Semitrailer steering angle measuring mechanism and system and semitrailer

Abstract

The invention discloses a semitrailer steering angle measuring mechanism and system and a semitrailer, the measuring mechanism comprises a traction plate assembly, a turntable assembly and an angle sensor, the traction plate assembly is arranged at the lower part of the front end of a semitrailer frame assembly; the rotary disc assembly is arranged on the upper portion of the traction plate assembly and connected with the traction plate assembly and the semitrailer frame assembly, the angle sensor comprises an angle sensor body fixed to the semitrailer frame assembly and an induction magnetic core fixed to the traction plate assembly, and the angle sensor body and the induction magnetic core are coaxially arranged in an up-down opposite mode; the induction magnetic core can rotate along with the traction plate assembly, and the angle sensor body is used for measuring the rotation angle of the induction magnetic core and converting the rotation angle into electric signals to be output. The measuring system comprises the angle measuring mechanism and a semitrailer steering electric control system connected with the angle measuring mechanism. The semitrailer comprises the measuring system. The system has the advantages that the control precision is high, and the signal transmission is fast; the use and maintenance cost is low; the tire abrasion is small.

Description

Technical Field

[0001] This invention relates to the field of semi-trailer steering technology, specifically to a semi-trailer steering angle measuring mechanism, system, and semi-trailer. Background Technology

[0002] Currently, the steering angle measurement mechanisms used in the market for semi-trailers are generally hydraulic systems consisting of a swing arm and a cylinder. These mechanisms typically have the following problems: 1. Hydraulic control systems are complex and require high sealing performance for hydraulic cylinders, valve bodies, etc. Otherwise, the control accuracy will be greatly affected.

[0003] 2. High maintenance and repair costs. After long-term use, it is necessary to regularly check the wear of the shafts (including the swing arm shaft and the cylinder shaft), the deformation of the swing arm, and the internal discharge of the cylinder and valve. Summary of the Invention

[0004] In view of the problems in the background art, the purpose of this invention is to provide a semi-trailer steering angle measuring mechanism, system and semi-trailer to solve the problems in the background art.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, a semi-trailer steering angle measuring mechanism is provided, comprising a tow plate assembly, a turntable assembly, and an angle sensor. The tow plate assembly is rotatably mounted on the lower front end of the semi-trailer frame assembly and is used to connect with a tractor saddle mounted on a tractor. The turntable assembly is mounted on the upper part of the tow plate assembly and is connected to both the tow plate assembly and the semi-trailer frame assembly. The angle sensor includes an angle sensor body fixedly mounted on the semi-trailer frame assembly and an induction magnetic core fixedly mounted on the tow plate assembly, with the angle sensor body and the induction magnetic core being coaxially aligned vertically. The induction magnetic core can rotate with the tow plate assembly, and the angle sensor body is used to measure the rotation angle of the induction magnetic core and convert it into an electrical signal output.

[0006] Furthermore, the semi-trailer frame assembly is also provided with a fixed traction plate, and the fixed traction plate is fixedly connected to the lower front end of the semi-trailer frame assembly. The traction plate assembly is movably inserted inside the fixed traction plate and connected to the turntable assembly.

[0007] Furthermore, the semi-trailer frame assembly is also provided with a turntable mounting flange, which is located on the upper part of the fixed traction plate and is fixedly connected to the semi-trailer frame assembly. The turntable assembly is fixedly installed at the bottom of the turntable mounting flange, and the angle sensor body is fixedly installed at the top of the turntable mounting flange.

[0008] Furthermore, the turntable assembly includes an upper flange ring fixedly connected to the turntable mounting flange and a lower flange ring fixedly connected to the traction plate assembly. The lower end of the upper flange ring and the upper end of the lower flange ring are fitted together. A plurality of steel balls are embedded between the lower end of the upper flange ring and the upper end of the lower flange ring. The upper flange ring and the lower flange ring can rotate relative to each other.

[0009] Furthermore, the traction plate assembly includes a movable traction plate, a traction pin, a traction pin reinforcing beam, and a wedge-shaped limiting block. The movable traction plate is movably inserted inside the fixed traction plate and is fixedly connected to the lower flange ring of the turntable assembly. The traction pin is movably inserted inside the movable traction plate and is fixedly connected to the traction pin reinforcing beam. The traction pin reinforcing beam is fixedly installed on the top of the movable traction plate, and an induction magnetic core is fixedly installed on the top of the traction pin reinforcing beam. The wedge-shaped limiting block is fixedly installed at the bottom of the movable traction plate and is used to engage with a dovetail groove provided at the rear of the tractor saddle.

