A damper-based passive multi-condition lower limb exoskeleton robot

Abstract

The present invention discloses a passive multi-condition lower limb exoskeleton robot based on a damper, which includes a back lumbar plate, thigh components, calf components, and feet. The thigh components and calf components use dampers as actuators. The damper includes a plunger cylinder assembly, a valve group, an accumulator assembly, and an oil tank. The plunger cylinder assembly includes a plunger chamber. The valve group includes an electromagnetic directional valve, check valve one, check valve two, and servo valve. Port one of the electromagnetic directional valve is connected to the plunger chamber. Port two of the electromagnetic directional valve is connected to the oil tank through check valve one. Port two of the electromagnetic directional valve is connected to ports B and P of the servo valve through check valve two. The oil tank is connected to ports A and T of the servo valve. Port three of the electromagnetic directional valve is connected to the accumulator assembly. Port one of the electromagnetic directional valve is switched and connected to port two and port three. The present invention realizes a lightweight and long-endurance lower limb assistive exoskeleton robot, achieving the purposes of multi-conditions such as assisting repeated squatting and standing up, quickly walking with a load on flat ground, and standing for a long time.

Description

Technical Field

[0001] The present invention relates to the technical field of lower limb exoskeleton robots, and in particular to a passive multi-condition lower limb exoskeleton robot based on dampers. Background Art

[0002] Actuators are an essential and important part of an automatic control system. There are various actuators in robot control systems such as exoskeletons and prosthetics to assist the joint movement of the robot. Currently, active drives or passive actuators applicable only to a single condition are mostly used on the knee joints of exoskeleton robots. The former requires a high-power power source, the actuator has a large volume and mass and a short endurance time, while the latter can only be used for a single condition and cannot make the exoskeleton robot applicable to different conditions.

[0003] In existing passive lower limb exoskeleton robots, the stiffness and damping of their actuators often cannot meet the smooth and gentle movement of the human knee joint under multiple conditions. For example, when a human walks on flat ground, the knee joint mainly acts as a damper, while when squatting and standing up, the knee joint is more like a spring. However, existing passive actuators cannot meet these two conditions simultaneously. In addition, existing passive lower limb exoskeleton robots mostly directly use springs for the knee joint. The existence of the spring force can provide assistance during the stance phase, but it will hinder the human movement during the swing phase, causing discomfort to the wearer and being difficult to be well applied in actual exoskeleton robots.

[0004] In order to overcome these defects, it is necessary to design a lightweight actuator with a long endurance time, good assistance effect, adaptable to multiple conditions and not affecting the smooth movement of the knee joint for application in lower limb exoskeleton robots. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art, and provide a passive multi-condition lower limb exoskeleton robot based on dampers. By removing the high-power power source and using only low-power electromagnets and torque motors, a lightweight and long-endurance lower limb assistance exoskeleton robot is realized. The two dampers designed according to the new damper principle both adopt semi-active control, separate the functions of replaceable springs and controllable dampers, and can realize the specific stiffness-damping requirements of the knee joint of the exoskeleton robot under different conditions, achieving the purpose of assisting repetitive squatting and standing up, quickly walking with load on flat ground, and standing for a long time under multiple conditions.

[0006] To achieve the above purpose, the technical solution of the present invention is:

[0007] A passive multi-condition lower limb exoskeleton robot based on a damper, comprising a back lumbar plate, thigh components, calf components, and feet. The back lumbar plate and the thigh components are connected by a hip joint ball hinge. The thigh components and the calf components are connected by a knee joint hinge. The calf components and the feet are connected by an ankle joint ball hinge. The thigh components and the calf components use dampers as actuators. The damper comprises a plunger cylinder assembly, a valve group, an accumulator assembly, and an oil tank. The plunger cylinder assembly comprises a plunger chamber. The valve group comprises an electromagnetic reversing valve, check valve one, check valve two, and servo valve. Port one of the electromagnetic reversing valve communicates with the plunger chamber. Port two of the electromagnetic reversing valve communicates with the oil tank through check valve one. Port two of the electromagnetic reversing valve communicates with port B and port P of the servo valve through check valve two. The oil tank communicates with port A and port T of the servo valve. Port three of the electromagnetic reversing valve communicates with the accumulator assembly. Port one of the electromagnetic reversing valve is switched to communicate with port two and port three.

