All-terrain multifunctional four-wheel-drive vehicle and control method thereof

Abstract

The invention discloses an all-terrain multifunctional four-wheel-drive vehicle and a control method thereof. The four-wheel-drive vehicle comprises a vehicle body, an electric control system, a hydraulic driving system, four sets of steering executing mechanisms and a hydraulic motor for driving wheels to steer. The hydraulic driving system comprises a hydraulic pump and a plurality of electromagnetic proportional directional valves which are connected with an outlet of the hydraulic pump and are matched with the hydraulic motors and the hydraulic cylinders; the hydraulic driving system selectively provides hydraulic power for hydraulic motors and hydraulic cylinders in all the steering executing mechanisms through all the electromagnetic proportional reversing valves. The electric control system collects displacement signals of the hydraulic cylinders and rotating speed signals of the hydraulic motors and controls the opening degrees of the electromagnetic proportional reversing valves connected with the hydraulic cylinders and the hydraulic motors, so that the steering speed and angle of the wheels are cooperatively adjusted, and steering and running of the four-wheel-drive vehicle are flexibly controlled by setting a four-wheel independent driving mode and a four-wheel independent steering mode. Intelligent and automatic remote operation of the vehicle is achieved through an electric control system and a wireless signal receiving system.

Description

Technical Field

[0001] The present invention relates to the field of vehicle engineering, and in particular to an all-terrain multifunctional four-wheel drive vehicle and a control method thereof. Background Art

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

[0003] Traditional four-wheel-drive vehicle control methods mostly rely on sophisticated mechanical structures, with low levels of automation and intelligence, and limited use of precise and reliable sensing equipment. A Chinese patent application with publication number CN111483522A discloses a new heavy-duty four-wheel-drive mining vehicle and its control method. The vehicle uses a tension cylinder to rotate the vehicle body to turn. The angle of the front wheels relative to the front frame remains unchanged, and the angle of the rear wheels relative to the rear frame remains unchanged. Travel control is based on the principle of vehicle power distribution, improving vehicle stability. However, the cylinder-driven turning method used in this device places high demands on the strength of the cylinder and vehicle body, and unreasonable force application causes significant wear on the wheels.

[0004] In addition, the existing engineering four-wheel drive vehicles have low levels of automation and intelligence, weak terrain adaptability, and few functions, and are unable to solve the problems of narrow space and complex working conditions faced in mines, mine shafts and other projects. Summary of the Invention

[0005] In response to the aforementioned technical deficiencies, the present invention aims to provide an all-terrain multifunctional four-wheel drive vehicle and a control method thereof. By setting independent drive modes and steering modes for each of the four wheels, the vehicle's steering and travel can be flexibly controlled. Intelligent and automated remote control of the vehicle is achieved through an electronic control system and a wireless signal receiving system.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions: The present invention provides an all-terrain multifunctional four-wheel drive vehicle, comprising a vehicle body, an electronic control system, a hydraulic drive system, and four sets of steering actuators, wherein the steering actuators comprise a rotating pin rotatably connected to the vehicle body, a drive shaft assembly mounted on the rotating pin, wheels mounted on the ends of the drive shaft assembly, and a hydraulic motor for driving the wheels to rotate; The steering actuator also includes a tilting lever hinged to the vehicle body at the middle, one end of the tilting lever cooperates with a pin on the hydraulic cylinder piston rod through a sliding groove to form a slidable and rotatable connection mechanism; the other end of the tilting lever is hinged to the hydraulic motor housing through a connecting rod; The hydraulic drive system includes a hydraulic pump, a plurality of electromagnetic proportional reversing valves connected to the hydraulic pump outlet and adapted to 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 reversing valve; The electronic control system includes a main controller, a cylinder displacement sensor that collects hydraulic cylinder displacement signals in real time, and an encoder that collects hydraulic motor speed information 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 a preset correspondence between cylinder displacement and wheel angle. The main controller controls the opening of each electromagnetic proportional reversing valve connected to the hydraulic cylinder, thereby collaboratively adjusting the steering speed and angle of the wheel.

