Electro-hydrostatic active ankle joint prosthesis and walking method

Abstract

The invention discloses an electro-hydrostatic active ankle joint artificial limb and a walking method, and relates to the technical field of artificial limb technologies and additive manufacturing. The electro-hydrostatic active ankle joint artificial limb comprises a motor pump, a hydraulic cylinder, a hydraulic manifold block, an energy accumulator set and an integrated topological sole; the motor pump, the hydraulic cylinder, the energy accumulator set and the integrated topological sole are all integrated on the hydraulic manifold block, the motor pump is used for charging energy to the energy accumulator set, the motor pump and the energy accumulator set are both used for being connected with the hydraulic cylinder, and the hydraulic cylinder is used for being connected with the integrated topological sole. According to the electro-hydrostatic active ankle joint artificial limb and the walking method, the motor pump, the hydraulic cylinder, the energy accumulator set and the integrated topological sole are all integrated on the hydraulic manifold block, and the overall size and weight are reduced.

Description

Technical Field

[0001] The present invention relates to the fields of prosthetic technology and additive manufacturing technology, and in particular to an electrostatic-hydraulic active ankle joint prosthesis and a walking method. Background Art

[0002] The loss of limbs can seriously affect the normal life and work of disabled people. Prosthesis is one of the important tools to help disabled people solve the problem of movement barriers. Unlike upper limb prosthesis, lower limb prosthesis needs to solve the problem of human movement balance. The ankle joint of the lower limb is an important weight-bearing joint that can withstand a force equivalent to 5 times the body weight. During walking, the main force is the coordinated force of the ankle muscles and ligaments, especially when pushing the body forward and upward, about 60% of the force is provided by the ankle joint. Therefore, the stability and flexibility of the ankle joint are essential for movement and coordination of the movements of the whole body.

[0003] For amputees, ankle prostheses can provide basic movement functions, but prostheses in the prior art are usually large in size and weight. Summary of the invention

[0004] The purpose of the present invention is to provide an electrostatic-hydraulic active ankle joint prosthesis and a walking method, by integrating a motor pump, a hydraulic cylinder, an accumulator group and an integrated topological sole on a hydraulic integrated block, thereby reducing the overall volume and weight.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] The present invention provides an electrostatic-hydraulic active ankle joint prosthesis, comprising: a motor pump, a hydraulic cylinder, a hydraulic integrated block, an accumulator group, and an integrated topological sole. The motor pump, the hydraulic cylinder, the accumulator group, and the integrated topological sole are all integrated on the hydraulic integrated block. The motor pump is used to charge the accumulator group. The motor pump and the accumulator group are both used to be connected to the hydraulic cylinder. The hydraulic cylinder is used to be connected to the integrated topological sole.

[0007] Preferably, the motor pump comprises a motor and two plunger pumps, the power output end of the motor is provided with an eccentric shaft, the eccentric shaft is connected to the rotor swash plate of the plunger pump, and the power output end of the motor drives the two plunger pumps to operate once respectively in one rotation cycle.

[0008] Preferably, the integrated topological foot includes an ankle skeleton, a forefoot, a heel and a support shaft. The middle part of the ankle skeleton is rotatably connected to the hydraulic integrated block via a support shaft. An angle sensor is provided on the support shaft. The front end of the ankle skeleton is hinged to the telescopic end of the hydraulic cylinder, the rear end of the forefoot is connected to the ankle skeleton, and the front end of the heel is connected to the ankle skeleton.

[0009] Preferably, the integrated topological sole is made of carbon fiber.

[0010] Preferably, the hydraulic cylinder is a double-rod hydraulic cylinder.

[0011] Preferably, it further comprises a control board and a drive board, and both the control board and the drive board are integrated on the hydraulic integrated block.

