A miniature electro-hydraulic actuation system and control method for an ankle joint

Abstract

This disclosure relates to the field of robot hydraulic control technology, and in particular to a miniature electro-hydraulic actuation system and control method for an ankle joint. The miniature electro-hydraulic actuation system for an ankle joint includes: a bidirectional hydraulic cylinder; a bidirectional hydraulic pump having a first port and a second port, the first port being connected to a first chamber of the bidirectional hydraulic cylinder via a first pipeline; the second port being connected to a second chamber of the bidirectional hydraulic cylinder via a second pipeline; a first hydraulically controlled check valve connected in series on the first pipeline; the hydraulically controlled port of the first hydraulically controlled check valve being connected to the second port; a second hydraulically controlled check valve connected in series on the second pipeline; the hydraulically controlled port of the second hydraulically controlled check valve being connected to the first port; and a bypass damping unit whose first end is connected to the first pipeline between the first hydraulically controlled check valve and the bidirectional hydraulic cylinder, and whose second end is connected to the second pipeline between the second hydraulically controlled check valve and the bidirectional hydraulic cylinder. This disclosure can reduce the impact load during the switching between active and passive working modes.

Description

Technical Field

[0001] This disclosure relates to the field of robot hydraulic control technology, and in particular to a miniature electro-hydraulic actuation system and control method for ankle joints. Background Technology

[0002] In the field of hydraulic control technology, especially in the design and application of micro-miniature lower limb joint actuators, there is an urgent need for high performance, high reliability, and high power density. These actuators are widely used in high-end wearable devices such as robots, prostheses, and exoskeletons, and their performance directly affects the motion capabilities and adaptability of these devices. Traditional hydraulic systems are favored for their high power-to-weight ratio and large output force, but they also suffer from problems such as significant energy loss, oil contamination, leakage, and operating noise. These issues limit the application of traditional hydraulic systems in precision operation fields.

[0003] In existing technologies, various EHA (Extended Harness) configurations have been proposed and applied to address the specific needs of ankle-like joints. For example, an ankle joint actuator powered by an EHA has proposed a special configuration of a bypass damping switching valve to address the load characteristics of long-term passive damping and instantaneous peak actuation of the ankle joint, enabling rapid switching between active and passive modes of the EHA. To allow a low-power motor to meet the requirements of instantaneous high-power actuation, the motor is under high overload during peak actuation. Although experiments show that this prosthesis can meet the requirements for restoring a normal gait, the heat generated by the motor overload significantly reduces its lifespan. Furthermore, during the swing phase, the prosthesis needs to actively dorsiflex to lift the toes. During this phase, the hydraulic cylinder is in a bypass state, and some high-pressure oil flows through the damping orifice to the low-pressure chamber, greatly reducing the efficiency of the EHA.

[0004] A hybrid active-passive driven ankle prosthesis uses a hydraulically controlled check valve to isolate the active and passive states, and a directional valve to switch bypass damping, achieving different damping characteristics in both passive states. The motor-pump section connects the motor and hydraulic pump via a coupling, resulting in a heavier weight compared to a wet-type motor-pump of the same power. During instantaneous peak operation, the motor is subjected to high overload.

[0005] In existing technologies, EHA configurations have some shortcomings in terms of active and passive isolation and shock load protection. In traditional ankle-joint-like miniature EHA systems, under on-load conditions, the hydraulic fluid may push against the motor pump, leading to reduced system efficiency and additional wear on the motor pump. Under shock loads, the hydraulically controlled check valves in existing technologies may fail to close in time, thus failing to effectively protect the motor pump, which limits the system's reliability and durability.

[0006] In conclusion, how to solve the above problems is one of the most important issues that urgently need to be addressed in this field. Summary of the Invention

[0007] This disclosure is made in view of the above-mentioned problems. This disclosure provides a miniature electro-hydraulic actuation system and control method for an ankle joint.

[0008] This disclosure proposes a miniature electro-hydraulic actuation system similar to an ankle joint, comprising,

[0009] A two-way hydraulic cylinder is used to drive ankle joints to achieve passive plantar flexion, passive dorsiflexion, active plantar flexion, and active dorsiflexion.

