Electro-hydraulic active ankle prosthesis and walking method

Abstract

The application discloses an electro-hydraulic active ankle prosthesis and a walking method, relates to the technical field of prostheses and additive manufacturing technology, and discloses an electro-hydraulic active ankle prosthesis, which comprises a motor pump, a hydraulic cylinder, a hydraulic integrated block, an accumulator group and an integrated topology instep, wherein the motor pump, the hydraulic cylinder, the accumulator group and the integrated topology instep are all integrated on the hydraulic integrated block, the motor pump is used for charging the accumulator group, the motor pump and the accumulator group are both used for being connected with the hydraulic cylinder, and the hydraulic cylinder is used for being connected with the integrated topology instep. The electro-hydraulic active ankle prosthesis and the walking method have the advantages that the motor pump, the hydraulic cylinder, the accumulator group and the integrated topology instep are all integrated on the hydraulic integrated block, so that the overall volume and weight are reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of prosthetic technology and additive manufacturing technology, in particular to an electro-hydraulic active ankle joint prosthesis and a walking method. BACKGROUND

[0002] The loss of limbs can seriously affect the normal life and work of the disabled. Prostheses are one of the important tools to help the disabled solve the problem of movement obstacles. Unlike upper limb prostheses, lower limb prostheses need to solve the problem of human body movement balance. The ankle joint of the lower limb is an important weight-bearing joint and can bear a force equivalent to 5 times the body weight. During walking, the ankle joint mainly relies on the coordinated effort of ankle joint 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 crucial for movement and coordination of the whole body.

[0003] For amputees, installing an ankle joint prosthesis can provide basic movement functions. However, the prostheses in the prior art are usually large in size and heavy in weight. SUMMARY

[0004] The purpose of the present application is to provide an electro-hydraulic active ankle joint prosthesis and a walking method, which reduces the overall size and weight by integrating the motor pump, hydraulic cylinder, accumulator group and integrated topology foot sole on the hydraulic integrated block.

[0005] To achieve the above-mentioned purpose, the present application provides the following solutions:

[0006] The present application provides an electro-hydraulic active ankle joint prosthesis, comprising: a motor pump, a hydraulic cylinder, a hydraulic integrated block, an accumulator group and an integrated topology foot sole, the motor pump, the hydraulic cylinder, the accumulator group and the integrated topology foot 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 connect with the hydraulic cylinder, and the hydraulic cylinder is used to connect with the integrated topology foot 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 with the swash plate of the rotor of the plunger pump, and the power output end of the motor drives each of the two plunger pumps to run once in one rotation cycle.

[0008] Preferably, the integrated topology foot sole comprises an ankle skeleton, a forefoot, a heel and a support shaft, the middle part of the ankle skeleton is rotationally connected with the hydraulic integrated block through the support shaft, an angle sensor is arranged on the support shaft, the front end of the ankle skeleton is hingedly connected with the telescopic end of the hydraulic cylinder, the rear end of the forefoot is connected with the ankle skeleton, and the front end of the heel is connected with 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, a control board and a driving board are further included, and the control board and the driving board are both integrated on the hydraulic integrated block.

[0012] The application provides a walking method using the electro-hydrostatic active ankle prosthesis, including 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 cavity of the hydraulic cylinder and the lower cavity of the hydraulic cylinder are connected through the first normally open switch valve and the second normally open switch valve, the pressure of the upper cavity of the hydraulic cylinder and the lower cavity of the hydraulic cylinder is equal, the hydraulic cylinder is in a suspended state, the opening degree of the first normally open switch valve is controlled by PWM-PFM, the flow damping of the hydraulic oil is adjusted, so that the electro-hydrostatic active ankle prosthesis can absorb the impact of touching the ground, at this time, the oil output by the motor pump directly charges the motor energy accumulator;

[0014] Passive dorsal flexion 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 gravity works on the electro-hydrostatic active ankle prosthesis, the hydraulic oil in the system oil cylinder accumulator enters the lower cavity of the hydraulic cylinder through the first normally open switch valve, the hydraulic oil energy of the upper cavity of the hydraulic cylinder is recovered to the gravity recovery accumulator, and meanwhile, the motor energy accumulator continues to charge;

[0015] Active plantar flexion stage: the first normally closed switch valve and the first normally open switch valve are turned on, the second normally closed switch valve and the second normally open switch valve 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 accumulator all enter the upper cavity of the hydraulic cylinder through the first normally closed switch valve, and the hydraulic oil in the lower cavity of the hydraulic cylinder enters the system oil cylinder accumulator through the first normally open switch valve.