[0012] The present invention provides a walking method using the electrostatic-hydraulic active ankle joint prosthesis, comprising the following stages:

[0013] Passive plantar flexion stage: the first normally open switch valve and the second normally open switch valve are both turned on, the first normally closed switch valve and the second normally closed switch valve remain closed, the upper chamber of the hydraulic cylinder and the lower chamber of the hydraulic cylinder are turned on through the first normally open switch valve and the second normally open switch valve, the pressures of the upper chamber of the hydraulic cylinder and the lower chamber of the hydraulic cylinder are equal, the hydraulic cylinder is in a suspended state, the opening of the first normally open switch valve is controlled by PWM-PFM, and the flow damping of the hydraulic oil is adjusted to enable the electrostatic active ankle joint prosthesis to absorb the impact of touching the ground. At this time, the oil output by the motor pump directly charges the motor energy storage accumulator;

[0014] Passive dorsiflexion stage: the first normally open switch valve is turned on, the second normally open switch valve is not turned on, the first normally closed switch valve and the second normally closed switch valve remain closed, the human body's gravity works on the electrostatic active ankle joint prosthesis, the hydraulic oil in the system cylinder accumulator enters the lower chamber of the hydraulic cylinder through the first normally open switch valve, the hydraulic oil energy in the upper chamber of the hydraulic cylinder is recovered to the gravity recovery accumulator, and at the same time, the motor energy storage accumulator continues to charge;

[0015] Active plantar flexion stage: the first normally closed switch valve and the first normally open switch valve are connected, the second normally closed switch valve and the second normally open switch valve are not connected, the hydraulic oil output by the motor pump, the hydraulic oil in the gravity recovery accumulator and the hydraulic oil in the motor energy storage accumulator all enter the upper chamber of the hydraulic cylinder through the first normally closed switch valve, and the hydraulic oil in the lower chamber of the hydraulic cylinder enters the system cylinder accumulator through the first normally open switch valve;

[0016] Active dorsiflexion stage: the second normally open switch valve and the second normally closed switch valve are connected, and the first normally closed switch valve and the first normally open switch valve are not connected; the hydraulic oil of the motor pump enters the lower chamber of the hydraulic cylinder through the second normally closed switch valve, and the hydraulic oil in the upper chamber of the hydraulic cylinder flows back to the system cylinder accumulator through the second normally open switch valve.

[0017] Compared with the prior art, the present invention has achieved the following technical effects:

[0018] The electrostatic-hydraulic active ankle joint prosthesis and walking method of the present invention integrates the motor pump, hydraulic cylinder, accumulator group and integrated topological sole on the hydraulic integrated block to reduce the overall volume and weight. Through the dynamic regulation of energy during the prosthetic walking process and the lightweight design of the whole machine, the output power-to-weight ratio of the prosthesis is improved, the output performance problem caused by the weight limit of the wearable device is solved, and the contradiction between the high peak power output and the light weight and small volume of the ankle joint prosthesis is greatly improved, making the electrostatic-hydraulic active ankle joint prosthesis of the present invention closer to the movement performance of a normal human leg. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 Axonometric measurement of the electrostatic-hydraulic active ankle prosthesis of the present invention Figure 1 ;

[0021] Figure 2 Axonometric measurement of the electrostatic-hydraulic active ankle prosthesis of the present invention Figure 2 ;

[0022] Figure 3 It is a side view of the electrostatic fluid active ankle joint prosthesis of the present invention;

[0023] Figure 4 A top view of the electrostatic-fluid active ankle prosthesis of the present invention;

[0024] Figure 5 A schematic diagram of the integrated topological sole of the electrostatic-hydraulic active ankle prosthesis of the present invention;

[0025] Figure 6 It is a schematic diagram of the motor pump of the present invention;

[0026] Figure 7 A schematic diagram of a walking method of the electrostatic-hydraulic active ankle joint prosthesis of the present invention;

[0027] Figure 8 It is a schematic diagram of the main energy optimization chain in each gait stage of the walking process of the electrostatic-hydraulic active ankle joint prosthesis of the present invention;

[0028] In the figure: 1-motor, 2-plunger pump, 3-hydraulic cylinder, 4-hydraulic integrated block, 5-motor energy storage accumulator, 6-system cylinder accumulator, 7-gravity recovery accumulator, 8-first normally closed switch valve, 9-second normally closed switch valve, 10-first normally open switch valve, 11-second normally open switch valve, 12-ankle skeleton, 13-forefoot, 14-heel, 15-support shaft, 16-angle sensor, 17-adapter connector, 18-eccentric shaft, 19-rotor swash plate, 20-drive plate. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The purpose of the present invention is to provide an electrostatic-hydraulic active ankle joint prosthesis and a walking method, by integrating a motor pump, a hydraulic cylinder, an accumulator group and an integrated topological sole on a hydraulic integrated block, thereby reducing the overall volume and weight.