[0010] Secondly, a semi-trailer steering angle measurement system is provided, including a semi-trailer steering angle measuring mechanism as described in the first aspect and a semi-trailer steering electronic control system electrically connected to an angle sensor in the semi-trailer steering angle measuring mechanism. The semi-trailer steering electronic control system is used to control the wheels of the semi-trailer to steer accordingly based on the electrical signal output by the angle sensor.

[0011] Furthermore, the semi-trailer steering electronic control system includes a steering ECU electrically connected to an angle sensor, a CAN bus and a power module electrically connected to the steering ECU, and a steering actuator electrically connected to the CAN bus.

[0012] Furthermore, the steering actuator includes a servo motor, a hydraulic pump, a hydraulic directional valve, a hydraulic oil tank, and a hydraulic steering cylinder; The servo motor is electrically connected to the steering ECU via a CAN bus. The hydraulic pump is connected to the servo motor via a coupling and to the hydraulic directional valve and hydraulic tank via hydraulic oil pipes. The hydraulic directional valve is connected to the hydraulic steering cylinder and hydraulic tank via hydraulic oil pipes. One end of the hydraulic steering cylinder is hinged to the axle, and the other end is hinged to a wheel located at one end of the axle. The two wheels located at both ends of the axle are connected by a steering linkage.

[0013] Thirdly, a semi-trailer is provided, including the semi-trailer steering angle measurement system of the second aspect.

[0014] Compared with the prior art, the advantages of the present invention are as follows: (1) The measuring mechanism is simple, the control accuracy is high, and the signal transmission is fast; (2) Low usage and maintenance costs; (3) Less tire wear. Attached Figure Description

[0015] Figure 1 This is a top view of a specific embodiment of the semi-trailer steering angle measuring mechanism involved in the present invention; Figure 2 for Figure 1 Sectional view of AA; Figure 3 An exploded view of a specific embodiment of the semi-trailer steering angle measuring mechanism involved in this invention; Figure 4 This is a partial top view of a specific embodiment of a semi-trailer chassis assembly; Figure 5 yes Figure 4 BB section view; Figure 6 This is a schematic diagram of a specific embodiment of the traction plate assembly; Figure 7 This is a cross-sectional schematic diagram of a specific embodiment of the turntable assembly; Figure 8 This is a schematic diagram of a specific embodiment of the semi-trailer steering angle measurement system involved in the present invention; Figure 9 This is a hydraulic schematic diagram of the hydraulic steering cylinder of the steering actuator in the extended state. Figure 10 This is a hydraulic schematic diagram of the hydraulic steering cylinder of the steering actuator in the shortened state. Figure 11 yes Figure 9 A magnified view of a portion of the image; Figure 12 yes Figure 10 A magnified view of a portion of the image; Figure 13 This is a top view of a specific embodiment of the semi-trailer involved in the present invention; Figure 14 yes Figure 13 CC section view; Figure 15 This is a schematic diagram of the connection between a semi-trailer and a tractor unit, as per the present invention. Figure 16 yes Figure 15 A schematic diagram of a medium-sized tractor unit; Figure 17 yes Figure 16 Top view of the tractor's saddle; Explanation of reference numerals in the attached drawings: 1. Towing plate assembly; 2. Turntable assembly; 3. Angle sensor; 301. Angle sensor body; 302. Induction magnetic core; 4. Semi-trailer frame assembly; 5. Fixed towing plate; 6. Turntable mounting flange; 7. Axle; 8. Wheel; 9. Steering linkage; 10. Semi-trailer steering electronic control system; 1001. Steering ECU; 1002. CAN bus; 1003. Steering actuator; 1003a. Servo motor; 1003b. Hydraulic pump; 1003c. Hydraulic directional valve; 1003d. Hydraulic oil tank; 1003e. Hydraulic steering cylinder; 1004. Power module; 11. Tractor; 12. Tractor saddle. Detailed Implementation

[0016] To make the technical means, creative features, objectives and effects of this invention easier to understand, the following description, in conjunction with the accompanying drawings and specific embodiments, further explains how this invention is implemented.