[0016] Active dorsal flexion stage: the second normally open switch valve and the second normally closed switch valve are turned on, the first normally closed switch valve and the first normally open switch valve are not turned on; the hydraulic oil of the motor pump enters the lower cavity of the hydraulic cylinder through the second normally closed switch valve, and the hydraulic oil of the upper cavity of the hydraulic cylinder flows back to the system oil cylinder accumulator through the second normally open switch valve.

[0017] The application has the following technical effects compared with the prior art:

[0018] The electro-hydrostatic active ankle prosthesis and walking method of the application, by integrating the motor pump, hydraulic cylinder, accumulator group and integrated topology foot sole on the hydraulic integrated block, reduces the overall volume and weight. Through energy dynamic regulation and control during the walking process of the prosthesis and 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 limitation of wearable devices is solved, and the contradiction between high peak power output and small weight and small volume of the ankle prosthesis is greatly improved, so that the electro-hydrostatic active ankle prosthesis of the application is closer to the movement performance of the normal human leg. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0020] Figure 1 The isometric view of the electro-hydrostatic active ankle prosthesis of the application Figure 1 ;

[0021] Figure 2 The isometric view of the electro-hydrostatic active ankle prosthesis of the application Figure 2 ;

[0022] Figure 3 The side view of the electro-hydrostatic active ankle prosthesis of the application

[0023] Figure 4 The top view of the electro-hydrostatic active ankle prosthesis of the application

[0024] Figure 5 The integrated topology foot sole schematic diagram of the electro-hydrostatic active ankle prosthesis of the application

[0025] Figure 6 The schematic diagram of the motor pump of the application

[0026] Figure 7 The walking method schematic diagram of the electro-hydrostatic active ankle prosthesis of the application

[0027] Figure 8 The main energy optimization schematic diagram of the electro-hydrostatic active ankle prosthesis of the application in the walking process of each gait stage

[0028] In the diagram: 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 frame, 13-Forefoot, 14-Heel, 15-Support shaft, 16-Angle sensor, 17-Adapter connector, 18-Eccentric shaft, 19-Rotor swashplate, 20-Drive board. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] The purpose of this invention is to provide an electro-hydraulic active ankle prosthesis and a walking method, which reduces the overall size and weight by integrating the motor pump, hydraulic cylinder, accumulator group and integrated topology foot into a hydraulic integrated block.

[0031] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] Example 1

[0033] like Figures 1 to 6 As shown, this embodiment provides an electro-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, hydraulic cylinder 3, accumulator group, and integrated topological foot are all integrated on the hydraulic integrated block 4. The motor pump is used to charge the accumulator group. Both the motor pump and the accumulator group are used to connect to the hydraulic cylinder 3. 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 complete functional transmission element for the rest of the components of the electro-hydrostatic active ankle prosthesis and the hydraulic system, and has a built-in closed hydraulic pipeline. Based on the additive manufacturing method, the internal porous structure is optimized according to the stress analysis results. The upper end of the hydraulic integrated block 4 is also provided with an adapter connecting seat 17 for connecting with the lower extremity of the disabled person. In order to optimize the space utilization, all the slender elements with an axial length greater than a radial diameter, including three liquid pressure sensors, a motor energy storage accumulator 5, a gravity recovery accumulator 7, an oil storage accumulator and an adapter connecting seat 17, are placed on the top of the hydraulic integrated block 4. This not only realizes the uniform distribution of each element in a limited area, but also maximizes the connection distance between the oil ports, thereby effectively reducing the cross-sectional area of the electro-hydrostatic active ankle prosthesis and reducing the volume interference when worn.