[0008] It includes a pressure accumulation mode. In the pressure accumulation mode, port one of the electromagnetic reversing valve communicates with port three, and the plunger chamber communicates with the accumulator assembly.

[0009] It includes a downward pressure self-locking mode. In the downward pressure self-locking mode, port one of the electromagnetic reversing valve communicates with port two, the servo valve is in the middle position, and the plunger chamber communicates with the oil tank through check valve one.

[0010] It includes a downward pressure adjustable damping mode. In the downward pressure adjustable damping mode, port one of the electromagnetic reversing valve communicates with port two, and the plunger chamber, check valve two, port P of the servo valve, port A of the servo valve, and the oil tank are communicated. Port P, port B, port T, port A, and the oil tank of the servo valve are communicated in sequence.

[0011] The damper is a centralized damper. The centralized damper comprises a plunger cylinder and a plunger rod. The valve group is installed on the outer wall of the plunger cylinder. The upper end of the plunger cylinder is connected to an end cover. The plunger chamber and the oil tank are both located inside the plunger cylinder. The accumulator assembly is connected to the tail of the plunger cylinder. One end of the plunger rod extends into the plunger chamber, and the other end of the plunger rod is connected with a spherical eye joint. The accumulator assembly comprises a pressure accumulation spring, a piston, and a pressure accumulation cylinder. The piston is located inside the pressure accumulation cylinder. The piston, the pressure accumulation cylinder, and the plunger cylinder cooperate to form a pressure accumulation chamber. The pressure accumulation chamber communicates with port three of the electromagnetic reversing valve. The two ends of the pressure accumulation spring respectively abut against the piston and the pressure accumulation cylinder.

[0012] The oil tank is located on the periphery of the plunger chamber and is concentrically distributed with it.

[0013] The spherical eye joint is hinged to connect the calf components, and the pressure accumulation cylinder is hinged to connect the thigh components.

[0014] The damper is a distributed damper, and the distributed damper includes a plunger cylinder and a plunger rod. The upper end of the plunger cylinder is connected to an end cover. The plunger chamber is located inside the plunger cylinder. One end of the plunger rod extends into the plunger chamber, and a spherical eye joint is connected to the other end of the plunger rod. Port 1 of the electromagnetic directional valve is connected to the plunger chamber through an oil pipe.

[0015] The other end of the plunger cylinder is connected to a spherical eye joint. The spherical eye joint of the plunger rod is hinged to the calf component, and the spherical eye joint of the plunger cylinder is hinged to the thigh component.

[0016] The accumulator assembly and the fuel tank are installed on the side of the valve group, and the valve group is connected to the plunger cylinder through an oil pipe.

[0017] The beneficial effects of the present invention are as follows:

[0018] First, according to the stiffness-damping requirements of the human knee joint under different working conditions, a new damper principle is proposed, which can realize the pressure accumulation mode, the downward pressure self-locking mode, and the downward pressure adjustable damping mode. In the pressure accumulation mode, the oil circuit is directly connected to the accumulator assembly. At this time, it is in the spring state to realize energy storage and energy release. In the downward pressure self-locking mode, the plunger rod cannot move downward. In the downward pressure adjustable damping mode, the flow rate is adjusted through the servo valve. At this time, it is in the damping state to realize the controllable damping effect. The switching of multiple modes realizes the separation of the spring and the controllable damping, and provides the stiffness-damping requirements for the knee joint during movement under different working conditions.

[0019] Second, the centralized damper places the fuel tank inside the plunger cylinder, integrates the accumulator assembly and the plunger cylinder into one body, has a compact structure, a small volume and mass, and the accumulator assembly can be disassembled, which is convenient to select accumulator springs with different stiffnesses according to the stiffness requirements of different working conditions; the distributed damper separates the fuel tank, the accumulator assembly and the plunger cylinder, and is connected to the valve group. On this basis, the plunger cylinder and the valve group can be separated and arranged at different parts of the passive exoskeleton robot respectively. Both dampers adopt the same principle. According to the characteristics of adjustable damping, both dampers have realized the functions of replaceable springs and controllable damping, and one of the dampers can be selected according to the actual use situation and arranged on the exoskeleton robot.

