A steering wheel device and control method for a tracked vehicle

Abstract

A steering wheel device and control method for a tracked vehicle includes a straight-line operating mechanism, a steering wheel operating mechanism, a tracked chassis, a controller, and a hydraulic motor. The tracked chassis is mounted and fixed on track supports above the left and right tracks. The tracked chassis is used to mount the straight-line operating mechanism, the steering wheel operating mechanism, the controller, and the hydraulic motor. The straight-line operating mechanism controls the tracked vehicle to move forward and backward. The steering wheel operating mechanism transmits the rotation angle to the controller via an angle encoder. The controller, based on the action of the shift lever, further adjusts the rotation angle and direction of the first or second motor, causing a speed difference between the first and second hydraulic motors to control the tracked vehicle to turn. This invention solves the problems of difficulty in controlling and easy misalignment when using a joystick to control the movement and turning of tracked vehicles. By using a steering wheel instead of a joystick for straight-line and turning of tracked vehicles, the operational performance is improved.

Description

Technical Field

[0001] This invention relates to the field of agricultural machinery, and in particular to a steering wheel device and control method for tracked vehicles. Background Technology

[0002] Hydraulic tracked vehicles are an important type of engineering machinery, widely used in agriculture. They are well-suited to complex terrains such as hilly areas and heavy clay soils. Their key advantages lie in their superior traction and adhesion, strong adaptability to complex road conditions, and excellent passability. Compared to wheeled vehicles, they also have lower ground pressure, resulting in superior obstacle-crossing and load-bearing capabilities. They can operate efficiently in complex terrains and harsh conditions. For example, a hydraulic chassis and shore-based material delivery robot (patent number 202210992496.X) uses a wheeled chassis with differential steering. However, this type of wheeled differential steering has relatively low passability in complex terrains. Due to the small contact area between the tires and the ground, it relies solely on friction for traction, making it prone to slipping or getting stuck on low-traction terrains such as mud and snow. The tires are constantly subjected to friction and loads, resulting in significant wear and tear. The hydraulic system is the core component of hydraulic tracked vehicles, including the engine, hydraulic pump, and hydraulic motor. For example, a lightweight intelligent electric tracked transport vehicle for mountainous terrain and its usage method, patent number 202310281031.8, utilizes electric energy to drive the tracked vehicle. Compared to hydraulic systems, electric tracks have limited load-bearing capacity. In applications requiring heavy loads, the electric motor and transmission may be limited by overload. Hydraulic systems, on the other hand, have a significant advantage in load-bearing capacity. By utilizing the incompressibility of liquids, hydraulic systems can provide stable force and torque output under heavy loads. Directly connecting the hydraulic pump and hydraulic motor in a hydraulic system eliminates the need for gearboxes, differentials, and other mechanisms, greatly improving transmission efficiency and reducing vehicle weight. Continuously variable transmission can be achieved by changing the displacement and direction of the variable pump. However, currently, the adjustment of the variable pump displacement is mostly achieved through a rack and pinion transmission mechanism or a lever-operated valve to adjust the pump's flow control. This control method suffers from inflexible control, susceptibility to misalignment, and unstable hydraulic pump oil supply, seriously affecting the driving and safety performance of tracked vehicles. Summary of the Invention

[0003] This invention addresses the shortcomings of existing technologies by providing a steering wheel device and control method for tracked vehicles that uses steering wheel angle information as a signal to transmit to a controller and uses a motor to control the valve opening of a series variable displacement piston pump.

[0004] To achieve the above objectives, the present invention first proposes a steering wheel device for a tracked vehicle, comprising a straight-line operating mechanism, a steering wheel operating mechanism, a tracked chassis, a controller, and a hydraulic motor; the tracked chassis is mounted and fixed on track supports above the left and right tracks, and is used to mount the straight-line operating mechanism, the steering wheel operating mechanism, the controller, and the hydraulic motor; the hydraulic motor includes a first hydraulic motor and a second hydraulic motor, the first hydraulic motor driving the left track to rotate, and the second hydraulic motor driving the right track to rotate; the straight-line operating mechanism includes a motor, a series variable displacement piston pump, and a shift lever; the motor includes a first motor, a second... Two motors are connected to the series variable displacement piston pump, which is fixedly connected to the tracked chassis. The first motor controls the opening of the first flow control valve on the series variable displacement piston pump, and the second motor controls the opening of the second flow control valve on the series variable displacement piston pump. The first hydraulic motor is connected to the inlet and outlet of the first flow control valve of the series variable displacement piston pump, and the second hydraulic motor is connected to the inlet and outlet of the second flow control valve of the series variable displacement piston pump. The shift lever is connected to the controller, which controls the rotation of the first motor and the second motor. When the shift lever is activated, the first motor and the second motor rotate at the same speed, in the same direction, and at the same angle.

[0005] The steering wheel operating mechanism includes a steering wheel, a steering shaft, and an angle encoder. The steering wheel is coaxially connected to the steering shaft. The angle encoder is located at the bottom of the steering shaft, and the rotation shaft of the angle encoder is coaxially and fixedly connected to the steering shaft. The angle encoder is connected to the controller. The steering wheel transmits the rotation angle to the controller through the angle encoder. Based on the action of the gear shift lever, the controller further adjusts the rotation angle and rotation direction of the first motor or the second motor, so that the first hydraulic motor and the second hydraulic motor generate a speed difference, thereby controlling the tracked vehicle to steer.

[0006] In this embodiment, the gear shift lever has five gears: forward fast gear D3, forward medium gear D2, forward slow gear D1, parking gear P, and reverse gear R. The five gears are connected to the controller via five DuPont wires to transmit five different signals.