[0017] Example 1: See Figures 1 to 7 This invention provides a semi-trailer steering angle measuring mechanism, including a towing plate assembly 1, a turntable assembly 2, and an angle sensor 3. The towing plate assembly 1 is rotatably mounted on the lower front end of the semi-trailer frame assembly 4 and is connected to a tractor saddle 12 mounted on a tractor 11. The turntable assembly 2 is mounted on the upper part of the towing plate assembly 1 and is connected to both the towing plate assembly 1 and the semi-trailer frame assembly 4. The angle sensor 3 includes an angle sensor body 301 fixedly mounted on the semi-trailer frame assembly 4 and an induction magnetic core 302 fixedly mounted on the towing plate assembly 1, with the angle sensor body 301 and the induction magnetic core 302 coaxially aligned vertically. The induction magnetic core 302 can rotate with the towing plate assembly 1. The angle sensor body 301 measures the rotation angle of the induction magnetic core 302 and converts it into an electrical signal output.

[0018] In practical applications, the semi-trailer steering angle measuring mechanism provided in this embodiment of the invention specifically measures the steering angle of the semi-trailer by measuring the rotation angle of the induction magnetic core 302 through the angle sensor body 301.

[0019] Specifically, in this embodiment of the invention, in practical application, when the tractor 11 turns, the tractor saddle 12 will drive the towing plate assembly 1 to rotate. At this time, the induction magnetic core 302 installed on the towing plate assembly 1 will generate a deflection angle with the angle sensor body 301 installed on the semi-trailer frame assembly 4. This deflection angle is the rotation angle of the induction magnetic core 302, which is also the steering angle of the semi-trailer. This deflection angle will be measured by the angle sensor body 301 and converted into an electrical signal output. Then, the semi-trailer steering electronic control system 10 can analyze the electrical signal output by the angle sensor body 301 to control the wheels 8 of the semi-trailer to make corresponding steering operations, thereby achieving synchronous steering of the tractor 8 and the semi-trailer, reducing the turning radius and the wear of the semi-trailer tires.

[0020] Specifically, in this embodiment of the invention, the angle sensor 3 is preferably a GTE series or GTF series angle sensor from Taizhou Quantum Electronics Technology Co., Ltd.; the angle sensor body 301 specifically consists of an electronic signal sensing chamber and a power signal line connected to the electronic signal sensing chamber; the sensing magnetic core 302 specifically consists of a copper magnetic base and a magnet mounted on the copper magnetic base. In this embodiment of the invention, the working principle and installation method of the angle sensor 3 are detailed in the GTE series or GTF series angle sensors from Taizhou Quantum Electronics Technology Co., Ltd., and will not be repeated here.

[0021] Specifically, in some specific embodiments, see [reference] Figure 2 and Figure 5 The semi-trailer frame assembly 4 is also equipped with a fixed traction plate 5, and the fixed traction plate 5 is fixedly connected to the lower front end of the semi-trailer frame assembly 4. The traction plate assembly 1 is movably inserted inside the fixed traction plate 5 and connected to the turntable assembly 2.

[0022] Specifically, in some specific embodiments, see [reference] Figure 2 and Figure 5 The semi-trailer frame assembly 4 is also equipped with a turntable mounting flange 6, which is located on the upper part of the fixed traction plate 5 and is fixedly connected to the semi-trailer frame assembly 4. The turntable assembly 2 is fixedly installed at the bottom of the turntable mounting flange 6, and the angle sensor body 301 is fixedly installed on the top of the turntable mounting flange 6.

[0023] Specifically, in some specific embodiments, see [reference] Figure 2 and Figure 7The turntable assembly 2 includes an upper flange ring 201 that is fixedly connected to the turntable mounting flange 6 (e.g., by bolting or welding) and a lower flange ring 202 that is fixedly connected to the traction plate assembly 1 (e.g., by bolting or welding). The lower end of the upper flange ring 201 and the upper end of the lower flange ring 202 are fitted together. Several steel balls 203 are embedded between the lower end of the upper flange ring 201 and the upper end of the lower flange ring 202. Under the action of these steel balls 203, the upper flange ring 201 and the lower flange ring 202 can rotate relative to each other.

