Integrated electro-hydraulic control closed type suspension walking supporting leg system and control method

Abstract

The invention discloses an integrated electro-hydraulic control closed type suspension walking supporting leg system and a control method. The closed type suspension walking supporting leg system comprises a walking control unit, a suspension control unit and a wheel assembly. Each of the suspension control unit and the walking control unit comprises a two-way pump, a servo motor, a proportional reversing valve and an execution element; the servo motor is connected with the two-way pump; two control oil ports and two execution oil ports are formed in the proportional reversing valve, the two control oil ports are communicated with the two oil ports of the two-way pump respectively, and the two execution oil ports are communicated with the two oil ports of the execution element; an execution element of the walking control unit is a hydraulic motor, and an execution element of the suspension control unit is a double-outlet-rod oil cylinder. Wherein the walking control unit is communicated with the suspension control unit through a first oil way, and a first two-position one-way valve is arranged in the first oil way. The supporting leg system integrates walking and suspension electro-hydraulic control systems, can independently complete supporting leg steady state posture control, and is high in integration, small in size and fast in response.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electro-hydraulic control, in particular to a closed suspension walking outrigger system integrated with electro-hydraulic control and a control method. BACKGROUND

[0002] In the outrigger system of the automatic control mobile platform, part of the suspension system adopts a mechanical structure, such as a steel plate spring structure or a shock baffle structure. However, the mechanical structure is difficult to adapt to heavy load and variable load scenes, and has poor ability to adapt to heavy load impact during movement, cannot timely adjust the change of suspension retraction position, is not suitable for complex scenes, and has poor adaptability to the road. When facing complex road conditions, the response speed is slow. Part of the suspension system adopts an oil-gas suspension or an independent hydraulic suspension system. In heavy load conditions, multiple support points are used for leveling to control the balance and stability of the platform. However, the oil-gas suspension structure is complex, has high manufacturing and maintenance costs, and the sealing element is prone to aging and damage, which can easily lead to system leakage and affect system performance. The independent hydraulic suspension system uses an open hydraulic system and multiple pipeline layouts for long-distance arrangement when multiple outriggers or multiple suspension combinations are used. There are problems such as increase in oil tank volume and increase in system leakage points. At the same time, due to the increase in the elastic modulus characteristics of the hydraulic oil and the loss of the hydraulic pipeline, the control response speed of the system is slow, and the control stability is poor.

[0003] The walking system is usually driven by a combination of an engine, a speed reducer and a drive axle, or by a multi-axis hydraulic motor speed reduction method. However, the mechanical driving method is suitable for light and medium loads, and has insufficient capacity for heavy load driving, and the structure is complex, with high use and maintenance costs. In the electric driving method, the energy density of the battery is relatively low, and the endurance capacity is limited, requiring frequent charging. The external power supply needs to lay cables or build infrastructure such as contact nets, which will limit the activity range of the platform, increase the construction cost and the use limitation. The hydraulic driving system can meet the needs of heavy load mobile platforms, but the leakage problem is more prominent, which not only causes environmental pollution, but also affects the working performance and efficiency of the system.

[0004] In related technologies, the suspension system and the walking system are difficult to achieve high-speed response and stable control in heavy load scenes, different speed conditions and different road conditions. SUMMARY

[0005] The present application aims to solve at least one of the technical problems in the prior art. To this end, one object of the present application is to provide a closed suspension walking outrigger system integrated with electro-hydraulic control and a control method, which aims to solve the problem that the outrigger system of the mobile platform is difficult to achieve high-speed response and stable control in heavy load scenes, different speed conditions and different road conditions.

[0006] The application provides an integrated electro-hydraulic control closed suspension walking support leg system, which comprises a walking control unit, a suspension control unit and a wheel assembly; the suspension control unit comprises a first bidirectional pump, a first servo motor, a double-rod oil cylinder and a suspension control valve group; the first servo motor is connected with the first bidirectional pump; the suspension control valve group comprises a first proportional directional valve; the first proportional directional valve is formed with two first control oil ports and two first execution oil ports, the two first control oil ports are communicated with two oil ports of the first bidirectional pump respectively, and the two first execution oil ports are communicated with two oil ports of the double-rod oil cylinder; the walking control unit comprises a second bidirectional pump, a second servo motor, a hydraulic motor and a walking control valve group; the second servo motor is connected with the second bidirectional pump; the walking control valve group comprises a second proportional directional valve, the second proportional directional valve is formed with two second control oil ports and two second execution oil ports, the two second control oil ports are communicated with two oil ports of the second bidirectional pump respectively, and the two second execution oil ports are communicated with two oil ports of the hydraulic motor; wherein the walking control unit is communicated with the suspension control unit through a first oil path, a first two-position two-way valve suitable for controlling on-off of the first oil path is arranged in the first oil path; and the wheel assembly is connected with the hydraulic motor and the double-rod oil cylinder.

[0007] According to some embodiments of the application, the suspension control valve group further comprises a first overflow valve, the first overflow valve is connected with the first bidirectional pump in parallel, the first overflow valve is constructed as two and is reversely arranged; the walking control valve group further comprises a second overflow valve, the second overflow valve is connected with the second bidirectional pump in parallel, the second overflow valve is constructed as two and is reversely arranged.