[0007] In this embodiment, the steering shaft is rotatably mounted in the steering wheel support frame, the steering wheel support frame is fixed on the tracked chassis, the connecting plate is fixed below the steering wheel support frame, a first bearing seat is mounted on the connecting plate, a first bearing is installed in the first bearing seat, the steering shaft passes through the first bearing and is rotatably connected to the connecting plate through the first bearing, a pinion is coaxially mounted on one end of the steering shaft passing through the first bearing, the pinion is linked with the steering shaft, an encoder mounting frame is also fixed below the connecting plate, an angle encoder is mounted on the encoder mounting frame, and a limiting device is also installed on the connecting plate to limit the number of rotations of the pinion in both directions.

[0008] In this embodiment, the limiting device includes a second bearing seat disposed on the connecting plate, a second bearing installed in the second bearing seat, a transmission shaft parallel to the steering shaft installed in the second bearing, a large gear coaxially mounted on the transmission shaft, the large gear meshing with a small gear, a limiting stop installed on the large gear, the limiting stop being fixed in the tooth gap of the large gear, the limiting stop being used to limit the number of revolutions of the small gear in both directions, and to ensure that the rotation degrees of the small gear in both directions are the same.

[0009] In this embodiment, the series variable displacement piston pump includes a first flow control valve and a second flow control valve. When the first flow control valve and the second flow control valve are in the middle position, the displacement of the series variable displacement piston pump is zero. When the first flow control valve and the second flow control valve are rotated to the maximum angle in the forward direction, the forward flow of the series variable displacement piston pump is the maximum. When the first flow control valve and the second flow control valve are rotated to the maximum angle in the reverse direction, the reverse flow of the series variable displacement piston pump is the maximum.

[0010] In this embodiment, both the first motor and the second motor are stepper motors.

[0011] The present invention also includes a control method based on the above-mentioned steering wheel device for tracked vehicles, specifically comprising the following steps:

[0012] S1. The controller determines the gear control signal of the straight-line operating mechanism:

[0013] Let θ be the maximum forward and reverse rotation angle of the flow control valve of the series variable displacement piston pump, N be the number of pulses required for the motor shaft to rotate 360 ​​degrees, and n be the number of gear positions. Let α be the rotation angle of the flow control valve corresponding to different gear positions. n Degree (n = 1, 2, 3, ..., α) n ≦θ);

[0014] Each gear shift lever corresponds to a gear position in the controller, and each external interrupt corresponds to an interrupt function within the controller. The number of pulses in the interrupt function is α. n *N / 360, depending on the gear, the controller sends the corresponding number of pulses to the first motor and the second motor simultaneously, and the first motor and the second motor control the first flow control valve and the second flow control valve respectively;

[0015] S2. After the gear is engaged in step S1, the controller then judges the steering control signal of the steering wheel operating mechanism:

[0016] Let β be the maximum clockwise and counterclockwise rotation angle of the steering wheel starting from the center position, and let γ be the angle detected by the angle encoder starting from the center position, where γ≦β.

[0017] The rotation angle α of the flow control valve at different speeds will be adjusted. n Corresponding to the steering wheel rotation angle γ, the number of degrees β that the flow control valve needs to rotate for every 1 degree of steering wheel rotation starting from the center position can be calculated. n =2α n / β,

[0018] When the steering wheel is turned clockwise by γ degrees from the center position, the first motor remains stationary, and the controller controls the second motor to turn in the opposite direction |γβ. n |degrees, when the steering wheel returns to center by γ degrees, the first motor remains stationary, and the controller controls the second motor to return to its original position|γβ n |Degree,

[0019] When the steering wheel is turned counterclockwise by γ degrees from the center position, the second motor remains stationary, and the controller controls the first motor to rotate in the opposite direction |γβ. n |degrees, when the steering wheel returns to center by γ degrees, the second motor remains stationary, and the controller controls the first motor to return to its original position|γβ n |Degree,

[0020] By controlling the first motor and the second motor, a speed difference is created between the first hydraulic motor and the second hydraulic motor, thereby controlling the tracked vehicle to steer.

[0021] In the above embodiment, the gear shift lever is provided with five gears: forward fast gear D3, forward medium gear D2, forward slow gear D1, parking gear P, and reverse gear R. The rotation angles of the flow control valves corresponding to these gears are α1, α2, α3, α4, and α5, respectively. Here, α1 is the maximum forward rotation opening of the flow control valve, α2 is the median forward rotation opening of the flow control valve, α3 is the minimum forward rotation opening of the flow control valve, α4 is zero, and α5 is the minimum reverse rotation opening of the flow control valve.

[0022] When the gear is in parking position P, α4 = 0, the first and second motors do not rotate, the first and second flow control valves are closed, the displacement of the series variable piston pump is zero, and the tracked vehicle stops at this time.

[0023] When the gear is in forward fast gear D3, the controller controls the first motor and the second motor to rotate forward α1 degrees simultaneously, the first and second flow control valves have the maximum forward opening, the series variable piston pump has the maximum flow, the first hydraulic motor and the second hydraulic motor have the fastest forward rotation speed, and the tracked vehicle moves forward quickly.

[0024] When the gear is in forward middle gear D2, the controller controls the first motor and the second motor to rotate forward α2 degrees simultaneously, the first and second flow control valves have a moderate forward opening, the series variable piston pump has a moderate flow, the first hydraulic motor and the second hydraulic motor rotate clockwise at a medium speed, and the tracked vehicle moves forward at a medium speed.