[0035] In this embodiment, the hydraulic cylinder 3 is a double-rod hydraulic cylinder. As the power output unit of the entire hydraulic system, the double-rod hydraulic cylinder is directly connected with the integrated topology foot sole to complete the precise actuation control of the prosthesis. The inside of the hydraulic integrated block 4 is a closed flow channel, one end of which is connected with the hydraulic cylinder 3 and the other end is connected with the plunger pump 2, which is completely enclosed inside the prosthesis. In order to meet the portability and lightness requirements of wearable devices, no additional oil cylinder is introduced into the system. Since the accumulator group cannot store a large amount of oil, it is necessary to maintain the constant total amount of oil inside the system. 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. Therefore, the use of the double-rod hydraulic cylinder can satisfy the constant total amount of oil inside the motor 1 and the hydraulic cylinder 3 during operation, and realize the long-time transmission requirement. In the design process, the maximum instantaneous power required by the prosthesis and the swing angle range of the integrated topology foot sole are considered comprehensively, 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 under the premise of ensuring performance, meeting the requirement of lightness of the device, ensuring the stability and efficiency of the prosthesis in actual application, and improving the comfort and range of motion of the user.

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

[0037] The embodiment also comprises 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 connected with one end of the first normally closed switch valve 8 and one end of the second normally closed switch valve 9 respectively, the other end of the first normally closed switch valve 8 is connected with the upper cavity of the hydraulic cylinder 3, and the other end of the second normally closed switch valve 9 is connected with the lower cavity of the hydraulic cylinder 3; the oil port of the system oil cylinder accumulator 6 is connected with one end of the first normally open switch valve 10 and one end of the second normally open switch valve 11 respectively, the other end of the first normally open switch valve 10 is connected with the lower cavity of the hydraulic cylinder 3, and the other end of the second normally open switch valve 11 is connected with the upper cavity of the hydraulic cylinder 3.

[0038] In the 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 cavity of the hydraulic cylinder 3, and a third liquid pressure sensor is arranged between the lower cavity of the hydraulic cylinder 3 and the second normally closed switch valve 9 or between the lower cavity of the hydraulic cylinder 3 and the first normally open switch valve 10.

[0039] In the embodiment, the motor pump comprises a motor 1 and two plunger pumps 2, the motor 1 is a small brushless DC motor, one plunger pump 2 is arranged at each of 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 with a 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 rotary 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 respective operation of the two plunger pumps 2 once in a rotation cycle, thereby realizing efficient energy conversion and transmission, and significantly improving the operation efficiency of the system. The electro-hydrostatic active ankle prosthesis of the embodiment is fixed to the lower extremity of the disabled person through the adapter connecting seat 17, the plunger pump 2 is continuously operated by the motor 1, the hydraulic oil in the system oil cylinder accumulator 6 is extracted and supplied to the hydraulic cylinder 3 through the pipeline according to the states 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, and the energy in the motor energy storage accumulator 5 and the gravity recovery accumulator 7 are combined to provide thrust or pull force for the integrated topology foot.

[0040] In order to realize that the overall output capacity of the prosthesis meets the requirements of human motion, the electro-hydrostatic active ankle prosthesis adds an integrated small brushless DC motor and two plunger pumps 2. At the same time, according to the actuation mechanism of human joints, the accumulator group is used to realize the time domain optimization of driving energy, different storage and recovery accumulators in the accumulator group accumulate and release energy in stages, complete the time domain deployment of energy and the instantaneous high power output demand, and the motor energy storage accumulator 5, the system oil cylinder accumulator 6 and the gravity recovery accumulator 7 cooperate with each other to realize lower energy consumption of the device as a whole under the premise of ensuring the output capacity.