[0020] Third, for the passive multi-condition lower limb exoskeleton robot based on the damper, compared with the existing active assist exoskeleton robot, the present invention omits power output components such as high-power motors and hydraulic pumps, and realizes the purposes of weight reduction and endurance while ensuring the assist effect; compared with the existing passive assist exoskeleton robot, the present invention actively switches the spring and damping of the damper, so that the exoskeleton robot can be applied to multiple working conditions, especially suitable for working conditions such as picking goods, airport security inspection, and grain moistening that require frequent squatting and standing up, and does not affect normal walking while assisting multiple squatting and standing up.

[0021] IV. All dampers adopt electromagnetic directional control valves and servo valves for semi-active control. The solenoid valve is used to achieve autonomous switching of modes, ensuring system automation. The servo valve is used to control the flow rate, improving the responsiveness of the damping adjustment system during fast walking.

[0022] V. Plunger cylinders are adopted, which are simple to machine, have good sealing performance, and high motion stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is the schematic diagram of a single leg of the present invention;

[0024] Figure 2 is the structural schematic diagram of the centralized damper of the present invention;

[0025] Figure 3 is the structural schematic diagram of the distributed damper of the present invention;

[0026] Figure 4 is the layout diagram of the centralized damper installed on the lower limb exoskeleton robot;

[0027] Figure 5 is the layout diagram of the distributed damper installed on the lower limb exoskeleton robot;

[0028] Figure 6 is the schematic diagram of the working oil circuit of the pressure accumulator mode of the present invention;

[0029] Figure 7 is the schematic diagram of the working oil circuit of the downward pressure self-locking mode of the present invention;

[0030] Figure 8 is the schematic diagram of the working oil circuit of the downward pressure adjustable damping mode of the present invention.

[0031] In the figure: hip joint ball hinge 1, knee joint hinge 2, ankle joint ball hinge 3, centralized damper 4A, distributed damper 4B, plunger cylinder assembly 41, plunger cavity 411, plunger cylinder 412, plunger rod 413, fish-eye joint 414, end cover 415, valve group 42, electromagnetic directional control valve 421, check valve one 422, check valve two 423, servo valve 424, pressure accumulator assembly 43, pressure accumulator cavity 431, pressure accumulator spring 432, piston 433, pressure accumulator cylinder 434, fuel tank 44, oil pipe 45, back lumbar plate 5, thigh component 6, calf component 7, foot 8. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The technical solutions of the present invention will be further described below through embodiments in conjunction with the drawings.

[0033] As Figures 1 - 8As shown in the figure, a passive multi-condition lower limb exoskeleton robot based on a damper includes a back lumbar plate 5, a thigh component 6, a calf component 7, and a foot 8. The back lumbar plate 5 and the thigh component 6 are connected by a hip joint ball hinge 1, and the calf component 7 and the foot 8 are connected by an ankle joint ball hinge 3. Using ball hinges can ensure the passive degrees of freedom of movement. The back lumbar plate 5 connects the left and right legs, and the two legs are symmetric with each other and have the same structure.

[0034] The thigh component 6 and the calf component 7 are connected by a knee joint hinge 2. The thigh component 6 and the calf component 7 use dampers as actuators. The dampers include a centralized damper 4A and a distributed damper 4B. The dampers are installed at the hinge of the thigh component 6 and the calf component 7 and are used for the knee joint of the passive lower limb exoskeleton robot.