[0025] When the gear is in forward slow gear D1, the controller controls the first motor and the second motor to rotate forward α3 degrees simultaneously. The first and second flow control valves have the smallest forward opening, the series variable piston pump has the smallest flow, the first hydraulic motor and the second hydraulic motor rotate at the slowest forward speed, and the tracked vehicle moves forward slowly.

[0026] When the gear is in reverse (R), the controller controls the first and second motors to rotate in opposite directions by α5 degrees simultaneously, the first and second flow control valves to rotate in opposite directions, the first hydraulic motor and the second hydraulic motor to rotate in opposite directions, and the tracked vehicle to reverse.

[0027] The present invention has the following beneficial effects:

[0028] 1. This invention utilizes an angle encoder to transmit the steering wheel rotation angle information as a signal to a controller. The controller then matches the angle information with the shift signal of the gear shift lever to achieve differential steering of the tracked vehicle in different gears. This invention abandons mechanical transmission. After receiving the corresponding signals, the controller controls the rotation angle and rotation direction of the first and second motors, thereby controlling the valve opening of the series variable piston pump and achieving control of the speed of the left and right tracks. By adopting the above method, the overall mechanical structure is simpler and the equipment cost is reduced.

[0029] 2. The power of the first and second motors in this invention is transmitted to the flow control valve of the series variable displacement piston pump via a coupling, realizing stepless variation between the positive and negative maximum displacements of the series variable displacement piston pump. The series variable displacement piston pump is equipped with a first flow control valve and a second flow control valve, which are controlled by the first and second motors respectively. The first motor drives the first flow control valve of the series variable displacement piston pump alone, thereby controlling the speed and rotation direction of the first hydraulic motor. The second motor drives the second flow control valve of the series variable displacement piston pump alone, thereby controlling the speed and rotation direction of the second hydraulic motor. The controller controls the first and second motors to achieve differential speed between the two tracks, thereby achieving steering.

[0030] 3. The gear shift lever provides three forward speed modes (D3), one forward medium speed mode (D2), one forward slow speed mode (D1), and one reverse speed mode (R) for tracked vehicles. The tracked vehicle speed corresponding to each of the D3, D2, D1, and R gears can be adjusted via the control program.

[0031] 4. The driver turns the tracked vehicle by using the steering wheel. Through the control method of this invention, on the one hand, the larger the steering wheel rotation angle, the smaller the turning radius of the tracked vehicle. On the other hand, it can match the steering wheel rotation angle with the motor rotation angle under different gears, so that the turning radius of the tracked vehicle can be determined by the steering wheel rotation angle. This allows for smooth steering and reduces the difference between operating a tracked vehicle and operating a regular vehicle, greatly improving the vehicle's drivability, operability, safety, and comfort.

[0032] In summary, this invention utilizes an angle encoder to transmit the steering wheel rotation angle information as a signal to the controller, thereby controlling the rotation of the first and second motor shafts. The first and second motors then control the valve opening of the series variable displacement piston pump, accurately controlling the flow control valve opening. This allows for control of the flow rate and direction of the series variable displacement piston pump and hydraulic motor simply by turning the steering wheel, enabling differential steering of the tracked vehicle. The turning radius can also be controlled by the steering wheel. Therefore, this invention uses a steering wheel to control the steering of the tracked vehicle, solving the problems of difficulty in control and easy misalignment when using a joystick to control the movement and turning of the tracked vehicle. Using a steering wheel instead of a joystick for straight-line turning of the tracked vehicle improves operational performance. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of the present invention.

[0034] Figure 2 This is a schematic diagram of the straight-line operating mechanism of the present invention.

[0035] Figure 3 This is a schematic diagram of the steering wheel operating mechanism of the present invention.

[0036] Figure 4 for Figure 3 Enlarged view of point A.

[0037] Figure 5 This is the control flowchart of the present invention.

[0038] In the diagram: 1. Straight-line operating mechanism; 2. Steering wheel operating mechanism; 3. Tracked chassis; 4. First hydraulic motor; 5. Second hydraulic motor; 110. First motor; 120. Second motor; 130. First motor support; 140. Second motor support; 150. First coupling; 160. Second coupling; 170. Series variable displacement piston pump; 210. Steering wheel support frame; 220. First bearing; 230. Connecting plate; 240. First bearing housing; 250. Second bearing housing; 260. Steering shaft; 270. Drive shaft; 280. Pinion; 290. Gear; 291. Limit stop; 292. Encoder mounting bracket; 293. Angle encoder. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0040] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0041] like Figures 1 to 4 As shown, a steering wheel device for a tracked vehicle includes a straight-line operating mechanism 1, a steering wheel operating mechanism 2, a tracked chassis 3, a controller, and a hydraulic motor.

[0042] The track chassis 3 is mounted and fixed on the track brackets above the left and right tracks. The track chassis 3 is used to mount and place other mechanism components of the tracked vehicle.

[0043] One part of the straight-moving operating mechanism 1 is fixedly connected to the tracked chassis 3 and located at the rear of the tracked vehicle, while the other part is installed on the right side of the steering wheel operating mechanism 2. The straight-moving operating mechanism 1 is used to control the tracked vehicle to move forward and backward.

[0044] The steering wheel operating mechanism 2 is mounted on the tracked chassis 3, and the steering wheel operating mechanism 2 is used to control the tracked vehicle to steer.