[0010] A bidirectional hydraulic pump has a first port and a second port. The first port is connected to the first chamber of the bidirectional hydraulic cylinder via a first pipeline; the second port is connected to the second chamber of the bidirectional hydraulic cylinder via a second pipeline.

[0011] A first hydraulically controlled check valve is connected in series on the first pipeline to restrict the flow of liquid in the first chamber to the first port; the hydraulically controlled port of the first hydraulically controlled check valve is connected to the second port; it is used to prevent oil from impacting the bidirectional hydraulic pump through the first pipeline when switching working modes.

[0012] A second hydraulically controlled check valve is connected in series on the second pipeline to restrict the flow of liquid in the second chamber to the second port; the hydraulically controlled port of the second hydraulically controlled check valve is connected to the first port; it is used to prevent oil from impacting the bidirectional hydraulic pump through the second pipeline when switching working modes.

[0013] A bypass damping unit, wherein a first end of the bypass damping unit is connected to a first pipeline between the first hydraulically controlled check valve and the bidirectional hydraulic cylinder, and a second end is connected to a second pipeline between the second hydraulically controlled check valve and the bidirectional hydraulic cylinder; the bypass damping unit is used to provide damping force during passive plantar flexion and passive dorsiflexion.

[0014] The ankle-like micro electro-hydraulic actuation system described above may optionally include an oil tank, a first check valve, and a second check valve.

[0015] The oil tank is connected to the first pipeline between the bidirectional hydraulic pump and the first hydraulic control check valve via a third pipeline.

[0016] The first check valve is connected in series on the third pipeline to prevent the oil in the first pipeline from flowing back into the oil tank.

[0017] The oil tank is connected to the second pipeline between the bidirectional hydraulic pump and the second hydraulic control check valve via a fourth pipeline;

[0018] The second check valve is connected in series on the third pipeline to prevent the oil in the second pipeline from flowing back into the oil tank.

[0019] In the ankle-like micro electro-hydraulic actuation system described above, the bypass damping unit optionally includes a throttle valve and a solenoid valve;

[0020] The throttle valve is connected in series with the solenoid valve, which is used to close during active plantar flexion and active dorsiflexion, and open during passive plantar flexion and passive dorsiflexion to provide damping force.

[0021] In the ankle-like micro-electro-hydraulic actuation system described above, optionally, the motor stops working and the solenoid valve opens during passive plantar flexion and passive dorsiflexion; the first chamber and the second chamber are connected through the throttle valve and the solenoid valve.

[0022] The ankle-like micro electro-hydraulic actuation system described above may optionally include a support point and a drive rod, wherein the middle part of the drive rod is rotatably connected to the support point.

[0023] One end of the hydraulic rod of the bidirectional hydraulic cylinder is hinged to one end of the drive rod, so as to achieve active plantar flexion and active dorsiflexion through the reciprocating movement of the hydraulic rod.

[0024] The ankle-like micro electro-hydraulic actuation system described above may optionally include a drive motor that rotates with the bidirectional hydraulic pump to establish high pressure at the first or second port.

[0025] When high pressure is established at the first port, the first hydraulic control check valve opens; the pressure at the first port is transmitted to the hydraulic control port of the second hydraulic control check valve, so that the second hydraulic control check valve is opened, forming a conductive circuit to drive the hydraulic rod of the bidirectional hydraulic cylinder to move in the first direction;

[0026] When high pressure is established at the second port, the second hydraulic control check valve opens; the pressure at the second port is transmitted to the hydraulic control port of the first hydraulic control check valve, so that the first hydraulic control check valve is opened, forming a conductive circuit to drive the hydraulic rod of the bidirectional hydraulic cylinder to move in the second direction.

[0027] The present invention also proposes a control method for the ankle-like micro-electro-hydraulic actuation system described in any of the above claims, comprising:

[0028] During passive plantar flexion or passive dorsiflexion, the bidirectional hydraulic pump is shut down, and the bypass damping unit is activated to prevent oil from impacting the bidirectional hydraulic pump and to provide damping force.