[0041] In this embodiment, the integrated topology foot sole is made of carbon fiber, based on additive manufacturing means, according to the load and stress relationship in walking, the lightweight topology optimization that meets the strength requirement is carried out, the integrated topology foot sole includes ankle skeleton 12, forefoot 13, heel 14 and support shaft 15, the middle part of ankle skeleton 12 is rotatably connected with hydraulic integrated block 4 through support shaft 15 and ball bearing, support shaft 15 and ball bearing limit the axial freedom degree of support shaft 15, angle sensor 16 is arranged on support shaft 15, the front end of ankle skeleton 12 is hingedly connected with the telescopic end of hydraulic cylinder 3 through connecting shaft and ball bearing, realizing effective transmission of prosthesis power, ankle skeleton 12 is stably connected with forefoot 13 through the front end chamfer of lower surface and the bolt of rear end, and heel 14 is connected with ankle skeleton 12 through two flange screws on the bottom surface and the front end step, which ensures the overall stability of the integrated topology foot sole when bearing the ground impact.

[0042] In this embodiment, ankle skeleton 12 is a mechanical structural part, which mainly bears the pressure in the vertical direction in the human gait process, and the stress condition is relatively simple. Based on the known load condition, constraint condition and performance index, the lightweight optimization framework is constructed by using ANSYS software based on the principle of structural topology optimization, the ankle skeleton 12 model is optimized and designed and the strength is analyzed, and through multiple iterations, the mass is reduced to the greatest extent under the premise of meeting the mechanical performance requirements, the material consumption is reduced, the use experience of the prosthesis can be optimized without sacrificing the structural integrity, and the functionality and comfort are improved.

[0043] In order to meet the weight limit requirement of human wearable equipment, while improving the performance of output element, the overall electro-hydraulic active ankle joint prosthesis keeps the overall weight of the machine equivalent to the weight of the lower leg part of the human body through integrated lightweight optimization design, each element is integrated on the center position of hydraulic integrated block 4 and realizes space layout optimization to reduce the overall volume. The heavy weight component hydraulic integrated block 4 and the integrated topology foot sole complete the optimization of surface additive manufacturing means, and finally the overall weight of the prosthesis is less than the average weight of the lower leg of the human body with the same functional range under the condition of meeting the mechanical performance requirements.

[0044] The embodiment also includes a control board and a driving board 20, both of which are integrated on the hydraulic integrated block 4, and the driving board 20 is closely integrated at the back of the motor 1, optimizing the spatial layout. The control board is integrated with a DSP chip and provides a signal interface and a power supply interface of the liquid pressure sensor. The driving board 20 is responsible for the power supply of the control board, the first normally closed on-off valve 8, the second normally closed on-off valve 9, the first normally open on-off valve 10, the second normally open on-off valve 11 and the motor 1. Such a separate design not only improves the modularization of the system, but also facilitates the later maintenance and upgrading. Through the optimized layout, the arrangement of each element is more compact and reasonable, ensuring the overall performance of the prosthesis and the comfort of the user.

[0045] The overall electric-hydraulic active ankle joint prosthesis of the embodiment is based on the bionic shape of the lower leg for the layout of each element. With the hydraulic integrated block 4 as the main body, the plunger pump 2, the first normally closed on-off valve 8, the second normally closed on-off valve 9, the first normally open on-off valve 10 and the second normally open on-off valve 11 are all embedded in the hydraulic integrated block 4 through the riveting process, reducing unnecessary fixing mechanisms, better integration, and helping to reduce the volume of the prosthesis. The hydraulic cylinder 3 and the motor 1 are connected to the hydraulic integrated block 4 through plate connection and are fixed by bolts.