[0045] The hydraulic motors include a first hydraulic motor 4 and a second hydraulic motor 5. The first hydraulic motor 4 is fixed inside the left track of the tracked vehicle and drives the left track to rotate. The second hydraulic motor 5 is fixed inside the right track of the tracked vehicle and drives the right track to rotate.

[0046] In this embodiment, both the first hydraulic motor 4 and the second hydraulic motor 5 are BM5-200 type hydraulic motors. The BM5-200 type hydraulic motor has a shaft diameter of 32mm, a working pressure of 21Mpa, a maximum speed of 365RPM, and a torque of 550N / m. Of course, the above-mentioned hydraulic motor model is only one embodiment and does not limit the patent scope of this invention.

[0047] like Figure 2 As shown, the straight-line operating mechanism 1 includes a motor, a first motor support 130, a second motor support 140, a first coupling 150, a second coupling 160, a series variable displacement piston pump 170, and a gear shift handle.

[0048] The motor includes a first motor 110 and a second motor 120. The first motor 110 is fixed to the track support by a first motor support 130; the second motor 120 is fixed to the track support by a second motor support 140.

[0049] The series variable displacement piston pump 170 is fixedly connected to the tracked chassis 3; the first coupling 150 connects the motor shaft of the first motor 110 to the first flow control valve of the series variable displacement piston pump 170, the first motor 110 controls the opening of the first flow control valve, and the rotation angle of the output shaft of the first motor is the same as the rotation angle of the first flow control valve; the second coupling 160 connects the motor shaft of the second motor 120 to the second flow control valve of the series variable displacement piston pump 170, the second motor 120 controls the opening of the second flow control valve, and the rotation angle of the output shaft of the second motor is the same as the rotation angle of the second flow control valve; when the two first motors 110 and the second motor 120 rotate, they respectively drive the first flow control valve and the second flow control valve of the series variable displacement piston pump 170 to rotate, thereby controlling the output of different flow rates; the first hydraulic motor 4 is connected to the inlet and outlet ports of the first flow control valve of the series variable displacement piston pump 170, and the second hydraulic motor 5 is connected to the inlet and outlet ports of the second flow control valve of the series variable displacement piston pump 170.

[0050] In this embodiment, the series variable displacement piston pump 170 is of type HZA-13, with a rated speed of 3600 r / min, a rated pressure of 15 MPa, and a displacement of 13 ml / r. By controlling the opening and rotation direction of the flow control valve of the series variable displacement piston pump 170, the flow rate and direction of the series variable displacement piston pump 170 are controlled. When the flow control valve of the series variable displacement piston pump 170 is in the middle position, the displacement of the series variable displacement piston pump 170 is zero. When the flow control valve of the series variable displacement piston pump 170 rotates 20 degrees forward, the forward flow rate of the series variable displacement piston pump 170 is the maximum. When the flow control valve of the series variable displacement piston pump 170 rotates 20 degrees in the reverse direction, the reverse flow rate of the series variable displacement piston pump 170 is the maximum.

[0051] Both the first motor 110 and the second motor 120 are 86-type stepper motors with a maximum torque of 12 N / m and a shaft diameter of 14 mm. The flow control valve of the series variable displacement piston pump 170 has a rotation torque of 6.6 N / m, and this type of stepper motor meets the requirements. The first motor 110 and the second motor 120 are controlled by a controller.

[0052] The first flow control valve and the second flow control valve of the series variable piston pump 170 rotate at the same angle, the first hydraulic motor 4 and the second hydraulic motor 5 rotate at the same speed, and the tracked vehicle moves forward in a straight line.

[0053] like Figure 3 , 4 As shown, the steering wheel operating mechanism 2 includes a steering wheel, a steering wheel support frame 210, a first bearing 220, a connecting plate 230, a first bearing seat 240, a second bearing seat 250, a steering shaft 260, a transmission shaft 270, a pinion 280, a gear 290, a limit stop 291, a spring retaining ring, a baffle plate, an encoder mounting bracket 292, and an angle encoder 293; the steering wheel support frame 210 is fixed to the tracked chassis 3 by four bolts;

[0054] The steering wheel is coaxially connected to the steering shaft 260, which is rotatably mounted within the steering wheel support frame 210. A connecting plate 230 is positioned below the steering wheel support frame 210. The connecting plate 230 has two mounting holes, each housing a first bearing seat 240 and a second bearing seat 250. A first bearing seat 240 houses a first bearing 220. The steering shaft 260 passes through the first bearing 220 and is rotatably connected to the connecting plate 230 via the first bearing 220. A pinion 280 is coaxially fitted onto one end of the steering shaft 260 passing through the first bearing 220. The pinion 280 is linked to the steering shaft 260. An encoder mounting bracket 292 is also fixed below the plate 230. The angle encoder 293 is mounted on the encoder mounting bracket 292. The rotation shaft of the angle encoder 293 is coaxially set at the bottom of the steering shaft 260 and fixedly connected to the steering shaft 260. The rotation shaft of the angle encoder 293 is linked with the steering shaft 260. The angle encoder 293 is connected to the controller. The steering wheel transmits the rotation angle to the controller through the angle encoder 293. The controller then controls the first motor 110 and the second motor 120 to control the flow rate and direction of the series variable piston pump 170. This causes the two hydraulic motors to generate different speeds, creating a speed difference that allows the tracked vehicle to steer.

[0055] A second bearing is installed inside the second bearing housing 250, and a drive shaft 270 is installed inside the second bearing. A large gear 290 is coaxially installed on the drive shaft 270. The large gear 290 meshes with a small gear 280. A limit stop 291 is installed on the large gear 290 and is fixed in the tooth gap of the large gear 290. The limit stop 291 is used to limit the number of revolutions of the small gear in both directions.