[0029] During active plantar flexion or active dorsiflexion, the bidirectional hydraulic pump is activated, and the bypass damping unit is controlled to close. The bidirectional hydraulic pump establishes high pressure at the first or second port and drives the first and second hydraulically controlled check valves to open, thereby controlling the operation of the bidirectional hydraulic cylinder.

[0030] As will be described in detail below, the ankle-like micro-electro-hydraulic actuation system according to an embodiment of the present disclosure uses a bidirectional hydraulic cylinder for actuation. The two chambers of the bidirectional hydraulic cylinder are connected to the two ports of a bidirectional hydraulic pump through a first pipeline and a second pipeline, respectively. A first hydraulically controlled check valve and a second hydraulically controlled check valve are respectively installed on the first pipeline and the second pipeline. By installing the hydraulically controlled check valve, it can be ensured that when the bidirectional hydraulic pump is working, both the first hydraulic control unit and the second hydraulic control unit can be opened, so as to directly control the bidirectional hydraulic cylinder through the bidirectional hydraulic pump to achieve active plantar flexion or active dorsiflexion. When passive plantar flexion or passive dorsiflexion occurs, the bidirectional hydraulic pump stops working, and both the first hydraulically controlled check valve and the second hydraulically controlled check valve are not open, which can prevent the oil from impacting the bidirectional hydraulic pump.

[0031] It should be understood that both the foregoing general description and the following detailed description are exemplary and intended to provide further illustration of the claimed technology. Attached Figure Description

[0032] The above and other objects, features, and advantages of this disclosure will become more apparent from the more detailed description of the embodiments thereof in conjunction with the accompanying drawings. The drawings are provided to further illustrate the embodiments of this disclosure and form part of the specification. They are used together with the embodiments of this disclosure to explain the disclosure and do not constitute a limitation thereof. In the drawings, the same reference numerals generally represent the same components or steps.

[0033] Figure 1 This is a schematic diagram of the structure of the ankle-like micro-electro-hydraulic actuation system proposed in this disclosure;

[0034] Figure 2 This is a schematic diagram of the gait cycle phases and leg movements presented in this publication.

[0035] Explanation of reference numerals in the attached figures:

[0036] 1-Two-way hydraulic cylinder, 2-Two-way hydraulic pump, 3-First pipeline, 4-First hydraulic control check valve, 5-Second hydraulic control check valve, 6-Second pipeline, 7-Bypass damping unit, 8-Oil tank, 9-First check valve, 10-Second check valve;

[0037] 11-First chamber, 12-Second chamber, 13-Support point, 14-Drive rod;

[0038] 21-First port, 22-Second port, 23-Drive motor;

[0039] 71-Throttle valve, 72-Solenoid valve. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this disclosure more apparent, exemplary embodiments according to this disclosure will now be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this disclosure, and not all embodiments of this disclosure. It should be understood that this disclosure is not limited to the exemplary embodiments described herein.

[0041] For the issues raised in the background section, please refer to... Figure 1 This invention proposes a miniature electro-hydraulic actuation system similar to an ankle joint, which includes a bidirectional hydraulic cylinder 1, a bidirectional hydraulic pump 2, a first hydraulically controlled check valve 4, a second hydraulically controlled check valve 5, and a bypass damping unit 7.

[0042] The bidirectional hydraulic cylinder 1 is used to drive the ankle joint to achieve passive plantar flexion, passive dorsiflexion, active plantar flexion, and active dorsiflexion. Specifically, active plantar flexion and active dorsiflexion are achieved by the reciprocating movement of the hydraulic rod of the bidirectional hydraulic cylinder 1. During passive plantar flexion and passive dorsiflexion, the bidirectional hydraulic pump 2 does not work, and the bidirectional hydraulic cylinder 1 does not output driving force.