[0024] Specifically, in some specific embodiments, see [reference] Figure 2 and Figure 6 The traction plate assembly 1 includes a movable traction plate 101, a traction pin 102, a traction pin reinforcing beam 103, and a wedge-shaped limiting block 104. The movable traction plate 101 is movably inserted inside the fixed traction plate 5 and is fixedly connected to the lower flange ring 202 of the turntable assembly 2. The traction pin 102 is movably inserted inside the movable traction plate 101 and is fixedly connected to the traction pin reinforcing beam 103. The traction pin reinforcing beam 103 is fixedly installed on the top of the movable traction plate 101, and an induction magnetic core 302 is fixedly installed on the top of the traction pin reinforcing beam 103. The wedge-shaped limiting block 104 is fixedly installed at the bottom of the movable traction plate 101 and is used to engage with the dovetail groove 1201 provided at the rear of the tractor saddle 12. When the tractor 8 docks with the semi-trailer, the traction pin 102 and the wedge-shaped limiting block 104 are both inserted into the dovetail groove 1201 at the rear of the tractor saddle 12. The wedge-shaped limiting block 104 can limit the traction pin 102 inside the dovetail groove 1201 and prevent the traction pin 102 from rotating with the tractor saddle 12.

[0025] Example 2: This embodiment of the invention provides a semi-trailer steering angle measurement system, including the semi-trailer steering angle measurement mechanism in Example 1 above and a semi-trailer steering electronic control system 10 electrically connected to the angle sensor 3 in the semi-trailer steering angle measurement mechanism in Example 1 above. The semi-trailer steering electronic control system 10 is used to control the wheels 8 of the semi-trailer to turn accordingly based on the electrical signal output by the angle sensor 3.

[0026] Specifically, in some specific embodiments, see [reference] Figure 8 The semi-trailer steering electronic control system 10 includes a steering ECU 1001 electrically connected to the angle sensor 3, a CAN bus 1002 and a power module 1004 electrically connected to the steering ECU 1001, and a steering actuator 1003 electrically connected to the CAN bus 1002.

[0027] More specifically, in some specific embodiments, see [reference] Figures 9 to 12The steering actuator 1003 includes a servo motor 1003a, a hydraulic pump 1003b, a hydraulic directional valve 1003c, a hydraulic oil tank 1003d, and a hydraulic steering cylinder 1003e. The servo motor 1003a is electrically connected to the steering ECU 1001 via a CAN bus 1002. The hydraulic pump 1003b is connected to the servo motor 1003a via a coupling (not shown in the figure) and to the hydraulic directional valve 1003c and the hydraulic oil tank 1003d via hydraulic oil pipes. The hydraulic directional valve 1003c is connected to the hydraulic steering cylinder 1003e and the hydraulic oil tank 1003d via hydraulic oil pipes. One end of the hydraulic steering cylinder 1003e is hinged to the axle 7, and the other end is hinged to a wheel 8 located at one end of the axle 7. The two wheels 8 located at both ends of the axle 7 are connected by a steering linkage 9.

[0028] Figure 9 and Figure 11 The diagram shown is a hydraulic schematic of the hydraulic steering cylinder 1003e in the extended state of the steering actuator 1003. Figure 10 and Figure 12 The diagram shows the hydraulic schematic of the hydraulic steering cylinder 1003e in the steering actuator 1003 in the shortened state. Figures 9 to 12 In the diagram, P and T represent the inlet and outlet ports of the hydraulic directional valve 1003c, respectively; A1 and B1 form a set of working ports, A2 and B2 form a set of working ports, and A3 and B3 form a set of working ports. Each of the three sets of working ports corresponds to a hydraulic steering cylinder 1003e, which is used to control the extension and retraction of the corresponding hydraulic steering cylinder 1003e to achieve steering control of the corresponding wheel 8.