[0056] Both the first bearing housing 240 and the second bearing housing 250 are square 6006-60 embedded type, with the upper boss of the bearing housing embedded in two 62mm diameter round holes of the connecting plate 230 respectively.

[0057] In this embodiment, the pinion 280 has 21 teeth in 2 modules, and the gear 290 has 67 teeth in 2 modules. Among the 67 teeth of the gear 290, two tooth gaps are blocked by the limiting stop 291. The center distance between the two circular holes of the connecting plate 230 is 88mm. The pinion and gears mesh with each other. The angle encoder adopts the RS458 communication protocol and has a resolution of 1024P.

[0058] In this embodiment, the gear shift lever has five gears: forward fast gear D3, forward medium gear D2, forward slow gear D1, parking gear P, and reverse gear R. The five gears generate five different signals to the controller. According to the different signals, the controller controls the motor shafts of the two motors to rotate, which drives the flow control valve of the series variable piston pump 170 to rotate at different angles, so that the hydraulic motor generates different speeds, thereby controlling the forward and reverse speeds of the tracked vehicle.

[0059] In this embodiment, the gear shift lever is modified from an automatic transmission gearbox in an automobile. It is connected to the controller via five DuPont wires to transmit five signals, enabling the controller to control the first motor 110 and the second motor 120 to rotate simultaneously by the same angle. The angle encoder 293 uses RS485 serial communication and requires an RS485 to TTL chip to communicate with the controller. The controller is connected to the drivers of the first motor 110 and the second motor 120 to send pulses to control the first motor 110 and the second motor 120.

[0060] Specifically:

[0061] When the gear is in parking position P, the first motor 110 and the second motor 120 do not rotate, the displacement of the series variable piston pump is zero, and the tracked vehicle stops at this time.

[0062] When the gear is in forward fast gear D3, the controller controls the first motor 110 and the second motor 120 to rotate 20 degrees forward simultaneously, the flow control valve opens to the maximum, the series variable piston pump has the maximum flow, the first hydraulic motor 4 and the second hydraulic motor 5 rotate clockwise at the fastest speed, and the tracked vehicle moves forward quickly.

[0063] When the gear is in forward middle gear D2, the controller controls the first motor 110 and the second motor 120 to rotate forward 12 degrees simultaneously, the flow control valve opens to a moderate degree, the series variable piston pump has a moderate flow, the first hydraulic motor 4 and the second hydraulic motor 5 rotate clockwise at a moderate speed, and the tracked vehicle moves forward at a moderate speed.

[0064] When the gear is in forward slow gear D1, the controller controls the first motor 110 and the second motor 120 to rotate forward 6 degrees simultaneously, the flow control valve has the smallest forward opening, the series variable piston pump has the smallest flow, the first hydraulic motor 4 and the second hydraulic motor 5 rotate clockwise at the slowest speed, and the tracked vehicle moves forward slowly.

[0065] When the gear is in reverse (R), the controller controls the first motor 110 and the second motor 120 to rotate 6 degrees in opposite directions simultaneously, the flow control valve rotates in opposite directions, the first hydraulic motor 4 and the second hydraulic motor 5 rotate counterclockwise, and the tracked vehicle moves backward.

[0066] like Figure 5As shown, the present invention also includes a control method for a steering wheel device of a tracked vehicle, comprising the following steps:

[0067] S1. The controller determines the gear control signal of the straight-line operating mechanism:

[0068] Let θ be the maximum forward and reverse rotation angle of the flow control valve of the series variable displacement piston pump, N be the number of pulses required for the motor shaft to rotate 360 ​​degrees, and n be the number of gear positions. Let α be the rotation angle of the flow control valve corresponding to different gear positions. n Degree (n = 1, 2, 3, ..., α) n ≦θ);

[0069] Each gear shift lever corresponds to a gear position in the controller, and each external interrupt corresponds to an interrupt function within the controller. The number of pulses in the interrupt function is α. n *N / 360, depending on the gear, the controller sends the corresponding number of pulses to the first motor and the second motor simultaneously, and the first motor and the second motor control the first flow control valve and the second flow control valve respectively;

[0070] S2. After the gear is engaged in step S1, the controller then judges the steering control signal of the steering wheel operating mechanism:

[0071] Let β be the maximum clockwise and counterclockwise rotation angle of the steering wheel starting from the center position, and let γ be the angle detected by the angle encoder starting from the center position, where γ≦β.

[0072] The rotation angle α of the flow control valve at different speeds will be adjusted. n Corresponding to the steering wheel rotation angle γ, the number of degrees β that the flow control valve needs to rotate for every 1 degree of steering wheel rotation starting from the center position can be calculated. n =2α n / β,

[0073] When the steering wheel is turned clockwise by γ degrees from the center position, the first motor remains stationary, and the controller controls the second motor to turn in the opposite direction |γβ. n |degrees, when the steering wheel returns to center by γ degrees, the first motor remains stationary, and the controller controls the second motor to return to its original position|γβ n |Degree;

[0074] When the steering wheel is turned counterclockwise by γ degrees from the center position, the second motor remains stationary, and the controller controls the first motor to rotate in the opposite direction |γβ. n |degrees, when the steering wheel returns to center by γ degrees, the second motor remains stationary, and the controller controls the first motor to return to its original position|γβ n |Degree,

[0075] By controlling the first motor and the second motor, a speed difference is created between the first hydraulic motor and the second hydraulic motor, thereby controlling the tracked vehicle to steer.