[0043] The bidirectional hydraulic pump 2 has a first port 21 and a second port 22. The first port 21 is connected to the first chamber 11 of the bidirectional hydraulic cylinder 1 through a first pipe 3; the second port 22 is connected to the second chamber 12 of the bidirectional hydraulic cylinder 1 through a second pipe 6. The bidirectional hydraulic pump 2 can pump oil from the first port 21 to the second port 22, or it can pump oil from the second port 22 to the first port 21.

[0044] A first hydraulically controlled check valve 4 is connected in series with the first pipeline 3 to restrict the flow of liquid in the first chamber 11 to the first port 21. The hydraulically controlled port of the first hydraulically controlled check valve 4 is connected to the second port 22. This prevents oil from impacting the bidirectional hydraulic pump 2 via the first pipeline 3 when switching operating modes. The first hydraulically controlled check valve 4 can be activated in two ways: one is by generating high pressure at the first port 21 to drive the first hydraulically controlled check valve 4 to open; the other is by generating high pressure at the second port 22 to open the first hydraulically controlled check valve 4. That is, regardless of which direction the bidirectional hydraulic pump 2 pumps oil, as long as the bidirectional hydraulic pump 2 is working, the first hydraulically controlled check valve 4 will be activated. When the bidirectional hydraulic pump 2 is not working, the oil in the first chamber 11 cannot flow into the bidirectional hydraulic pump 2 via the first hydraulically controlled check valve 4, thereby reducing the impact load.

[0045] The second hydraulically controlled check valve 5 is connected in series with the second pipeline 6 to restrict the flow of liquid in the second chamber 12 to the second port 22. The hydraulically controlled port of the second hydraulically controlled check valve 5 is connected to the first port 21. It is used to prevent oil from impacting the bidirectional hydraulic pump 2 through the second pipeline 6 when switching working modes. The second hydraulically controlled check valve 5 has two conduction methods: one is that high pressure is generated at the second port 22 to drive the second hydraulically controlled check valve 5 to conduct; the other is that high pressure is generated at the first port 21 to make the second hydraulically controlled check valve 5 conduct. That is, no matter which direction the bidirectional hydraulic pump 2 pumps oil, as long as the bidirectional hydraulic pump 2 is working, the second hydraulically controlled check valve 5 will be conducted. When the bidirectional hydraulic pump 2 is not working, the oil in the second chamber 12 cannot flow into the bidirectional hydraulic pump 2 through the second hydraulically controlled check valve 5, thereby reducing the impact load.

[0046] The first end of the bypass damping unit 7 is connected to the first pipeline 3 between the first hydraulically controlled check valve 4 and the bidirectional hydraulic cylinder 1, and the second end is connected to the second pipeline 6 between the second hydraulically controlled check valve 5 and the bidirectional hydraulic cylinder 1. The bypass damping unit 7 is used to provide damping force during passive plantar flexion and passive dorsiflexion. When switching from active plantar flexion or active dorsiflexion to passive plantar flexion or passive dorsiflexion, the bidirectional hydraulic pump 2 stops working, and both the first hydraulically controlled check valve 4 and the second hydraulically controlled check valve 5 are not conducting, with the bypass damping unit 7 providing resistance.

[0047] In practical implementation, since both ends of the bidirectional hydraulic pump 2 can serve as outlets, directly connecting one end to the oil tank 8 would prevent the establishment of high pressure at that end. Therefore, this disclosure redesigns the connection method of the oil tank 8, including the oil tank 8, a first check valve 9, and a second check valve 10. The oil tank 8 is connected to the first pipeline 3 between the bidirectional hydraulic pump 2 and the first hydraulically controlled check valve 4 via a third pipeline; the first check valve 9 is connected in series on the third pipeline to prevent the backflow of oil in the first pipeline 3 into the oil tank 8; the oil tank 8 is connected to the second pipeline 6 between the bidirectional hydraulic pump 2 and the second hydraulically controlled check valve 5 via a fourth pipeline; the second check valve 10 is connected in series on the third pipeline to prevent the backflow of oil in the second pipeline 6 into the oil tank 8. This ensures that oil can be replenished when needed and prevents the inability to establish high pressure due to connection to the oil tank 8, guaranteeing that the bidirectional hydraulic pump 2 can pump oil normally in both directions.

