All-terrain multi-functional four-wheel drive vehicle and control method thereof

Abstract

The application discloses a kind of all-terrain multifunctional four-wheel drive vehicle and its control method, four-wheel drive vehicle includes car body, electric control system, hydraulic drive system and four sets of steering execution mechanism, the hydraulic motor of driving wheel steering, hydraulic drive system includes hydraulic pump, several connection hydraulic pump export and with each hydraulic motor and hydraulic cylinder adaptation electromagnetic proportional reversing valve;Hydraulic drive system is selectively provided with hydraulic power to the hydraulic motor and hydraulic cylinder in each steering execution mechanism by each electromagnetic proportional reversing valve;Electric control system acquires hydraulic cylinder displacement signal and hydraulic motor speed signal, controls the opening of each electromagnetic proportional reversing valve connected with hydraulic cylinder and hydraulic motor, to cooperatively adjust the steering speed and angle of wheel, the application is by setting four-wheel independent driving mode and steering mode, flexibly controls the steering and travel of four-wheel drive vehicle. Through electric control system and wireless signal receiving system, realize the remote operation of vehicle intelligentization, automation.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of vehicle engineering, in particular to a full-terrain multifunctional four-wheel drive vehicle and a control method thereof. BACKGROUND

[0002] Compared with ordinary vehicles, four-wheel drive vehicles have the advantages of fast starting, high safety, good maneuverability, good cornering performance, strong off-road performance, etc. In engineering vehicle application scenarios that require better traction and higher passability, four-wheel drive vehicles are often used.

[0003] Traditional four-wheel drive vehicle control methods are mostly realized by sophisticated mechanical structures, and the degree of automation and intelligence is not high, and precise and reliable sensing devices are less used. The Chinese patent application with publication number CN111483522A discloses a new type of mine heavy four-wheel drive vehicle and a control method thereof. The vehicle uses a pulling oil cylinder to rotate the vehicle body for turning, the angle of the front wheels relative to the front frame remains unchanged, the angle of the rear wheels relative to the rear frame remains unchanged, and the whole vehicle power distribution principle is used for walking control, thereby improving the stability of vehicle operation. However, the turning mode of the oil cylinder driving the vehicle body used by the device has high requirements for the strength of the oil cylinder and the vehicle body, and the unreasonable stress causes large wear of the wheels.

[0004] In addition, the existing engineering four-wheel drive vehicles have low degree of automation and intelligence, weak terrain adaptability, and fewer functions, and cannot solve the problems of narrow space and complex working conditions in mines and mine shafts. SUMMARY

[0005] In view of the above technical deficiencies, the purpose of the present application is to provide a full-terrain multifunctional four-wheel drive vehicle and a control method thereof, which flexibly controls the steering and driving of the four-wheel drive vehicle by setting four-wheel independent driving mode and steering mode. Through the electric control system and the wireless signal receiving system, remote operation of the vehicle is realized.

[0006] To solve the above technical problems, the present application adopts the following technical solutions:

[0007] The present application provides a full-terrain multifunctional four-wheel drive vehicle, which comprises a vehicle body, an electric control system, a hydraulic drive system and four sets of steering execution mechanisms. The steering execution mechanism comprises a rotating pin rotatably connected with the vehicle body, a driving shaft assembly installed on the rotating pin, a wheel installed at the end of the driving shaft assembly, and a hydraulic motor driving the wheel to rotate.

[0008] The steering execution mechanism further comprises a jack rod hingedly connected to the vehicle body at the middle part. One end of the jack rod is matched with a pin shaft on the piston rod of the hydraulic cylinder through a sliding groove to form a slidable and rotatable connecting mechanism. The other end of the jack rod is hingedly connected to the hydraulic motor shell through a connecting rod.

[0009] The hydraulic drive system comprises a hydraulic pump, a plurality of electromagnetic proportional directional valves connected to the outlet of the hydraulic pump and matched with each hydraulic motor and hydraulic cylinder; the hydraulic drive system selectively provides hydraulic power to the hydraulic motor and hydraulic cylinder in each steering actuator through each electromagnetic proportional directional valve;

[0010] The electric control system comprises a main controller, a cylinder displacement sensor for collecting the displacement signal of the hydraulic cylinder in real time and an encoder for collecting the rotation speed information of the hydraulic motor in real time; the cylinder displacement sensor transmits the collected information to the main controller, and outputs the steering angle of the wheel based on the preset correspondence between the cylinder displacement and the wheel rotation angle; the main controller controls the opening degree of each electromagnetic proportional directional valve connected with the hydraulic cylinder, thereby cooperatively adjusting the steering speed and angle of the wheel.