[0031] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] Embodiment 1

[0033] like Figures 1 to 6 As shown, this embodiment provides an electrostatic-hydraulic active ankle prosthesis, including: a motor pump, a hydraulic cylinder 3, a hydraulic integrated block 4, an accumulator group, and an integrated topological foot. The motor pump, the hydraulic cylinder 3, the accumulator group and the integrated topological foot are all integrated on the hydraulic integrated block 4. The motor pump is used to charge the accumulator group. The motor pump and the accumulator group are both used to connect to the hydraulic cylinder 3, and the hydraulic cylinder 3 is used to connect to the integrated topological foot.

[0034] Specifically, in this embodiment, the hydraulic integrated block 4 is a transmission element that provides complete functions for the integrated base and hydraulic system of the remaining components of the electrostatic-hydraulic active ankle joint prosthesis. It has a built-in closed hydraulic pipeline, and the internal porous structure is optimized based on the additive manufacturing method according to the stress analysis results. The upper end of the hydraulic integrated block 4 is also provided with an adapter connection seat 17, and the adapter connection seat 17 is used to connect with the lower limb end of the disabled. In order to optimize the use of space, all slender elements with an axial length greater than the radial diameter, including three liquid pressure sensors, motor energy storage accumulators 5, gravity recovery accumulators 7, oil storage accumulators and adapter connection seats 17 are placed on the top of the hydraulic integrated block 4, which not only realizes the uniform distribution of each component in a limited area, but also minimizes the connection distance between the oil ports, thereby effectively reducing the cross-sectional area of ​​the electrostatic-hydraulic active ankle joint prosthesis and reducing the volume interference when wearing.

[0035] In this embodiment, the hydraulic cylinder 3 is a double-rod hydraulic cylinder. The double-rod hydraulic cylinder is the power output unit of the entire hydraulic system, which is directly connected to the integrated topological sole to complete the precise actuation control of the prosthesis. The interior of the hydraulic integrated block 4 is a closed flow channel, one end of which is connected to the hydraulic cylinder 3 and the other end is connected to the plunger pump 2, which is completely enclosed inside the prosthesis. In order to meet the portability and lightweight requirements of the wearable device, no additional oil cylinder is introduced into the system. Since the accumulator group cannot store a large amount of oil, it is necessary to keep the total amount of oil in the system constant. The upper and lower end areas of the piston rod of the double-rod hydraulic cylinder are consistent, and the total amount of oil in the cylinder is constant during movement, so the use of a double-rod hydraulic cylinder can meet the requirement of constant total amount of internal oil when the motor 1 and the hydraulic cylinder 3 are in operation, and realize the long-term transmission requirement. In the design process, the maximum instantaneous power required by the prosthesis and the swing angle range of the integrated topological sole are comprehensively considered, and the maximum working pressure in the hydraulic cylinder 3 and the stroke of the piston rod are accurately calculated. The wall thickness and length of the hydraulic cylinder 3 are optimized, and the overall weight is reduced as much as possible while ensuring performance, meeting the requirements of lightweight equipment, ensuring the stability and efficiency of the prosthesis in actual application, and improving the user's comfort and range of motion.