[0007] Preferably, it also includes a wireless signal receiving system, 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; the electronic control system controls the operation of the hydraulic motor and hydraulic cylinder through each electromagnetic proportional reversing valve based on the control instructions.

[0008] Preferably, the hydraulic drive system also includes a relief valve provided at the hydraulic pump outlet and a filter provided at the hydraulic pump inlet, and the oil tank is also provided with an air filter, a thermometer and a temperature level sensor; an air cooler is also provided between the electromagnetic proportional reversing valve of the hydraulic motor and the oil tank.

[0009] Preferably, it also includes a brake actuator, which includes a front wheel brake solenoid valve and a rear wheel brake solenoid valve independently controlled by the electronic control system, the front wheel brake solenoid valve is connected to two hydraulic motors adapted for the front wheels of the four-wheel drive vehicle, and the rear wheel brake solenoid valve is connected to two hydraulic motors adapted for the rear wheels of the four-wheel drive vehicle; the brake solenoid valve performs a braking operation on the vehicle by controlling the hydraulic motor brake.

[0010] Preferably, 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, and the ultrasonic ranging radar is symmetrically arranged on both sides of the vehicle body.

[0011] The present invention also provides a control method for the all-terrain multi-functional four-wheel drive vehicle, comprising: Steering control: The electronic control system responds to steering commands, controls the opening of the electromagnetic proportional reversing valve connected to the hydraulic cylinder, and drives the hydraulic cylinder to extend and retract. The hydraulic cylinder drives the tilting rod to rotate, which drives the hydraulic motor housing to deflect through the connecting rod, causing the wheel to turn around the rotating pin. The hydraulic cylinder displacement sensor collects the hydraulic cylinder displacement signal in real time and converts it into the wheel steering angle by the main controller. The steering speed of the wheel is controlled by adjusting the opening of the electromagnetic proportional reversing valve adapted to the hydraulic cylinder. Drive control: The electronic control system responds to drive commands, controls the opening of the electromagnetic proportional reversing valve connected to the hydraulic motor, and thus controls the rotation of the drive wheels. The speed signal of the hydraulic motor is collected through an encoder, and the main controller performs closed-loop speed regulation. Multi-mode execution: Execution is selected based on driving mode commands, including: Normal mode: Only the steering actuators of the front wheels are controlled; Sharp turn mode: controls the steering actuators of the four wheels to steer in conjunction to reduce the turning radius; Rotation mode: Control the front and rear wheels on the same side to rotate in opposite directions to achieve zero-radius steering; Braking control: Based on the vehicle status, the action sequence and duration of the front wheel brake solenoid valve and the rear wheel brake solenoid valve are independently controlled.

[0012] Preferably, according to the characteristics of each wheel's adjustable steering and speed, when turning, the wheel on the inside of the turn and the wheel on the outside have the same rotation center, and the rotation center is on the center line of the front and rear rows of wheels. The direction of the front or rear wheel forms an angle of different sizes with the vertical direction of the vehicle body. The turning angle of the wheel on the inside of the turn is θ, and the turning angle of the wheel on the outside of the turn is φ. The vehicle body axle moment and wheelbase are L and W respectively, and θ and φ satisfy At this time, the ratio of the rotational speeds of the wheel on the inside of the turn to the wheel on the outside is the same as the ratio of the corresponding turning radius.

[0013] Preferably, the ratio of the rotational speed of the inner wheel of the turn to the rotational speed of the outer wheel of the turn is equal to the ratio of the turning radius of the two, that is, or , L1 is the turning radius of the inner steering wheel, and L2 is the turning radius of the outer steering wheel.

[0014] Preferably, the wireless signal receiving system can transmit signals to and from the remote control and the ground control center. The control instructions of the remote control have a higher priority than those of the ground control center. When the remote control and the ground control center send instructions at the same time, the remote control instructions are executed first. The remote server can only take over control when the remote control is not connected. Preferably, the four-wheel drive vehicle has multiple drive modes including front-wheel drive, rear-wheel drive and all-wheel drive in normal mode and sharp turn mode, and can select the corresponding driving mode according to road conditions and needs. The four-wheel drive vehicle brake can achieve anti-lock braking through the controller. On downhill sections, the rear brake will be activated first, and then the front brake will be activated to prevent rollover caused by excessive speed.