[0011] Preferably, a wireless signal receiving system is further included, which is used to establish a wireless communication connection with an external control device and transmit the received control instruction to the electric control system; the electric control system controls the hydraulic motor and hydraulic cylinder to work through each electromagnetic proportional directional valve based on the control instruction.

[0012] Preferably, the hydraulic drive system further comprises an overflow valve arranged at the outlet of the hydraulic pump and a filter arranged at the inlet of the hydraulic pump, and an air filter, a thermometer and a temperature liquid level sensor are further arranged on the oil tank; a air cooler is further arranged between the electromagnetic proportional directional valve of the hydraulic motor and the oil tank.

[0013] Preferably, a brake actuator is further included, which comprises a front wheel brake electromagnetic valve and a rear wheel brake electromagnetic valve independently controlled by the electric control system; the front wheel brake electromagnetic valve is connected with two hydraulic motors matched with the front wheels of the four-wheel drive vehicle, and the rear wheel brake electromagnetic valve is connected with two hydraulic motors matched with the rear wheels of the four-wheel drive vehicle; the brake electromagnetic valve controls the hydraulic motor brake to brake the vehicle.

[0014] Preferably, a sensing unit is further included, which comprises a laser ranging sensor for detecting distance information and an ultrasonic ranging radar; the laser ranging sensor is arranged at the head and tail of the vehicle body, and the ultrasonic ranging radar is symmetrically arranged on both sides of the vehicle body.

[0015] The application further provides a control method of the all-terrain multifunctional four-wheel drive vehicle, comprising:

[0016] Steering control: the electric control system controls the opening degree of the electromagnetic proportional directional valve connected with the hydraulic cylinder in response to the steering instruction, and drives the hydraulic cylinder to extend and retract; the hydraulic cylinder pushes the rocker to rotate, drives the hydraulic motor housing to deflect through the connecting rod, and makes the wheel rotate around the rotating pin to steer;

[0017] The displacement signal of the hydraulic cylinder is collected by the cylinder displacement sensor in real time and converted into the steering angle of the wheel by the main controller; the steering speed of the wheel is controlled by adjusting the opening of the electromagnetic proportional directional valve matched with the hydraulic cylinder;

[0018] Drive control: the electronic control system responds to the drive instruction to control the opening of the electromagnetic proportional directional valve connected to the hydraulic motor, thereby controlling the rotation of the drive wheel; the rotation speed signal of the hydraulic motor is collected by the encoder, and the main controller performs closed-loop speed regulation;

[0019] Multi-mode execution: based on the driving mode instruction selection execution, specifically including:

[0020] Normal mode: only control the steering of the front wheel steering actuator;

[0021] Quick turn mode: control the steering actuator of the four wheels to turn together, reducing the turning radius;

[0022] Self-turning mode: control the same side front and rear two wheels to rotate in opposite directions to realize zero-radius turning;

[0023] Brake control: through the vehicle state, independently control the action sequence and time length of the front wheel brake electromagnetic valve and the rear wheel brake electromagnetic valve.

[0024] Preferably, according to the adjustable characteristics of the steering and rotation speed of each wheel, when turning, the wheels inside the turn and the wheels outside the turn have the same rotation center, which is on the center line of the front and rear two rows of wheels, and the front or rear end of the wheel forms an angle with the vertical direction of the vehicle body, the turning angle of the wheels inside the turn is θ, the turning angle of the wheels outside the turn is φ, the vehicle body axis moment and the wheel track are L and W respectively, and θ and φ satisfy ; At this time, the ratio of the rotation speed of the wheels inside the turn to the wheels outside the turn is the same as the ratio of the corresponding turning radius.

[0025] Preferably, the ratio of the rotation speed of the wheels inside the turn to the rotation speed of the wheels outside the turn is equal to the ratio of the turning radius of the two.

