Automatic driving hydraulic steering modification control system and control method

Abstract

The hydraulic steering retrofit control system for automatic driving disclosed in the present application includes a steering wheel, a hydraulic steering mechanism and a steering wheel, the hydraulic steering mechanism is connected to the steering wheel and the steering wheel respectively, the steering wheel and the hydraulic steering mechanism are connected through a first pivot shaft and a second pivot shaft, one end of the first pivot shaft is connected to the steering wheel and the other end of the first pivot shaft is connected to one end of the second pivot shaft through a steering connector, the other end of the second pivot shaft is connected to the hydraulic steering mechanism, and a steering motor is provided on the second pivot shaft to drive and rotate the hydraulic steering mechanism so as to rotate the steering wheel. The above control system provides a steering motor on the second pivot shaft, i.e., downstream of the steering connector, so that when the steering motor is activated to act on the hydraulic steering mechanism, the mechanical error of the steering connector can be avoided, and the accuracy and response speed of the hydraulic steering can be improved, thereby meeting the steering accuracy requirements of automatic driving.

Description

[Technical field]

[0001] The present application relates to the field of autonomous driving technology, and more particularly to an autonomous driving hydraulic steering retrofit control system and control method.

[0002] This application claims priority to a Chinese patent application filed with the China Patent Office on September 8, 2022, bearing application number 202211105656.0 and entitled "Automatic Driving Hydraulic Steering Modification Control System and Control Method," the entire contents of which are incorporated herein by reference. [Background technology]

[0003] The accuracy of the hydraulic steering system of the manned vehicle is generally not high, so the error of the wheel turning angle is large and the response speed is slow, and when this type of hydraulic steering system is applied to the scene of automatic driving, it is difficult to meet the steering accuracy requirements of automatic driving, and the response speed is limited, which is disadvantageous to improving the efficiency of the automatic driving work situation. Furthermore, when developing a new hydraulic steering system set, the original vehicle needs to be significantly modified, which not only requires high development costs, but also has a complex structure and requires significant modifications to the original vehicle, which limits the modification efficiency of the original vehicle and the time for production and use. Summary of the Invention [Problem to be solved by the invention]

[0004] In order to solve one or more technical problems in the prior art, or at least to provide a useful choice, the present application provides an automatic driving hydraulic steering modification control system and control method, which solves the problems of current hydraulic steering such as low accuracy and slow response speed. [Means for solving the problem]

[0005] In one aspect, the present application provides an autonomous hydraulic steering retrofit control system, comprising: a steering wheel, a hydraulic steering mechanism, and a steering wheel; the hydraulic steering mechanism is connected to the steering wheel and the steering wheel, respectively; the steering wheel and the hydraulic steering mechanism are connected via a first pivot shaft and a second pivot shaft; one end of the first pivot shaft is connected to the steering wheel, and the other end of the first pivot shaft is connected to one end of the second pivot shaft via a steering connector, and the other end of the second pivot shaft is connected to the hydraulic steering mechanism; and the second pivot shaft is provided with a steering motor for driving and rotating the hydraulic steering mechanism to rotate the steering wheel.

[0006] Furthermore, the steering motor is a dual output shaft motor.

[0007] Furthermore, a transmission mechanism is provided between the steering motor and the second rotating shaft, the transmission mechanism including a pinion gear connected to an output shaft of the steering motor and a gear wheel meshingly connected to the pinion gear.

[0008] Furthermore, a preset included angle is formed between the first pivot shaft and the second pivot shaft.

[0009] Furthermore, the control system further includes a controller and a turning angle measuring device provided on the steering shaft of the steering wheel, the turning angle measuring device and the steering motor being each electrically connected to the controller.

[0010] In another aspect, the present application provides a hydraulic steering retrofit control method for autonomous driving, which is based on the above-mentioned hydraulic steering retrofit control system for autonomous driving, and the control system further includes a controller electrically connected to the steering motor, and the control method includes the steps of obtaining current turning angle data of a steering wheel, comparing the current turning angle data of the steering wheel with an expected turning angle data of the steering wheel to calculate a difference value therebetween, and determining whether the difference value is within a preset accuracy range.