[0008] According to some embodiments of the application, the suspension control valve group further comprises a first accumulator and a first three-position two-way valve; the first accumulator is suitable for storing hydraulic oil; the first three-position two-way valve is formed with a first oil inlet, a first upper oil outlet, a first lower oil outlet and a middle oil port; the first oil inlet is communicated with the first accumulator; the first upper oil outlet and the first lower oil outlet are communicated with oil outlets of the two first overflow valves respectively; the middle oil port is communicated with the first oil path; upper and lower cavities of the first three-position two-way valve are communicated with oil inlets of the two first overflow valves respectively, so that one of the first upper oil outlet and the first lower oil outlet is selectively communicated with the first oil inlet under the action of oil pressure;

[0009] The walking control valve group further comprises a second accumulator and a second three-position two-way valve; the second accumulator is adapted to store hydraulic oil; the second three-position two-way valve is formed with a second oil inlet, a second upper oil outlet and a second lower oil outlet; the second oil inlet is communicated with the second accumulator through a supplementary oil pipeline; the second upper oil outlet and the second lower oil outlet are respectively communicated with oil outlets of two second overflow valves; a supplementary oil port is arranged on the supplementary oil pipeline; upper and lower cavities of the second three-position two-way valve are respectively communicated with oil inlets of the two second overflow valves, so as to selectively connect one of the second upper oil outlet and the second lower oil outlet to the second oil inlet under the action of oil pressure.

[0010] According to some embodiments of the present application, the wheel assembly comprises a brake; the suspension control valve group further comprises a first high-pressure one-way selection valve, two oil inlets of the first high-pressure one-way selection valve are respectively communicated with two oil ports of the first bidirectional pump; an oil outlet of the first high-pressure one-way selection valve is communicated with the brake through a second oil path, and a second three-position two-way valve is arranged on the second oil path.

[0011] According to some embodiments of the present application, the walking control valve group further comprises a second high-pressure one-way selection valve, two oil inlets of the second high-pressure one-way selection valve are respectively communicated with two oil ports of the second bidirectional pump, and an oil outlet of the second high-pressure one-way selection valve is communicated with the first oil path.

[0012] According to some embodiments of the present application, a pressure reducing valve is arranged in each of the first oil path and the second oil path.

[0013] According to some embodiments of the present application, pressure sensors are arranged on the two oil ports of the first bidirectional pump and the two oil ports of the second bidirectional pump.

[0014] According to some embodiments of the present application, a damping hole is formed in each of the upper cavity and the lower cavity of the first three-position two-way valve, and the damping hole is communicated with the middle cavity of the first proportional reversing valve.

[0015] The present application further provides a control method of the integrated electro-hydraulic control closed suspension walking outrigger system, and the control method comprises the following steps:

[0016] a dynamic model and a hydraulic system model of the outrigger system are constructed;

[0017] a small-amplitude high-frequency response output control model in a high-speed running state, a large-amplitude high-frequency response output control model in a low-speed running state and a sine high-frequency impact load adaptive control model in a stationary or parking brake state are established;

[0018] actual state parameters of the outrigger system are collected when the outrigger system is running, parking braking or stationary;

[0019] Adapt to the constant load in the vertical direction as the expected attitude, obtain the difference between the actual state parameters of the outrigger system and the standard parameters of the expected attitude; adopt a discrete PID control method to perform feedforward compensation on displacement and lag compensation on pressure.

[0020] According to some embodiments of the application, when the plurality of outrigger systems are combined, the control method further comprises:

[0021] According to the operating conditions, the control model of each outrigger system is selected and called, and the control signals of each outrigger system are calculated and output according to the operating instruction parameters and the attitude standard parameters;

[0022] The feedback operating parameters of each outrigger system are collected, front and rear compensation calculations are performed, and then closed-loop iterative integration is performed with the attitude standard parameters to output the corrected control instruction to drive each outrigger system to achieve the expected attitude.

[0023] According to the closed suspension walking outrigger system and the control method, the closed hydraulic control system is adopted, the servo motor controls the output flow of the bidirectional pump, the flow and pressure of the walking hydraulic motor are provided, and the flow and pressure of the suspension double-rod cylinder are provided, the combination of the pump control volume speed regulation mode and the valve control throttling speed regulation mode based on the servo motor is realized, and the advantages and functions of the two are possessed. Moreover, the closed hydraulic circuit is adopted to replace the open hydraulic circuit system, the volume is reduced, there is no external connecting pipeline, the leakage points and fault points can be reduced, the system configuration is more compact, the space occupation is less, and the response is faster. The single outrigger system integrated with the walking and suspension electro-hydraulic control system can independently complete the outrigger steady attitude control, is highly integrated, has small volume and fast response speed, can solve the problems of the stable attitude control of the heavy load single outrigger under the uneven road condition and the low-speed large-amplitude road steady attitude control, and makes the outrigger system of the mobile platform realize high-speed response and stable control under the heavy load scene, different speed conditions and different road conditions.

[0024] Further, the closed suspension walking outrigger system can be controlled in multiple groups, multiple integrated electro-hydraulic control closed suspension walking outrigger systems are combined in parallel to provide large heavy load platform or heavy load multi-axle joint travel control and multiple suspension joint control.

[0025] Additional aspects and advantages of the application will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following and / or can be learned by practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0026] The above and / or additional aspects and advantages of the application will become apparent and be readily understood by considering the following detailed description, from which the above-mentioned aspects and advantages will become apparent and be readily understood, in which:

[0027] Figure 1is a structural schematic diagram of a closed suspension walking outrigger system according to some embodiments of the present application;

[0028] Figure 2 is a structural sectional view of a wheel assembly according to some embodiments of the present application;

[0029] Figure 3 is a structural sectional view of a wheel assembly according to some embodiments of the present application;

[0030] Figure 4 is a schematic diagram of the combined cooperative control of a multi-outrigger system according to some embodiments of the present application.