[0026] Preferably, the wireless signal receiving system can transmit signals with the remote controller and the ground centralized control center, the control instruction of the remote controller has higher priority than the ground centralized control center, when the remote controller and the ground centralized control center send instructions at the same time, the remote controller instruction is executed first; the remote server can only take control when the remote controller is not connected.

[0027] Preferably, the four-wheel drive vehicle has front drive, rear drive, and all-wheel drive driving modes in normal mode and quick turn mode, and can select the corresponding driving mode according to the road conditions and needs, and the brakes of the four-wheel drive vehicle can realize anti-lock braking through the controller, and on the downhill section, the rear brakes are used first, and then the front brakes are used, to prevent the vehicle from overturning due to excessive speed.

[0028] The present application has the advantages of:

[0029] (1) By setting a wireless signal receiving system, the four-wheel drive vehicle can be monitored and operated by a remote controller and a remote control center.

[0030] (2) The steering and driving of the four-wheel drive vehicle are independently controllable, and the four-wheel drive vehicle can be turned sharply and rotated in place, which is suitable for more narrow and complex working requirements. The braking of the four-wheel drive vehicle is controlled according to the sensor detection of the vehicle body condition, and the sequence and time of the front braking and rear braking are controlled to prevent the brake from locking and the external force from uncontrolled load deviation.

[0031] (3) When the wheels turn, the corner θ of the inner measuring wheel of the turn and the corner φ of the outer wheel of the turn have a certain numerical relationship, and the ratio of the rotation speed of the inner measuring wheel of the turn to the rotation speed of the outer wheel of the turn is equal to the ratio of the turn radii of the two. When turning, the stress of the wheel is more reasonable, and it is not easy to slip, and the safety is higher. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0033] Figure 1 A structural schematic diagram of a full-terrain multifunctional four-wheel drive vehicle provided by the embodiment of the present application;

[0034] Figure 2 A flowchart of a vehicle control method provided by the embodiment of the present application.

[0035] Figure 3 A hydraulic principle diagram of a hydraulic drive system of the present application;

[0036] Figure 4 A turning schematic diagram in normal mode of the present application (taking left turn as an example);

[0037] Figure 5 A turning schematic diagram in sharp turning mode of the present application (taking left turn as an example);

[0038] Figure 6 A self-rotation schematic diagram in self-rotation mode of the present application (taking clockwise self-rotation as an example).

[0039] Explanation of reference signs:

[0040] 1, body; 2, wireless signal receiving system; 3, electric control system; 4, hydraulic drive system; 5, rotating pin; 6, drive shaft assembly; 7, hydraulic motor; 8, wheel; 9, connecting rod; 10, rocker; 11, hydraulic cylinder; 12, hydraulic cylinder displacement signal channel; 13, hydraulic motor rotating speed signal channel; 4-1, oil tank; 4-2, filter; 4-3, overflow valve; 4-4, motor; 4-5, hydraulic pump; 4-6, right rear motor electromagnetic proportional directional valve; 4-7, left rear motor electromagnetic proportional directional valve; 4-8, right front motor electromagnetic proportional directional valve; 4-9, left front motor electromagnetic proportional directional valve; 4-10, hydraulic motor brake; 4-11, rear wheel brake electromagnetic valve; 4-12, front wheel brake electromagnetic valve; 4-13 left front oil cylinder electromagnetic proportional directional valve; 4-14, right front oil cylinder electromagnetic proportional directional valve; 4-15, left rear oil cylinder electromagnetic proportional directional valve; 4-16, right rear oil cylinder electromagnetic proportional directional valve; 4-17, air cooler; 4-18, temperature liquid level sensor; 4-19, thermometer; 4-20, air cleaner; 7-1, left front hydraulic motor; 7-2, right front hydraulic motor; 7-3, left rear hydraulic motor; 7-4, right rear hydraulic motor; 11-1, left front steering oil cylinder; 11-2, right front steering oil cylinder; 11-3, left rear steering oil cylinder; 11-4, right rear steering oil cylinder. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0042] As shown in Figure 1 , Figure 3 , the present embodiment provides an all-terrain multifunctional four-wheel drive vehicle, comprising a body 1, an electric control system 3, a hydraulic drive system 4 and four sets of steering execution mechanisms. The steering execution mechanism comprises a rotating pin 5 rotatably connected with the body 1, a drive shaft assembly 6 installed on the rotating pin 5, a wheel 8 installed at the end of the drive shaft assembly 6, and a hydraulic motor 7 driving the wheel 8 to rotate.