[0011] Furthermore, a transmission mechanism is provided between the steering motor and the second pivot shaft, and a transmission ratio of the transmission mechanism is adjusted when the difference value is not within the preset accuracy range.

[0012] Further, the steering wheel is provided with an encoder, and the control method further includes the steps of inputting the difference value into a PID controller to obtain expected turning speed and expected turning angle data of the steering motor, controlling the steering motor to operate according to the expected turning speed and expected turning angle data of the steering motor, and returning the feedback turning angle data collected by the encoder to the controller.

[0013] Furthermore, the turning angle data of the steered wheels=the feedback turning angle data of the encoder×a, where a is the correspondence between the data of the encoder and the angle of the steered wheels.

[0014] Furthermore, the expected turning speed of the steering motor = the expected turning speed of the steered wheels x b, and the expected turning angle of the steering motor = the expected turning angle of the steered wheels x b, where b is the relationship between the angle change of the steering motor and the angle change of the steered wheels. Effect of the Invention

[0015] By using the above technical means, the present application has the following beneficial effects.

[0016] 1. The hydraulic steering modified control system for automatic driving of the present application is provided with a steering motor between the steering wheel and the hydraulic steering mechanism, which can meet the application of automatic driving, and maintains the structure of the original steering wheel, etc., and can achieve both human driving and automatic driving, thereby expanding the application scenarios of vehicles; furthermore, by optimizing the installation position of the steering motor, the steering motor is provided on the second turning axis, that is, downstream of the steering connector, so that when the steering motor is started and acts on the hydraulic steering mechanism, the mechanical error of the steering connector can be avoided, the accuracy and response speed of hydraulic steering can be improved, and the error between the turning angle of the steering wheel and the turning angle of the steering wheel can be greatly reduced, thereby meeting the steering accuracy requirements of automatic driving.

[0017] 2. In one embodiment, the steering motor is a dual output shaft motor. By providing this type of steering motor, the structure is simple, it is easy to modify, the cost is reduced, and the efficiency of the modification can be improved.

[0018] 3. In one embodiment, a transmission mechanism including a pinion gear connected to the output shaft of the steering motor and a gear wheel meshed with the pinion gear is provided between the steering motor and the second turning shaft. By installing a transmission mechanism that can further improve the accuracy with which the steering motor acts on the hydraulic steering mechanism, the turning angle accuracy of the steering wheel is improved and the driving requirements for special working situations of autonomous driving are met.

[0019] 4. In one embodiment, a preset angle is formed between the first and second rotating shafts, and the method of arranging the first and second rotating shafts is optimized to optimize the transmission from the second rotating shaft to the hydraulic steering mechanism. This makes it possible to install the second rotating shaft and the hydraulic steering mechanism more smoothly while minimizing the impact on the steering wheel arrangement, thereby improving transmission accuracy.

[0020] 5. In one embodiment, the control system further includes a controller and a turning angle measuring device provided on the steering shaft of the steering wheel, and the turning angle measuring device and the steering motor are electrically connected to the controller, respectively, thereby monitoring the steering motor and the turning angle measuring device by the controller, i.e., the controller compares and processes the actual turning angle of the steering wheel measured by the turning angle measuring device and the expected turning angle provided by the system, and based on this, controls the steering motor so that the steering wheel rotates according to the expected turning angle data, thereby realizing closed-loop control and ensuring that the steering accuracy is controlled within the range of autonomous driving requirements.

[0021] 6. The hydraulic steering modification control method for automatic driving of the present application can clearly grasp the control situation of the steering wheel turning angle accuracy by comparing the actual turning angle of the steering wheel with the expected turning angle during structural modification, and can reflect the results of the modification and provide guide data for the structural modification, that is, conversely, it can serve as the basis for structural modification, thereby refining the structural modification strategy.