[0015] The beneficial effects of the present invention are: (1) By setting up a wireless signal receiving system, the four-wheel drive vehicle can be monitored and operated through the remote control and the remote control center.

[0016] (2) The steering and drive of the four-wheel drive vehicle are independently controllable, allowing for sharp turns and rotations on the spot, adapting to narrower and more complex work requirements. The braking of the four-wheel drive vehicle is controlled by sensors based on the vehicle body condition, and the sequence and timing of front and rear braking are controlled to prevent brake locking and loss of control due to external load.

[0017] (3) When the wheels turn, the turning angle θ of the inner wheel and the turning angle φ of the outer wheel have a certain numerical relationship. The ratio of the rotation speed of the inner wheel to the rotation speed of the outer wheel is equal to the ratio of the turning radius of the two. This makes the force on the wheels more reasonable when turning, less likely to slip, and safer. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 A schematic structural diagram of an all-terrain multi-functional four-wheel drive vehicle provided by an embodiment of the present invention; Figure 2 This is a flow chart of a vehicle control method provided by an embodiment of the present invention.

[0020] Figure 3 It is a hydraulic principle diagram of the hydraulic drive system of the present invention; Figure 4 This is a schematic diagram of turning in the normal mode of the present invention (taking left turning as an example); Figure 5 This is a schematic diagram of turning in the sharp turn mode of the present invention (taking left turn as an example); Figure 6 Schematic diagram of the rotation in the rotation mode of the present invention (taking clockwise rotation as an example).

[0021] Description of reference numerals: 1. Car body; 2. Wireless signal receiving system; 3. Electronic control system; 4. Hydraulic drive system; 5. Rotating pin; 6. Drive shaft assembly; 7. Hydraulic motor; 8. Wheel; 9. Connecting rod; 10. Crank lever; 11. Hydraulic cylinder; 12. Hydraulic cylinder displacement signal channel; 13. Hydraulic motor speed signal channel; 4-1. Fuel tank; 4-2. Filter; 4-3. Overflow valve; 4-4. Motor; 4-5. Hydraulic pump; 4-6. Solenoid proportional reversing valve for right rear motor; 4-7. Solenoid proportional reversing valve for left rear motor; 4-8. Solenoid proportional reversing valve for right front motor; 4-9. Solenoid proportional reversing valve for left front motor; 4-10. Hydraulic motor brake; 4-11. Rear wheel brake solenoid valve; 4-12, front wheel brake solenoid valve; 4-13, left front cylinder solenoid proportional reversing valve; 4-14, right front cylinder solenoid proportional reversing valve; 4-15, left rear cylinder solenoid proportional reversing valve; 4-16, right rear cylinder solenoid proportional reversing valve; 4-17, air cooler; 4-18, temperature and liquid level sensor; 4-19, thermometer; 4-20, air filter; 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 cylinder; 11-2, right front steering cylinder; 11-3, left rear steering cylinder; 11-4, right rear steering cylinder. DETAILED DESCRIPTION