[0029] For example: Figures 9 to 12 The image shows three hydraulic steering cylinders 1003e from left to right. The working ports A1 and B1 of the hydraulic directional valve 1003c are connected to the rodless and rod chambers of the hydraulic steering cylinder 1003e on the left, respectively. The working ports A2 and B2 of the hydraulic directional valve 1003c are connected to the rodless and rod chambers of the hydraulic steering cylinder 1003e in the middle, respectively. The working ports A3 and B3 of the hydraulic directional valve 1003c are connected to the rodless and rod chambers of the hydraulic steering cylinder 1003e on the right. When the three hydraulic steering cylinders 1003e extend, the working ports A1, A2, and A3 of the hydraulic directional valve 1003 will connect with the inlet port P of the hydraulic directional valve 1003, and the working ports B1, B2, and B3 of the hydraulic directional valve 1003 will connect with the return port T of the hydraulic directional valve 1003. (See also...) Figure 9 and Figure 11As shown; at this time, the hydraulic oil in the hydraulic oil tank 1003d will be sequentially delivered to the oil inlet P of the hydraulic directional valve 1003 via the hydraulic pump 1003b, and then delivered to the rodless chambers of the three hydraulic steering cylinders 1003e via the working oil ports A1, A2, and A3 of the hydraulic directional valve 1003, causing the piston rods of the three hydraulic steering cylinders 1003e to extend outward (i.e., the three hydraulic steering cylinders 1003e extend outward); at the same time, the rodless chambers of the three hydraulic steering cylinders 1003e will be connected to the working oil ports B1, B2, and B3 of the hydraulic directional valve 1003, respectively. If there is hydraulic oil in the rodless chambers of the three hydraulic steering cylinders 1003e, it will flow back to the hydraulic directional valve 1003 via the working oil ports B1, B2, and B3 of the hydraulic directional valve 1003, and then be output through the return oil port T of the hydraulic directional valve 1003 and flow back to the hydraulic oil tank 1003d; When the three hydraulic steering cylinders 1003e shorten, the working ports A1, A2, and A3 of the hydraulic directional valve 1003 will connect with the return port T of the hydraulic directional valve 1003, and the working ports B1, B2, and B3 of the hydraulic directional valve 1003 will connect with the inlet port P of the hydraulic directional valve 1003. (See also...) Figure 10 and Figure 12 As shown; at this time, the hydraulic oil in the hydraulic oil tank 1003d will be sequentially delivered to the oil inlet P of the hydraulic directional valve 1003 via the hydraulic pump 1003b, and then delivered to the rod chambers of the three hydraulic steering cylinders 1003e via the working oil ports B1, B2, and B3 of the hydraulic directional valve 1003, causing the piston rods of the three hydraulic steering cylinders 1003e to retract inward (i.e., the three hydraulic steering cylinders 1003e shorten inward); at the same time, the rodless chambers of the three hydraulic steering cylinders 1003e will be connected to the working oil ports A1, A2, and A3 of the hydraulic directional valve 1003, respectively. If there is hydraulic oil in the rodless chambers of the three hydraulic steering cylinders 1003e, it will flow back to the hydraulic directional valve 1003 via the working oil ports A1, A2, and A3 of the hydraulic directional valve 1003, and then be output through the return oil port T of the hydraulic directional valve 1003 and flow back to the hydraulic oil tank 1003d.

[0030] The working principle of the semi-trailer steering angle measurement system provided by this invention is as follows: During operation, the angle sensor 3 first converts the detected steering angle signal into a voltage signal, and then transmits the voltage signal to the steering ECU 1001 in the semi-trailer steering electronic control system 10. The steering ECU 1001 then analyzes the voltage signal and converts it into a command, which is sent to the steering actuator 1003. Subsequently, the steering actuator 1003 controls the number of rotations of the servo motor 1003a to supply hydraulic oil of different flow rates to the hydraulic system (composed of hydraulic pump 1003b, hydraulic directional valve 1003c, hydraulic oil tank 1003d, and hydraulic steering cylinder 1003e), thereby controlling the different strokes of the hydraulic steering cylinder 1003e. Different strokes of the hydraulic steering cylinder 1003e correspond to different steering angles on the wheel 8.

[0031] Example 3: See Figures 11 to 15 This invention provides a semi-trailer, including the semi-trailer steering angle measurement system described in Embodiment 2 above.

[0032] Specifically, the semi-trailer provided in this embodiment of the invention also includes a semi-trailer frame assembly 4 and a running mechanism (composed of axle 7, wheels 8 and air suspension, etc.) disposed below the semi-trailer frame assembly 4.

[0033] Finally, it should be noted that the above description is only an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A semi-trailer steering angle measuring mechanism, characterized in that: The system includes a towing plate assembly (1), a turntable assembly (2), and an angle sensor (3). The towing plate assembly (1) is rotatably mounted on the lower front end of the semi-trailer frame assembly (4) and is used to connect with the tractor saddle (12) mounted on the tractor (11). The turntable assembly (2) is mounted on the upper part of the towing plate assembly (1) and is connected to both the towing plate assembly (1) and the semi-trailer frame assembly (4). The angle sensor (3) includes an angle sensor body (301) fixedly mounted on the semi-trailer frame assembly (4) and an induction magnetic core (302) fixedly mounted on the towing plate assembly (1). The angle sensor body (301) and the induction magnetic core (302) are coaxially aligned and directly opposite each other. The induction magnetic core (302) can rotate with the towing plate assembly (1). The angle sensor body (301) is used to measure the rotation angle of the induction magnetic core (302) and convert it into an electrical signal output.