[0043] The steering execution mechanism further comprises a rocker 10 hingedly connected to the body 1 at the middle part. One end of the rocker 10 is matched with a pin shaft on a piston rod of a hydraulic cylinder 11 through a sliding groove to form a slidable and rotatable connecting mechanism. The other end of the rocker 10 is hingedly connected to a housing of the hydraulic motor 7 through a connecting rod 9.

[0044] Referring to Figure 3The hydraulic drive system 4 comprises a hydraulic pump 4-5, a plurality of electromagnetic proportional directional valves connected to the outlet of the hydraulic pump 4-5 and matched with each hydraulic motor 7 and hydraulic cylinder 11; the hydraulic drive system 4 selectively provides hydraulic power to the hydraulic motor 7 and hydraulic cylinder 11 in each steering actuator through each electromagnetic proportional directional valve; the hydraulic pump 4-5 is matched with a motor 4-4;

[0045] The four hydraulic motors 7 are respectively a left front hydraulic motor 7-1, a right front hydraulic motor 7-2, a left rear hydraulic motor 7-3 and a right rear hydraulic motor 7-4.

[0046] The four hydraulic motors 7 correspond to four electromagnetic proportional directional valves, which are respectively a right rear motor electromagnetic proportional directional valve 4-6, a left rear motor electromagnetic proportional directional valve 4-7, a right front motor electromagnetic proportional directional valve 4-8 and a left front motor electromagnetic proportional directional valve 4-9.

[0047] The four hydraulic cylinders 11 are respectively a left front steering oil cylinder 11-1, a right front steering oil cylinder 11-2, a left rear steering oil cylinder 11-3 and a right rear steering oil cylinder 11-4.

[0048] The four hydraulic cylinders 11 correspond to four electromagnetic proportional directional valves, which are respectively a left front oil cylinder electromagnetic proportional directional valve 4-13, a right front oil cylinder electromagnetic proportional directional valve 4-14, a left rear oil cylinder electromagnetic proportional directional valve 4-15 and a right rear oil cylinder electromagnetic proportional directional valve 4-16.

[0049] The electronic control system 3 comprises a main controller, an oil cylinder displacement sensor for collecting displacement signals of the hydraulic cylinder 11 in real time, and an encoder for collecting rotation speed information of the hydraulic motor 7 in real time; the oil cylinder displacement sensor transmits the collected information to the main controller through a hydraulic cylinder displacement signal channel 12, and outputs the steering angle of the wheel 8 based on a preset correspondence between the oil cylinder displacement and the wheel rotation angle; the encoder transmits the hydraulic motor rotation speed information to the electronic control system 3 through a hydraulic motor rotation speed signal channel 13; the main controller controls the opening degree of each electromagnetic proportional directional valve connected to the hydraulic cylinder 11, thereby cooperatively adjusting the steering speed and angle of the wheel 8.

[0050] In this embodiment, the four-wheel drive vehicle further comprises a wireless signal receiving system 2, which is used to establish a wireless communication connection with an external control device and transmit the received control instructions to the electronic control system 3; the electronic control system 3 controls the hydraulic motor 7 and hydraulic cylinder 11 to work through each electromagnetic proportional directional valve based on the control instructions.

[0051] The hydraulic drive system 4 further comprises an overflow valve 4-3 arranged at the outlet of the hydraulic pump 4-5 and a filter 4-2 arranged at the inlet of the hydraulic pump 4-5, and the oil tank 4-1 is further provided with an air filter 4-20, a thermometer 4-19 and a temperature liquid level sensor 4-18; a fan cooler 4-17 is further arranged between the electromagnetic proportional reversing valve of the hydraulic motor 7 and the oil tank 4-1.

