Crossing vertical obstacle control method for tandem double-swing-arm suspension system

Abstract

The application provides a control method for a series double-swing-arm suspension system to cross vertical obstacles. The control method controls the pressure of hydraulic oil and the transmission route of the hydraulic oil by driving the opening and closing combination of various electromagnetic valves in a hydraulic system and the opening and closing of a hydraulic pump, so as to realize the vertical freedom motion of a single wheel of a vehicle, the longitudinal freedom motion of the single wheel, and the motion combination of multiple wheels of the vehicle. The control method can drive the vertical hydraulic cylinder to elongate or compress to realize the rising or falling of the wheel in a suspended state, and the longitudinal hydraulic cylinder to elongate to realize the forward motion or backward motion of the suspension swing arm to drive the wheel, so as to change the single-side or double-side wheelbase of the vehicle. When obstacles that cannot be directly passed through or bypassed by a traditional motion mode are encountered, the control method can be switched to a wheel-leg walking mode, actively adjusts the relative position relationship between the wheel and the obstacle, changes the contact form of the wheel and the obstacle, and then changes the direction and size of the force received by the wheel, so as to improve the force received by the wheel and the suspension, and improve the ability of the vehicle to pass through the obstacles.

Description

Technical Field

[0001] This invention relates to a control method for wheeled vehicles equipped with a tandem double swing arm suspension system to cross vertical obstacles, belonging to the field of vehicles. Background Technology

[0002] Special vehicles performing special missions in urban or wilderness areas need to face various complex road environments, whether man-made or naturally formed. Wheeled vehicles equipped with traditional suspension systems, such as double wishbone, MacPherson strut, and multi-link systems, have limited suspension functionality, with only one controllable degree of freedom in the vertical direction. They can only adapt to complex terrain by actively adjusting the vehicle's attitude and height. This approach is far from meeting the actual needs of special vehicles, especially for two-axle, four-wheeled vehicles requiring high maneuverability. Adjusting the vehicle's attitude and height alone makes it difficult to traverse some high vertical obstacles and wide trenches. Adjusting the vehicle's attitude by separately controlling the suspension's vertical travel can only help the vehicle pass more stably over some side slopes and longitudinal slopes. Controlling the suspension height to change the ground clearance allows the vehicle to directly traverse some large gravel obstacles, improving its passability to some extent. However, due to limitations in wheelbase, tire size, and suspension travel, traditional suspension vehicles cannot overcome vertical obstacles exceeding the wheel's mid-diameter or trenches exceeding the wheel's diameter using common methods of adjusting vehicle attitude and height.

[0003] Vehicles equipped with a tandem double-swing arm wheel-leg suspension system combine the advantages of legged robots and wheeled vehicles, featuring high mobility and strong environmental adaptability. They can conduct wide-area surveys of terrain and traverse large obstacles. Wheel-leg vehicles, through coupled control of the vertical and longitudinal motion of the suspension and the rotational motion of the wheels, not only exhibit wheeled and legged gaits but also possess unique gait variations to adapt to complex and changing environments. However, currently, most vehicles equipped with wheel-leg suspensions are small and lightweight demonstration vehicles. Due to their small size and light weight, they primarily use motors to drive the joints to achieve gait movement. This drive actuator and control method are not suitable for large-tonnage special vehicles with heavy workloads. There is a need to develop new walking control methods suitable for hydraulic systems, specifically for hydraulically driven pneumatic wheel-leg suspensions. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a control method for wheeled vehicles equipped with a tandem double swing arm suspension system to cross vertical obstacles.

[0005] The specific technical solution is as follows:

[0006] A method for controlling vertical obstacle crossing with a tandem double swing arm suspension system, including...

[0007] 1) The rear suspension moves forward to its limit position, and the front wheel on one side moves backward to its limit position. Adjust the relative position of the vehicle's center of gravity and the support points of each wheel so that the projection of the vehicle's center of gravity on the ground falls within the triangular area formed by the front wheels that have moved backward to their limit positions.

[0008] 2) The other front wheel moves upward to its limit position and then forward to its limit position;

[0009] 3) The other front wheel moves downwards until it contacts the edge of the vertical obstacle and meets the set conditions;

[0010] 4) The front wheel, which has moved backward to its limit position, moves upward to its limit position, moves forward to its limit position, and moves downward until it contacts the edge of the vertical obstacle and meets the set conditions.

[0011] 5) Drive forward until the rear axle wheels are close to the vertical obstacle, then slowly lower the vehicle until the bottom deck of the vehicle touches the vertical obstacle.

[0012] 6) The rear wheel on one side moves upward to its limit position, forward to its limit position, and downward until it contacts the edge of the vertical obstacle and meets the set conditions.

[0013] 7) The other single rear wheel moves upward to its limit position, forward to its limit position, and downward until it contacts the vertical obstacle and meets the set conditions;

[0014] 8) Drive forward until the rear wheels are completely on the vertical obstacle.

[0015] Furthermore, the set condition is that the force state of the wheel contacting the obstacle is a combination of vertical support force and friction force.

[0016] Furthermore, the set conditions are that the vertical hydraulic cylinder pressure is greater than the pressure threshold, and the angle between the line connecting the edge and the wheel center and the horizontal plane is greater than the angle threshold.

[0017] Furthermore, the tandem double swing arm suspension system is driven by a hydraulic system, which includes a first charging / discharging integrated valve (1), a second charging / discharging integrated valve (2), a first normally open integrated valve (3), a second normally open integrated valve (4), an oil supply distribution valve (5), a third charging / discharging integrated valve (6), a fourth charging / discharging integrated valve (7), a third normally open integrated valve (8), a fourth normally open integrated valve (9), a main oil tank (10), a first hydraulic lock (11), a second hydraulic lock (12), a third hydraulic lock (13), a fourth hydraulic lock (14), a fifth hydraulic lock (15), and a sixth hydraulic lock. Hydraulic lock (16), seventh hydraulic lock (17), eighth hydraulic lock (18), hydraulic pump (19), fine filter (20), first locking integrated valve (21), second locking integrated valve (22), third locking integrated valve (23), fourth locking integrated valve (24), left wheel 1 longitudinal hydraulic cylinder (25), right wheel 1 longitudinal hydraulic cylinder (26), left wheel 1 vertical hydraulic cylinder (27), right wheel 1 vertical hydraulic cylinder (28), left wheel 2 longitudinal hydraulic cylinder (29), right wheel 2 longitudinal hydraulic cylinder (30), left wheel 2 vertical hydraulic cylinder (31), right wheel 2 vertical hydraulic cylinder (32).