[0035] The damper includes a plunger cylinder assembly 41, a valve group 42, an accumulator assembly 43, and an oil tank 44. The plunger cylinder assembly 41 includes a plunger chamber 411. The valve group 42 includes an electromagnetic reversing valve 421, a check valve one 422, a check valve two 423, and a servo valve 424. The electromagnetic reversing valve 421 is a two-position three-way reversing valve, and the servo valve 424 is a direct drive servo valve. Port one of the electromagnetic reversing valve 421 communicates with the plunger chamber 411. Port two of the electromagnetic reversing valve 421 communicates with the oil tank 44 through the check valve one 422. Port two of the electromagnetic reversing valve 421 communicates with port B and port P of the servo valve 424 through the check valve two 423 (refer to Figure 2 、 Figure 3 、 Figure 8 ). The oil tank 44 communicates with port A and port T of the servo valve 424 (refer to Figure 2 、 Figure 3 、 Figure 8 ). Port three of the electromagnetic reversing valve 421 communicates with the accumulator assembly 43. Port one of the electromagnetic reversing valve 421 is switched to communicate with port two or port three, that is, port one of the electromagnetic reversing valve 421 communicates with port two, or port one of the electromagnetic reversing valve 421 communicates with port three.

[0036] According to the two major characteristics of the knee joint squatting and rising spring state and the flat ground walking damping state, the principle of the damper used for the knee joint is as follows: According to different working states of the electromagnetic reversing valve 421 and the servo valve 424, three working modes can be realized, namely the pressure accumulation mode, the downward pressure self-locking mode, and the downward pressure adjustable damping mode.

[0037] Refer to Figure 6 . In the pressure accumulation mode, port one of the electromagnetic reversing valve 421 communicates with port three (for the statement about port one and port three, refer to Figure 2 and Figure 3The Arabic numerals marked on the electromagnetic directional valve 421, where 1 represents port one, 2 represents port two, and 3 represents port three), the plunger chamber 411 is connected to the accumulator assembly 43, that is, the accumulator assembly 43 is connected to the rodless chamber of the plunger cylinder assembly 41, and this mode is used for knee joint squatting and standing up.

[0038] In this mode, when the electromagnet of the electromagnetic directional valve 421 is energized and the spool of the electromagnetic directional valve 421 switches to the left position, at this time the plunger chamber 411 is directly connected to the accumulator chamber 431 where the accumulator spring 432 is located. During the movement of the plunger rod 413, the purpose of energy storage and energy release can be achieved by compressing and releasing the accumulator spring 432. For example, it can assist in the picking operation that requires repetitive squatting and standing up, reducing the physical loss and knee injury of the picker.

[0039] Refer to Figure 7 , in the downward pressure self-locking mode, port one and port two of the electromagnetic directional valve 421 are connected, the servo valve 424 is in the middle position (representing that the servo valve 424 is closed), the plunger chamber 411 is connected to the fuel tank 44 through the one-way valve 422, the input end of the one-way valve 422 is connected to the fuel tank 44, and the output end of the one-way valve 422 is connected to port two of the electromagnetic directional valve 421. In this mode, the plunger rod 413 cannot move downward (taking the plunger rod 413 in Figure 7 as the reference direction), and it is used for long-term knee joint standing or squatting.

[0040] In this mode, the electromagnet of the electromagnetic directional valve 421 is de-energized, the spool of the electromagnetic directional valve 421 is in the right position, the torque motor of the servo valve 424 controls its own spool to be in the middle position, and the plunger chamber 411 is only connected to the fuel tank 44 through the one-way valve 422. At this time, due to the existence of the one-way valve 422, the plunger rod 413 cannot be compressed inward and can only extend outward, forming a downward pressure self-locking state. This state can help the knee joint to be locked in a posture for a long time without consuming human energy. For example, it can assist a sentry who needs to stand for a long time or a worker who needs to maintain a semi-squatting position for a long time.

[0041] Refer to Figure 8 , in the downward pressure adjustable damping mode, the servo valve 424 is in the left position, port one and port two of the electromagnetic directional valve 421 are connected, the plunger chamber 411, the one-way valve 423, the P port of the servo valve 424, the A port of the servo valve 424, and the fuel tank 44 are connected ( Figure 8 the lines in thick black solid lines in), for the convenience of observation and understanding, the letters P, B, T, A of the P port, B port, T port, and A port are marked in Figure 7 the. The P port, B port, T port, A port of the servo valve 424 and the fuel tank 44 are connected in sequence ( Figure 8The line of thick solid medium gray (i.e., the hydraulic oil in the line of thick solid black is diverted before reaching the P port (after diversion, it is the line of thick solid gray), first enters the B port, flows out from the T port, and then converges into the line of thick solid black. The convergence point is after the A port. In this mode, the flow rate is adjusted by the servo valve 424 to achieve a controllable damping effect, which is used for flat walking of the knee joint.)