[0031] Reference signs:

[0032] First servo motor 101; first bidirectional pump 102; first pressure sensors 103a, 103b; first high-pressure selection check valve 104; first pressure reducing valve 105; first overflow valves 106a, 106b; first three-position two-way valve 107; damping holes 107a, 107b; first accumulator 108; first proportional directional valve 109; double-rod cylinder 110; displacement sensor 111; second two-position two-way electromagnetic valve 112; suspension control valve group 120;

[0033] Second servo motor 201; second bidirectional pump 202; second pressure sensors 203a, 203b; second high-pressure selection check valve 204; second pressure reducing valve 205; second overflow valves 206a, 206b; second three-position two-way valve 207; second accumulator 208; second proportional directional valve 209; hydraulic motor 210; rotational speed sensor 211; first two-position two-way electromagnetic valve 212; oil supplement port 213; walking control valve group 220;

[0034] Hub tire 301; drive axle 302; speed reducer 303; brake 304. DETAILED DESCRIPTION

[0035] Embodiments of the present application are described in detail below with reference to examples illustrated in the accompanying drawings, in which the same or similar components have the same or similar designations throughout, and in which:

[0036] Reference is made below to Figures 1-3 A closed suspension walking outrigger system with integrated electro-hydraulic control according to embodiments of the present application is described.

[0037] The application provides an integrated electro-hydraulic control closed suspension walking support leg system, which comprises a walking control unit, a suspension control unit and a wheel assembly; the suspension control unit comprises a first bidirectional pump 102, a first servo motor 101, a double-rod oil cylinder 110 and a suspension control valve group 120; the first servo motor 102 is connected with the first bidirectional pump 102; the suspension control valve group 120 comprises a first proportional directional valve 109; the first proportional directional valve 109 is formed with two first control oil ports and two first execution oil ports, the two first control oil ports are communicated with two oil ports of the first bidirectional pump 102 respectively, and the two first execution oil ports are communicated with two oil ports of the double-rod oil cylinder 110; the walking control unit comprises a second bidirectional pump 202, a second servo motor 201, a hydraulic motor 210 and a walking control valve group 220; the second servo motor 201 is connected with the second bidirectional pump 202; the walking control valve group 220 comprises a second proportional directional valve 209, the second proportional directional valve 209 is formed with two second control oil ports and two second execution oil ports, the two second control oil ports are communicated with two oil ports of the second bidirectional pump 202 respectively, and the two second execution oil ports are communicated with two oil ports of the hydraulic motor 210; wherein the walking control unit is communicated with the suspension control unit through a first oil line, a first two-position two-way valve 212 suitable for controlling the on-off of the first oil line is arranged in the first oil line; and the wheel assembly is connected with the hydraulic motor 210 and the double-rod oil cylinder 110.

[0038] According to the closed suspension walking support leg system, the first bidirectional pump 102 is formed with an oil port 102a and an oil port 102b, the two oil ports are communicated with two control oil ports of the first proportional directional valve 109 through oil lines respectively, two execution oil ports of the first proportional directional valve 109 are communicated with two oil ports of the double-rod oil cylinder 110, and a closed hydraulic system is formed; the first proportional directional valve 109 is powered on the left and right sides, the extension direction and extension displacement of the double-rod oil cylinder 110 are proportionally controlled; the first servo motor 101 drives the first bidirectional pump 102 to operate and controls the operation direction of the first bidirectional pump 102, so that the switching of the oil discharge direction is realized; the extension direction and extension speed of the double-rod oil cylinder 110 can be controlled by changing the oil discharge direction of the first bidirectional pump 102; wherein when the oil port 102a discharges oil, the oil line communicated therewith is an oil supply pipeline, i.e. the oil supply side of the suspension system, and the oil line communicated with the oil port 102b is an oil return pipeline, i.e. the oil return side of the suspension system; when the oil port 102b discharges oil, the situation is reversed.

[0039] The second bidirectional pump 202 is formed with an oil port 202a and an oil port 202b, both of which are communicated with two control oil ports of the second proportional directional valve 209 through oil lines, two execution oil ports of the second proportional directional valve 209 are communicated with two oil ports of the hydraulic motor 210, forming a closed hydraulic system; the second proportional directional valve 209 is powered on the left and right, and the rotation direction and rotation speed of the proportional control hydraulic motor 210 are controlled. The second servo motor 201 can control the running direction of the second bidirectional pump 202, realizing the switching of the oil discharge direction; by changing the oil discharge direction of the second bidirectional pump 202, the rotation speed and rotation direction of the hydraulic motor 210 can be controlled. Among them, when the oil port 202a discharges oil, the oil line connected therewith is the oil supply pipeline, and the oil line connected with the oil port 202b is the oil return pipeline; when the oil port 202b discharges oil, it is the opposite.

[0040] Further, the walking control unit and the suspension control unit are connected through the first oil line, so that the hydraulic oil can flow between the two units, and are integrated into a closed outrigger system. Among them, the first two-position one-way valve 212 can control the on-off of the first oil line. Specifically, the first two-position one-way valve 212 is configured as an electromagnetic valve, when the first two-position one-way valve 212 is not powered, the first oil line is disconnected; when the first two-position one-way valve 212 is powered, the oil of the walking control unit is supplemented to the suspension system through the first oil line.

[0041] In the prior art, the mobile platform usually has multiple outriggers, each of which has multiple independent suspension and walking control units, and the structure of the hydraulic system is connected through multiple and long pipelines, the response speed is slow, and the influence of pipeline vibration and rupture loss is large; when multiple outriggers are used cooperatively, the synchronization stability and reliability of multiple motors, oil cylinders and other control adjustments are low. The integrated closed hydraulic system adopted by the present application has a compact structure, can reduce pipeline connection and improve response speed.

[0042] The closed suspension walking outrigger system according to the present application adopts a closed electro-hydraulic control system, controls the output flow of a bidirectional pump through a servo motor, provides the flow and pressure of a walking hydraulic motor, and simultaneously provides the flow and pressure of a suspension double-rod oil cylinder, realizes the combination of the pump control volume speed regulation mode and the valve control throttling speed regulation mode based on the servo motor, and simultaneously has the advantages and functions of both; moreover, the closed hydraulic circuit is adopted to replace the open hydraulic circuit system, the volume is reduced, there is no external connecting pipeline, the leakage points and fault points can be reduced, the system configuration is more compact, the space occupation is less, and the response is faster. The single outrigger system integrated with the walking and suspension electro-hydraulic control system can independently complete the outrigger steady state attitude control, is highly integrated, small in volume and fast in response speed, can solve the problems of the stable attitude control of a heavy load single outrigger under the high-speed working condition of uneven road and the low-speed large-amplitude road steady state attitude control, and enables the outrigger system of the mobile platform to realize high-speed response and stable control under the heavy load scene, different speed working conditions and different road working conditions.