[0018] Furthermore, the control method for the forward and backward movement of the left wheel suspension assembly (33) is as follows: after starting the hydraulic pump (19) and the oil supply distribution valve (5) to supply power and allow oil to enter the main oil circuit, the hydraulic oil is controlled to pass through the first charging and discharging integrated valve (1) and the first hydraulic lock (11) in sequence to enter the left wheel longitudinal hydraulic cylinder (25). By pushing the left wheel longitudinal hydraulic cylinder (25), the left wheel vertical arm (38) is driven, which in turn drives the left wheel suspension assembly (33) to achieve forward and backward movement.

[0019] The control method for the front and rear movement of the left 2 wheel suspension assembly (35) is as follows: control hydraulic oil flows into the left 2 wheel longitudinal hydraulic cylinder (29) through the third oil filling and draining integrated valve (6) and the fifth hydraulic lock (15) in sequence. By pushing the left 2 wheel longitudinal hydraulic cylinder (29) to drive the left 2 vertical arm (44), the left 2 wheel suspension assembly (35) will move forward and backward.

[0020] The control method for the forward and backward movement of the right wheel suspension assembly (34) is as follows: control the hydraulic oil to flow into the right wheel longitudinal hydraulic cylinder (26) through the first charging and discharging integrated valve (1) and the second hydraulic lock (12) in sequence. By pushing the right wheel longitudinal hydraulic cylinder 26, the right wheel vertical arm (39) is driven, which in turn drives the right wheel suspension assembly (34) to move forward and backward.

[0021] The control method for the forward and backward movement of the right 2nd wheel suspension assembly (36) is as follows: control the hydraulic oil to flow into the right 2nd wheel longitudinal hydraulic cylinder (30) through the third charging and discharging integrated valve (6) and the sixth hydraulic lock (16) in sequence. By pushing the right 2nd wheel longitudinal hydraulic cylinder (30) to drive the right 2nd vertical arm (41), the right 2nd wheel suspension assembly (36) will move forward and backward.

[0022] Furthermore, the control method for the up-and-down movement of the left wheel suspension assembly (33) is as follows: control the hydraulic oil to flow into the left wheel vertical hydraulic cylinder (27) through the second charging and discharging integrated valve (2) and the third hydraulic lock (13) in sequence, push the left wheel vertical hydraulic cylinder (27) to contract, so that the left trailing arm (37) drives the left wheel suspension assembly (33) to move up and down; among them, when moving downward, control the second normally open integrated valve (4) to de-energize, so that the rod chamber of the left wheel vertical hydraulic cylinder (27) is connected to the accumulator of the right wheel suspension assembly (34), balance the pressure of the rod chamber of the left wheel vertical hydraulic cylinder (27), ensure that there is pressure in the charging circuit, and release the hydraulic control check valve of the return oil circuit of the third hydraulic lock (13);

[0023] The control method for the up-and-down movement of the left 2 wheel suspension assembly (35) is as follows: control the hydraulic oil to flow into the left 2 wheel vertical hydraulic cylinder (31) through the fourth charging and discharging integrated valve (7) and the seventh hydraulic lock (17) in sequence, push the left 2 wheel vertical hydraulic cylinder (31) to contract, so that the left 2 wheel vertical hydraulic cylinder (31) drives the left 2 wheel suspension assembly (35) to move up and down; among them, when moving downward, control the third normally open integrated valve (8) to de-energize, so that the rod chamber of the left 2 wheel vertical hydraulic cylinder (31) is connected to the accumulator of the right 2 wheel suspension assembly (36), balance the pressure of the rod chamber of the left 2 wheel vertical hydraulic cylinder (31), ensure that there is pressure in the charging circuit, and release the hydraulic control check valve of the return oil circuit of the seventh hydraulic lock (17);

[0024] The control method for the up-and-down movement of the right wheel suspension assembly (34) is as follows: control the hydraulic oil to flow into the right wheel vertical hydraulic cylinder (28) through the second charging and discharging integrated valve (2) and the fourth hydraulic lock (14) in sequence, push the right wheel vertical hydraulic cylinder (28) to contract, realize the right 1 longitudinal arm (40) to move upward and drive the right wheel suspension assembly (34) to move upward; when moving downward, control the first normally open integrated valve (3) to de-energize, so that the rod chamber of the right wheel vertical hydraulic cylinder (28) is connected to the accumulator of the left wheel suspension assembly (33), balance the pressure of the rod chamber of the right wheel vertical hydraulic cylinder (28), ensure that there is pressure in the charging circuit, and unlock the hydraulic control check valve of the return oil circuit of the fourth hydraulic lock (14);

[0025] The control method for the up-and-down movement of the right 2nd wheel suspension assembly (36) is as follows: control the hydraulic oil to flow into the right 2nd wheel vertical hydraulic cylinder (32) through the fourth charging and discharging integrated valve (7) and the eighth hydraulic lock (18) in sequence, push the right 2nd wheel vertical hydraulic cylinder (32) to contract, so that the right 2nd wheel vertical hydraulic cylinder (32) drives the right 2nd wheel suspension assembly (36) to move up and down; when moving downward, control the fourth normally open integrated valve (9) to de-energize, so that the rod chamber of the right 2nd wheel vertical hydraulic cylinder (32) is connected to the accumulator of the left 2nd wheel suspension assembly (35), balance the pressure of the rod chamber of the right 2nd wheel vertical hydraulic cylinder (32), ensure that there is pressure in the charging circuit, and release the hydraulic control check valve of the return oil circuit of the eighth hydraulic lock (18).

[0026] Beneficial effects

[0027] 1. This system enables the forward and backward movement of the vertical arm and the up and down movement of the longitudinal arm in a tandem double-wishbone hydropneumatic suspension, allowing for changes in both wheelbase and track width. A series of complex motion sequences drive the vertical hydraulic cylinders of the suspension system to extend or compress, raising or lowering the wheels. Extending the longitudinal hydraulic cylinders causes the suspension arms to move the wheels forward or backward, altering the wheelbase on one or both sides of the vehicle. The driving force of the wheels propels the vehicle forward or backward.