[0036] In this embodiment, the accumulator group includes a motor energy storage accumulator 5, a system cylinder accumulator 6 and a gravity recovery accumulator 7. The motor pump is used to charge the motor energy storage accumulator 5. The oil outlet of the motor pump is respectively connected to the upper chamber of the hydraulic cylinder 3 and the lower chamber of the hydraulic cylinder 3. The oil port of the motor energy storage accumulator 5 is respectively connected to the upper chamber of the hydraulic cylinder 3 and the lower chamber of the hydraulic cylinder 3. The oil port of the system cylinder accumulator 6 is respectively connected to the oil inlet of the motor pump, the upper chamber of the hydraulic cylinder 3 and the lower chamber of the hydraulic cylinder 3. The oil port of the gravity recovery accumulator 7 is connected to the upper chamber of the hydraulic cylinder 3.

[0037] This embodiment also includes a first normally closed switch valve 8, a second normally closed switch valve 9, a first normally open switch valve 10 and a second normally open switch valve 11; the oil port of the motor energy storage accumulator 5 is respectively connected to one end of the first normally closed switch valve 8 and one end of the second normally closed switch valve 9, the other end of the first normally closed switch valve 8 is connected to the upper chamber of the hydraulic cylinder 3, and the other end of the second normally closed switch valve 9 is connected to the lower chamber of the hydraulic cylinder 3; the oil port of the system cylinder accumulator 6 is respectively connected to one end of the first normally open switch valve 10 and one end of the second normally open switch valve 11, the other end of the first normally open switch valve 10 is connected to the lower chamber of the hydraulic cylinder 3, and the other end of the second normally open switch valve 11 is connected to the upper chamber of the hydraulic cylinder 3.

[0038] In this embodiment, a first liquid pressure sensor is arranged between the motor energy storage accumulator 5 and the first normally closed switch valve 8, a second liquid pressure sensor is arranged between the gravity recovery accumulator 7 and the upper chamber of the hydraulic cylinder 3, and a third liquid pressure sensor is arranged between the lower chamber of the hydraulic cylinder 3 and the second normally closed switch valve 9 or between the lower chamber of the hydraulic cylinder 3 and the first normally open switch valve 10.

[0039] In this embodiment, the motor pump includes a motor 1 and two plunger pumps 2. The motor 1 is a small brushless DC motor. A plunger pump 2 is respectively arranged at the upper and lower ends of the motor 1. An eccentric shaft 18 is arranged at the power output end of the motor 1. The eccentric shaft 18 is connected to the rotor swash plate 19 of the plunger pump 2. When the eccentric shaft 18 rotates, the rotor swash plate 19 moves up and down. The rotor swash plate 19 converts the rotational power of the motor 1 into the reciprocating motion required by the plunger pump 2, and drives the two plunger pumps 2 to work respectively. The power output end of the motor 1 drives the two plunger pumps 2 to run once respectively in one rotation cycle, thereby realizing efficient energy conversion and transmission, and significantly improving the operation efficiency of the system. The electrostatic-hydraulic active ankle prosthesis of this embodiment is fixed to the end of the lower limb of the disabled person through an adapter connector 17, and the motor 1 drives the plunger pump 2 to operate continuously, extracting the hydraulic oil in the system cylinder accumulator 6 and supplying it to the hydraulic cylinder 3 through a pipeline according to the state of the first normally closed switch valve 8, the second normally closed switch valve 9, the first normally open switch valve 10 and the second normally open switch valve 11. Combined with the energy in the motor energy storage accumulator 5 and the gravity recovery accumulator 7, they jointly provide thrust or pulling force for the integrated topological foot.

[0040] In order to achieve the overall output capacity of the prosthesis to meet the requirements of human movement, the electrostatic active ankle joint prosthesis has added an integrated small brushless DC motor and two plunger pumps 2. At the same time, according to the human joint actuation mechanism, the accumulator group is used to achieve the time domain optimization of the driving energy. Different storage and recovery accumulators in the accumulator group are used to accumulate and release energy in stages to complete the energy time domain allocation and instantaneous high power output requirements. The motor energy storage accumulator 5, the system cylinder accumulator 6 and the gravity recovery accumulator 7 cooperate with each other to achieve lower energy consumption of the device as a whole while ensuring the output capacity.