[0042] In this mode, the plunger rod 413 compresses inward. The electromagnetic directional valve 421 is in the right position, the servo valve 424 is in the left position and adopts the flow multiplication connection method. The oil in the plunger chamber 411 enters the oil tank 44 through the thickened flow path in the figure. In this case, the torque motor of the servo valve 424 can adjust the opening of its spool to control the flow rate through the servo valve 424 to achieve the purpose of throttling and realize the downward adjustable damping state. This state can assist the torque required when bending the leg during the stance phase of walking and standing, and can adjust the damping to be smaller during the swing phase of bending the leg without affecting the normal gait during the swing phase. For example, it can be used for long-distance flat walking when carrying a load.)

[0043] The passive multi-condition lower limb exoskeleton robot based on the damper is driven without a power source, achieving lightweight and long battery life. According to the characteristics of the spring state of the human knee joint during squatting and standing and the damping state during flat walking, a damper designed based on the principle of a new type of damper is used as the knee joint actuator of the exoskeleton robot, enabling it to assist in multiple conditions: the damper pressure storage mode can assist in repetitive squatting and standing; the damper downward self-locking mode can assist in long-term standing; the damper downward adjustable damping mode can assist in flat walking with a load.)

[0044] Refer to Figure 2 、 Figure 4 , the centralized damper 4A is arranged at the knee joint, with a compact structure. Refer to Figure 3 、 Figure 5 , for the distributed damper 4B, the plunger cylinder assembly 41 is arranged at the knee joint, while the valve group 42 connecting the accumulator assembly 43 and the oil tank 44 is integrally arranged at the back lumbar plate 5, distributing the overall weight and volume of the damper throughout the exoskeleton robot, reducing its weight and volume on the leg. For the above arrangement schemes of the centralized damper 4A and the distributed damper 4B, one of the arrangement schemes can be selected according to the actual use situation: if the volume and weight of the lower limb are too large, the distributed damper 4B arrangement scheme can be selected; if the volume and weight of the lower limb are small, the centralized damper 4A arrangement scheme can be selected.)

[0045] Refer to Figure 2 、 Figure 4, the centralized damper 4A includes a plunger cylinder 412 and a plunger rod 413. The valve group 42 is installed on the outer wall of the plunger cylinder 412. The upper end of the plunger cylinder 412 is connected to an end cover 415. Both the plunger chamber 411 and the oil tank 44 are located inside the plunger cylinder 412. The oil tank 44 is located around the plunger chamber 411 and they are concentrically distributed, with a small overall volume. The plunger chamber 411, the accumulator assembly 43, and the oil tank 44 are all connected to the valve group 42 through oil circuits. The oil fluid returns to the plunger chamber 411 through the valve group 42 and finally enters the accumulator assembly 43 or the oil tank 44.

[0046] The accumulator assembly 43 is threadedly connected to the tail of the plunger cylinder 412 and is detachable to replace the accumulator spring 432 with different stiffness. One end of the plunger rod 413 extends into the plunger chamber 411, and a ball joint 414 is connected to the other end of the plunger rod 413. The accumulator assembly 43 includes an accumulator spring 432, a piston 433, and an accumulator cylinder 434. The piston 433 is located inside the accumulator cylinder 434. The piston 433, the accumulator cylinder 434, and the plunger cylinder 412 cooperate to form an accumulator chamber 431. The accumulator chamber 431 communicates with port three of the electromagnetic directional control valve 421. The two ends of the accumulator spring 432 respectively abut against the piston 433 and the accumulator cylinder 434.

[0047] The ball joint 414 is hingedly connected to the calf component 7, and the accumulator cylinder 434 is hingedly connected to the thigh component 6.