[0028] 2. The innovative hydraulically driven suspension system control method enables two hydraulic actuators to drive the vertical and longitudinal control arms respectively, actively achieving wheel movement in both forward / backward and vertical directions, thus enabling wheel-leg-like movement. When encountering obstacles that cannot be directly passed or bypassed using traditional methods, the tandem double-swing arm hydro-pneumatic suspension system can switch to wheel-leg walking mode, actively adjusting the relative position of the wheels and the obstacle. By changing the contact pattern between the wheels and the obstacle, it alters the direction and magnitude of the force on the wheels, improving the stress on the wheels and suspension, and enhancing the vehicle's obstacle-crossing ability.

[0029] 3. This control method enables vehicles to traverse vertical obstacles using a combined wheel-leg walking mode, breaking away from the traditional obstacle-crossing mode where wheeled vehicles rely on the high torque output of the motor to forcefully propel the rear wheels and pull the front wheels across vertical obstacles. By actively adjusting the relative positions of the wheel support points and the vehicle's center of gravity through the suspension's forward and backward, and up and down dual-degree-of-freedom movement, the method ensures stable forward movement even with one wheel suspended and the other three supported. By actively changing the relative positions of the wheel and the vertical obstacle contact point through a wheel-lifting and leg-stepping motion, the method alters the wheel's force state. This transforms the force state of the wheel contacting the obstacle from a purely frictional state to a combined state of vertical support force and friction. This allows the wheel's driving torque to be used to overcome the resistance of the vehicle's forward movement, rather than to overcome the vehicle's weight and lift it. This more effectively utilizes the motor's driving capability during vertical obstacle crossing. With the same driving torque output from the motor, this significantly improves the vehicle's obstacle-crossing ability and greatly enhances the passability of four-wheel-drive wheeled vehicles. Attached Figure Description

[0030] Figure 1 Tandem double swing arm hydropneumatic suspension hydraulic system

[0031] Figure 2 Hierarchical planning and control strategy

[0032] Figure 3 Exploded view of the obstacle crossing process using wheel-legged method

[0033] Figure 4 Schematic diagram of the actuator

[0034] Figure 5 Flowchart for overcoming vertical obstacles Detailed Implementation

[0035] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0036] The tandem double wishbone suspension system obstacle crossing control method is primarily designed for four-wheeled special vehicles traversing vertical obstacles. This control method consists of a series of control commands. By controlling the opening and closing combinations of various solenoid valves in the hydraulic system and the switching of the hydraulic pump, the pressure and transmission path of the hydraulic oil are controlled to achieve the vertical and longitudinal freedom of movement of individual wheels, as well as the combined movement of multiple wheels. Leveraging the suspension system's hydraulic system's ability to simultaneously adjust and lock the wheelbase of the front and rear axles and the vertical position of the wheels, the tandem double wishbone suspension system adjusts the vehicle's suspension state to complete a series of complex actions, maximizing the vehicle's obstacle crossing capabilities.

[0037] The tandem double swing arm suspension system is driven by a hydraulic system, which consists of: 1-injection / discharge integrated valve, 2-injection / discharge integrated valve, 3-normally open integrated valve, 4-normally open integrated valve, 5-oil supply distribution valve, 6-injection / discharge integrated valve, 7-injection / discharge integrated valve, 8-normally open integrated valve, 9-normally open integrated valve, 10-main oil tank, 11-hydraulic lock, 12-hydraulic lock, 13-hydraulic lock, 14-hydraulic lock, 15-hydraulic lock, 16-hydraulic lock, 17-hydraulic lock, 18- Hydraulic lock, 19-Hydraulic pump, 20-Fine filter, 21-Lock-off integrated valve, 22-Lock-off integrated valve, 23-Lock-off integrated valve, 24-Lock-off integrated valve, 25-Left 1 wheel longitudinal hydraulic cylinder, 26-Right 1 wheel longitudinal hydraulic cylinder, 27-Left 1 wheel vertical hydraulic cylinder, 28-Right 1 wheel vertical hydraulic cylinder, 29-Left 2 wheel longitudinal hydraulic cylinder, 30-Right 2 wheel longitudinal hydraulic cylinder, 31-Left 2 wheel vertical hydraulic cylinder, 32-Right 2 wheel vertical hydraulic cylinder, hydraulic lines and other accessories, as shown in the attached document. Figure 1 The tandem double swing arm hydropneumatic suspension hydraulic system is shown.

[0038] During normal driving, the locking integrated valve is in the normally open state. The vertical hydraulic cylinders 27 (left wheel 1), 28 (right wheel 1), 31 (left wheel 2), and 32 (right wheel 2) are connected to the accumulator to form the air-hydraulic spring assembly. The suspension stiffness ensures smoothness, high-speed driving ability, climbing ability, and off-road passability during normal off-road driving. During normal driving, the normally open integrated valves 3, 4, 8, and 9 are in the normally open state. At this time, the vehicle's hydraulic interconnection function is activated, and the counter-pressure chamber of the left air-hydraulic spring is connected to the right spring accumulator. This effectively increases the vehicle's roll stiffness, reduces roll during high-speed cornering, and significantly improves stability during off-road driving.

[0039] This control method divides the process of a two-axle vehicle equipped with a tandem double-wishbone suspension system climbing a vertical obstacle into four processes, totaling eight steps (see below): the front wheels stepping over the vertical obstacle, the drive wheels moving the vehicle body forward, the rear wheels gripping the vertical obstacle with the vehicle's bottom plate as support, and the drive wheels completely crossing the vertical obstacle. The suspension vertical obstacle crossing control method adopts a rule-based hierarchical planning control strategy, comprising three parts: online planning of behavior command sequences, construction of a behavior interpretation knowledge base, and establishment of a motion control strategy. To improve the universality of the planning control strategy and meet the mission requirements of special vehicles, a rule-based hierarchical planning control strategy is used for wheel-leg walking to cross vertical obstacles. A multi-sensor detection system efficiently analyzes the special vehicle's pose and environmental information. The behavior planning layer provides behavior command sequences for vehicle behavior decisions, while the motion planning layer provides drive commands for the suspension system's hydraulic actuators based on an offline-built behavior interpretation knowledge base. After driving the special vehicle, its motion state changes are fed back to the behavior planning layer, thereby iteratively updating the vehicle's motion and ultimately driving the vehicle to complete the mission requirements, as shown in the attached diagram. Figure 2 As shown.

