following steps:

[0061] S1: Fix the steering wheel 2 to restrict the rotation of the steering wheel 2. Since the steering wheel 2 is fixedly connected to the spindle 3, the input shaft 11 of the EPS system 1 is fixedly connected to the spindle 3, so that the input shaft 11 is also fixed. At the same time, when the vehicle power supply is on and the engine is off, perform four-wheel alignment on the vehicle.

[0062] S2: During the four-wheel alignment process, the inner tie rod 61 of the steering tie rod 6 is rotated to drive the outer tie rod 62 of the steering tie rod 6 to move axially, thereby causing the wheel 8 to rotate around the front pillar 7. At this time, if the vehicle control system detects that the torsion bar 12 of the EPS system 1 is bearing torque, the vehicle control system activates the auxiliary function of the EPS system 1, causing the EPS system 1 to output power assistance, causing the output shaft 13 to rotate and thus release the torque of the torsion bar 12. When the vehicle control system detects that the torque borne by the torsion bar 12 has been released, the vehicle control system stops the EPS system 1 from outputting power assistance.

[0063] S3: Repeat step S2 until the wheels are adjusted to the target position, thus completing the four-wheel alignment of the vehicle;

[0064] S4: After completing the four-wheel alignment of the vehicle, release the fixation of steering wheel 2.

[0065] like Figures 1 to 3 As shown, the spindle 3 is fixedly connected to the steering wheel 2, and the spindle 3 is connected to the input shaft 11 of the EPS system 1 via a spline. In the EPS system 1, the input shaft 11 is fixedly connected to the torsion bar 12, and the torsion bar 12 is fixedly connected to the output shaft 13. When the movements between the spindle 3 and the output shaft 13 are asynchronous, the torsion bar 12 will bear torque. At the same time, the output shaft 13 of the EPS system 1 is connected to the wheel 8 through components such as the steering tie rod 6, the steering gear 5, and the steering intermediate shaft 4. Since the steering wheel 2 is fixed, the spindle 3 is also fixed.

[0066] like Figure 1 and Figure 2As shown, during the four-wheel alignment process, the steering wheel 2 is first fixed in place with a fixture. Then, the inner tie rod 61 is rotated. Since the outer tie rod 62 is threaded onto the inner tie rod 61, rotating the inner tie rod 61 is equivalent to pushing the outer tie rod 62 out or retracting it. Figure 2 As indicated by the arrows, rotating the inner tie rod 61 causes the outer tie rod 62 to move left and right. Simultaneously, rotating the inner tie rod 61 also changes the overall length of the steering tie rod 6, thus adjusting it. The left and right movement of the outer tie rod 62 causes the wheel 8 to rotate left and right around the front strut 7. Simultaneously, the inner tie rod 61 also moves left and right under the reaction force of the wheel 8, driving the steering intermediate shaft 4 via the steering gear 5, which in turn drives the output shaft 13 to rotate. Because the steering wheel 2 is fixed, the input shaft 11 is also fixed, causing the torsion bar 12 of the EPS system 1 to experience a torque due to deformation. If the torque of the torsion bar 12 is not released, releasing the fixation of the steering wheel 2 will cause the steering wheel 2 to rotate, resulting in the steering wheel 2 being misaligned. The torque borne by the torsion bar 12 can only be released by rotating either the input shaft 11 or the output shaft 13. Therefore, in this invention, as long as the torsion bar 12 experiences torque, the torque can be released by rotating the output shaft 13 to drive the wheel 8 to rotate around the front strut 7. This invention utilizes the EPS system 1 to provide an auxiliary function. When the vehicle control system detects the torque borne by the torsion bar 12 of the EPS system 1, it activates the auxiliary function, causing the EPS system 1 to output power assist. The EPS system 1 then rotates the output shaft 13, which, through the steering intermediate shaft 4 and the steering gear 5, moves the inner steering tie rod 61, thereby releasing the torque on the torsion bar 12 caused by the movement of the inner tie rod 61. Once the vehicle control system detects that the torque borne by the torsion bar 12 has been released, it stops the EPS system 1 from outputting power assist. At this point, because the length of the tie rod 6 has changed, the position of the wheel 8 has also changed.

[0067] When the inner tie rod 61 is rotated, the wheel rotates left and right around the front strut, and before the torque of the torsion bar 12 is released, the wheel 8 is in the intermediate posture. After the torque of the torsion bar 12 is released, the force continues to be transmitted to the wheel 8, causing the wheel 8 to rotate in the opposite direction. The wheel 9 has now rotated relative to the intermediate posture, so step S2 needs to be repeated until the torque of the torsion bar 12 is released and the wheel 8 has rotated due to the torque release. At this point, the position of the wheel 8 is exactly the target position.