[0048] To avoid the influence of the bypass damping unit 7 on active plantar flexion and active dorsiflexion, this application further designs the on / off state of the bypass damping unit 7. Specifically, the bypass damping unit 7 includes a throttle valve 71 and a solenoid valve 72. The throttle valve 71 is connected in series with the solenoid valve 72. The solenoid valve 72 is used to close during active plantar flexion and active dorsiflexion, and to open during passive plantar flexion and passive dorsiflexion to provide damping force and prevent conduction during active plantar flexion and active dorsiflexion, thus preventing interference with the control of the bidirectional hydraulic pump 2 on the bidirectional hydraulic cylinder 1. Further, during passive plantar flexion and passive dorsiflexion, the motor stops working, and the solenoid valve 72 opens; the first chamber 11 and the second chamber 12 are connected through the throttle valve 71 and the solenoid valve 72. At this time, the motor stops working. Since the two ends of the bidirectional hydraulic pump 2 no longer establish high pressure, the first hydraulic control check valve 4 and the second hydraulic control check valve 5 are no longer open. The oil in the bidirectional hydraulic cylinder 1 cannot flow back to the bidirectional hydraulic pump 2, thus preventing the impact caused by the oil backflow.

[0049] In practical implementation, to achieve active plantar flexion and active dorsiflexion, a support point 13 and a drive rod 14 are included. The middle part of the drive rod 14 is rotatably connected to the support point 13. One end of the hydraulic rod of the bidirectional hydraulic cylinder 1 is hinged to one end of the drive rod 14, so that active plantar flexion and active dorsiflexion are achieved through the reciprocating movement of the hydraulic rod. For example, please refer to... Figure 1 ,exist Figure 1 The hydraulic rod moves downward to achieve active dorsiflexion; the hydraulic rod moves upward to achieve active plantarflexion.

[0050] In specific implementation, to achieve the above effects, a drive motor 23 is also included. The drive motor 23 rotates with the bidirectional hydraulic pump 2 to establish high pressure at the first port 21 or the second port 22. When high pressure is established at the first port 21, the first hydraulically controlled check valve 4 opens; the pressure at the first port 21 is transmitted to the hydraulic control port of the second hydraulically controlled check valve 5, causing the second hydraulically controlled check valve 5 to open, forming a conductive circuit to drive the hydraulic rod of the bidirectional hydraulic cylinder 1 to move in the first direction. When high pressure is established at the second port 22, the second hydraulically controlled check valve 5 opens; the pressure at the second port 22 is transmitted to the hydraulic control port of the first hydraulically controlled check valve 4, causing the first hydraulically controlled check valve 4 to open, forming a conductive circuit to drive the hydraulic rod of the bidirectional hydraulic cylinder 1 to move in the second direction. Specifically, the second direction is opposite to the first direction. It should be noted that the circuit forming the conduction referred to in this disclosure means that the oil can flow from the bidirectional hydraulic pump 2 to the bidirectional hydraulic cylinder 1, or from the bidirectional hydraulic cylinder 1 to the bidirectional hydraulic pump, rather than the first chamber 11 and the second chamber 12 being directly connected.

[0051] Through the above design, the oil backflow of the bidirectional hydraulic pump 2 is prevented under normal load conditions, ensuring complete active and passive isolation. When facing impact loads, the first hydraulic control check valve 4 and the second hydraulic control check valve 5 are automatically closed to effectively protect the bidirectional hydraulic pump 2 and the drive motor 23.

[0052] In passive operating mode, i.e., during passive plantar flexion or passive dorsiflexion, drive motor 23 is disabled, solenoid valve 72 opens, and the oil in bidirectional hydraulic cylinder 1 is exchanged through throttle valve 71, providing the necessary damping and cushioning effect for the ankle joint. The first hydraulically controlled check valve 4 and the second hydraulically controlled check valve 5 are closed at this time to ensure isolation between active and passive modes.