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] like Figure 1 、 Figure 3 As shown, this embodiment provides an all-terrain multifunctional four-wheel drive vehicle, including a body 1, an electronic control system 3, a hydraulic drive system 4, and four steering actuators, each of which includes a rotation pin 5 rotatably connected to the body 1, a drive shaft assembly 6 mounted on the rotation pin 5, a wheel 8 mounted at the end of the drive shaft assembly 6, and a hydraulic motor 7 for driving the wheel 8 to rotate; The steering actuator also includes a tilting lever 10 hinged at the middle portion to the vehicle body 1. One end of the tilting lever 10 cooperates with a pin on the piston rod of the hydraulic cylinder 11 through a slide groove to form a slidable and rotatable connection mechanism. The other end of the tilting lever 10 is hinged to the housing of the hydraulic motor 7 through a connecting rod 9. See also Figure 3The hydraulic drive system 4 includes a hydraulic pump 4-5, a plurality of electromagnetic proportional reversing 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 reversing valve; the hydraulic pump 4-5 is adapted to the motor 4-4; 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; The four hydraulic motors 7 correspond to four electromagnetic proportional reversing valves, namely: the electromagnetic proportional reversing valve 4-6 of the right rear motor, the electromagnetic proportional reversing valve 4-7 of the left rear motor; the electromagnetic proportional reversing valve 4-8 of the right front motor, and the electromagnetic proportional reversing valve 4-9 of the left front motor; The four hydraulic cylinders 11 are respectively a left front steering cylinder 11-1, a right front steering cylinder 11-2, a left rear steering cylinder 11-3 and a right rear steering cylinder 11-4: The four hydraulic cylinders 11 correspond to four electromagnetic proportional reversing valves, namely: the electromagnetic proportional reversing valve 4-13 of the left front cylinder, the electromagnetic proportional reversing valve 4-14 of the right front cylinder, the electromagnetic proportional reversing valve 4-15 of the left rear cylinder and the electromagnetic proportional reversing valve 4-16 of the right rear cylinder.

[0024] 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 through the hydraulic cylinder displacement signal channel 12, and outputs the steering angle of the wheel 8 based on the preset correspondence between the cylinder displacement and the wheel angle. The encoder transmits the hydraulic motor speed information to the electronic control system 3 through the hydraulic motor speed signal channel 13. The main controller controls the opening of each electromagnetic proportional reversing valve connected to the hydraulic cylinder 11, thereby collaboratively adjusting the steering speed and angle of the wheel 8.

[0025] In this embodiment, the four-wheel drive vehicle 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 instructions to the electronic control system 3; the electronic control system 3 controls the operation of the hydraulic motor 7 and the hydraulic cylinder 11 through each electromagnetic proportional reversing valve based on the control instructions.

[0026] The hydraulic drive system 4 also includes a relief valve 4-3 provided at the outlet of the hydraulic pump 4-5 and a filter 4-2 provided at the inlet of the hydraulic pump 4-5. The oil tank 4-1 is also provided with an air filter 4-20, a thermometer 4-19 and a temperature level sensor 4-18; an air cooler 4-17 is also provided between the electromagnetic proportional reversing valve of the hydraulic motor 7 and the oil tank 4-1.

[0027] In this embodiment, the four-wheel drive vehicle also includes a brake 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 for 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 for the rear wheels of the four-wheel drive vehicle; the brake solenoid valve performs a braking operation on the vehicle by controlling the hydraulic motor brake 4-10.

[0028] In this embodiment, the four-wheel drive vehicle 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.

[0029] See also Figure 4-Figure 6 The embodiment of the present invention further provides a control method for the all-terrain multi-functional four-wheel drive vehicle, comprising: Steering control: The electronic control system 3 responds to steering commands, controls the opening of the electromagnetic proportional reversing valve connected to the hydraulic cylinder 11, and drives the hydraulic cylinder 11 to extend and retract. The hydraulic cylinder 11 rotates the tilting rod 10, which drives the hydraulic motor 7 housing to deflect via the connecting rod 9, causing the wheel 8 to turn around the rotating pin 5. The displacement signal of the hydraulic cylinder 11 is collected in real time by the oil 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 reversing valve adapted to the hydraulic cylinder 11; Drive control: The electronic control system 3 responds to drive commands, controls the opening of the electromagnetic proportional reversing valve connected to the hydraulic motor 7, and thus controls the rotation of the drive wheels 8. The speed signal of the hydraulic motor 7 is collected through an encoder, and the main controller performs closed-loop speed regulation. Multi-mode execution: Execution is selected based on driving mode commands, including: Normal mode: only controls the steering actuator of the front wheels 8; Sharp turn mode: controls the steering actuators of the four wheels 8 to steer in conjunction with each other to reduce the turning radius; Rotation mode: controls the front and rear wheels on the same side to rotate in opposite directions to achieve zero-radius steering; Braking control: The action sequence and duration of the front wheel brake solenoid valve 4-12 and the rear wheel brake solenoid valve 4-11 are independently controlled according to the vehicle status.