[0076] Furthermore, taking a gear shift lever with five gears as an example, the five gears are forward fast gear D3, forward medium gear D2, forward slow gear D1, parking gear P and reverse gear R, and the corresponding rotation angles of the flow control valve are α1, α2, α3, α4 and α5, respectively. Among them, α1 is the maximum value of the forward rotation opening of the flow control valve, α2 is the middle value of the forward rotation opening of the flow control valve, α3 is the minimum value of the forward rotation opening of the flow control valve, α4 is zero, and α5 is the minimum value of the reverse rotation opening of the flow control valve.

[0077] When the gear is in parking position P, α4 = 0, the first and second motors do not rotate, the first and second flow control valves are closed, the displacement of the series variable piston pump is zero, and the tracked vehicle stops at this time.

[0078] When the gear is in forward fast gear D3, the controller controls the first motor and the second motor to rotate forward α1 degrees simultaneously, the first and second flow control valves have the maximum forward opening, the series variable piston pump has the maximum flow, the first hydraulic motor and the second hydraulic motor have the fastest forward rotation speed, and the tracked vehicle moves forward quickly.

[0079] When the gear is in forward middle gear D2, the controller controls the first motor and the second motor to rotate forward α2 degrees simultaneously, the first and second flow control valves have a moderate forward opening, the series variable piston pump has a moderate flow, the first hydraulic motor and the second hydraulic motor rotate clockwise at a medium speed, and the tracked vehicle moves forward at a medium speed.

[0080] When the gear is in forward slow gear D1, the controller controls the first motor and the second motor to rotate forward α3 degrees simultaneously. The first and second flow control valves have the smallest forward opening, the series variable piston pump has the smallest flow, the first hydraulic motor and the second hydraulic motor rotate at the slowest forward speed, and the tracked vehicle moves forward slowly.

[0081] When the gear is in reverse (R), the controller controls the first and second motors to rotate in opposite directions by α5 degrees simultaneously, the first and second flow control valves to rotate in opposite directions, the first hydraulic motor and the second hydraulic motor to rotate in opposite directions, and the tracked vehicle to reverse.

[0082] The workflow of this invention is as follows:

[0083] First, the operator starts the machine, and the engine drives the series variable displacement piston pump to rotate. The gear selector is adjusted to engage the gear, causing the first and second motors to rotate clockwise simultaneously. The first and second flow control valves of the series variable displacement piston pump also rotate clockwise by a certain angle, causing the first and second hydraulic motors to rotate at the same speed and in the same direction, and the tracked vehicle begins to move forward. If the steering wheel is turned to the left from the starting position, the tracked vehicle turns to the left; the larger the steering wheel angle, the smaller the turning radius. Returning the steering wheel to the starting position, the tracked vehicle continues to move straight. If the steering wheel is turned to the right from the starting position, the tracked vehicle turns to the right; the larger the steering wheel angle, the smaller the turning radius. Returning the steering wheel to the starting position, the tracked vehicle continues to move straight. The tracked vehicle can achieve straight-line turning movement through gear selection and steering wheel operation.

[0084] Example:

[0085] In this embodiment, the maximum clockwise and counterclockwise rotation angle of the flow control valve of the series variable displacement piston pump 170 is set to θ = 20 degrees. The number of pulses N required for the motor driver's rotating shaft to rotate 360 ​​degrees is set to 3200. Therefore, based on N / 360, it can be calculated that the interrupt function generates 8.9 pulses to control the motor to rotate 1 degree. Based on the maximum rotation angle of the series variable displacement piston pump 170, the rotation angles of the flow control valves corresponding to the forward fast gear D3, forward medium gear D2, forward slow gear D1, parking gear P, and reverse gear R are set to α1 = 20 degrees forward, α2 = 12 degrees forward, α3 = 6 degrees forward, α4 = 0 degrees, and α5 = 6 degrees reverse, respectively. The steering wheel is set to rotate a maximum of one and a half turns clockwise and counterclockwise from the center position (i.e., β = 540 degrees). Based on β... n =2α n / β is calculated, β1=0.07, β2=0.04, β3=0.02, β4=0, β5=0.02;

[0086] When the gear is in D3, the motor shaft rotates 1 degree for every 13.5 degrees the steering wheel turns. When the steering wheel rotates counterclockwise to its maximum angle β, the first motor shaft rotates from +20 degrees to -40 degrees, returning to the -20 degree position. Meanwhile, the second flow control valve of the series variable displacement piston pump remains at the +20 degree position. The two hydraulic motors rotate at the same speed but in opposite directions, allowing the tracked vehicle to turn in place. When the steering wheel is returned to center, the first motor rotates from -20 degrees to +40 degrees, returning to the +20 degree position. The tracked vehicle then continues to move forward at its original speed.

[0087] When the gear is in D2, the motor shaft rotates 1 degree for every 22.5 degrees the steering wheel turns. When the steering wheel rotates counterclockwise to its maximum angle β, the first motor shaft rotates from +12 degrees to -24 degrees, reaching the -12 degree position. Meanwhile, the second flow control valve of the series variable displacement piston pump remains at the +12 degree position. The two hydraulic motors rotate at the same speed but in opposite directions, allowing the tracked vehicle to turn in place. When the steering wheel is straightened, the first motor rotates from -12 degrees to +24 degrees, returning to the +12 degree position. The tracked vehicle then continues to move forward at the original speed.