[0043] Further, the closed suspension walking outrigger system according to the present application can be controlled in multiple groups, realizes the parallel combination of multiple integrated electro-hydraulic control closed suspension walking outrigger systems, and provides the multi-axle joint travel control and multiple suspension joint control of a large heavy load platform or heavy load.

[0044] In some embodiments, as shown in FIG. 3, Figure 1 , 2 The wheel assembly includes a hub tire 301, a drive axle 302, a speed reducer 303, a brake 304, the hydraulic motor 210 is connected with the speed reducer 303, the speed reducer 303 is connected with the drive axle 302, the drive axle 302 is connected with the hub tire 301, and the speed reducer 303 is connected with the brake 304. The hub tire 301 is the basic part of the wheel, responsible for supporting the weight of the vehicle and contacting the ground. The speed reducer 303 is connected between the hydraulic motor 210 and the drive axle 302, and functions to reduce the rotating speed and increase the torque; the hydraulic motor 210 serves as a power source, transmits power to the drive axle 302 through the speed reducer 303, and the drive axle 302 is responsible for transmitting power to the hub tire 301; at the same time, the speed reducer 303 is also connected with the brake 304, which can be used for power cut-off or speed reduction during braking.

[0045] In some embodiments, the wheel assembly further includes a rotating speed sensor 211, the hydraulic motor 210 is connected with the rotating speed sensor 211, and the rotating speed sensor 211 can monitor the rotating speed of the hydraulic motor 210 in real time. Further, the outrigger system further includes a controller, the detection result of the rotating speed sensor 211 is fed back to the controller, and walking control calculation can be performed.

[0046] In some embodiments, the cylinder rod of the double-rod cylinder 110 is connected to the drive axle 302, and the cylinder barrel is the interface for the outrigger system to be connected to the outside. The double-rod cylinder 110 is embedded with a displacement sensor 111, which can detect the position signal of the double-rod cylinder 110 and feed back to the controller for suspension control calculation.

[0047] In some embodiments, as shown in FIG. 2, the walking control valve group 220 is arranged on the wheel assembly and connected to the drive axle 302; the second bidirectional pump 202 is directly embedded with the valve block of the walking control valve group 220, and the oil ports of each valve are connected through the oil channels inside the valve block. The suspension control valve group 120 is fixedly embedded with the double-rod cylinder 110; the first bidirectional pump 102 is directly embedded with the valve block of the suspension control valve group 120, and the connection between the oil ports of each valve is through the oil channels inside the valve block. This embodiment can reduce the pipeline pressure loss, reduce the leakage points, and increase the response efficiency of the system. Figure 3

[0048] In the above embodiments, the outrigger system adopts the embedded connection of the pump and the valve group, and uses the internal pipeline to connect the oil ports, which can further reduce the leakage points, make the system configuration more compact, and respond faster.

[0049] According to some embodiments of the present application, the suspension control valve group 120 further comprises a first overflow valve, which is connected in parallel with the first bidirectional pump 102, and the first overflow valve is configured as two and arranged reversely; the walking control valve group 220 further comprises a second overflow valve, which is connected in parallel with the second bidirectional pump 202, and the second overflow valve is configured as two and arranged reversely.

[0050] In this embodiment, the overflow valve acts as a safety valve. When the pressure in the oil circuit exceeds the set value, the valve port opens, and the excess oil is transported to the low-pressure side oil circuit, preventing the hydraulic motor 210, double-rod cylinder 110 and other elements from being damaged due to overpressure. The overflow valve can protect the oil port pressure of the bidirectional pump, stabilize the system pressure, and maintain the smooth operation of the executing elements. Specifically, as shown in FIG. 2, the overflow valve is connected to the oil port of the bidirectional pump through the oil circuit, and the valve port is opened when the pressure exceeds the set value, so that the excess oil is transported to the low-pressure side oil circuit. Figure 1 ​As shown, the first overflow valves are configured as two, i.e. the first overflow valve 106a and the first overflow valve 106b; the oil inlet of the first overflow valve 106a is communicated with the oil port 102b of the first bidirectional pump 102, and the oil outlet is communicated with the oil port 102a of the first bidirectional pump 102; when the oil pressure of the oil port 102b reaches a certain limit, the first overflow valve 106a is opened to allow the hydraulic oil to flow to the oil port 102a, i.e. the low-pressure oil return side of the system. The first overflow valve 106b has the same operating principle, the oil inlet is communicated with the oil port 102a of the first bidirectional pump 102, and the oil outlet is communicated with the oil port 102b of the first bidirectional pump 102; when the oil pressure on the oil port 102a side is too high, the valve is opened to allow the hydraulic oil to flow from the high-pressure side to the low-pressure side of the oil port 102b. Similarly, the second overflow valves are configured as two, i.e. the second overflow valve 206a and the second overflow valve 206b; the oil inlet of the second overflow valve 206a is communicated with the oil port 102b of the second bidirectional pump 202, and the oil outlet is communicated with the oil port 102a of the second bidirectional pump 202; the oil inlet of the second overflow valve 206b is communicated with the oil port 102a of the second bidirectional pump 202, and the oil outlet is communicated with the oil port 102b of the second bidirectional pump 202; when the oil pressure of the high-pressure side of the second bidirectional pump 202 is too high, the hydraulic oil flows to the low-pressure side.