[0022] 7. In one embodiment, a transmission mechanism is provided between the steering motor and the second turning shaft, and a transmission ratio of the transmission mechanism is adjusted when the differential value is not within the preset accuracy range. In this embodiment, by providing a transmission mechanism between the steering motor and the second turning shaft, on the one hand, the transmission accuracy can be improved and the turning angle accuracy control of the steering wheel can be improved; on the other hand, by adjusting the transmission ratio, the transmission accuracy can be refined and adjusted within an extremely small range, thereby easily controlling the accuracy of the steering system to within one degree, and meeting the driving requirements in special working situations of automatic driving.

[0023] 8. In one embodiment, the steering wheel is provided with an encoder, and the control method further includes the steps of inputting the difference value into a PID controller to obtain expected turning speed and expected turning angle data of the steering motor, controlling the steering motor to operate according to the expected turning speed and expected turning angle data of the steering motor, and returning the feedback turning angle data collected by the encoder to the controller. The present application can realize closed-loop control by utilizing the association of the controller with the steering motor and the encoder, which can further compensate for the accuracy error from the steering motor to the hydraulic steering mechanism as another barrier to improving the steering system accuracy, ensure the actual turning angle accuracy of the steering wheel, and improve the use reliability of the entire system. [Brief description of the drawings]

[0024] The drawings described herein are intended to provide further understanding of the present application, constitute a part of the present application, and the schematic embodiments and the description thereof are used to interpret the present application and are not intended to unduly limit the present application.

[0025] [Figure 1] FIG. 1 is a schematic simplified diagram of the structure of a hydraulic steering retrofit control system in one embodiment of the present application. [Diagram 2] FIG. 2 is a schematic simplified diagram of the structure of a hydraulic steering retrofit control system in another embodiment of the present application. [Diagram 3] FIG. 2 is a schematic simplified diagram of the structure of a hydraulic steering retrofit control system in another embodiment of the present application. [Figure 4] 2 is a flowchart of a hydraulic steering retrofit control method in one embodiment of the present application. [Diagram 5] 4 is a flowchart of a hydraulic steering retrofit control method in another embodiment of the present application. [Figure 6] FIG. 2 is a block diagram of a closed-loop control flow in one embodiment of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] In order to more clearly explain the overall concept of the present application, the following detailed description will be given in an exemplary manner with reference to the drawings in the specification.

[0027] In order to make the above objects, features and advantages of the present application more clearly understandable, the present application will be described in more detail below with reference to the drawings and specific embodiments. It should be noted that, unless contradictory, the embodiments of the present application and the features in the embodiments may be combined with each other.

[0028] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application; however, the present application may be embodied in forms other than those described herein, and therefore the scope of protection of the present application is not limited to the specific embodiments disclosed below.

[0029] In addition, in the description of this application, the orientations or positional relationships indicated by terms such as "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," "circumferential," and the like are based on the orientations or positional relationships shown in the drawings, and are intended merely to facilitate the description and simplification of the description of this application, and are not intended to indicate or imply that the devices or components shown must have a specific orientation or be configured or operated in a specific orientation, and therefore cannot be understood as limiting this application.

[0030] Additionally, the terms "first" and "second" are used merely for descriptive purposes and should not be understood to express or imply a relative importance or to implicitly indicate the number of technical features depicted. Thus, a feature qualified by "first" or "second" may explicitly or implicitly include one or more of the feature. In the description of this application, "plurality" means two or more, unless otherwise clearly and specifically limited.

[0031] In this application, unless otherwise clearly specified and limited, the terms "attached", "coupled", "connected", "fixed" and the like should be understood in a broad sense, for example, they may be fixedly connected, detachably connected, or integrated, may be directly connected, may be indirectly connected through an intermediate medium, may be internal communication between two components, or may be an interaction relationship between two components. However, when it is specified that the two connected bodies are connected to each other only by a connection structure to form an integrated body, rather than a connection relationship being established between the two bodies by a transition structure, a person skilled in the art can understand the specific meaning of the above terms in this application according to the specific situation.