[0040] Online planning of behavior command sequences. A hierarchical planning control strategy based on a rule base. A multi-sensor detection system incorporating multi-flow information is constructed to efficiently analyze the pose and environmental information of special vehicles, based on obstacle calibration and recognition results. Referring to the vehicle's kinematics and dynamics model, macro commands (behavior command sequences) for robot behavior decisions are provided online using the behavior planning layer.

[0041] Construction of the Behavior Interpretation Knowledge Base. After completing the online planning of the behavior command sequence, it is necessary to establish the relationship between the behavior command sequence and the action command sequence using the behavior interpretation knowledge base. For typical vertical obstacles, the behavior commands and action commands are manually calibrated. Based on the results of the online behavior sequence planning, the behavior sequence is decomposed into a command sequence using the behavior interpretation knowledge base. The system monitors whether conditions are triggered at a preset frequency and executes the command sequence sequentially based on the condition judgment.

[0042] The implementation process of the tandem double swing arm suspension system for vertical obstacle crossing control is divided into 8 steps.

[0043] Before the obstacle crossing process begins, it is necessary to energize valves 3-normally open integrated valve, 4-normally open integrated valve, 8-normally open integrated valve, 9-normally open integrated valve, 21-locked integrated valve, 22-locked integrated valve, 23-locked integrated valve, and 24-locked integrated valve to close the relevant oil circuits, so as to ensure that the wheel leg movement can proceed smoothly during the obstacle crossing process.

[0044] Step 1: Move the rear suspension forward to its limit position and the left front wheel backward to its limit position. Adjust the relative position of the vehicle's center of gravity and the wheel support points, aligning the projection of the vehicle's center of gravity onto the ground within the triangular area formed by the support points of the left front wheel, right rear wheel, and left rear wheel. Start the 19-hydraulic pump, allowing hydraulic oil supplied by the 5-oil distribution valve to flow into the main hydraulic system's oil circuit from port A of the 5-oil distribution valve. Connect the P port and ZC port of the 1-charge / discharge integrated valve, and connect the T port and ZF port. The hydraulic oil flows sequentially through the P port and ZC port of the 1-charge / discharge integrated valve, and the 11-hydraulic lock into the rodless chamber of the 25-left 1 wheel longitudinal hydraulic cylinder, pushing the 25-left 1 wheel longitudinal hydraulic cylinder to extend. The pressure in the charging circuit releases the 11-hydraulic lock, and the hydraulic oil in the rod chamber of the return oil circuit hydraulic control check valve flows sequentially through the ZF port and T port of the 1-charge / discharge integrated valve back to the 10-main oil tank, causing the 38-left 1 drop arm to move backward, driving the 33-left 1 wheel suspension assembly to move backward. After the left wheel suspension assembly moves backward to the designated position, control 5-oil supply distribution valve is de-energized, 1-filling and draining integrated valve is de-energized and returns to the neutral position, and 19-hydraulic pump is shut down.

[0045] The control valve 6 connects port P to port ZF and port T to port ZC. Hydraulic oil flows sequentially through port P and port ZF of the control valve 6 and through port 15 (hydraulic lock) into the rod chamber of the longitudinal hydraulic cylinder of wheel 29 (left 2nd wheel), pushing the cylinder to retract. Pressure in the charging circuit releases the hydraulic control check valve of the return circuit of the hydraulic lock (port 15). Hydraulic oil in the rodless chamber flows sequentially through port ZC and port T of the control valve 6 back to the main oil tank (port 10), causing the left 2nd drop arm (port 44) to move forward, driving the suspension assembly of wheel 35 (left 2nd wheel) forward. After the suspension assembly of wheel 35 (left 2nd wheel) moves forward to the designated position, the control valve 5 (oil supply distribution valve) is de-energized, the control valve 6 (charge / discharge integrated valve) is de-energized and returns to the neutral position, and the hydraulic pump (port 19) is shut down.

[0046] The control valve 6 connects port P to port YF and port T to port YC. Hydraulic oil flows sequentially through port P and port YF of the control valve 6 and through port 16 (hydraulic lock) into the rod chamber of the longitudinal hydraulic cylinder of wheel 30 (right 2nd wheel), pushing the cylinder to retract. Pressure in the charging circuit releases the hydraulic control check valve of the return circuit of the hydraulic lock (port 16). Hydraulic oil in the rodless chamber returns sequentially through port YC and port T of the control valve 6 to the main oil tank (port 10), causing the right 2nd drop arm (port 41) to move forward, driving the suspension assembly of wheel 36 (right 2nd wheel) forward. After the suspension assembly of wheel 36 (right 2nd wheel) moves forward to the designated position, the control valve 5 (oil supply distribution valve) is de-energized, the control valve 6 (charge / discharge integrated valve) is de-energized and returns to the neutral position, and the hydraulic pump (port 19) is shut down.