[0053] In active operating mode, i.e., during active plantar flexion or dorsiflexion, solenoid valve 72 closes, and drive motor 23 is energized to rotate the bidirectional hydraulic pump 2 and discharge oil. High pressure is established in the oil circuit at either the first port 21 or the second port 22, opening the first hydraulically controlled check valve 4 on the first pipeline 3 and the second hydraulically controlled check valve 5 on the second pipeline 6. The high-pressure oil flows into the corresponding chamber of the bidirectional hydraulic cylinder, pushing the rod to move and achieving plantar flexion or dorsiflexion of the ankle joint. Please refer to... Figure 1 During plantar flexion, high-pressure oil flows into the second chamber 12, pushing the hydraulic rod upward, causing the ankle joint to plantar flex and the body's center of gravity to shift forward; during dorsiflexion, high-pressure oil flows into the upper chamber of the hydraulic cylinder, pushing the hydraulic rod downward, causing the ankle joint to dorsiflex, lifting the toes, and preparing for the next heel strike.

[0054] When faced with impact loads, the first hydraulic check valve 4 and the second hydraulic check valve 5 are designed to automatically close to protect the drive motor 23 and the bidirectional hydraulic pump 2 from damage. During the switching response, after receiving the switching signal, the EHA is energized, driving the drive motor 23 to rotate the pump. Oil enters the pipeline, increasing the hydraulic pressure inside the pipeline. This pushes the valve cores of the first hydraulic check valve 4 and the second hydraulic check valve 5 to move, opening the first hydraulic check valve 4 and the second hydraulic check valve 5. The first port 21 and the second port 22 of the bidirectional hydraulic pump 2 are then connected to the first chamber 11 and the second chamber 12 of the bidirectional hydraulic cylinder 1, respectively. Simultaneously, the solenoid valve 72 is energized to cut off the bypass, completing the switching between active and passive modes.

[0055] On the other hand, this disclosure also proposes a control method for a miniature electro-hydraulic actuation system similar to an ankle joint, comprising:

[0056] During passive plantar flexion or passive dorsiflexion, the bidirectional hydraulic pump 2 is shut down, and the bypass damping unit 7 is turned on to prevent oil from impacting the bidirectional hydraulic pump 2 and to provide damping force.

[0057] During active plantar flexion or active dorsiflexion, the bidirectional hydraulic pump 2 is turned on, and the bypass damping unit 7 is turned off. The bidirectional hydraulic pump 2 establishes high pressure at the first port 21 or the second port 22, and drives the first hydraulic control check valve 4 and the second hydraulic control check valve 5 to open, so as to control the bidirectional hydraulic cylinder 1 to work.

[0058] The working process corresponding to the above method can be referred to the miniature electro-hydraulic actuation system for ankle joints proposed in this disclosure, and will not be repeated here.

[0059] For better understanding of this disclosure, please refer to Figure 2 The gait cycle can be divided into a stance phase and a swing phase based on whether the foot is in contact with the ground. At the start of the swing, the ankle actively dorsiflexes, lifting the toes to prepare for the next heel strike. In the stance phase, the ankle performs other major functions. Based on the direction of foot movement, the stance phase can be further subdivided into three stages: plantar flexion, dorsiflexion, and replantar flexion. In the first two stages, the ankle is passive, while in the third stage, it actively performs external work. When walking on flat ground, the ankle periodically repeats four movements: passive plantar flexion, passive dorsiflexion, active plantar flexion, and active dorsiflexion. The gait cycle is a continuous movement of alternating stance and swing of the legs during walking, divided into three main phases: the double stance phase, the single stance phase, and the swing phase. In the double stance phase, both legs simultaneously contact the ground to provide stable support, occurring between 0%-10% and 70%-80% of the gait cycle. Both legs are in contact with the ground, providing stable support; this is the period in the gait cycle when both legs simultaneously bear the body weight.