[0088] When the gear is in D1, the motor shaft rotates 1 degree for every 45 degrees the steering wheel turns. When the steering wheel is rotated counterclockwise to the maximum angle β, the first motor shaft rotates from +6 degrees to -12 degrees, reaching the -6 degree position. Meanwhile, the second flow control valve of the series variable piston pump remains at the +6 degree position. The two hydraulic motors rotate at the same speed but in opposite directions, allowing the tracked vehicle to turn in place. When the steering wheel is straightened, the first motor rotates from -6 degrees to +12 degrees, returning to the +6 degree position. At this point, the tracked vehicle continues to move forward at the original speed.

[0089] When the gear is in reverse (R), the motor shaft rotates 1 degree for every 45 degrees the steering wheel turns. When the steering wheel rotates counterclockwise to its maximum angle β, the first motor shaft rotates from -6 degrees to +12 degrees, reaching the +6 degree position. Meanwhile, the second flow control valve of the series variable displacement piston pump remains at the -6 degree position. The two hydraulic motors rotate at the same speed but in opposite directions, allowing the tracked vehicle to turn in place. When the steering wheel is returned to center, the first motor rotates from +6 degrees to -12 degrees, returning to the +6 degree position. The tracked vehicle then continues to reverse at the original speed.

[0090] In this embodiment, the working principles of the large gear and the small gear are as follows:

[0091] The rotation of the steering wheel drives the steering shaft 260 to rotate, which in turn drives the pinion 280 to rotate. Due to the meshing of the large and small gears, the limiting stop 291 on the large gear 290 prevents the pinion 280 from rotating one and a half turns to the left and one and a half turns to the right. This ensures that the steering wheel support frame 210 can only rotate one and a half turns to the left (540 degrees to the left) from the starting position and one and a half turns to the right (540 degrees to the right) from the starting position. The rotation of the steering wheel drives the steering shaft 260 to rotate together. The angle encoder 293 rotates synchronously with the steering shaft 260 and records the rotation angle of the steering wheel support frame 210. The rotation angle information is then transmitted to the controller. The controller calculates the number of pulses based on the angle information and then controls the first motor 110 and the second motor 120 to rotate. The first flow control valve and the second flow control valve of the series variable piston pump 170 will also rotate differently, thereby causing the first hydraulic motor 4 and the second hydraulic motor 5 to generate different speeds, creating a speed difference that allows the tracked vehicle to steer.

[0092] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural transformations made under the concept of the present invention using the description and drawings of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A track vehicle steering wheel steering device, comprising a straight running operating mechanism (1), a steering wheel operating mechanism (2), a track chassis (3), a controller and a hydraulic motor; the track chassis (3) is fixedly installed on the track supports above the left and right tracks, and the track chassis (3) is used to install the straight running operating mechanism (1), the steering wheel operating mechanism (2), the controller and the hydraulic motor, characterized in that: The hydraulic motor comprises a first hydraulic motor (4) and a second hydraulic motor (5), the first hydraulic motor (4) drives the left side track to rotate, and the second hydraulic motor (5) drives the right side track to rotate, the straight travel operating mechanism (1) comprises a motor, a series variable piston pump (170) and a gear shift handle; the motor comprises a first motor (110) and a second motor (120), the series variable piston pump (170) is fixedly connected to the track chassis (3); the first motor (110) controls the opening of the first flow control valve on the series variable piston pump (170) to rotate, the second motor (120) controls the opening of the second flow control valve on the series variable piston pump (170) to rotate, the first hydraulic motor (4) is connected with the inlet and outlet oil ports of the first flow control valve of the series variable piston pump (170), and the second hydraulic motor (5) is connected with the inlet and outlet oil ports of the second flow control valve of the series variable piston pump (170); the gear shift handle is connected with the controller, the controller controls the rotation of the first motor (110) and the second motor (120), when the gear shift handle is actuated, the first motor (110) and the second motor (120) rotate at the same speed, in the same direction and at the same angle. The steering wheel operating mechanism (2) comprises a steering wheel, a steering shaft (260) and an angle encoder (293); the steering wheel is coaxially connected to the steering shaft (260) in linkage, the angle encoder (293) is arranged at the bottom of the steering shaft (260), the rotation shaft of the angle encoder (293) is coaxially fixedly connected to the steering shaft (260), the angle encoder (293) is connected to the controller, the steering wheel transmits the rotation angle to the controller through the angle encoder (293), and the rotation angle and the rotation direction of the first motor (110) or the second motor (120) are further adjusted on the basis of the action of the gear shift handle through the controller, so that the first hydraulic motor (4) and the second hydraulic motor (5) generate a speed difference, and the track vehicle is controlled to turn.

2. The track vehicle steering wheel steering apparatus of claim 1, wherein: The gear shift handle has five gears, namely a fast forward gear D3, a medium forward gear D2, a slow forward gear D1, a parking gear P and a reverse gear R; the five gears are connected with the controller through five Dupont wires and are used to transmit five different signals.

3. The track-laying vehicle steering wheel steering apparatus of claim 2, wherein: The steering shaft (260) is rotatably installed in a steering wheel support frame (210) fixed on the tracked chassis (3), a connecting plate (230) is fixed below the steering wheel support frame (210), a first bearing seat (240) is installed on the connecting plate (230), a first bearing (220) is installed in the first bearing seat (240), the steering shaft (260) passes through the first bearing (220) and is rotatably connected with the connecting plate (230) through the first bearing (220), a pinion (280) is coaxially installed on one end of the steering shaft (260) passing through the first bearing (220), the pinion (280) is linked with the steering shaft (260), an encoder fixing frame (292) is also fixed below the connecting plate (230), an angle encoder (293) is installed on the encoder fixing frame (292), and a limiting device limiting the number of rotations of the pinion (280) is also installed on the connecting plate (230).