[0047] Step 2: Move the right front wheel upwards to its limit position, then move the right front wheel forward to its limit position. Start the 19-hydraulic pump, allowing hydraulic oil supplied by the 5-oil supply distribution valve to flow into the main oil circuit of the hydraulic system from port A of the 5-oil supply distribution valve. Control the 2-charge / discharge integrated valve to connect port P to port YC and port T to port YF. Hydraulic oil flows sequentially through port P, port YC of the 2-charge / discharge integrated valve, and port 14-hydraulic lock into the rod chamber of the 28-right 1 wheel vertical hydraulic cylinder, pushing the 28-right 1 wheel vertical hydraulic cylinder to retract. Pressure in the charging circuit releases the hydraulic control check valve of the 14-hydraulic lock return oil circuit. Hydraulic oil in the rodless chamber returns sequentially through port YF and port T of the 2-charge / discharge integrated valve to the 10-main oil tank, thus enabling the 40-right 1 trailing arm to move upwards, driving the 34-right 1 wheel suspension assembly to move upwards. 34-After the right wheel suspension assembly moves upward to the designated position, control 5-the oil supply distribution valve is de-energized, 2-the oil filling and draining integrated valve is de-energized and returns to the neutral position, and 19-the hydraulic pump is shut down;

[0048] Control 1 - Connect port P and port YF of the integrated charging / draining valve, and port T and port YC. Hydraulic oil flows sequentially through port P and port YF of the integrated charging / draining valve, and through port 15 (hydraulic lock) into the rod chamber of the right wheel longitudinal hydraulic cylinder (26), pushing the cylinder to retract. Pressure in the charging circuit releases the hydraulic control check valve in the return circuit of the hydraulic lock (12). Hydraulic oil in the rodless chamber flows sequentially through port YC and port T of the integrated charging / draining valve back to the main oil tank (10), causing the right wheel drop arm (39) to move forward, driving the right wheel suspension assembly (34) forward. After the right wheel suspension assembly (34) moves forward to the designated position, control 5 - de-energizes the oil supply distribution valve, and control 1 - de-energizes the integrated charging / draining valve back to the neutral position, shutting off the hydraulic pump (19).

[0049] Step 3: Move the right front wheel downwards until it contacts the edge of the vertical obstacle and the pressure in the vertical hydraulic cylinder is greater than 8 MPa. The angle between the line connecting the edge and the wheel center and the horizontal plane is greater than 40 degrees. Start the 19-hydraulic pump, so that the hydraulic oil supplied by the 5-oil supply distribution valve flows into the main oil circuit of the hydraulic system from port A of the 5-oil supply distribution valve. Control the 2-filling and discharging integrated valve to connect port P and port YF, and port T and port YC. The hydraulic oil flows sequentially through port P and port YF of the 2-filling and discharging integrated valve, and port 14-hydraulic lock into the rodless chamber of the 28-right wheel 1 vertical hydraulic cylinder, pushing the 28-right wheel 1 vertical hydraulic cylinder to extend. De-energize the normally open integrated valve 3, connecting the rod chamber of the right wheel 1 vertical hydraulic cylinder 28 to the accumulator of the left wheel 1 suspension assembly 33. This balances the pressure in the rod chamber of the right wheel 1 vertical hydraulic cylinder 28, ensuring pressure in the charging circuit. Release the hydraulic control check valve 14 of the hydraulic lock return circuit, allowing the hydraulic oil in the rod chamber to return to the main oil tank 10 via the YC and T ports of the charging / draining integrated valve 2. This causes the right wheel 1 to move downwards, driving the right wheel 1 suspension assembly 34 to move downwards. After the right wheel 1 suspension assembly 34 moves downwards to the designated position, de-energize the oil supply distribution valve 5, de-energize the charging / draining integrated valve 2, returning it to the neutral position, energize the normally open integrated valve 3, and shut down the hydraulic pump 19.

[0050] Step 4: Move the left front wheel upwards to its limit position, then forwards to its limit position, and finally downwards until it contacts the edge of the vertical obstacle and the pressure in the vertical hydraulic cylinder exceeds 8 MPa. The angle between the line connecting the edge and the wheel center and the horizontal plane is greater than 40 degrees. Start the 19-hydraulic pump, allowing hydraulic oil supplied by the 5-oil distribution valve to flow into the main oil circuit of the hydraulic system from port A of the 5-oil distribution valve. Control the 2-filling / draining integrated valve to connect port P and port ZF, and port T and port ZC. Hydraulic oil flows sequentially through port P and port ZF of the 2-filling / draining integrated valve and port 13-hydraulic lock into the rod chamber of the 27-left 1 wheel vertical hydraulic cylinder, pushing the 27-left 1 wheel vertical hydraulic cylinder to contract. Pressure in the filling circuit releases the hydraulic control check valve of the 1-hydraulic lock return oil circuit. Hydraulic oil in the rodless chamber returns sequentially through port ZC and port T of the 2-filling / draining integrated valve to the 10-main oil tank, thus enabling the 37-left 1 trailing arm to move upwards, driving the 33-left 1 wheel suspension assembly to move upwards. 33-After the left 1st wheel suspension assembly moves upward to the designated position, control 5-oil supply distribution valve is de-energized, 2-filling and draining integrated valve is de-energized and returns to the neutral position, and 19-hydraulic pump is shut down;

[0051] Start the 19-hydraulic pump, allowing hydraulic oil supplied to the 5-supply distribution valve to flow into the main hydraulic circuit from port A of the 5-supply distribution valve. Connect the P port and ZF port, and the T port and ZC port of the 1-charge / discharge integrated valve. Hydraulic oil flows sequentially through the P port and ZF port of the 1-charge / discharge integrated valve, and then through the 11-hydraulic lock into the rod chamber of the 25-left 1 wheel longitudinal hydraulic cylinder, pushing the 25-left 1 wheel longitudinal hydraulic cylinder to retract. Pressure in the charging circuit releases the hydraulic control check valve of the 11-hydraulic lock return circuit. Hydraulic oil in the rodless chamber returns sequentially through the ZC port and T port of the 1-charge / discharge integrated valve to the 10-main oil tank, causing the 38-left 1 drop arm to move forward, driving the 33-left 1 wheel suspension assembly forward. After the 33-left 1 wheel suspension assembly moves forward to the designated position, de-energize the 5-supply distribution valve, de-energize the 1-charge / discharge integrated valve back to the neutral position, and shut down the 19-hydraulic pump.