[0041] In this embodiment, the integrated topological sole is made of carbon fiber. Based on additive manufacturing, lightweight topological optimization that meets the strength requirements is performed according to the load and force relationship during walking. The integrated topological sole includes an ankle skeleton 12, a forefoot 13, a heel 14 and a support shaft 15. The middle part of the ankle skeleton 12 is rotatably connected to the hydraulic integrated block 4 through the support shaft 15 and a ball bearing. The support shaft 15 and the ball bearing limit the axial freedom of the support shaft 15. An angle sensor 16 is provided on the support shaft 15. The front end of the ankle skeleton 12 is hinged to the telescopic end of the hydraulic cylinder 3 through a connecting shaft and a ball bearing to achieve effective transmission of prosthetic power. The ankle skeleton 12 firmly connects the forefoot 13 through the front end chamfer of the lower surface and the bolts at the rear end, and the heel 14 is connected to the ankle skeleton 12 through two flange screws on the bottom surface and the front end step. This design ensures the overall stability of the integrated topological sole when it is subjected to ground impact.

[0042] In this embodiment, the ankle skeleton 12 is a mechanical structural component that mainly bears pressure in the vertical direction during human gait, and the stress condition is relatively simple. Based on the principle of structural topology optimization, the lightweight optimization framework is constructed using ANSYS software for the known load conditions, constraints and performance indicators. The ankle skeleton 12 model is optimized and designed and strength analyzed. Through multiple iterations, it is ensured that the weight is reduced to the greatest extent and the material consumption is reduced while meeting the mechanical performance requirements. It can optimize the user experience of the prosthesis without sacrificing structural integrity and improve its functionality and comfort.

[0043] In order to maintain the weight limit requirements of wearable devices for the human body, while improving the performance of the output components, the electrostatic active ankle joint prosthesis is designed to keep the weight of the whole machine equivalent to that of the human calf through integrated lightweight optimization. Each component is integrated on the hydraulic integrated block 4 at the center and the spatial layout is optimized to reduce the overall volume. The hydraulic integrated block 4 of the heavy weight component and the integrated topological sole complete the optimization of the surface additive manufacturing method. Finally, while meeting the mechanical performance requirements, the overall weight of the prosthesis is less than the average weight of the human calf with the same functional range.

[0044] The present embodiment also includes a control board and a drive board 20, which are both integrated on the hydraulic integrated block 4, and the drive board 20 is tightly integrated on the back of the motor 1, optimizing the spatial layout. A DSP chip is integrated on the control board, and a signal interface and a power supply interface of a liquid pressure sensor are provided. The drive board 20 is responsible for the power supply of the control board, the first normally closed switch valve 8, the second normally closed switch valve 9, the first normally open switch valve 10, the second normally open switch valve 11 and the motor 1. Such a separate design not only improves the modularity of the system, but also facilitates later maintenance and upgrading. By optimizing the layout, the arrangement of each component is more compact and reasonable, ensuring the overall performance of the prosthesis and the comfort of the user.

[0045] The overall layout of the electrostatic-hydraulic active ankle joint prosthesis of this embodiment is based on the bionic shape of the lower leg. The hydraulic integrated block 4 is the main body, and the plunger pump 2, the first normally closed switch valve 8, the second normally closed switch valve 9, the first normally open switch valve 10 and the second normally open switch valve 11 are all embedded in the hydraulic integrated block 4 through the riveting process, which reduces unnecessary fixing mechanisms, improves integration, and helps to reduce the volume of the prosthesis. The hydraulic cylinder 3 and the motor 1 are connected to the hydraulic integrated block 4 through a plate connection and fixed by bolts.