[0030] According to the characteristics of each wheel 8 having adjustable steering and speed, when turning, the wheel 8 on the inside of the turn and the wheel 8 on the outside have the same rotation center, which is on the center line of the front and rear rows of wheels 8. The direction of the front or rear wheel 8 forms different angles with the vertical direction of the vehicle body 1. The turning angle of the wheel 8 on the inside of the turn is θ, and the turning angle of the wheel 8 on the outside of the turn is φ. The axle moment and wheelbase of the vehicle body 1 are L and W respectively, and θ and φ satisfy At this time, the ratio of the rotational speeds of the wheel 8 on the inside of the turn and the wheel 8 on the outside is the same as the ratio of the corresponding turning radius.

[0031] The ratio of the rotation speed of the inner wheel 8 to the rotation speed of the outer wheel 8 is equal to the ratio of the turning radius, that is, or , L1 is the turning radius of the inner steering wheel, and L2 is the turning radius of the outer steering wheel.

[0032] The wireless signal receiving system 2 can transmit signals to and from the remote control and the ground control center. The control instructions of the remote control have higher priority than those of the ground control center. When the remote control and the ground control center send instructions at the same time, the remote control instructions are executed first. The remote server can only take over control when the remote control is not connected. The four-wheel drive vehicle has multiple drive modes including front-wheel drive, rear-wheel drive and all-wheel drive in normal mode and sharp turn mode, and can select the corresponding driving mode according to road conditions and needs. The four-wheel drive vehicle brake can achieve anti-lock braking through the controller. On downhill sections, the rear brake will be activated first, and then the front brake will be activated to prevent rollover caused by excessive speed.

[0033] See also Figure 2 After starting the vehicle, the remote control automatically connects to the remote server. If the connection fails, the vehicle cannot be started. If the connection is successful, a check is performed in either mode to determine whether the vehicle is under remote control. If the vehicle is under remote control, the remote server can only monitor the vehicle's operating status and cannot control it. If the vehicle is under remote control, the remote server can exchange signals with the autonomous driving system via the wireless base station. The vehicle then selects a mode. In Normal mode, only the front wheels can be used for turning, which is consistent with normal driving habits. In Sharp Turn mode, all four wheels are linked to each other, reducing the turning radius. In Rotation mode, the vehicle can rotate around the center of the vehicle. Within Normal and Sharp Turn modes, selectable drive modes are available to accommodate a variety of road conditions and operational requirements. During braking, the electronic control system 3 analyzes the vehicle's status through various sensors to control the sequence and timing of the rear and front brake solenoid valves 4-11 and 4-12, preventing locking and unbalanced loads that could cause the vehicle to lose control.

[0034] In order to adapt to various terrains and make the four-wheel drive vehicle have stronger grip, when the four-wheel drive vehicle turns, the turning angle θ of the inner wheel and the turning angle φ of the outer wheel are , meaning the size of one angle can be inferred from the size of the other. The ratio of the speed of the wheel on the inside of a turn to the speed of the wheel on the outside of the turn is equal to the ratio of their turning radii, L1 / L2 or L1' / L2'.

[0035] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. An all-terrain multifunctional four-wheel drive vehicle, comprising a vehicle body (1), an electronic control system (3), a hydraulic drive system (4) and four sets of steering actuators, characterized in that: The steering actuator comprises 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 on the end of the drive shaft assembly (6), and a hydraulic motor (7) for driving the wheel (8) to rotate; The steering actuator further includes a tilting lever (10) whose middle portion is hinged to the vehicle body (1), one end of the tilting lever (10) cooperates with a pin on a piston rod of a hydraulic cylinder (11) through a sliding groove to form a slidable and rotatable connection mechanism, and the other end of the tilting lever (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), a plurality of electromagnetic proportional reversing valves connected to the outlets of the hydraulic pumps (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 reversing valve; The electronic control system (3) includes a main controller, a cylinder displacement sensor for real-time acquisition of displacement signals of the hydraulic cylinder (11), and an encoder for real-time acquisition of rotational speed information of the hydraulic motor (7). The cylinder displacement sensor transmits the acquired information to the main controller, and outputs the steering angle of the wheel (8) based on a preset correspondence between the cylinder displacement and the wheel angle. The main controller controls the opening of each electromagnetic proportional reversing valve connected to the hydraulic cylinder (11), thereby collaboratively adjusting the steering speed and angle of the wheel (8).