[0052] Start the 19-hydraulic pump, allowing hydraulic oil supplied to the 5-oil supply distribution valve to flow into the main oil circuit of the hydraulic system from port A of the 5-oil supply distribution valve. Connect the P port and ZC port of the 2-charge / discharge integrated valve, and connect the T port and ZF port. The hydraulic oil flows sequentially through the P port and ZC port of the 2-charge / discharge integrated valve, and then through the 13-hydraulic lock into the rodless chamber of the 27-left 1 wheel vertical hydraulic cylinder, pushing the 27-left 1 wheel vertical hydraulic cylinder to extend. De-energize the 4-normally open integrated valve, connecting the rod chamber of the 27-left 1 wheel vertical hydraulic cylinder to the accumulator of the 34-right 1 wheel suspension assembly, balancing the pressure in the rod chamber of the 27-left 1 wheel vertical hydraulic cylinder and ensuring pressure in the charging circuit. Release the 13-hydraulic lock return oil circuit hydraulic control check valve, allowing the hydraulic oil in the rod chamber to return sequentially through the ZF port and T port of the 2-charge / discharge integrated valve to the 10-main oil tank, enabling the 37-left 1 trailing arm to move downwards, driving the 33-left 1 wheel suspension assembly downwards. 33-After the left 1st wheel suspension assembly moves downward to the designated position, control 5-oil supply distribution valve to de-energize, control 2-oil charging and discharging integrated valve to de-energize and return to the neutral position, control 4-normally open integrated valve to energize, and shut down 19-hydraulic pump;

[0053] Step 5: Move forward until the rear axle wheels are close to the vertical obstacle, then slowly lower the vehicle until the bottom plate at the rear of the vehicle touches the vertical obstacle.

[0054] Step 6: The left rear wheel moves upward to its limit position, then forward to its limit position, and finally downward until it contacts the edge of the vertical obstacle and the pressure in the vertical hydraulic cylinder is greater than 8 MPa. The angle between the line connecting the edge and the wheel center and the horizontal plane is greater than 35 degrees. Start the 19-hydraulic pump, so that the hydraulic oil supplied by the 5-oil distribution valve flows into the main oil circuit of the hydraulic system from the A port of the 5-oil distribution valve. Control the 7-filling and discharging integrated valve to connect the P port and ZF port, and the T port and ZC port. The hydraulic oil flows sequentially through the P port and ZF port of the 7-filling and discharging integrated valve, and the 17-hydraulic lock into the rod chamber of the 31-left 2 wheel vertical hydraulic cylinder, pushing the 31-left 2 wheel vertical hydraulic cylinder to retract. The pressure in the filling circuit releases the hydraulic control check valve of the 17-hydraulic lock return oil circuit. The hydraulic oil in the rodless chamber returns to the 10-main oil tank sequentially through the ZC port and T port of the 7-filling and discharging integrated valve, realizing the upward movement of the 43-left 2 trailing arm, which drives the 35-left 2 wheel suspension assembly to move upward. Now, after the left 2nd wheel suspension assembly moves upward to the designated position, control 5 - oil supply distribution valve is de-energized, 7 - oil filling and draining integrated valve is de-energized and returns to the neutral position, and 19 - hydraulic pump is shut down;

[0055] Start the 19-hydraulic pump, allowing hydraulic oil supplied to the 5-oil supply distribution valve to flow into the main hydraulic circuit from port A of the 5-oil supply distribution valve. Connect the P port and ZF port, and the T port and ZC port of the 6-charge / discharge integrated valve. Hydraulic oil flows sequentially through the P port and ZF port of the 6-charge / discharge integrated valve, and then through the 15-hydraulic lock into the rod chamber of the 29-left 2 wheel longitudinal hydraulic cylinder, pushing the 29-left 2 wheel longitudinal hydraulic cylinder to retract. Pressure in the charging circuit releases the hydraulic control check valve of the 15-hydraulic lock return circuit. Hydraulic oil in the rodless chamber returns sequentially through the ZC port and T port of the 6-charge / discharge integrated valve to the 10-main oil tank, causing the 44-left 2 drop arm to move forward, driving the 35-left 2 wheel suspension assembly forward. After the 35-left 2 wheel suspension assembly moves forward to the designated position, de-energize the 5-oil supply distribution valve, de-energize the 6-charge / discharge integrated valve to return to the neutral position, and shut down the 19-hydraulic pump.

[0056] Start the 19-hydraulic pump, allowing hydraulic oil supplied to the 5-oil supply distribution valve to flow into the main oil circuit of the hydraulic system from port A of the 5-oil supply distribution valve. Connect the P port and ZC port of the 7-charge / discharge integrated valve, and connect the T port and ZF port. The hydraulic oil flows sequentially through the P port and ZC port of the 7-charge / discharge integrated valve, and then through the 17-hydraulic lock into the rodless chamber of the 31-left 2 wheel vertical hydraulic cylinder, pushing the 31-left 2 wheel vertical hydraulic cylinder to extend. De-energize the 8-normally open integrated valve, connecting the rod chamber of the 31-left 2 wheel vertical hydraulic cylinder to the accumulator of the 36-right 2 wheel suspension assembly, balancing the pressure in the rod chamber of the 31-left 2 wheel vertical hydraulic cylinder and ensuring pressure in the charging circuit. Release the 17-hydraulic lock return oil circuit hydraulic control check valve, allowing the hydraulic oil in the rod chamber to return sequentially through the ZF port and T port of the 7-charge / discharge integrated valve to the 10-main oil tank, enabling the 43-left 2 trailing arm to move downwards, driving the 35-left 2 wheel suspension assembly downwards. 35 - After the left 2nd wheel suspension assembly moves downward to the designated position, control 5 - de-energize the oil supply distribution valve, control 7 - de-energize the oil filling and draining integrated valve to return to the neutral position, control 8 - normally open integrated valve to be energized, and shut down 19 - hydraulic pump;

[0057] Step 7: The right rear wheel moves upward to its limit position, then forward to its limit position, and finally downward until it contacts the vertical obstacle and the pressure in the vertical hydraulic cylinder is greater than 8 MPa. The angle between the line connecting the edge and the wheel center and the horizontal plane is greater than 35 degrees. Start the 19-hydraulic pump, so that the hydraulic oil supplied by the 5-oil supply distribution valve flows into the main oil circuit of the hydraulic system from the A port of the 5-oil supply distribution valve. Control the 7-filling and discharging integrated valve to connect the P port and YC port, and the T port and YF port. The hydraulic oil flows sequentially through the P port and YC port of the 7-filling and discharging integrated valve, and the 18-hydraulic lock into the rod chamber of the 32-right 2 wheel vertical hydraulic cylinder, pushing the 32-right 2 wheel vertical hydraulic cylinder to retract. The pressure in the filling circuit releases the 18-hydraulic lock return oil circuit hydraulic control check valve rodless chamber hydraulic oil sequentially returns to the 10-main oil tank through the YF port and T port of the 7-filling and discharging integrated valve, realizing the upward movement of the 42-right 2 trailing arm, which drives the 36-right 2 wheel suspension assembly to move upward. 36 - After the right 2-wheel suspension assembly moves upward to the designated position, control 5 - the oil supply distribution valve is de-energized, 7 - the charging and discharging integrated valve is de-energized and returns to the neutral position, and 19 - the hydraulic pump is shut down;