[0046] The complex internal flow channel of the hydraulic manifold block 4 adopts the additive manufacturing process. Compared with the traditional machining method, the customized design of the flow channel can be realized. The required pipelines can be arranged in a smaller volume, and the hydraulic components can be arranged more closely, making full use of the various surface areas of the hydraulic manifold block 4, thereby effectively reducing the system size and reducing the system weight. The specific component layout is as follows: the hydraulic manifold block 4 is located in the center and is the mounting base of the overall structure. The top of the hydraulic manifold block 4 is provided with an adapter connection seat 17, three liquid pressure sensors and an accumulator group. The front of the hydraulic manifold block 4 is a double-rod hydraulic cylinder. The left area of ​​the hydraulic manifold block 4 is the installation space of the control panel. The right side of the hydraulic manifold block 4 is designed with a first normally closed switch valve 8, a second normally closed switch valve 9, a first normally open switch valve 10 and a second normally open switch valve 11 and a system oil filling port with a one-way valve. The rear of the hydraulic manifold block 4 is a motor 1 and two plunger pumps 2. The motor 1 and the two plunger pumps 2 are embedded in the hydraulic manifold block 4 through a riveting process and are not visible from the outside. The bottom of the hydraulic manifold block 4 is an integrated topological sole. The arrangement of the overall components of the electrostatic-hydraulic active ankle prosthesis of this embodiment fully utilizes the space of the hydraulic integrated block 4 .

[0047] The electrostatic-hydraulic active ankle prosthesis of the present embodiment is similar in weight to the human calf, and can actively provide sufficient driving force, so that the wearer can obtain a walking gait similar to the biological characteristics of the human body. The output capacity of the electrostatic-hydraulic active ankle prosthesis of the present embodiment can meet the human body's running requirements in the full gait stage including the peak demand, while reducing the weight of the whole machine through lightweight design, and can achieve a high output power-to-weight ratio (i.e., the ratio of high output power to the weight of the whole machine). The core of the high output power-to-weight ratio in the present embodiment is to achieve a high peak power output while maintaining lightweight and small size, and can achieve a good balance between achieving a high peak power output and maintaining a light weight and small size, and has a high output power-to-weight ratio and high energy efficiency as a whole. Based on human gait analysis, the electrostatic-hydraulic active ankle prosthesis realizes the design of the motor energy storage accumulator 5, the system cylinder accumulator 6 and the gravity recovery accumulator 7 for the four gait characteristics through the stage regulation of hydraulic energy, optimizes the energy transmission chain, realizes the overall regulation and loss reduction of the prosthesis energy to meet the instantaneous high power demand during walking; through the lightweight design of key components, based on the additive manufacturing method, the porous structure filled in the hydraulic manifold 4 and the structural topology optimization of the integrated topological sole are realized, which greatly reduces the weight of the whole machine. Finally, the electrostatic-hydraulic active ankle prosthesis with high output power-to-weight ratio and high energy utilization efficiency is designed.

[0048] The electrostatic-hydraulic active ankle prosthesis proposed in this embodiment analyzes the movement state of the human body during walking to achieve dynamic energy regulation in the prosthesis and lightweight design of the whole device, thereby solving the output performance problem caused by weight limitations of wearable devices and greatly improving the contradiction between high peak power output and light weight and small volume of the ankle prosthesis, making it closer to the walking movement performance of a normal human leg.

[0049] Embodiment 2

[0050] like Figure 7 and Figure 8 As shown, this embodiment provides a walking method using the electrostatic-hydraulic active ankle joint prosthesis of the first embodiment, comprising the following stages:

[0051] Passive plantar flexion stage: the first normally open switch valve 10 and the second normally open switch valve 11 are both turned on, the first normally closed switch valve 8 and the second normally closed switch valve 9 remain closed, the upper chamber of the hydraulic cylinder 3 and the lower chamber of the hydraulic cylinder 3 are turned on through the first normally open switch valve 10 and the second normally open switch valve 11, the pressures of the upper chamber of the hydraulic cylinder 3 and the lower chamber of the hydraulic cylinder 3 are equal, the hydraulic cylinder 3 is in a suspended state, the opening of the first normally open switch valve 10 is controlled by PWM-PFM, and the flow damping of the hydraulic oil is adjusted to enable the electrostatic active ankle joint prosthesis to absorb the impact of touching the ground. At this time, the oil output by the motor pump directly charges the motor energy storage accumulator 5;