[0051] According to some embodiments of the present application, the suspension control valve group 120 further comprises a first accumulator 108 and a first three-position two-way valve 107; the first accumulator 108 is adapted to store hydraulic oil; the first three-position two-way valve 107 is formed with a first oil inlet, a first upper oil outlet, a first lower oil outlet and a middle oil outlet; the first oil inlet is communicated with the first accumulator 108; the first upper oil outlet and the first lower oil outlet are respectively communicated with the oil outlets of the two first overflow valves; the middle oil outlet is communicated with the first oil circuit; the upper chamber and the lower chamber of the first three-position two-way valve 107 are respectively communicated with the oil inlets of the two first overflow valves, so as to selectively connect one of the first upper oil outlet and the first lower oil outlet to the first oil inlet under the action of oil pressure.

[0052] The travel control valve group 220 further comprises a second accumulator 208 and a second three-position two-way valve 207; the second accumulator 208 is adapted to store hydraulic oil; the second three-position two-way valve 207 is formed with a second oil inlet, a second upper oil outlet and a second lower oil outlet; the second oil inlet is communicated with the second accumulator 208 through a replenishing oil circuit; the second upper oil outlet and the second lower oil outlet are respectively communicated with the oil outlets of the two second overflow valves; a replenishing oil port 213 is arranged on the replenishing oil circuit; the upper chamber and the lower chamber of the second three-position two-way valve 207 are respectively communicated with the oil inlets of the two second overflow valves, so as to selectively connect one of the second upper oil outlet and the second lower oil outlet to the second oil inlet under the action of oil pressure.

[0053] In this embodiment, the increased oil supply pressure of the bidirectional pump drives the three-position one-way valve to operate, enabling the accumulator to replenish oil to the system. By setting up the accumulator and the three-position one-way valve, oil can be replenished to the closed system to compensate for oil losses caused by leakage, compressibility, or thermal expansion, thus maintaining stable system pressure. Specifically, the accumulator functions to replenish oil, and the three-position one-way valve can switch the oil replenishment path, controlling the connection between the accumulator and the closed system. When the valve core of the three-position one-way valve is in the neutral position, the accumulator is isolated from the closed loop, and the system maintains the current pressure. When the valve core is in the upper or lower position, the accumulator is connected to the low-pressure side of the system, releasing stored oil to replenish oil losses.

[0054] Specifically, in the suspension control unit, the first three-position one-way valve 107 has an upper chamber and a lower chamber, and a spring for controlling the position of the valve core is installed in the chamber. For example... Figure 1 As shown, the upper chamber is connected to the inlet of the first relief valve 106a via a control oil circuit, and the lower chamber is connected to the inlet of the first relief valve 106b via a control oil circuit. Oil is supplied from one side of the second bidirectional pump 102. When oil exits from port 102b of the first bidirectional pump 102, and the pressure difference between the oil pressure at port 102b and port 102a reaches a certain limit, i.e., the pressure at the inlet of the first relief valve 106a increases, the second three-position one-way valve 107 connects to the control port of the control oil circuit for oil intake. When the oil pressure exceeds the spring return force, the spring deforms and pushes the valve core to switch positions, connecting the first inlet and the first upper outlet. The hydraulic oil in the first accumulator 108 flows to the low-pressure side of the system through the first inlet and the first upper outlet, replenishing the low-pressure side of the closed system. When oil flows out of port 102a and the pressure difference between the supply side and the return side is greater than the spring return force, the first inlet port and the first lower outlet port are connected, and the hydraulic oil in the first accumulator 108 flows to the low-pressure side to replenish the system. When the control oil at both ends and its own return spring are balanced, the first three-position one-way valve 107 stays in the middle position, and the first accumulator 108 is filled with liquid.

[0055] Furthermore, the first oil circuit is connected to the middle position oil port of the second three-position one-way valve 107, and the first two-position one-way valve 212 is constructed as a solenoid valve, the outlet of which is connected to the middle position oil outlet of the first three-position one-way valve 107; when the first two-position one-way valve 212 is not energized, the first oil circuit is disconnected; when the first two-position one-way solenoid valve 212 is energized, the working oil in the travel control unit flows to the first accumulator 108 through the first oil circuit and the first three-position one-way valve 107, replenishing the first accumulator 108 with oil.

[0056] In the walking control unit, the control principle and the oil supplement principle of the second three-position two-way valve 207 are the same as those of the first three-position two-way valve 107. The second three-position two-way valve 207 is formed with an upper cavity and a lower cavity, and a spring for controlling the position of the valve core is arranged in the cavity. The middle oil outlet of the second three-position two-way valve 207 is closed. One side of the second double-acting pump 202 is supplied with oil. When the oil inlet pressure of the second overflow valve 206a increases, the control oil port of the second three-position two-way valve 207 is connected with the control oil, and when the oil pressure is greater than the spring restoring force of the second three-position two-way valve 207, the valve core is pushed to change position, the second oil inlet is communicated with the second lower oil outlet, the second accumulator 208 outputs hydraulic oil, and flows to the outlet end of the second overflow valve 206a to supplement the low-pressure side of the closed system. When the oil inlet pressure of the second overflow valve 206b increases, and the oil pressure is greater than the spring restoring force of the second three-position two-way valve 207, the second oil inlet is communicated with the second upper oil outlet, and the hydraulic oil in the second accumulator 208 flows to the outlet end of the second overflow valve 206b to supplement the low-pressure side of the closed system. When the two ends of the second three-position two-way valve 207 are balanced by the control oil and the self-resetting spring, the valve core stays in the middle position, the middle oil outlet is closed, and the second accumulator 208 does not release hydraulic oil.

[0057] Further, in the walking control unit, an oil supplement port 213 is arranged on the oil supplement pipeline connecting the second accumulator 208 and the second oil inlet, so that an external oil source can be used to inject and supplement oil to the outrigger system, to provide continuous and stable oil supplement, and to ensure sufficient oil during long-term operation of the system. Further, the oil injected from the walking control unit through the oil supplement port 213 can flow into the suspension control unit through the first oil pipeline, to maintain stable operation of the entire outrigger system.