[0058] The control valve 6 connects port P to port YF and port T to port YC. Hydraulic oil flows sequentially through port P and port YF of the control valve 6 and through port 16 (hydraulic lock) into the rod chamber of the longitudinal hydraulic cylinder of wheel 30 (right 2nd wheel), pushing the cylinder to retract. Pressure in the charging circuit releases the hydraulic control check valve of the return circuit of the hydraulic lock (port 16). Hydraulic oil in the rodless chamber returns sequentially through port YC and port T of the control valve 6 to the main oil tank (port 10), causing the right 2nd drop arm (port 41) to move forward, driving the suspension assembly of wheel 36 (right 2nd wheel) forward. After the suspension assembly of wheel 36 (right 2nd wheel) moves forward to the designated position, the control valve 5 (oil supply distribution valve) is de-energized, the control valve 6 (charge / discharge integrated valve) is de-energized and returns to the neutral position, and the hydraulic pump (port 19) is shut down.

[0059] Start the 19-hydraulic pump, allowing hydraulic oil supplied to the 5-oil supply distribution valve to flow into the main oil circuit of the hydraulic system from port A of the 5-oil supply distribution valve. Connect the P port and YF port, and the T port and YC port of the 7-charge / discharge integrated valve. The hydraulic oil flows sequentially through the P port, YF port of the 7-charge / discharge integrated valve, and the 18-hydraulic lock into the rodless chamber of the 32-right 2-wheel vertical hydraulic cylinder, pushing the 32-right 2-wheel vertical hydraulic cylinder to extend. De-energize the 9-normally open integrated valve, connecting the 32-right 2-wheel vertical hydraulic cylinder's rod chamber to the 35-left 2-wheel suspension assembly accumulator, balancing the pressure in the 31-right 2-wheel vertical hydraulic cylinder's rod chamber and ensuring pressure in the charging circuit. Release the 18-hydraulic lock return oil circuit hydraulic control check valve, allowing the hydraulic oil in the rod chamber to return sequentially through the YC port and T port of the 7-charge / discharge integrated valve to the 10-main oil tank, enabling the 42-right 2-wing arm to move downwards, driving the 36-right 2-wheel suspension assembly downwards. 36 - After the right 2nd wheel suspension assembly moves downward to the designated position, control 5 - de-energize the oil supply distribution valve, control 7 - de-energize the oil filling and draining integrated valve to return to the neutral position, control 9 - normally open integrated valve to be energized, and shut down 19 - hydraulic pump;

[0060] Step 8: Drive forward until the rear wheels are completely on the vertical obstacle. During the drive, the vehicle's bottom plate will automatically detach from the vertical obstacle due to the change in the wheel contact position.

[0061] It should be noted that the present invention is a control method for vertical obstacle crossing of a tandem double swing arm suspension system. The control method is simple and clear, easy to implement, and reliable in performance. It can be easily understood by those skilled in the art. The control method for vertical obstacle crossing of a tandem double swing arm suspension system designed in this invention can be implemented on different types of vehicle bodies. Furthermore, various modifications and alterations can be made to the present invention without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A method for controlling vertical obstacle crossing with a tandem double swing arm suspension system, characterized in that: 1) The rear suspension moves forward to its limit position, and the front wheel on one side moves backward to its limit position. Adjust the relative position of the vehicle's center of gravity and the support points of each wheel so that the projection of the vehicle's center of gravity on the ground falls within the triangular area formed by the front wheels that have moved backward to their limit positions. 2) The other front wheel moves upward to its limit position and then forward to its limit position; 3) The other front wheel moves downwards until it contacts the edge of the vertical obstacle and meets the set conditions; 4) The front wheel, which has moved backward to its limit position, moves upward to its limit position, moves forward to its limit position, and moves downward until it contacts the edge of the vertical obstacle and meets the set conditions. 5) Drive forward until the rear axle wheels are close to the vertical obstacle, then slowly lower the vehicle until the bottom deck of the vehicle touches the vertical obstacle. 6) The rear wheel on one side moves upward to its limit position, forward to its limit position, and downward until it contacts the edge of the vertical obstacle and meets the set conditions. 7) The other single rear wheel moves upward to its limit position, forward to its limit position, and downward until it contacts the vertical obstacle and meets the set conditions; 8) Drive forward until the rear wheels are completely on the vertical obstacle.

2. The method for controlling vertical obstacle crossing of a tandem double swing arm suspension system according to claim 1, characterized in that: The set condition is that the force state of the wheel in contact with the obstacle is a combination of vertical support force and friction force.

3. The method for controlling vertical obstacle crossing of a tandem double swing arm suspension system according to claim 2, characterized in that: The set conditions are that the vertical hydraulic cylinder pressure is greater than the pressure threshold, and the angle between the line connecting the edge and the center of the wheel and the horizontal plane is greater than the angle threshold.

4. A method for controlling vertical obstacle crossing of a tandem double swing arm suspension system according to any one of claims 1-3, characterized in that: The tandem double swing arm suspension system is driven by a hydraulic system, which includes a first charging / draining integrated valve (1), a second charging / draining integrated valve (2), a first normally open integrated valve (3), a second normally open integrated valve (4), an oil supply distribution valve (5), a third charging / draining integrated valve (6), a fourth charging / draining integrated valve (7), a third normally open integrated valve (8), a fourth normally open integrated valve (9), a main oil tank (10), a first hydraulic lock (11), a second hydraulic lock (12), a third hydraulic lock (13), a fourth hydraulic lock (14), a fifth hydraulic lock (15), and a sixth hydraulic lock (6). 16), Seventh hydraulic lock (17), Eighth hydraulic lock (18), Hydraulic pump (19), Fine filter (20), First locking integrated valve (21), Second locking integrated valve (22), Third locking integrated valve (23), Fourth locking integrated valve (24), Left 1 wheel longitudinal hydraulic cylinder (25), Right 1 wheel longitudinal hydraulic cylinder (26), Left 1 wheel vertical hydraulic cylinder (27), Right 1 wheel vertical hydraulic cylinder (28), Left 2 wheel longitudinal hydraulic cylinder (29), Right 2 wheel longitudinal hydraulic cylinder (30), Left 2 wheel vertical hydraulic cylinder (31), Right 2 wheel vertical hydraulic cylinder (32).