2. The all-terrain multi-functional four-wheel drive vehicle according to claim 1, characterized in that: The invention also includes a wireless signal receiving system (2), wherein the wireless signal receiving system (2) 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 operation of the hydraulic motor (7) and the hydraulic cylinder (11) through each electromagnetic proportional reversing valve based on the control instructions.

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

4. The all-terrain multi-function four-wheel drive vehicle according to claim 2, characterized in that: The invention also includes a brake 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 for 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 for the rear wheels of the four-wheel drive vehicle; the brake solenoid valve performs a 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 the 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 reversing valve connected to the hydraulic cylinder (11), and drives the hydraulic cylinder (11) to extend and retract; the hydraulic cylinder (11) pushes the tilting rod (10) to rotate, and drives the hydraulic motor (7) housing to deflect through 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 oil cylinder displacement sensor and converted into a wheel steering angle by the main controller; the steering speed of the wheel (8) is controlled by adjusting the opening of the electromagnetic proportional reversing 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 reversing 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 through the encoder, and the main controller performs closed-loop speed regulation; Multi-mode execution: Execution is selected based on driving mode commands, including: Normal mode: only the steering actuator of the front wheels (8) is controlled; Sharp turn mode: Control the steering actuators of the four wheels (8) to turn in conjunction with each other to reduce the turning radius; Rotation mode: Control the front and rear wheels (8) on the same side to rotate in opposite directions to achieve zero-radius steering; Braking control: The order and duration of the front wheel brake solenoid valve (4-12) and the rear wheel brake solenoid valve (4-11) are independently controlled according to the vehicle status.

7. The method according to claim 6, characterized in that: According to the characteristics of each wheel (8) being adjustable in steering and speed, when turning, the wheel (8) on the inside of the turn and the wheel (8) on the outside have the same rotation center, which is on the center line of the front and rear rows of wheels (8). The direction of the front or rear wheel (8) forms an angle of different sizes with the vertical direction of the vehicle body (1). The turning angle of the wheel (8) on the inside of the turn is θ, and the turning angle of the wheel (8) on the outside of the turn is φ. The axle moment and wheelbase of the vehicle body (1) are L and W respectively, and θ and φ satisfy At this time, the ratio of the rotational speeds of the wheel (8) on the inner side of the turn and the wheel (8) on the outer side is the same as the corresponding turning radius.

8. The method according to claim 6, wherein: The ratio of the rotation speed of the inner wheel (8) to the rotation speed of the outer wheel (8) is equal to the ratio of the turning radius of the two, that is, or , L1 is the turning radius of the inner steering wheel, and L2 is the turning radius of the outer steering wheel.

9. The method according to claim 6, wherein: The wireless signal receiving system (2) is capable of transmitting signals to and from the remote control and the ground centralized control center. The control instructions of the remote control have a higher priority than those of the ground centralized control center. When the remote control and the ground centralized control center send instructions at the same time, the remote control instructions are executed first. The remote server can only take over control when the remote control is not connected.

10. The method according to claim 6, wherein: The four-wheel drive vehicle has multiple drive modes including front-wheel drive, rear-wheel drive and all-wheel drive in normal mode and sharp turn mode, and can select the corresponding driving mode according to road conditions and needs. The four-wheel drive vehicle brake can achieve anti-lock braking through the controller. On downhill sections, the rear brake will be activated first, and then the front brake will be activated to prevent rollover caused by excessive speed.

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