[0032] In the present application, unless otherwise clearly defined and limited, a first feature being "on" or "under" a second feature may mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature via an intermediate medium. In the description of this specification, the description of terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" is intended to include specific features, structures, materials, or characteristics described with reference to the embodiment or example in at least one embodiment or example of this application. In the present specification, general expressions of the above terms do not necessarily refer to the same embodiment or example. And, specific features, structures, materials, or characteristics described in any one or more embodiments or examples may be combined in an appropriate manner.

[0033] As shown in Figures 2 and 3, the present application provides an automatic hydraulic steering retrofit control system, which includes a steering wheel 10, a hydraulic steering mechanism 20 and a steering wheel 30, the hydraulic steering mechanism 20 is connected to the steering wheel 10 and the steering wheel 30 respectively, the steering wheel 10 and the hydraulic steering mechanism 20 are connected via a first pivot shaft 11 and a second pivot shaft 12, one end of the first pivot shaft 11 is connected to the steering wheel 10 and the other end is connected to one end of the second pivot shaft 12 via a steering connector 13, the other end of the second pivot shaft 12 is connected to the hydraulic steering mechanism 20, and the second pivot shaft 12 is provided with a steering motor 14 for driving and rotating the hydraulic steering mechanism 20 so as to rotate the steering wheel 30.

[0034] In one aspect, the present application can realize automatic driving by adding a steering motor 14 and having it act on the hydraulic steering mechanism 20 to rotate the steering wheel 30. In addition, the present application can be modified based on the original vehicle, and still drive and rotate the steering wheel 30 via the steering wheel 10, which not only reserves the application of human driving, but also simplifies the modification flow, simplifies the structural layout, reduces costs, and improves the efficiency of modification.

[0035] In another aspect, the position of the steering motor 14 has a large effect on steering accuracy. When the steering motor 14 is provided on the first rotating shaft 11 as shown in Fig. 1, the transmission from the steering motor 14 to the hydraulic steering mechanism 20 must pass through the steering connector 13, and usually there is a transmission gap inside the steering connector 13, and the mechanical error caused by this inevitably affects the action and effect of the steering motor 14 on the hydraulic steering mechanism 20, which is disadvantageous for improving steering accuracy. In contrast, when the steering motor 14 is provided on the second rotating shaft 12 as shown in Fig. 2 or 3, the error of the steering motor 14 caused by the steering connector 13 can be avoided, which is advantageous for improving steering accuracy.

[0036] Furthermore, in a human driving scene, even if a steering connector 13 is provided between the first pivot axis 11 and the second pivot axis 12, the user can still utilize the steering motor 14 to provide additional assistance while operating the steering wheel 10, thereby compensating for errors caused by the steering connector 13 through the dual action of the steering wheel 10 and the steering motor 14.

[0037] Specifically, adding a steering motor 14 between the steering wheel 10 and the hydraulic steering mechanism 20 requires only a small change to the original vehicle, so it is easy to implement, has low modification costs, and is highly efficient. Here, the hydraulic steering mechanism 20 can refer to related structures in the prior art, for example, it can include a steering valve 21, a reservoir tank 22, a hydraulic pump, a steering cylinder 23, a fluid line, etc., and the operating principle of each member can refer to the contents of the prior art, and detailed explanations are omitted in this application. The steering motor 14 in this application can drive the steering valve 21 to act on the hydraulic steering mechanism 20 and operate the hydraulic steering system, thereby driving and rotating the steering wheel 30.

[0038] Here, regarding the structure of the steering connector 13, it may be, for example, any one of a steering knuckle, a universal joint, a coupling assembly, a sprocket transmission mechanism, a gear transmission mechanism, a rack and pinion transmission mechanism, and a worm and gear transmission mechanism, and may be provided according to actual needs, and the present application is not limited thereto.

[0039] In one embodiment of the present application, the steering motor 14 is a dual output shaft motor. In this embodiment, the output shafts at both ends of the steering motor 14 can be directly coupled to the second pivot shaft 12, which on the one hand simplifies the motor arrangement and on the other hand simplifies the assembly.