[0060] The single support phase occurs at 10%-40% and 40%-70% of the gait cycle, during which one leg supports the body weight while the other is in a swinging state. The swing phase occurs at 50%-100% and 0%-50% of the gait cycle, during which both legs successively leave the ground and swing forward, preparing for the next support phase. Images of the gait cycle and illustrations of leg movements clearly demonstrate the support and swing states of the legs during the gait cycle. Figure 2 This allows for a clear understanding of how the legs alternate between support and swing during the gait cycle, and the role of the double support phase within the gait cycle. This alternating movement is the foundation of walking, ensuring its continuity and stability. Figure 2 The image illustrates key movements in the gait cycle, including heel strike, ball of the foot strike, and toe lift. These are crucial factors to consider when designing miniature electro-hydraulic actuators for ankle joints to ensure the actuators provide appropriate support and power at different gait phases.

[0061] Based on actual test data from healthy individuals, the dynamic curve of the ankle joint within a single cycle was obtained. The passive phase lasts approximately 0.6 seconds. The active plantar flexion phase lasts 0.2 seconds, with a maximum output power of approximately 2.5 watts / kg of body weight. Considering the load characteristics of the ankle joint, the actuator must achieve isolation between a prolonged passive damping buffering mode and a momentary actuation output mode. Furthermore, given the short duration of the active plantar flexion phase (approximately 0.2 seconds), a prolonged response time when the actuator switches from passive to active mode would affect gait continuity; therefore, the EHA (Extended Actuation Harness) is required to have a fast switching response time.

[0062] The basic principles of this disclosure have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this disclosure are merely examples and not limitations, and should not be considered as essential features of each embodiment of this disclosure. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the scope of this disclosure to the necessity of employing the aforementioned specific details for implementation.

[0063] The block diagrams of devices, apparatuses, devices, and systems disclosed herein are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0064] Additionally, as used herein, the “or” used in a list of items beginning with “at least one” indicates a separate list, such that a list of, for example, “at least one of A, B, or C” means A or B or C, or AB or AC or BC, or ABC (i.e., A and B and C). Furthermore, the word “exemplary” does not imply that the described example is preferred or better than other examples.

[0065] It should also be noted that in the systems and methods of this disclosure, the components or steps can be decomposed and / or recombined. These decompositions and / or recombinations should be considered as equivalent solutions to this disclosure.

[0066] Various changes, substitutions, and modifications can be made to the technology described herein without departing from the teachings defined by the appended claims. Furthermore, the scope of the claims of this disclosure is not limited to the specific aspects of the processes, machines, manufactures, events, means, methods, and actions described above. Currently existing or later-developed processes, machines, manufactures, events, means, methods, or actions that perform substantially the same function or achieve substantially the same result as the corresponding aspects described herein can be utilized. Therefore, the appended claims include such processes, machines, manufactures, events, means, methods, or actions within their scope.

[0067] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this disclosure. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of this disclosure. Therefore, this disclosure is not intended to be limited to the aspects shown herein, but rather to be carried out within the widest scope consistent with the principles and novel features disclosed herein.

[0068] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this disclosure to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations therein.