[0052] In the embodiment, the four-wheel drive vehicle further comprises a brake actuating mechanism, the brake actuating mechanism comprises a front wheel brake electromagnetic valve 4-12 and a rear wheel brake electromagnetic valve 4-11 independently controlled by the electronic control system 3, the front wheel brake electromagnetic valve 4-12 is connected to two hydraulic motors 7 adapted to the front wheels of the four-wheel drive vehicle, and the rear wheel brake electromagnetic valve 4-11 is connected to two hydraulic motors 7 adapted to the rear wheels of the four-wheel drive vehicle; the brake electromagnetic valve controls the brake operation of the vehicle through the hydraulic motor brake 4-10.

[0053] In the embodiment, the four-wheel drive vehicle further comprises a sensing unit, the sensing unit comprises a laser ranging sensor and an ultrasonic ranging radar for detecting distance information, the laser ranging sensor is arranged at the head and tail of the vehicle body 1, and the ultrasonic ranging radar is symmetrically arranged on both sides of the vehicle body 1.

[0054] Referring to Figures 4-6 , the embodiment of the present application further provides a control method of the all-terrain multifunctional four-wheel drive vehicle, comprising:

[0055] Steering control: the electronic control system 3 controls the opening degree of the electromagnetic proportional reversing valve connected to the hydraulic cylinder 11 in response to the steering instruction, and drives the hydraulic cylinder 11 to extend or retract; the hydraulic cylinder 11 drives the rocker 10 to rotate, and drives the hydraulic motor 7 shell to deflect through the connecting rod 9, so that the wheel 8 rotates around the rotating pin 5;

[0056] The displacement signal of the hydraulic cylinder 11 is collected in real time by the cylinder displacement sensor, and the wheel steering angle is converted by the main controller; the opening degree of the electromagnetic proportional reversing valve adapted to the hydraulic cylinder 11 is adjusted, so as to control the steering speed of the wheel 8;

[0057] Drive control: the electronic control system 3 controls the opening degree of the electromagnetic proportional reversing valve connected to the hydraulic motor 7 in response to the drive instruction, so as to control the rotation of the drive wheel 8; the rotation speed signal of the hydraulic motor 7 is collected by the encoder, and the main controller is used for closed-loop speed regulation;

[0058] Multi-mode execution: based on the driving mode instruction selection execution, specifically comprising:

[0059] Normal mode: only control the steering of the steering actuating mechanism of the front wheel 8;

[0060] Quick turn mode: control the steering actuating mechanism of the four wheels 8 to turn together, so as to reduce the turning radius;

[0061] Rotation mode: control the same side of the front and rear wheels 8 reverse rotation to achieve zero radius steering;

[0062] Brake control: through the vehicle state, independent control of front wheel brake solenoid valve 4-12 and rear wheel brake solenoid valve 4-11 action sequence and time.

[0063] According to the steering and adjustable speed characteristics of each wheel 8, when turning, the inner turning wheel 8 and the outer turning wheel 8 have the same rotation center, which is on the center line of the front and rear wheels 8, and the front or rear wheel 8 is oriented at an angle to the vertical direction of the vehicle body 1, the turning angle of the inner turning wheel 8 is θ, the turning angle of the outer turning wheel 8 is φ, the axis moment and the wheel track of the vehicle body 1 are L and W respectively, and θ and φ satisfy ; At this time, the speed ratio of the inner turning wheel 8 and the outer turning wheel 8 is the same as the corresponding turning radius ratio.

[0064] The speed ratio of the inner turning wheel 8 and the outer turning wheel 8 is equal to the turning radius ratio of the two.

[0065] The wireless signal receiving system 2 can transmit signals with the remote controller and the ground control center, and the control instruction of the remote controller has higher priority than that of the ground control center. When the remote controller and the ground control center send instructions at the same time, the remote controller instruction is executed first. The remote server can only take control when the remote controller is not connected.

[0066] The four-wheel drive vehicle has front drive, rear drive and all-wheel drive driving modes in normal mode and rapid rotation mode, and can select the corresponding driving mode according to the road conditions and requirements. The brakes of the four-wheel drive vehicle can realize anti-lock braking through the controller. On the downhill section, the rear brake is used first, and then the front brake is used to prevent the vehicle from overturning due to excessive speed.