[0058] According to some embodiments of the present application, the wheel assembly comprises a brake 304; the suspension control valve group 120 further comprises a first high-pressure one-way selection valve 104, two oil inlets of the first high-pressure one-way selection valve 104 are communicated with two oil ports of the first double-acting pump 102 respectively; an oil outlet of the first high-pressure one-way selection valve 104 is communicated with the brake 304 through a second oil pipeline, and a second three-position two-way valve 112 is arranged on the second oil pipeline.

[0059] In the present embodiment, the second oil pipeline and the second three-position two-way valve 112 are arranged to realize hydraulic control of the brake of the wheel assembly by the suspension control unit. Specifically, the second three-position two-way valve 112 is configured as an electromagnetic valve, and an outlet thereof is communicated with an oil port of the brake 304; when the second three-position two-way valve 112 is not powered, the hydraulic oil of the suspension control unit is communicated with the brake 304 through the second oil pipeline to release the brake; when the second three-position two-way valve 112 is powered, the second oil pipeline is disconnected, the brake 304 is started, and the brake stops the walking rotation.

[0060] Further, by setting the first high-pressure one-way selection valve 104, the oil path selection in communication with the second oil path can be realized, so that the second oil path is always in communication with the high-pressure side of the system. Specifically, the first high-pressure one-way selection valve 104 is formed with two oil inlet ports and one oil outlet port; the oil inlet ports are connected with the oil port 102a and the oil port 102b of the first bidirectional pump 102 respectively, when the first bidirectional pump 102 works, the two oil inlet ports of the first high-pressure one-way selection valve 104 generate different pressure differences, the pressure is compared, the oil outlet port is connected with the oil inlet port with larger pressure, that is, when the pressure of the oil port 102a is greater than that of the oil port 102b, the hydraulic oil on the side of the oil port 102a enters the first high-pressure one-way selection valve 104, and flows to the second oil path from the oil outlet port; when the pressure of the oil port 102b is greater than that of the oil port 102a, the hydraulic oil on the side of the oil port 102b enters the first high-pressure one-way selection valve 104, and flows to the second oil path from the oil outlet port.

[0061] According to some embodiments of the application, the walking control valve group further comprises a second high-pressure one-way selection valve 204, two oil inlet ports of the second high-pressure one-way selection valve 204 are in communication with two oil ports of the second bidirectional pump 202 respectively, and an oil outlet port of the second high-pressure one-way selection valve 204 is in communication with the first oil path. Similarly to the principle of the first high-pressure one-way selection valve 104, in this embodiment, by setting the second high-pressure one-way selection valve 204, the oil path selection in communication with the first oil path can be realized, so that the first oil path is always in communication with the high-pressure side of the system. Specifically, the second high-pressure one-way selection valve 204 is formed with two oil inlet ports and one oil outlet port; the oil inlet ports are connected with the oil port 202a and the oil port 202b of the second bidirectional pump 202 respectively, when the second bidirectional pump 202 works, the two oil inlet ports of the second high-pressure one-way selection valve 204 generate different pressure differences, the pressure is compared, the oil outlet port is connected with the oil inlet port with larger pressure, that is, when the pressure of the oil port 202a is greater than that of the oil port 202b, the hydraulic oil on the side of the oil port 202a enters the second high-pressure one-way selection valve 204, and flows to the first oil path from the oil outlet port; when the pressure of the oil port 202b is greater than that of the oil port 202a, the hydraulic oil on the side of the oil port 202b enters the second high-pressure one-way selection valve 204, and flows to the first oil path from the oil outlet port.

[0062] According to some embodiments of the present application, a pressure reducing valve is arranged in each of the first oil path and the second oil path. In the present embodiments, the pressure reducing valve is arranged to convert the high-pressure oil inlet into stable low-pressure output, so that the outlet pressure is always maintained within a set range, avoiding damage to system components caused by high pressure. Specifically, the second pressure reducing valve 205 is arranged in the first oil path between the second high-pressure one-way selector valve 204 and the first two-position two-way valve 212. The oil flows from the oil outlet of the second high-pressure one-way selector valve 204 to the second pressure reducing valve 205, and then to the first two-position two-way valve 212 after pressure reduction and pressure stabilization, and then flows to the suspension control unit under the control of the first two-position two-way valve 212. The first pressure reducing valve 105 is arranged in the second oil path between the first high-pressure one-way selector valve 104 and the second two-position two-way valve 112. The oil flows from the oil outlet of the first high-pressure one-way selector valve 104 to the first pressure reducing valve 105, and then to the second two-position two-way valve 112 after pressure reduction and pressure stabilization, and then flows to the brake 304 under the control of the second two-position two-way valve 112.

[0063] According to some embodiments of the present application, a pressure sensor is arranged at each of the two oil ports of the first bidirectional pump 102 and the second bidirectional pump 202. In the present embodiments, the pressure sensor is arranged to monitor the oil pressure at the two oil ports of the first bidirectional pump 102 and the second bidirectional pump 202 in real time. As shown in FIG. 1, the oil port 102a of the first bidirectional pump 102 is provided with a pressure sensor 103a, and the oil port 102b is provided with a pressure sensor 103b. The oil port 202a of the second bidirectional pump 202 is provided with a pressure sensor 203a, and the oil port 202b is provided with a pressure sensor 203b. Figure 1