Claims

1. A miniature electro-hydraulic actuation system resembling an ankle joint, characterized in that, include, A two-way hydraulic cylinder (1) is used to drive ankle joints to achieve passive plantar flexion, passive dorsiflexion, active plantar flexion and active dorsiflexion; The bidirectional hydraulic pump (2) has a first port (21) and a second port (22). The first port (21) is connected to the first chamber (11) of the bidirectional hydraulic cylinder (1) through a first pipeline (3); the second port (22) is connected to the second chamber (12) of the bidirectional hydraulic cylinder (1) through a second pipeline (6). The first hydraulic control check valve (4) is connected in series on the first pipeline (3) to restrict the flow of liquid in the first chamber (11) to the first port (21); the hydraulic control port of the first hydraulic control check valve (4) is connected to the second port (22); it is used to prevent oil from impacting the bidirectional hydraulic pump (2) through the first pipeline (3) when the working mode is switched. The second hydraulic control check valve (5) is connected in series with the second pipeline (6) to restrict the flow of liquid in the second chamber (12) to the second port (22); the hydraulic control port of the second hydraulic control check valve (5) is connected to the first port (21); it is used to prevent oil from impacting the bidirectional hydraulic pump (2) through the second pipeline (6) when the working mode is switched. A bypass damping unit (7) is provided, with its first end connected to the first pipeline (3) between the first hydraulic check valve (4) and the bidirectional hydraulic cylinder (1), and its second end connected to the second pipeline (6) between the second hydraulic check valve (5) and the bidirectional hydraulic cylinder (1). The bypass damping unit (7) is used to provide damping force during passive plantar flexion and passive dorsiflexion. It also includes an oil tank (8), a first check valve (9), and a second check valve (10); The oil tank (8) is connected to the first pipeline (3) between the bidirectional hydraulic pump (2) and the first hydraulic control check valve (4) via a third pipeline; The first check valve (9) is connected in series on the third pipeline to restrict the oil in the first pipeline (3) from flowing back into the oil tank (8); The oil tank (8) is connected to the second pipeline (6) between the bidirectional hydraulic pump (2) and the second hydraulic control check valve (5) via the fourth pipeline; The second check valve (10) is connected in series on the third pipeline to restrict the oil in the second pipeline (6) from flowing back into the oil tank (8).

2. The ankle-like micro-electro-hydraulic actuation system as described in claim 1, characterized in that, The bypass damping unit (7) includes a throttle valve (71) and a solenoid valve (72). The throttle valve (71) is connected in series with the solenoid valve (72), which is used to close during active plantar flexion and active dorsiflexion and to open during passive plantar flexion and passive dorsiflexion to provide damping force.

3. The ankle-like micro-electro-hydraulic actuation system as described in claim 2, characterized in that, During passive plantar flexion and passive dorsiflexion, the motor stops working and the solenoid valve (72) opens; the first chamber (11) and the second chamber (12) are connected through the throttle valve (71) and the solenoid valve (72).

4. The ankle-like micro-electro-hydraulic actuation system as described in claim 1, characterized in that, It also includes a support point (13) and a drive rod (14), the middle part of which is rotatably connected to the support point (13); One end of the hydraulic rod of the bidirectional hydraulic cylinder (1) is hinged to one end of the drive rod (14) so ​​as to achieve active plantar flexion and active dorsiflexion through the reciprocating movement of the hydraulic rod.

5. The ankle-like micro-electro-hydraulic actuation system as described in claim 1, characterized in that, It also includes a drive motor (23) that rotates with the bidirectional hydraulic pump (2) to discharge oil from the first port (21) or the second port (22); When the first port (21) discharges oil, the first hydraulic control check valve (4) opens; the pressure of the first port (21) is transmitted to the hydraulic control port of the second hydraulic control check valve (5) so that the second hydraulic control check valve (5) is opened, forming a conductive circuit to drive the hydraulic rod of the bidirectional hydraulic cylinder (1) to move in the first direction; When the second port (22) discharges liquid oil, the second hydraulic control check valve (5) opens; the pressure of the second port (22) is transmitted to the hydraulic control port of the first hydraulic control check valve (4) so ​​that the first hydraulic control check valve (4) is opened, forming a conducting circuit to drive the hydraulic rod of the bidirectional hydraulic cylinder (1) to move in the second direction.

6. A control method for a miniature electro-hydraulic actuation system resembling an ankle joint as described in any one of claims 1-5, characterized in that, include: During passive plantar flexion or passive dorsiflexion, the bidirectional hydraulic pump (2) is shut off, and the bypass damping unit (7) is turned on; To prevent oil from impacting the bidirectional hydraulic pump (2) and to provide damping force; During active plantar flexion or active dorsiflexion, the bidirectional hydraulic pump (2) is turned on and the bypass damping unit (7) is turned off; the bidirectional hydraulic pump (2) discharges oil from the first port (21) or the second port (22) and drives the first hydraulic control check valve (4) and the second hydraulic control check valve (5) to open, so as to control the bidirectional hydraulic cylinder (1) to work.

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