[0046] The internal complex flow channel of the hydraulic integrated block 4 adopts the additive manufacturing process, which can realize customized design of the flow channel compared with the traditional machining method, arrange the required pipelines in a smaller volume, and arrange the hydraulic elements more closely, fully utilize each surface area of the hydraulic integrated block 4, thereby effectively reducing the system size and weight. The specific element layout is as follows: the hydraulic integrated block 4 is located at the center position and is the mounting base of the overall structure, the top of the hydraulic integrated block 4 is provided with an adapter connecting seat 17, three liquid pressure sensors and an accumulator group, the front part of the hydraulic integrated block 4 is a double-rod hydraulic cylinder, the left side area of the hydraulic integrated block 4 is a mounting space for the control board, the right side of the hydraulic integrated block 4 is designed with the first normally closed on-off valve 8, the second normally closed on-off valve 9, the first normally open on-off valve 10 and the second normally open on-off valve 11 and the system oil filling port with a one-way valve, the rear part of the hydraulic integrated block 4 is the motor 1 and the two plunger pumps 2, the motor 1 and the two plunger pumps 2 are embedded in the hydraulic integrated block 4 through the riveting process and are invisible from the outside, and the bottom of the hydraulic integrated block 4 is an integrated topology foot. The overall element arrangement of the electric-hydraulic active ankle joint prosthesis of the embodiment fully utilizes the space of the hydraulic integrated block 4.

[0047] The electro-hydraulic active ankle prosthesis of the 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 electro-hydraulic active ankle prosthesis of the embodiment can meet the human operation requirements in the whole gait phase including peak requirements, while the overall weight is reduced through lightweight design, and high output power to weight ratio (i.e. the ratio of high output power to the overall weight of the machine) can be achieved. The core of the high output power to weight ratio in the embodiment is to achieve large peak power output while maintaining lightweight and small size, a good balance between achieving large peak power output and maintaining lightweight and small size can be achieved, and the overall has high output power to weight ratio and high energy efficiency. Based on human gait analysis, the electro-hydraulic active ankle prosthesis realizes the design of motor energy accumulator 5, system cylinder accumulator 6 and gravity recovery accumulator 7 through hydraulic energy stage regulation, optimizes the energy transmission chain, realizes the overall regulation and loss reduction of the prosthesis energy to meet the instantaneous high power requirement in the walking process, and realizes the lightweight design of the key components based on the additive manufacturing method, realizes the filling of the porous structure in the hydraulic integrated block 4 and the structure topology optimization of the integrated topology foot, and greatly reduces the overall weight. Finally, an electro-hydraulic active ankle prosthesis with high output power to weight ratio and high energy utilization efficiency is designed.

[0048] The electro-hydraulic active ankle prosthesis provided in the embodiment realizes dynamic energy regulation and overall lightweight design of the prosthesis through analysis of the motion state in the human walking process, solves the output performance problem of wearable devices caused by weight limitation, greatly improves the contradiction between large peak power output and lightweight and small size of the ankle prosthesis, and is closer to the walking performance of a normal human leg.

[0049] Embodiment two

[0050] As shown in Figure 7 and Figure 8 , the embodiment provides a walking method using the electro-hydraulic active ankle prosthesis of embodiment one, including 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 connected through the first normally open switch valve 10 and the second normally open switch valve 11, the pressure of the upper chamber of the hydraulic cylinder 3 and the lower chamber of the hydraulic cylinder 3 is equal, the hydraulic cylinder 3 is in a suspended state, the opening degree of the first normally open switch valve 10 is controlled by PWM-PFM, and the flow damping of the hydraulic oil is adjusted, so that the electro-hydraulic active ankle prosthesis can absorb the impact of touching the ground, at this time, the oil output by the motor pump directly charges the motor energy 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 gravity works on the electro-hydraulic active ankle prosthesis, the hydraulic oil in the system oil cylinder accumulator 6 enters the lower cavity of the hydraulic cylinder 3 through the first normally open switch valve 10, the hydraulic oil energy of the upper cavity of the hydraulic cylinder 3 is recovered to the gravity recovery accumulator 7, and the motor energy storage accumulator 5 continues to charge at the same time;