[0067] Referring to Figure 2After starting the vehicle, the remote control and remote server connection are automatically performed. If the connection fails, the vehicle cannot be started. If the connection is successful, any mode will be judged whether the remote control is controlled. If the remote control is operated, the remote server can only monitor the operation state of the four-wheel drive vehicle and cannot control it. If the remote server is operated, it can interact with the wireless base station and automatically drive. Then, the mode selection is performed. In the normal mode, only the front wheels can be operated when turning, which is in line with the normal driving habit. In the sharp turning mode, the turning will be linked with the four wheels to reduce the turning radius. In the self-turning mode, the four-wheel drive vehicle can rotate around the center. In the normal mode and the sharp turning mode, the drive mode can be selected to adapt to more road conditions and work requirements. When braking, the electric control system 3 can analyze the state of the four-wheel drive vehicle through various sensors to control the sequence and time of the rear wheel brake electromagnetic valve 4-11 and the front wheel brake electromagnetic valve 4-12, preventing the vehicle from losing control due to locking and force bias.

[0068] To adapt to various terrains and make the four-wheel drive vehicle have stronger grip, when the four-wheel drive vehicle turns, the corner θ of the inner turning wheel and the corner φ of the outer turning wheel satisfy That is, the size of one angle can be calculated according to the size of the other angle. The ratio of the speed of the inner turning wheel to the speed of the outer turning wheel is equal to the ratio of the turning radii of the two.

[0069] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. An all-terrain multi-functional four-wheel drive vehicle, comprising a body (1), an electronic control system (3), a hydraulic drive system (4), and four sets of steering actuators, characterized in that: The steering actuator includes a rotating pin (5) rotatably connected to the vehicle body (1), a drive shaft assembly (6) mounted on the rotating pin (5), a wheel (8) mounted at the end of the drive shaft assembly (6), and a hydraulic motor (7) that drives the wheel (8) to rotate. The steering actuator also includes a rocker arm (10) hinged in the middle to the vehicle body (1). One end of the rocker arm (10) is engaged with the pin on the piston rod of the hydraulic cylinder (11) through a sliding groove to form a sliding and rotatable connection mechanism. The other end of the rocker arm (10) is hinged to the housing of the hydraulic motor (7) through a connecting rod (9). The hydraulic drive system (4) includes a hydraulic pump (4-5) and a plurality of electromagnetic proportional directional valves connected to the outlet of the hydraulic pump (4-5) and adapted to each hydraulic motor (7) and hydraulic cylinder (11); the hydraulic drive system (4) selectively provides hydraulic power to the hydraulic motor (7) and hydraulic cylinder (11) in each steering actuator through each electromagnetic proportional directional valve. The electronic control system (3) includes a main controller, a cylinder displacement sensor that collects the displacement signal of the hydraulic cylinder (11) in real time, and an encoder that collects the speed information of the hydraulic motor (7) in real time. The cylinder displacement sensor transmits the collected information to the main controller and outputs the steering angle of the wheel (8) based on the preset correspondence between the cylinder displacement and the wheel angle. The main controller controls the opening of each electromagnetic proportional directional valve connected to the hydraulic cylinder (11) to coordinate and adjust the steering speed and angle of the wheel (8). Based on the adjustable steering and speed characteristics of each wheel (8), when turning, the inner wheel (8) and the outer wheel (8) have the same center of rotation, which is located on the center line of the front and rear rows of wheels (8). The orientation of the front or rear wheel (8) forms an angle of different size with the vertical direction of the vehicle body (1). The turning angle of the inner wheel (8) is θ, and the turning angle of the outer wheel (8) is φ. The axle length and track width of the vehicle body (1) are L and W, respectively, and θ and φ satisfy... At this time, the ratio of the rotational speed of the inner wheel (8) to that of the outer wheel (8) is the same as the corresponding turning radius.

2. The all-terrain multi-functional four-wheel drive vehicle according to claim 1, characterized in that: It also includes a wireless signal receiving system (2), which is used to establish a wireless communication connection with an external control device and transmit the received control commands to the electronic control system (3); the electronic control system (3) controls the hydraulic motor (7) and hydraulic cylinder (11) to work through each electromagnetic proportional directional valve based on the control commands.