[0064] ​According to some embodiments of the present application, the upper chamber and the lower chamber of the first three-position two-way valve 107 are formed with damping holes, which are communicated with the middle chamber of the first proportional directional valve 109. In the present embodiment, the first three-position two-way valve 107 has three working positions of upper, middle and lower, the upper chamber is provided with a damping hole 107a, the lower chamber is provided with a damping hole 107b, and the damping holes are communicated with the middle chamber of the first proportional directional valve 109 to form a pressure transmission channel for releasing hydraulic oil; when the spool of the first three-position two-way valve 107 switches positions under the action of oil pressure, the hydraulic oil in the upper chamber and the lower chamber can be released through the damping holes, which can maintain the pressure balance of the upper / lower chambers of the first three-position two-way valve 107 and ensure smooth movement of the spool. Further, when the first three-position two-way valve 107 is in the middle position, oil is supplied to the upper and lower reset spring chambers through the damping holes 107a and 107b respectively, so that the two ends of the first three-position two-way valve 107 are simultaneously acted on by the spring force, the pressure in the spring chamber and the auxiliary oil line pressure, thereby ensuring the stability of the spool. Further, when the first proportional directional valve 109 is in the middle position, the two damping holes are communicated with the middle chamber of the first proportional directional valve 109 to ensure that the double-rod cylinder 110 is in a constant-pressure damping state; when the first proportional directional valve 109 is in the upper or lower position, the two damping holes are disconnected from the first proportional directional valve 109.

[0065] In the above embodiment, the proposed outrigger system is an integrated single outrigger system, which can independently complete the control of walking and suspension.

[0066] The present application also proposes a control method for the above-mentioned integrated electro-hydraulic control closed suspension walking outrigger system, which comprises the following steps:

[0067] S1, constructing a dynamics model and a hydraulic system model of the outrigger system;

[0068] S2, establishing a small-amplitude high-frequency response output control model in a high-speed running state, a large-amplitude high-frequency response output control model in a low-speed running state, and a sinusoidal high-frequency impact load adaptive control model in a stationary or parking brake state;

[0069] S3, collecting actual state parameters of the outrigger system when the outrigger system is walking or parking braking or stationary;

[0070] S4, taking the vertical direction adaptive constant load as the expected attitude, obtaining the difference between the actual state parameters of the outrigger system and the expected attitude standard parameters; using a discrete PID control method to perform feedforward compensation on displacement and lag compensation on pressure.

[0071] The step S1 comprises constructing an independent walking power model, an independent suspension dynamics model and a single-leg closed suspension walking integrated hydraulic system model. The step S3 comprises collecting a rotating speed sensor signal to measure the walking speed, collecting a displacement sensor signal to measure the suspension position, collecting a pressure signal of the double-out-rod oil cylinder and a pressure signal of the hydraulic motor.

[0072] According to the control method of the present application, by designing the geometric size power model and the closed hydraulic system model of the electro-hydraulic control leg system, the optimal control output model is calculated and established according to different working conditions, and the initial attitude command is output and the running, displacement, pressure, rotating speed and other parameters are collected, the difference value is calculated by comparing with the standard attitude, the output correction parameters are calculated by integral iteration, which can drive the single-leg system to realize the expected attitude. The present application can realize the stable attitude control of the leg system in different working conditions of driving, static and braking, and can solve the problems of stable attitude control of heavy single-leg in uneven road conditions under high speed and low speed large amplitude road conditions, so that the leg system of the mobile platform can realize high speed response and stable control under heavy load scene, different speed conditions and different road conditions.

[0073] It should be noted that the above leg system needs to be used in combination with multiple single-leg systems in actual application, such as application in vehicles. For this purpose, according to some embodiments of the present application, when multiple leg systems are combined, the control method further comprises:

[0074] S11, according to the running condition, the control model of each leg system is selected and called respectively, and according to the running instruction parameters and the attitude standard parameters, the control signals of each leg system are calculated and output, including the pressure control signal, the displacement instruction control signal and the like;

[0075] S12, the feedback running parameters of each leg system are collected, the front and back compensation calculation of each leg system is performed according to the step S4, and then the closed loop iterative integral is performed with the attitude standard parameters to output the correction control instruction of the load, position and the like, complete the final expected attitude control algorithm, and drive each leg system to realize the expected attitude according to the control algorithm.

[0076] In the present embodiment, as Figure 4As shown, the single-leg system can be applied in multiple combinations, and can provide walking power and suspension support stability for a heavy load moving platform. In each single-leg system, an independent walking actuator, i.e., a walking control unit, forms a closed-loop feedback pressure control with a standard attitude parameter by collecting a pressure signal; forms a closed-loop feedback flow control, i.e., a driving speed control, with a walking control instruction by collecting a flow signal (rotational speed parameter conversion calculation); an independent suspension actuator, i.e., a suspension control unit, forms a closed-loop feedback displacement control with a standard attitude parameter by collecting a displacement signal; forms a closed-loop feedback pressure control, i.e., a suspension lifting control, with a suspension control instruction by collecting a pressure signal. The embodiment adopts a distributed group control method, and can realize multiple combination control of a closed walking suspension integrated electro-hydraulic control leg, and complete multiple-leg collaborative operation.

[0077] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0078] In the description of the present application, "first feature" and "second feature" can include one or more features.

[0079] In the description of the present application, "a plurality of" means two or more.

[0080] In the description of the present application, "above", "over" and "on" of the first feature to the second feature can include that the first and second features are in direct contact, or can include that the first and second features are not in direct contact but are in contact through another feature between them.

[0081] In the description of the present application, "above", "over" and "on" of the first feature to the second feature include that the first feature is directly above and obliquely above the second feature, or only means that the first feature is higher in horizontal height than the second feature.

[0082] In the description of the specification, reference to "one embodiment", "some embodiments", "an exemplary embodiment", "an example", "a specific example" or "some examples" means that a particular feature, structure, material or characteristic is included in at least one embodiment or example of the present application. The appearances of the above expressions in various places in the specification do not necessarily refer to the same embodiment or example. Moreover, the particular features, structures, materials or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0083] Although embodiments of the present application have been shown and described, it would be appreciated by those skilled in the art that changes, modifications, alternatives and variations to these embodiments could be made without departing from the principles and spirit of the application, the scope of which is defined by the claims and their equivalents.