[0040] As one embodiment of the present application, a transmission mechanism is provided between the steering motor 14 and the second rotating shaft 12, the transmission mechanism including a pinion gear 151 connected to the output shaft of the steering motor 14 and a gear wheel 152 meshingly connected to the pinion gear 151.

[0041] In this embodiment, the steering motor 14 can be installed as the first stage of precision control, and the transmission mechanism can be installed as the second stage of precision control, and the gear wheel 152 is driven and transmitted by the pinion gear 151, thereby further improving the precision, thereby improving the turning angle precision of the steering wheel 30, and enabling the steering wheel 30 to achieve an ideal steering angle.

[0042] As shown in FIG. 3, in this embodiment, the steering motor 14 is, for example, a servo motor, and the transmission ratio of the pinion gear 151 and the gear wheel 152 can be set according to actual needs to meet the steering precision requirements.

[0043] In one embodiment of the present application, a preset included angle is formed between the first pivot shaft 11 and the second pivot shaft 12 .

[0044] 2, the second pivot shaft 12 extends, for example, vertically to promote a compact configuration and at the same time optimize its relative position with respect to the hydraulic steering mechanism 20 to minimize the transmission error from the steering motor 14 to the hydraulic steering mechanism 20. The first pivot shaft 11 and the second pivot shaft 12 are foldably connected, and form, for example, an obtuse included angle between them, and the first pivot shaft 11 extends toward the steering wheel 10, so that the angle of the steering wheel 10 can better meet the requirements of manual use and improve the comfort of manual operation.

[0045] As one embodiment of the present application, the control system further includes a controller and a turning angle measuring device 31 provided on the steering shaft of the steering wheel 30, and the turning angle measuring device 31 and the steering motor 14 are each electrically connected to the controller.

[0046] Specifically, the controller can be used to obtain the measurement data collected by the turning angle measuring device 31 and obtain the actual turning angle data of the steering wheel 30 based on the measurement data. Furthermore, the controller compares the expected turning angle data of the steering wheel 30 provided by the system with the actual turning angle data of the steering wheel 30, and performs corresponding calculations and other processing to obtain operation parameters such as the expected turning angle and expected turning speed of the steering motor 14, so that the controller controls the operation of the steering motor 14 based on the operation parameters such as the expected turning angle and expected turning speed of the steering motor 14 to control and rotate the steering wheel 30, and at the same time, the turning angle measuring device 31 can continue to measure the current rotation of the steering wheel 30 and feed back the measurement result to the controller. In this way, the present application can realize closed-loop control and ensure that the steering wheel 30 reaches an ideal steering angle. The controller is, for example, an ECU. The turning angle measuring device 31 is, for example, an angle encoder.

[0047] It should be understood that in some embodiments, the present application may omit the closed-loop control and act only on the steering motor 14 to control the steering accuracy to within 1 degree, or even 0.5 degrees. In some other embodiments, the closed-loop control may be increased to ensure reliability, thereby ensuring that the steering wheels 30 reach the ideal steering angle and improving response speed to accommodate more demanding working conditions.

[0048] In another aspect, the present application further provides an automatic driving hydraulic steering retrofit control method, which can be based on the above retrofit control system, and the control system includes a steering wheel 10, a hydraulic steering mechanism 20 and a steering wheel 30, where the steering wheel 10 and the hydraulic steering mechanism 20 are connected via a first pivot axis 11 and a second pivot axis 12, a steering connector 13 is provided between the first pivot axis 11 and the second pivot axis 12, and a steering motor 14 is provided on the second pivot axis 12. Furthermore, the control system further includes a controller electrically connected to the steering motor 14. As shown in FIG. 4, the control method includes: Step S1 of acquiring current turning angle data of a steering wheel; Step S2: comparing the current turning angle data of the steering wheels with the expected turning angle data of the steering wheels to calculate a difference between the two; and step S3 of determining whether the difference value is within a preset accuracy range.