5. The method for controlling vertical obstacle crossing of a tandem double swing arm suspension system according to claim 4, characterized in that: The control method for the forward and backward movement of the left wheel suspension assembly (33) is as follows: after starting the hydraulic pump (19) and the oil supply distribution valve (5) to supply power and make the oil enter the main oil circuit, the hydraulic oil is controlled to pass through the first charging and discharging integrated valve (1) and the first hydraulic lock (11) in sequence to enter the left wheel longitudinal hydraulic cylinder (25). By pushing the left wheel longitudinal hydraulic cylinder (25), the left wheel vertical arm (38) is driven, which in turn drives the left wheel suspension assembly (33) to achieve forward and backward movement. The control method for the front and rear movement of the left 2 wheel suspension assembly (35) is as follows: control hydraulic oil flows into the left 2 wheel longitudinal hydraulic cylinder (29) through the third oil filling and draining integrated valve (6) and the fifth hydraulic lock (15) in sequence. By pushing the left 2 wheel longitudinal hydraulic cylinder (29) to drive the left 2 vertical arm (44), the left 2 wheel suspension assembly (35) will move forward and backward. The control method for the front and rear movement of the right wheel suspension assembly (34) is as follows: control the hydraulic oil to flow into the right wheel longitudinal hydraulic cylinder (26) through the first filling and draining integrated valve (1) and the second hydraulic lock (12) in sequence. By pushing the right wheel longitudinal hydraulic cylinder 26, the right wheel vertical arm (39) is driven, which in turn drives the right wheel suspension assembly (34) to move back and forth. The control method for the forward and backward movement of the right 2nd wheel suspension assembly (36) is as follows: control the hydraulic oil to flow into the right 2nd wheel longitudinal hydraulic cylinder (30) through the third charging and discharging integrated valve (6) and the sixth hydraulic lock (16) in sequence. By pushing the right 2nd wheel longitudinal hydraulic cylinder (30) to drive the right 2nd vertical arm (41), the right 2nd wheel suspension assembly (36) will move forward and backward.

6. The method for controlling vertical obstacle crossing of a tandem double swing arm suspension system according to claim 4, characterized in that: The control method for the up-and-down movement of the left wheel suspension assembly (33) is as follows: control the hydraulic oil to flow into the left wheel vertical hydraulic cylinder (27) through the second charging and discharging integrated valve (2) and the third hydraulic lock (13) in sequence, push the left wheel vertical hydraulic cylinder (27) to contract, so that the left trailing arm (37) drives the left wheel suspension assembly (33) to move up and down; when moving downward, control the second normally open integrated valve (4) to de-energize, so that the rod chamber of the left wheel vertical hydraulic cylinder (27) is connected to the accumulator of the right wheel suspension assembly (34), balance the pressure of the rod chamber of the left wheel vertical hydraulic cylinder (27), ensure that there is pressure in the charging circuit, and unlock the hydraulic control check valve of the return oil circuit of the third hydraulic lock (13); The control method for the up-and-down movement of the left 2 wheel suspension assembly (35) is as follows: control the hydraulic oil to flow into the left 2 wheel vertical hydraulic cylinder (31) through the fourth charging and discharging integrated valve (7) and the seventh hydraulic lock (17) in sequence, push the left 2 wheel vertical hydraulic cylinder (31) to contract, so that the left 2 wheel vertical hydraulic cylinder (31) drives the left 2 wheel suspension assembly (35) to move up and down; among them, when moving downward, control the third normally open integrated valve (8) to de-energize, so that the rod chamber of the left 2 wheel vertical hydraulic cylinder (31) is connected to the accumulator of the right 2 wheel suspension assembly (36), balance the pressure of the rod chamber of the left 2 wheel vertical hydraulic cylinder (31), ensure that there is pressure in the charging circuit, and release the hydraulic control check valve of the return oil circuit of the seventh hydraulic lock (17); The control method for the up-and-down movement of the right wheel suspension assembly (34) is as follows: control the hydraulic oil to flow into the right wheel vertical hydraulic cylinder (28) through the second charging and discharging integrated valve (2) and the fourth hydraulic lock (14) in sequence, push the right wheel vertical hydraulic cylinder (28) to contract, realize the right 1 longitudinal arm (40) to move upward and drive the right wheel suspension assembly (34) to move upward; when moving downward, control the first normally open integrated valve (3) to de-energize, so that the rod chamber of the right wheel vertical hydraulic cylinder (28) is connected to the accumulator of the left wheel suspension assembly (33), balance the pressure of the rod chamber of the right wheel vertical hydraulic cylinder (28), ensure that there is pressure in the charging circuit, and unlock the hydraulic control check valve of the return oil circuit of the fourth hydraulic lock (14); The control method for the up-and-down movement of the right 2nd wheel suspension assembly (36) is as follows: control the hydraulic oil to flow into the right 2nd wheel vertical hydraulic cylinder (32) through the fourth charging and discharging integrated valve (7) and the eighth hydraulic lock (18) in sequence, push the right 2nd wheel vertical hydraulic cylinder (32) to contract, so that the right 2nd wheel vertical hydraulic cylinder (32) drives the right 2nd wheel suspension assembly (36) to move up and down; when moving downward, control the fourth normally open integrated valve (9) to de-energize, so that the rod chamber of the right 2nd wheel vertical hydraulic cylinder (32) is connected to the accumulator of the left 2nd wheel suspension assembly (35), balance the pressure of the rod chamber of the right 2nd wheel vertical hydraulic cylinder (32), ensure that there is pressure in the charging circuit, and release the hydraulic control check valve of the return oil circuit of the eighth hydraulic lock (18).

Images