Claims

1. An integrated electro-hydraulically controlled closed-type suspension walking leg system, characterized by, The application relates to a hydraulic control system for a wheel loader, comprising: a suspension control unit, which comprises a first bidirectional pump, a first servo motor, a double-rod oil cylinder and a suspension control valve group; the first servo motor is connected with the first bidirectional pump; the suspension control valve group comprises a first proportional directional valve; the first proportional directional valve is formed with two first control oil ports and two first execution oil ports, the two first control oil ports are communicated with two oil ports of the first bidirectional pump respectively, and the two first execution oil ports are communicated with two oil ports of the double-rod oil cylinder; a walking control unit, which comprises a second bidirectional pump, a second servo motor, a hydraulic motor and a walking control valve group; the second servo motor is connected with the second bidirectional pump; the walking control valve group comprises a second proportional directional valve, the second proportional directional valve is formed with two second control oil ports and two second execution oil ports, the two second control oil ports are communicated with two oil ports of the second bidirectional pump respectively, and the two second execution oil ports are communicated with two oil ports of the hydraulic motor; wherein, the walking control unit is communicated with the suspension control unit through a first oil path, and a first two-position valve suitable for controlling the opening and closing of the first oil path is arranged in the first oil path; a wheel assembly, which is connected with the hydraulic motor and the double-rod oil cylinder.

2. The integrated electro-hydraulically controlled closed suspension walking leg system of claim 1, wherein, The suspension control valve group further comprises: first overflow valves, which are connected with the first bidirectional pump in parallel, and are constructed as two and arranged reversely; The walking control valve group further comprises: second overflow valves, which are connected with the second bidirectional pump in parallel, and are constructed as two and arranged reversely.

3. The integrated electro-hydraulically controlled closed suspension walking leg system of claim 2, wherein, The suspension control valve group further comprises: a first accumulator, which is suitable for storing hydraulic oil; a first three-position valve, which is formed with a first oil inlet, a first upper oil outlet, a first lower oil outlet and a middle oil port; the first oil inlet is communicated with the first accumulator; the first upper oil outlet and the first lower oil outlet are communicated with oil outlets of the two first overflow valves respectively; and the middle oil port is communicated with the first oil path; upper and lower cavities of the first three-position valve are respectively communicated with oil inlets of the two first overflow valves, so that one of the first upper oil outlet and the first lower oil outlet is selectively communicated with the first oil inlet under the action of oil pressure; The walking control valve group further comprises: a second accumulator, which is suitable for storing hydraulic oil; a second three-position valve, which is formed with a second oil inlet, a second upper oil outlet and a second lower oil outlet; the second oil inlet is communicated with the second accumulator through a supplementary oil pipeline; the second upper oil outlet and the second lower oil outlet are respectively communicated with oil outlets of the two second overflow valves; a supplementary oil port is arranged on the supplementary oil pipeline; upper and lower cavities of the second three-position valve are respectively communicated with oil inlets of the two second overflow valves, so that one of the second upper oil outlet and the second lower oil outlet is selectively communicated with the second oil inlet under the action of oil pressure.

4. The integrated electro-hydraulically controlled closed suspension walking leg system of claim 3, wherein, The wheel assembly comprises a brake; The suspension control valve group further comprises: A first high-pressure one-way selection valve, two oil inlets of the first high-pressure one-way selection valve are communicated with two oil ports of the first bidirectional pump respectively; an oil outlet of the first high-pressure one-way selection valve is communicated with the brake through a second oil path, and a second two-position one-way valve is arranged on the second oil path.

5. The integrated electro-hydraulically controlled closed suspension walking leg system of claim 3, wherein, The walking control valve group further comprises: A second high-pressure one-way selection valve, two oil inlets of the second high-pressure one-way selection valve are communicated with two oil ports of the second bidirectional pump respectively, and an oil outlet of the second high-pressure one-way selection valve is communicated with the first oil path.

6. The integrated electro-hydraulically controlled closed suspension walking leg system of claim 4, wherein, A pressure reducing valve is arranged in each of the first oil path and the second oil path.

7. The integrated electro-hydraulically controlled closed suspension walking leg system of claim 1, wherein, Pressure sensors are arranged on the two oil ports of the first bidirectional pump and the two oil ports of the second bidirectional pump.

8. The integrated electro-hydraulically controlled closed suspension walking leg system of claim 3, wherein, Damping holes are formed in upper and lower position cavities of the first three-position one-way valve, and the damping holes are communicated with a middle position cavity of the first proportional reversing valve.

9. A method of controlling an integrated electro-hydraulically controlled closed-type suspension walking leg system according to any one of claims 1 to 8, characterized in that, The method comprises the following steps: A dynamic model and a hydraulic system model of the outrigger system are constructed; A small-amplitude high-frequency response output control model in a high-speed running state, a large-amplitude high-frequency response output control model in a low-speed running state, and a sine high-frequency impact load adaptive control model in a stationary or parking brake state are established; Actual state parameters of the outrigger system are collected when the outrigger system is running, parking braking or stationary; A difference between actual state parameters of the outrigger system and standard parameters of an expected attitude is obtained, taking vertical direction adaptive constant load as the expected attitude; a discrete PID control method is adopted to perform feedforward compensation on displacement and lag compensation on pressure.

10. The control method of the integrated electro-hydraulically controlled closed-type suspension walking leg system according to claim 9, characterized by, When a plurality of outrigger systems are combined, the control method further comprises: Control models of each outrigger system are respectively selected and called according to operating conditions, and control signals of each outrigger system are calculated and output according to operating instruction parameters and attitude standard parameters; Feedback operating parameters of each outrigger system are collected, front and back compensation calculations are performed, and then closed-loop iterative integration is performed with attitude standard parameters to output corrected control instructions, so as to drive each outrigger system to realize an expected attitude.

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