3. The all-terrain multi-functional four-wheel drive vehicle according to claim 1, characterized in that: The hydraulic drive system (4) also includes an overflow valve (4-3) located at the outlet of the hydraulic pump (4-5) and a filter (4-2) located at the inlet of the hydraulic pump (4-5). An air filter (4-20), a thermometer (4-19), and a temperature and liquid level sensor (4-18) are also provided on the oil tank (4-1). An air cooler (4-17) is also provided between the electromagnetic proportional directional valve of the hydraulic motor (7) and the oil tank (4-1).

4. The all-terrain multi-functional four-wheel drive vehicle according to claim 2, characterized in that: It also includes a braking actuator, which includes a front wheel brake solenoid valve (4-12) and a rear wheel brake solenoid valve (4-11) independently controlled by the electronic control system (3). The front wheel brake solenoid valve (4-12) is connected to two hydraulic motors (7) adapted to the front wheels of the four-wheel drive vehicle, and the rear wheel brake solenoid valve (4-11) is connected to two hydraulic motors (7) adapted to the rear wheels of the four-wheel drive vehicle. The brake solenoid valve performs braking operation on the vehicle by controlling the hydraulic motor brake (4-10).

5. The all-terrain multi-functional four-wheel drive vehicle according to claim 1, characterized in that: It also includes a sensing unit, which includes a laser ranging sensor and an ultrasonic ranging radar for detecting distance information. The laser ranging sensor is arranged at the head and tail of the vehicle body (1), and the ultrasonic ranging radar is symmetrically arranged on both sides of the vehicle body (1).

6. A control method for an all-terrain multi-functional four-wheel drive vehicle according to claim 5, characterized in that, include: Steering control: The electronic control system (3) responds to the steering command, controls the opening of the electromagnetic proportional directional valve connected to the hydraulic cylinder (11), and drives the hydraulic cylinder (11) to extend and retract; the hydraulic cylinder (11) pushes the rocker arm (10) to rotate, and drives the housing of the hydraulic motor (7) to deflect via the connecting rod (9), so that the wheel (8) turns around the rotating pin (5); The displacement signal of the hydraulic cylinder (11) is collected in real time by the hydraulic cylinder displacement sensor and converted into the wheel steering angle by the main controller; the steering speed of the wheel (8) is controlled by adjusting the opening of the electromagnetic proportional directional valve adapted to the hydraulic cylinder (11). Drive control: The electronic control system (3) responds to the drive command and controls the opening of the electromagnetic proportional directional valve connected to the hydraulic motor (7) to control the rotation of the drive wheel (8); the speed signal of the hydraulic motor (7) is collected by the encoder and the main controller performs closed-loop speed regulation; Multi-mode execution: Execution is based on driving mode command selection, specifically including: Normal mode: Only the steering actuators of the front wheels (8) are controlled to steer; Sharp turn mode: The steering actuators of the four wheels (8) are controlled to steer in unison, reducing the turning radius; Self-rotation mode: Control the front and rear wheels on the same side to rotate in opposite directions (8) to achieve zero-radius steering; Braking control: Based on the vehicle status, independently control the action sequence and duration of the front wheel brake solenoid valve (4-12) and the rear wheel brake solenoid valve (4-11).

7. The method according to claim 6, characterized in that: The ratio of the rotational speed of the inner turning wheel (8) to the rotational speed of the outer turning wheel (8) is equal to the ratio of their turning radii.

8. The method according to claim 6, characterized in that: The wireless signal receiving system (2) can transmit signals to the remote controller and the ground control center. The control commands of the remote controller have a higher priority than those of the ground control center. When the remote controller and the ground control center send commands at the same time, the remote controller commands are executed first. The remote server can only take over control when the remote controller is not connected.

9. The method according to claim 6, characterized in that: This four-wheel drive vehicle offers multiple driving modes, including front-wheel drive, rear-wheel drive, and all-wheel drive, in normal and sharp-turn modes. It can select the appropriate driving mode according to road conditions and needs. The vehicle's brakes can achieve anti-lock braking through a controller. On downhill sections, the rear brakes will be activated first, followed by the front brakes, to prevent the vehicle from overturning due to excessive speed.

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