[0049] In step S1, measurement data collected by a turning angle measuring device such as an encoder is available, and the controller can process the measurement data to obtain current turning angle data of the steering wheel, i.e., actual turning angle data of the steering wheel.

[0050] Furthermore, in step S2, the controller can further obtain expected turning angle data of the steered wheels, and calculate a difference value between the expected turning angle data and the actual turning angle data of the steered wheels obtained in step S1.

[0051] Furthermore, in step S3, the controller judges whether the system steering accuracy is within a preset accuracy range based on the above difference value result. For example, if the difference value between the actual turning angle data and the expected turning angle data of the steering wheel is less than 1 (corresponding to an angle of 1 degree), the accuracy requirement is met, that is, the difference value is within the preset accuracy range. Conversely, if the difference value is not within the preset accuracy range, the controller can provide a notification such as an alarm.

[0052] Thus, the above control method can reflect the modification results from application and data, and provide a modification evaluation. If the above difference value is not within the preset accuracy range, relevant technicians can improve the accuracy control by adjusting the modification strategy, for example, by converting the type of steering motor 14, adjusting the operating parameters of steering motor 14, etc., to meet the control of the difference value in the above step S3 within the preset accuracy range.

[0053] In one embodiment of the present application, a transmission mechanism is provided between the steering motor 14 and the second pivot shaft 12. As shown in Fig. 5, the control method further includes a step S4 of adjusting a transmission ratio of the transmission mechanism when the difference value is not within the preset accuracy range.

[0054] Specifically, in some embodiments, the transmission mechanism includes a pinion gear 151 connected to an output shaft of the steering motor 14 and a gear wheel 152 meshingly connected to the pinion gear 151. If the steering accuracy does not meet the requirements, the range of the above-mentioned difference value can be reduced by adjusting the transmission ratio by changing the pinion gear 151 and / or the gear wheel 152 with different numbers of teeth, so as to control the above-mentioned difference value within a preset accuracy range.

[0055] That is, the present application can understand the application effect of the modification based on step S3, and if the modification does not meet the precision requirements of autonomous driving, the modification strategy can be adjusted based on step S4 to further refine the modification effect. And by adjusting the transmission ratio, it can meet different precision, easily adapt to different working situations, and expand the application scenarios of autonomous driving.

[0056] In one embodiment of the present application, the steering wheel 30 is provided with an encoder, and the control method further comprises: Step S5: inputting the difference value into a PID controller to obtain expected turning speed and expected turning angle data of the steering motor; Step S6 of controlling the steering motor to operate in accordance with expected turning speed and expected turning angle data of the steering motor; and returning feedback slewing angle data collected by the encoder to the controller S7.

[0057] Referring to FIG. 6, by providing a controller, a steering motor 14 and an encoder, a closed-loop control can be realized, and the steering wheel 30 can be guaranteed to reach the ideal steering. The controller such as an ECU can collect the feedback turning angle data of the encoder, and after processing, obtain the actual turning angle data of the steering wheel 30, and the controller further receives the command of the expected turning angle data of the steering wheel 30 sent by the main control unit, and obtains the expected turning speed and expected turning angle data of the steering motor 14 according to the above two kinds of data, and then the controller sends an operation command / signal to the steering motor 14, and the steering wheel 30 is driven by the hydraulic steering mechanism 20 to rotate, and the encoder feedbacks the current turning angle of the steering wheel 30 to the controller, thereby performing closed-loop control of the turning angle of the steering wheel 30 until it is adjusted to a predetermined position. The closed-loop control can ensure the steering accuracy and improve the response speed.

[0058] Here, the turning angle data of the steered wheels=the feedback turning angle data of the encoder×a, where a is the correspondence between the data of the encoder and the angle of the steered wheels.

[0059] The above parameter a can be obtained by locating the zero point of the encoder and calculating the relationship between the encoder data and the steering wheel angle. The corresponding relationship may be linear or nonlinear. If it is nonlinear, it can be obtained by performing curve fitting with multiple samplings.