[0048] The oil fluid enters the valve group 42 from the plunger cylinder 412. After being reversed by the electromagnetic directional control valve 421, there are three oil circuits: First, when port one and port three of the electromagnetic directional control valve 421 are connected, the oil fluid directly returns from the plunger chamber 411 to the plunger cylinder 412 and is connected to the accumulator chamber 431, and the oil fluid exits from the accumulator chamber 431 and directly returns to the plunger cylinder 412 and is connected to the plunger chamber 411; Second, when port one and port two of the electromagnetic directional control valve 421 are connected, the oil fluid exits from the plunger chamber 411 and can return to the plunger cylinder 412 and is connected to the oil tank 44 after passing through check valve two 423 and servo valve 424; Third, when port one and port two of the electromagnetic directional control valve 421 are connected, the oil fluid exits from the oil tank 44 and can return to the plunger cylinder 412 and is connected to the plunger chamber 411 after passing through check valve one 422.

[0049] The electromagnetic directional control valve 421 is a cartridge valve inserted into a valve block (not labeled in the figure). The servo valve 424 is bolted to the valve block; Check valve one 422 and check valve two 423 are fixed inside the valve block.

[0050] Refer to Figure 3 、 Figure 5, the distributed damper 4B includes a plunger cylinder 412 and a plunger rod 413. The upper end of the plunger cylinder 412 is connected to an end cover 415. The plunger chamber 411 is located inside the plunger cylinder 412. One end of the plunger rod 413 extends into the plunger chamber 411, and the other end of the plunger rod 413 is connected with a spherical eye joint 414. The valve group 42 is connected to the plunger cylinder 412 through an oil pipe 45. Specifically, port one of the electromagnetic directional control valve 421 communicates with the plunger chamber 411 through the oil pipe 45. The oil fluid directly enters the oil tank 44 or the accumulator assembly 43 after passing through the valve group 42. The accumulator assembly 43 and the oil tank 44 are installed on the side of the valve group 42.

[0051] The other end of the plunger cylinder 412 is connected with a spherical eye joint 414. The spherical eye joint 414 of the plunger rod 413 is hinged to the calf component 7, and the spherical eye joint 414 of the plunger cylinder 412 is hinged to the thigh component 6.

[0052] The oil fluid enters the valve group 42 from the plunger cylinder 412 through the oil pipe 45. After being reversed by the electromagnetic directional control valve 421, there are three oil circuits: First, when port one and port three of the electromagnetic directional control valve 421 are connected, the oil fluid exits from the plunger chamber 411 and directly communicates with the accumulator assembly 43, and when the oil fluid exits from the accumulator assembly 43, it directly returns to the plunger cylinder 412 and communicates with the plunger chamber 411; Second, when port one and port two of the electromagnetic directional control valve 421 are connected, the oil fluid exits from the plunger chamber 411 and can communicate with the oil tank 44 after passing through the check valve two 423 and the servo valve 424; Third, when port one and port two of the electromagnetic directional control valve 421 are connected, the oil fluid exits from the oil tank 44 and can return to the plunger cylinder 412 and communicate with the plunger chamber 411 through the check valve one 422.

[0053] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A passive multi-condition lower limb exoskeleton robot based on a damper, comprising a back lumbar plate (5), a thigh component (6), a calf component (7), and a foot (8), characterized in that: The back lumbar plate (5) and the thigh component (6) are connected by a hip joint ball hinge (1), the thigh component (6) and the calf component (7) are connected by a knee joint hinge (2), the calf component (7) and the foot (8) are connected by an ankle joint ball hinge (3). The thigh component (6) and the calf component (7) use a damper as an actuator. The damper includes a plunger cylinder assembly (41), a valve group (42), an accumulator assembly (43) and an oil tank (44). The plunger cylinder assembly (41) includes a plunger chamber (411). The valve group (42) includes an electromagnetic directional valve (421), a check valve one (422), a check valve two (423), and a servo valve (424). Port one of the electromagnetic directional valve (421) communicates with the plunger chamber (411), port two of the electromagnetic directional valve (421) communicates with the oil tank (44) through the check valve one (422), port two of the electromagnetic directional valve (421) communicates with port B and port P of the servo valve (424) through the check valve two (423). The oil tank (44) communicates with port A and port T of the servo valve (424). Port three of the electromagnetic directional valve (421) communicates with the accumulator assembly (43). Port one of the electromagnetic directional valve (421) is switched to communicate with port two and port three.