4. The track-laying vehicle steering wheel steering apparatus of claim 3, wherein: The limiting device comprises a second bearing seat (250) arranged on the connecting plate, a second bearing is installed in the second bearing seat (250), a transmission shaft (270) parallel to the steering shaft (260) is installed in the second bearing, a large gear (290) is coaxially installed on the transmission shaft (270), the large gear (290) is engaged with the pinion (280), a limiting stop piece (291) is installed on the large gear (290), the limiting stop piece (291) is fixed in a tooth gap of the large gear (290), the limiting stop piece (291) is used for limiting the number of rotations of the pinion (280) and ensuring that the number of rotations of the pinion (280) in the forward direction is the same as that in the reverse direction.

5. The track-laying vehicle steering wheel steering apparatus of claim 4, wherein: The series variable plunger pump (170) comprises first and second flow control valves, when the first and second flow control valves are in the intermediate position, the displacement of the series variable plunger pump (170) is zero, when the first and second flow control valves are positively rotated to the maximum angle, the forward flow of the series variable plunger pump (170) is maximum, and when the first and second flow control valves are reversely rotated to the maximum angle, the reverse flow of the series variable plunger pump (170) is maximum.

6. The track-laying vehicle steering wheel steering apparatus of claim 5, wherein: The first motor (110) and the second motor (120) are both step motors.

7. A control method for the track vehicle steering apparatus of any one of claims 1 to 6, characterized by: Specifically comprising the following steps: S1, the controller judges the gear control signal of the straight operation mechanism: The maximum rotation angle of the flow control valve of the series variable plunger pump is θ degrees, the number of pulses required for the motor rotation shaft to rotate 360 degrees is N, the shift handle is provided with n gears, n = 1, 2, 3,..., n, and the rotation angle of the flow control valve corresponding to the shift handle at different gears is α n degrees, and α n ≦ θ. Each gear of the shift handle corresponds to an external interrupt in the controller, each external interrupt corresponds to an interrupt function in the controller, and the number of pulses of the interrupt function is α n *N / 360, according to different gears, the controller simultaneously sends corresponding pulse numbers to the first motor and the second motor, and controls the first flow control valve and the second flow control valve through the first motor and the second motor respectively. S2, the controller judges the steering control signal of the steering wheel operation mechanism after the gear control signal is judged in step S1: The maximum rotation angle of the steering wheel clockwise and counterclockwise is β, the angle encoder detects the angle of the steering wheel clockwise and counterclockwise, and γ≦β, The rotation angle α of the flow control valve at different gears n Corresponding to the steering wheel rotation angle γ, the degree β that the flow control valve needs to rotate when the steering wheel rotates 1 degree with the middle position as the starting point is obtained n = 2α n / β, When the steering wheel is turned clockwise by γ degrees from the center position, the first motor remains stationary, and the controller controls the second motor to turn in the opposite direction |γβ. n |degrees, when the steering wheel returns to center by γ degrees, the first motor remains stationary, and the controller controls the second motor to return to its original position|γβ n |Degree, When the steering wheel is turned counterclockwise by γ degrees from the center position, the second motor remains stationary, and the controller controls the first motor to rotate in the opposite direction |γβ. n |degrees, when the steering wheel returns to center by γ degrees, the second motor remains stationary, and the controller controls the first motor to return to its original position|γβ n |Degree, By controlling the first motor and the second motor, the first hydraulic motor and the second hydraulic motor generate a speed difference, so as to control the tracked vehicle to turn.

8. The control method according to claim 7, characterized in that: The shift handle is provided with five gears, namely forward high gear D3, forward middle gear D2, forward low gear D1, parking gear P and reverse gear R, and the corresponding rotation angles of the flow control valves are α1, α2, α3, α4 and α5, wherein α1 is the maximum positive rotation opening of the flow control valve, α2 is the middle positive rotation opening of the flow control valve, α3 is the minimum positive rotation opening of the flow control valve, α4 is zero, and α5 is the minimum reverse rotation opening of the flow control valve; When the gear is the parking gear P, α4=0, the first motor and the second motor do not rotate, the first and second flow control valves are closed, and the displacement of the series variable piston pump is zero, so that the tracked vehicle is parked; When the gear is the forward high gear D3, the controller controls the first motor and the second motor to rotate in the positive direction by α1 degrees, the first and second flow control valves have the maximum positive opening, the flow of the series variable piston pump is the largest, the first and second hydraulic motors rotate in the positive direction at the fastest speed, and the tracked vehicle advances at the fastest speed; When the gear is the forward middle gear D2, the controller controls the first motor and the second motor to rotate in the positive direction by α2 degrees, the first and second flow control valves have the moderate positive opening, the flow of the series variable piston pump is moderate, the first and second hydraulic motors rotate in the positive direction at the moderate speed, and the tracked vehicle advances at the moderate speed; When the gear is the forward low gear D1, the controller controls the first motor and the second motor to rotate in the positive direction by α3 degrees, the first and second flow control valves have the minimum positive opening, the flow of the series variable piston pump is the smallest, the first and second hydraulic motors rotate in the positive direction at the slowest speed, and the tracked vehicle advances at the slowest speed; When the gear is the reverse gear R, the controller controls the first motor and the second motor to rotate in the reverse direction by α5 degrees, the first and second flow control valves rotate in the reverse direction, the first and second hydraulic motors rotate in the reverse direction, and the tracked vehicle retreats.

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