[0052] Passive dorsiflexion stage: the first normally open switch valve 10 is turned on, the second normally open switch valve 11 is not turned on, the first normally closed switch valve 8 and the second normally closed switch valve 9 remain closed, the human body's gravity works on the electrostatic active ankle joint prosthesis, the hydraulic oil in the system cylinder accumulator 6 enters the lower chamber of the hydraulic cylinder 3 through the first normally open switch valve 10, the hydraulic oil energy in the upper chamber of the hydraulic cylinder 3 is recovered to the gravity recovery accumulator 7, and at the same time, the motor energy storage accumulator 5 continues to charge;

[0053] Active plantar flexion stage: the first normally closed switch valve 8 and the first normally open switch valve 10 are turned on, the second normally closed switch valve 9 and the second normally open switch valve 11 are not turned on, the hydraulic oil output by the motor pump, the hydraulic oil in the gravity recovery accumulator and the hydraulic oil in the motor energy storage accumulator 5 all enter the upper chamber of the hydraulic cylinder 3 through the first normally closed switch valve 8, and the hydraulic oil in the lower chamber of the hydraulic cylinder 3 enters the system cylinder accumulator 6 through the first normally open switch valve 10; this stage is a process of instantaneous high-power output to the outside, the prosthesis kicks the leg toward the ground, at this time the output torque demand and output power of the prosthesis are extremely large, the total input power of the hydraulic system is the sum of the input power of the hydraulic pump and the power of the accumulator group, and at this time the output power of the hydraulic cylinder 3 comes from: the piston pump 2 charges the motor energy storage accumulator 5 in the passive plantar flexion and passive dorsiflexion stages and the human body's gravity recovers the energy of the gravity recovery accumulator 7 in the passive dorsiflexion stage;

[0054] Active dorsiflexion stage: the second normally open switch valve 11 and the second normally closed switch valve 9 are connected, and the first normally closed switch valve 8 and the first normally open switch valve 10 are not connected; the hydraulic oil of the motor pump enters the lower chamber of the hydraulic cylinder 3 through the second normally closed switch valve 9, and the hydraulic oil in the upper chamber of the hydraulic cylinder 3 flows back to the system cylinder accumulator 6 through the second normally open switch valve 11.

[0055] Figure 8The schematic diagram of the main energy optimization chain of the electrostatic-hydraulic active ankle joint prosthesis of this embodiment in each gait stage during walking. Since the prosthesis is a wearable device limited by weight and endurance, it is impossible to use high-power output elements such as motor 1, plunger pump 2 and hydraulic cylinder 3, so it is necessary to meet the needs of human movement through a reasonable energy utilization strategy. The energy management strategy can be divided into two categories: time-sharing storage of energy and loss optimization. In the passive dorsiflexion stage, the duration is short, the power demand of the prosthesis is low, and the stroke of the hydraulic cylinder 3 is relatively small. Therefore, at this stage, the excess energy generated by the motor 1 can be stored to provide support for subsequent stages. In the passive plantar flexion stage, the duration is long and the power demand is low, the center of gravity of the human body gradually moves to the front sole, and the ankle joint is in a state of doing negative work. Therefore, while storing the energy of the motor 1, the energy generated by the human body's gravitational work can also be recovered to improve the energy utilization efficiency of the system. In the active plantar flexion stage, the duration is extremely short and the power demand is extremely high, and the stroke of the hydraulic cylinder 3 is large. At this time, all the stored energy in the accumulator group and the energy of the motor 1 work together to drive the hydraulic cylinder 3 to output efficiently. By optimizing the design of the pipeline, the energy transmission loss under high pressure and large flow can be greatly reduced. In the active dorsiflexion stage, the duration is longer and the power demand is relatively stable. In this stage, in addition to storing some excess motor 1 energy, the optimization of transmission loss can also significantly save energy.

[0056] In summary, through the rational optimization of the main energy in each stage, the energy utilization efficiency is improved, the energy loss is reduced, and the goals of high output performance of the prosthesis under a limited weight and high power-to-weight ratio of the whole machine are met.