[0068] The above process achieves the simultaneous elimination of torque on torsion bar 12 during the adjustment of four-wheel alignment parameters. This not only avoids the steering wheel 2 becoming misaligned after it is unsecured and rotated, but also improves the accuracy of four-wheel alignment.

[0069] In this embodiment, in step S2, rotating the inner tie rod 61 of the steering tie rod 6 causes the outer tie rod 62 of the steering tie rod 6 to move axially, thereby causing the wheel 8 to rotate around the front strut 7. At this time, under the reaction force of the wheel 8, the inner tie rod 61 leaves the initial position and moves towards the position of the torsion bar 12, causing the torsion bar 12 to bear torque. The vehicle control system activates the auxiliary function of the EPS system 1, causing the EPS system 1 to output power assistance, causing the output shaft 13 to rotate and drive the inner tie rod 61 to move axially in the opposite direction back to the initial position of the inner tie rod 61 through the intermediate shaft 4 and the steering gear 5, thereby releasing the torque of the torsion bar 12. The vehicle control system then stops the EPS system 1 from outputting power assistance.

[0070] During the four-wheel alignment process, before each rotation of the inner tie rod 61, its initial position is reached. Rotating the inner tie rod 61 causes the outer tie rod 62 to move left and right, thereby causing the wheel 8 to rotate left and right around the front strut 7. The inner tie rod 61 also moves left and right under the reaction force of the wheel 8, and through the steering gear 5, drives the steering intermediate shaft 4, which in turn drives the output shaft 13 to rotate. Because the steering wheel 2 is fixed, the input shaft 11 is also fixed, causing the torsion bar 12 to bear torque. The vehicle control system activates the auxiliary function of the EPS system 1, causing the EPS system 1 to output power assist. The EPS system 1 rotates the output shaft 13, which drives the steering intermediate shaft 4 and the steering gear 5 to move. This causes the intermediate shaft 4 and the steering gear 5 to move the inner tie rod 61 in the opposite direction to its initial position. At this point, the torque generated by the deformation of the torsion bar 12 has been released. Although the inner tie rod 61 returns to its initial position, the overall length of the steering tie rod 6 has changed after the inner tie rod 61 is rotated. Therefore, the position of the wheel 8 after the torque of the torsion bar 12 is released is still different from the position of the wheel 8 before the inner tie rod 61 is rotated, that is, the wheel positioning adjustment has been performed.

[0071] The entire four-wheel alignment process is as follows: Rotate the inner tie rod 61 → the outer tie rod 62 moves left and right → the wheel 8 rotates left and right around the front strut 7 → the inner tie rod 61 moves left and right under the reaction force of the wheel and the outer tie rod 62 → the steering intermediate shaft 4 rotates under the action of the inner tie rod 61 through the steering gear 5 → the output shaft 13 rotates under the drive of the steering intermediate shaft 4 → the torsion bar 12 bears the torque → the EPS system 1 outputs power assist and drives the steering inner tie rod 61 to move in the opposite direction to the initial position of the inner tie rod 61 through the steering intermediate shaft 4 and the steering gear 5. Repeat the above actions until the wheel 8 rotates to the correct position.

[0072] This embodiment also includes the following steps:

[0073] like Figure 6 As shown, after the four-wheel alignment is completed, before the vehicle leaves the production line, the vehicle control system disables the EPS system 1 auxiliary function so that the EPS system 1 provides normal assistance when the user drives the car.

[0074] To ensure that this function is no longer needed after the vehicle rolls off the production line or reaches the user, EPS system 1 needs to be in normal working condition. Therefore, during the vehicle production process in the factory, the auxiliary function of EPS system 1 needs to be turned off after the four-wheel alignment is completed.

[0075] In this embodiment, the following steps are also included between steps S3 and S4:

[0076] S4.1: Angle midpoint calibration for EPS system 1.

[0077] In this embodiment, the auxiliary functions of the EPS system 1 need to be turned off simultaneously under the following conditions:

[0078] like Figure 6 As shown, the offline configuration of EPS system 1 is complete; the angle median of EPS system 1 has been calibrated.

[0079] In this embodiment, the EPS system 1 can also provide normal assistance when the following conditions are met simultaneously:

[0080] like Figure 6 As shown, the vehicle is powered on; the vehicle control system detects engine ignition; the torsion bar 12 in EPS system 1 is subjected to torque.

[0081] To ensure that the driver can operate the steering wheel 2 normally during the normal circulation and driving of the vehicle within the factory, the vehicle control system provides normal power steering in this situation after detecting engine ignition.

[0082] In this invention, such as Figure 6 As shown, in the same column, each line segment represents the status of five indicators: the vehicle's power supply status, the engine status, the torque of the EPS system torsion bar, the lower limit configuration of the EPS system, and the angle median calibration of the EPS system. These indicators determine whether the EPS system is assisting the engine.