[0060] Furthermore, the expected turning speed of the steering motor = the expected turning speed of the steered wheels × b, and the expected turning angle of the steering motor = the expected turning angle of the steered wheels × b, where b is the relationship between the angle change of the steering motor and the angle change of the steered wheels, where the parameter b can be obtained according to (maximum value of the turning angle of the steering wheel - minimum value of the turning angle of the steering wheel) / (maximum value of the turning angle of the steered wheels - minimum value of the turning angle of the steered wheels).

[0061] The technical means protected by the present application are not limited to the above embodiments, and the combination of the technical means of any one embodiment with the technical means of one or more other embodiments is within the scope of protection of the present application. The present application has been described in detail above using general descriptions and specific embodiments, but some modifications or improvements can be made based on the present application, which are obvious to those skilled in the art. Therefore, any modifications or improvements made without departing from the spirit of the present application are within the scope of protection of the present application. [Explanation of symbols]

[0062] 10...steering wheel, 11...first pivot axis, 12...second pivot axis, 13...steering connector, 14...steering motor, 151...pinion gear, 152...gear wheel; 20...hydraulic steering mechanism, 21...steering valve, 22...reservoir tank, 23...steering cylinder; 30...steering wheel, 31...turning angle measuring device.

Claims

1. A hydraulic steering retrofit control method for automatic driving, comprising: The hydraulic steering retrofit control system for autonomous driving includes a steering wheel, a hydraulic steering mechanism, and a steering wheel. The hydraulic steering mechanism is connected to the steering wheel and the steering wheel, respectively. The steering wheel and the hydraulic steering mechanism are connected via a first pivot shaft and a second pivot shaft. One end of the first pivot shaft is connected to the steering wheel, and the other end is connected to one end of the second pivot shaft via a steering connector. The other end of the second pivot shaft is connected to the hydraulic steering mechanism. The second pivot shaft is provided with a steering motor for driving and rotating the hydraulic steering mechanism to rotate the steering wheel. The control system further includes a controller electrically connected to the steering motor and a turning angle measuring device provided on a steering shaft of the steering wheel, the turning angle measuring device being electrically connected to the controller; The control method includes: Obtaining current turning angle data of a steering wheel; A step of comparing the current turning angle data of the steering wheels with the expected turning angle data of the steering wheels to calculate a difference between the current turning angle data of the steering wheels and the expected turning angle data of the steering wheels; determining whether the difference value is within a preset accuracy range; a transmission mechanism is provided between the steering motor and the second pivot shaft; When the difference value is not within the preset accuracy range, the steering motor is set as a first-stage accuracy control and the transmission mechanism is set as a second-stage accuracy control to adjust a transmission ratio of the transmission mechanism to meet a steering accuracy requirement; The steering wheel is provided with an encoder; The control method includes inputting the difference value into a PID controller to obtain expected turning speed and expected turning angle data of the steering motor; controlling the steering motor to operate in accordance with expected turning speed and expected turning angle data of the steering motor; and returning feedback slewing angle data collected by the encoder to the controller; the transmission mechanism includes a pinion gear connected to an output shaft of the steering motor and a gear wheel meshingly connected to the pinion gear, Hydraulic steering modification control method for automatic driving.

2. 2. The hydraulic steering retrofit control method for automatic driving as claimed in claim 1, wherein the turning angle data of the steering wheel=the feedback turning angle data of the encoder×a, where a is the corresponding relationship between the data of the encoder and the angle of the steering wheel.

3. The expected turning speed of the steering motor = the expected turning speed of the steering wheel x b, The expected turning angle of the steering motor is equal to the expected turning angle of the steering wheel x b, where b is the angle change of the steering motor. The hydraulic steering retrofit control method for automatic driving according to claim 1, which is related to the change in steering wheel angle.

4. The hydraulic steering modification control method for automatic driving as described in claim 1, wherein the steering motor is a dual output shaft motor.

5. An automatic driving hydraulic steering modification control method as described in claim 1, wherein a predetermined angle is formed between the first rotation axis and the second rotation axis.

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