[0057] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. An electrostatic-hydraulic active ankle prosthesis, characterized in that: include: A motor pump, a hydraulic cylinder, a hydraulic integrated block, an accumulator group, and an integrated topological foot. The motor pump, the hydraulic cylinder, the accumulator group, and the integrated topological foot are all integrated on the hydraulic integrated block. The motor pump is used to charge the accumulator group. The motor pump and the accumulator group are both used to connect to the hydraulic cylinder. The hydraulic cylinder is used to connect to the integrated topological foot.

2. The electrostatic-hydraulic active ankle prosthesis according to claim 1, characterized in that: The motor pump comprises a motor and two plunger pumps. An eccentric shaft is provided at the power output end of the motor. The eccentric shaft is connected to the rotor swash plate of the plunger pump. The power output end of the motor drives the two plunger pumps to operate once respectively in one rotation cycle.

3. The electrostatic-hydraulic active ankle prosthesis according to claim 1, characterized in that: The integrated topological foot includes an ankle frame, a forefoot, a heel and a support shaft. The middle part of the ankle frame is rotatably connected to the hydraulic integrated block via a support shaft. An angle sensor is provided on the support shaft. The front end of the ankle frame is hinged to the telescopic end of the hydraulic cylinder, the rear end of the forefoot is connected to the ankle frame, and the front end of the heel is connected to the ankle frame.

4. The electrostatic-hydraulic active ankle joint prosthesis according to claim 1, characterized in that: The integrated topological sole is made of carbon fiber.

5. The electrostatic-hydraulic active ankle prosthesis according to claim 1, characterized in that: The hydraulic cylinder is a double-rod hydraulic cylinder.

6. The electrostatic-hydraulic active ankle joint prosthesis according to claim 1, characterized in that: It also includes a control board and a drive board, and the control board and the drive board are both integrated on the hydraulic integrated block.

7. A walking method for an electrostatic-hydraulic active ankle prosthesis according to any one of claims 1 to 6, characterized in that: The following phases are included: Passive plantar flexion stage: the first normally open switch valve and the second normally open switch valve are both turned on, the first normally closed switch valve and the second normally closed switch valve remain closed, the upper chamber of the hydraulic cylinder and the lower chamber of the hydraulic cylinder are turned on through the first normally open switch valve and the second normally open switch valve, the pressures of the upper chamber of the hydraulic cylinder and the lower chamber of the hydraulic cylinder are equal, the hydraulic cylinder is in a suspended state, the opening of the first normally open switch valve is controlled by PWM-PFM, and the flow damping of the hydraulic oil is adjusted to enable the electrostatic active ankle joint prosthesis to absorb the impact of touching the ground. At this time, the oil output by the motor pump directly charges the motor energy storage accumulator; Passive dorsiflexion stage: the first normally open switch valve is turned on, the second normally open switch valve is not turned on, the first normally closed switch valve and the second normally closed switch valve remain closed, the human body's gravity works on the electrostatic active ankle joint prosthesis, the hydraulic oil in the system cylinder accumulator enters the lower chamber of the hydraulic cylinder through the first normally open switch valve, the hydraulic oil energy in the upper chamber of the hydraulic cylinder is recovered to the gravity recovery accumulator, and at the same time, the motor energy storage accumulator continues to charge; Active plantar flexion stage: the first normally closed switch valve and the first normally open switch valve are connected, the second normally closed switch valve and the second normally open switch valve are not connected, the hydraulic oil output by the motor pump, the hydraulic oil in the gravity recovery accumulator and the hydraulic oil in the motor energy storage accumulator all enter the upper chamber of the hydraulic cylinder through the first normally closed switch valve, and the hydraulic oil in the lower chamber of the hydraulic cylinder enters the system cylinder accumulator through the first normally open switch valve; Active dorsiflexion stage: the second normally open switch valve and the second normally closed switch valve are connected, and the first normally closed switch valve and the first normally open switch valve are not connected; the hydraulic oil of the motor pump enters the lower chamber of the hydraulic cylinder through the second normally closed switch valve, and the hydraulic oil in the upper chamber of the hydraulic cylinder flows back to the system cylinder accumulator through the second normally open switch valve.

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