2. The semi-trailer steering angle measuring mechanism according to claim 1, characterized in that: The semi-trailer frame assembly (4) is also provided with a fixed traction plate (5), and the fixed traction plate (5) is fixedly connected to the lower front end of the semi-trailer frame assembly (4). The traction plate assembly (1) is movably inserted inside the fixed traction plate (5) and connected to the turntable assembly (2).

3. The semi-trailer steering angle measuring mechanism according to claim 2, characterized in that: The semi-trailer frame assembly (4) is also provided with a turntable mounting flange (6), and the turntable mounting flange (6) is located on the upper part of the fixed traction plate (5) and is fixedly connected to the semi-trailer frame assembly (4). The turntable assembly (2) is fixedly installed at the bottom of the turntable mounting flange (6), and the angle sensor body (301) is fixedly installed on the top of the turntable mounting flange (6).

4. The semi-trailer steering angle measuring mechanism according to claim 3, characterized in that: The turntable assembly (2) includes an upper flange ring (201) fixedly connected to the turntable mounting flange (6) and a lower flange ring (202) fixedly connected to the traction plate assembly (1). The lower end of the upper flange ring (201) and the upper end of the lower flange ring (202) are fitted together. A number of steel balls (203) are embedded between the lower end of the upper flange ring (201) and the upper end of the lower flange ring (202). The upper flange ring (201) and the lower flange ring (202) can rotate relative to each other.

5. The semi-trailer steering angle measuring mechanism according to claim 3, characterized in that: The traction plate assembly (1) includes a movable traction plate (101), a traction pin (102), a traction pin reinforcing beam (103), and a wedge-shaped limiting block (104). The movable traction plate (101) is movably inserted inside the fixed traction plate (5) and is fixedly connected to the lower flange ring (202) of the turntable assembly (2). The traction pin (102) is movably inserted inside the movable traction plate (101) and is fixedly connected to the traction pin reinforcing beam (103). The traction pin reinforcing beam (103) is fixedly installed on the top of the movable traction plate (101), and an induction magnetic core (302) is fixedly installed on the top of the traction pin reinforcing beam (103). The wedge-shaped limiting block (104) is fixedly installed at the bottom of the movable traction plate (101) and is used to engage with the dovetail groove (1201) provided at the rear of the tractor saddle (12).

6. A semi-trailer steering angle measurement system, characterized in that: The semi-trailer includes a semi-trailer steering angle measuring mechanism as described in any one of claims 1-5 and a semi-trailer steering electronic control system (10) electrically connected to the angle sensor (3) in the semi-trailer steering angle measuring mechanism. The semi-trailer steering electronic control system (10) is used to control the wheels (7) of the semi-trailer to turn accordingly based on the electrical signal output by the angle sensor (3).

7. The semi-trailer steering angle measurement system according to claim 6, characterized in that: The semi-trailer steering electronic control system (10) includes a steering ECU (1001) electrically connected to an angle sensor (3), a CAN bus (1002) electrically connected to the steering ECU (1001), a power module (1004), and a steering actuator (1003) electrically connected to the CAN bus (1002).

8. The semi-trailer steering angle measurement system according to claim 7, characterized in that: The steering actuator (1003) includes a servo motor (1003a), a hydraulic pump (1003b), a hydraulic directional valve (1003c), a hydraulic oil tank (1003d), and a hydraulic steering cylinder (1003e). The servo motor (1003a) is electrically connected to the steering ECU (1001) via the CAN bus (1002). The hydraulic pump (1003b) is connected to the servo motor (1003a) via a coupling and to the hydraulic directional valve (1003c) and the hydraulic oil tank (1003d) via hydraulic oil pipes. The hydraulic directional valve (1003c) is connected to the hydraulic steering cylinder (1003e) and the hydraulic oil tank (1003d) via hydraulic oil pipes. One end of the hydraulic steering cylinder (1003e) is hinged to the axle (7), and the other end is hinged to the wheel (8) located at one end of the axle (7). The two wheels (8) located at both ends of the axle (7) are connected by a steering linkage (9).

9. A semi-trailer, characterized in that: The system includes the semi-trailer steering angle measurement system according to any one of claims 6 to 8.

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