2. The passive multi-condition lower limb exoskeleton robot based on a damper according to claim 1, characterized in that: It includes a pressure accumulation mode. In the pressure accumulation mode, port one of the electromagnetic directional valve (421) communicates with port three, and the plunger chamber (411) communicates with the accumulator assembly (43).

3. The passive multi-condition lower limb exoskeleton robot based on a damper according to claim 1, characterized in that: It includes a downward pressure self-locking mode. In the downward pressure self-locking mode, port one of the electromagnetic directional valve (421) communicates with port two, the servo valve (424) is in the middle position, and the plunger chamber (411) communicates with the oil tank (44) through the check valve one (422).

4. The passive multi-condition lower limb exoskeleton robot based on a damper according to claim 1, wherein: It includes a downward pressure adjustable damping mode. In the downward pressure adjustable damping mode, port one of the electromagnetic directional valve (421) communicates with port two, the plunger chamber (411), the check valve two (423), port P of the servo valve (424), port A of the servo valve (424), and the oil tank (44) are communicated. Port P, port B, port T, port A of the servo valve (424), and the oil tank (44) are communicated in sequence.

5. A passive multi-condition lower limb exoskeleton robot based on a damper according to any one of claims 1-4, characterized in that: The damper is a centralized damper (4A). The centralized damper (4A) includes a plunger cylinder (412) and a plunger rod (413). The valve group (42) is installed on the outer wall of the plunger cylinder (412). The upper end of the plunger cylinder (412) is connected to an end cover (415). The plunger chamber (411) and the fuel tank (44) are both located inside the plunger cylinder (412). The accumulator assembly (43) is connected to the tail of the plunger cylinder (412). One end of the plunger rod (413) extends into the plunger chamber (411), and the other end of the plunger rod (413) is connected with a spherical eye joint (414). The accumulator assembly (43) includes an accumulator spring (432), a piston (433) and an accumulator cylinder (434). The piston (433) is located inside the accumulator cylinder (434). The piston (433), the accumulator cylinder (434) and the plunger cylinder (412) cooperate to form an accumulator chamber (431). The accumulator chamber (431) communicates with port three of the electromagnetic directional control valve (421). Both ends of the accumulator spring (432) abut against the piston (433) and the accumulator cylinder (434) respectively.

6. The passive multi-condition lower limb exoskeleton robot based on a damper according to claim 5, wherein: The fuel tank (44) is located around the plunger chamber (411) and they are concentrically distributed.

7. The passive multi-condition lower limb exoskeleton robot based on a damper according to claim 5, characterized in that: The spherical eye joint (414) is hinged to the calf component (7), and the accumulator cylinder (434) is hinged to the thigh component (6).

8. The passive multi-condition lower limb exoskeleton robot based on a damper according to any one of claims 1-4, characterized in that: The damper is a distributed damper (4B). The distributed damper (4B) includes a plunger cylinder (412) and a plunger rod (413). The upper end of the plunger cylinder (412) is connected to an end cover (415). The plunger chamber (411) is located inside the plunger cylinder (412). One end of the plunger rod (413) extends into the plunger chamber (411), and the other end of the plunger rod (413) is connected with a spherical eye joint (414). Port one of the electromagnetic directional control valve (421) communicates with the plunger chamber (411) through an oil pipe (45).

9. The passive multi-condition lower limb exoskeleton robot based on a damper according to claim 8, characterized in that: The other end of the plunger cylinder (412) is connected with a spherical eye joint (414). The spherical eye joint (414) of the plunger rod (413) is hinged to the calf component (7), and the spherical eye joint (414) of the plunger cylinder (412) is hinged to the thigh component (6).

10. The passive multi-condition lower limb exoskeleton robot based on a damper according to claim 8, wherein: The accumulator assembly (43) and the fuel tank (44) are installed on the side of the valve group (42). The valve group (42) is connected to the plunger cylinder (412) through an oil pipe (45).

Images