[0083] In this embodiment, when fixing the steering wheel 2, the steering wheel 2 is locked using a positioning fixture.

[0084] The positioning fixture can be a car anti-theft lock or other device that can restrict the rotation of the steering wheel 2, or the car's own steering wheel 2 lock can be used to lock the steering wheel 2.

[0085] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention.

Claims

1. A method for operating auxiliary functions of an EPS system, characterized in that, Includes the following steps: When performing four-wheel alignment on the vehicle, and the vehicle power supply is on and the engine is off, when the vehicle control system detects that the torsion bar (12) of the electric power steering system (EPS system) is bearing torque, the vehicle control system activates the auxiliary function of the EPS system (1), causing the EPS system (1) to output power assistance, so that the EPS system (1) drives the output shaft (13) to rotate, thereby releasing the torque borne by the torsion bar (12). When the vehicle control system detects that the torque borne by the torsion bar (12) of the vehicle control system has been released, the vehicle control system stops the EPS system (1) from outputting power assistance.

2. The working method of the EPS system auxiliary function according to claim 1, characterized in that, When the auxiliary function of the EPS system (1) is working, the output of the assistance is 20%-50% of the normal assistance of the EPS system (1).

3. The working method of the EPS system auxiliary function according to claim 2, characterized in that, When the auxiliary function of the EPS system (1) is working, the output of the assistance is 30% of the normal assistance of the EPS system (1).

4. A method for four-wheel alignment of a vehicle, characterized in that, Includes the following steps: S1: Fix the steering wheel (2) to restrict the rotation of the steering wheel (2). Since the steering wheel (2) is fixedly connected to the spindle (3), the input shaft (11) of the EPS system (1) is fixedly connected to the spindle (3), so that the input shaft (11) is also fixed. At the same time, when the vehicle power supply is on and the engine is off, perform four-wheel alignment on the vehicle. S2: During the four-wheel alignment process, the inner tie rod (61) of the steering tie rod (6) is rotated to drive the outer tie rod (62) of the steering tie rod (6) to move axially, thereby causing the wheel (8) to rotate around the front pillar (7). At this time, if the vehicle control system detects that the torsion bar (12) of the EPS system (1) is bearing torque, the vehicle control system activates the auxiliary function of the EPS system (1) to output power, so that the output shaft (13) rotates to release the torque of the torsion bar (12). When the vehicle control system detects that the torque borne by the torsion bar (12) has been released, the vehicle control system stops the EPS system (1) from outputting power. S3: Repeat step S2 until the wheels are adjusted to the target position, thus completing the four-wheel alignment of the vehicle; S4: After completing the four-wheel alignment of the vehicle, release the fixation of the steering wheel (2).

5. The vehicle four-wheel alignment method according to claim 4, characterized in that, In step S2, by rotating the inner tie rod (61) of the steering tie rod (6), the outer tie rod (62) of the steering tie rod (6) is driven to move axially, thereby causing the wheel (8) to rotate around the front pillar (7). At this time, the inner tie rod (61) moves away from the initial position to the position of the torsion bar (12) under the reaction force of the wheel (8), causing the torsion bar (12) to bear torque. The vehicle control system activates the EPS system (1) auxiliary function, causing the EPS system (1) to output power, causing the output shaft (13) to rotate and drive the inner tie rod (61) to move axially in the opposite direction to the initial position of the inner tie rod (61) through the intermediate shaft (4) and the steering gear (5), thereby releasing the torque of the torsion bar (12). The vehicle control system stops the EPS system (1) from outputting power.

6. The vehicle four-wheel alignment method according to claim 5, characterized in that, It also includes the following steps: After the four-wheel alignment is completed, before the vehicle leaves the production line, the vehicle control system shuts down the EPS system (1) auxiliary function so that the EPS system (1) provides normal assistance when the user drives the car.

7. The vehicle four-wheel alignment method according to claim 6, characterized in that, The following steps are also included between steps S3 and S4: S4.1: Angle median calibration of EPS system (1).

8. The vehicle four-wheel alignment method according to claim 7, characterized in that, The auxiliary function of the EPS system (1) needs to meet the following conditions simultaneously to be turned off: Complete the offline configuration of EPS system (1); the angle median of EPS system (1) has been calibrated.

9. The vehicle four-wheel alignment method according to any one of claims 4 to 8, characterized in that, The EPS system (1) can also provide normal assistance when the following conditions are met simultaneously: The vehicle is powered on; the vehicle control system detects engine ignition; the torsion bar (12) in the EPS system (1) is subjected to torque.

10. The vehicle four-wheel alignment method according to any one of claims 4 to 8, characterized in that, When fixing the steering wheel (2), the steering wheel (2) is locked using a positioning fixture.

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