[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 energy storage device and the hydraulic oil in the motor energy storage accumulator 5 all enter the upper cavity of the hydraulic cylinder 3 through the first normally closed switch valve 8, and the hydraulic oil in the lower cavity of the hydraulic cylinder 3 enters the system oil cylinder accumulator 6 through the first normally open switch valve 10; this stage is a process of external instantaneous high-power output, the prosthesis kicks the leg to the ground, at this time, the output torque demand and the 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 is derived from: the charging of the motor energy storage accumulator 5 by the plunger pump 2 in the passive plantar flexion and passive dorsiflexion stages and the energy recovered to the gravity recovery accumulator 7 by the human body gravity 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 turned on, the first normally closed switch valve 8 and the first normally open switch valve 10 are not turned on; the hydraulic oil of the motor pump enters the lower cavity of the hydraulic cylinder 3 through the second normally closed switch valve 9, and the hydraulic oil of the upper cavity of the hydraulic cylinder 3 flows back to the system oil cylinder accumulator 6 through the second normally open switch valve 11.

[0055] Figure 8The main energy optimization diagram of the electro-hydrostatic active ankle prosthesis in the walking process of each gait phase. Due to the limitation of weight and endurance of the prosthesis as a wearable device, high-power motors 1, plunger pumps 2 and hydraulic cylinders 3 and other output elements cannot be used, so a reasonable energy utilization strategy is needed to meet the needs of human motion. The energy management strategy can be divided into two categories: time-sharing energy storage and loss optimization. In the passive dorsiflexion phase, the duration is short, the power demand of the prosthesis is low, and the stroke of the hydraulic cylinder 3 is relatively small. Therefore, in this stage, the excess energy generated by the motor 1 can be stored to provide support for the subsequent stage. In the passive plantar flexion phase, the duration is long and the power demand is low, the center of gravity of the human body gradually moves to the forefoot, and the ankle joint is in a negative work state. Therefore, while storing the motor 1 energy, the energy generated by the human body gravity work can also be recovered to improve the energy utilization efficiency of the system. In the active plantar flexion phase, 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 motor 1 energy work together to drive the hydraulic cylinder 3 to perform efficient output. Through the optimization design of the pipeline, the energy transmission loss under high pressure and large flow can be greatly reduced. In the active dorsiflexion phase, the duration is long, and the power demand is relatively stable. In this stage, in addition to being able to store part of the excess motor 1 energy, the optimization of transmission loss can also significantly save energy.

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

[0057] The principles and implementation manners of the present application are described by applying specific examples in the present application, and the above examples are only used to help understand the method of the present application and its core idea; at the same time, for those skilled in the art, according to the idea of the present application, the specific implementation manners and application ranges will be changed. In summary, the content of the specification should not be understood as a limitation of the present application.

Claims

1. An electro-hydrostatic active ankle prosthesis, characterized by: Comprise: A motor pump, a hydraulic cylinder, a hydraulic integrated block, an accumulator group, an integrated topology foot, the motor pump, the hydraulic cylinder, the accumulator group and the integrated topology foot are integrated on the hydraulic integrated block, the motor pump is used to charge the accumulator group, the motor pump and the accumulator group are used to connect with the hydraulic cylinder, the hydraulic cylinder is used to connect with the integrated topology foot; The accumulator group includes a motor energy storage accumulator, a system oil cylinder accumulator and a gravity recovery accumulator, the motor pump is used to charge the motor energy storage accumulator, the oil outlet of the motor pump is connected with the upper cavity of the hydraulic cylinder and the lower cavity of the hydraulic cylinder respectively, the oil port of the motor energy storage accumulator is connected with the upper cavity of the hydraulic cylinder and the lower cavity of the hydraulic cylinder respectively, the oil port of the system oil cylinder accumulator is connected with the oil inlet of the motor pump, the upper cavity of the hydraulic cylinder and the lower cavity of the hydraulic cylinder respectively, and the oil port of the gravity recovery accumulator is connected with the upper cavity of the hydraulic cylinder; It also includes a first normally closed switch valve, a second normally closed switch valve, a first normally open switch valve and a second normally open switch valve; the oil port of the motor energy storage accumulator is connected with one end of the first normally closed switch valve and one end of the second normally closed switch valve respectively, the other end of the first normally closed switch valve is connected with the upper cavity of the hydraulic cylinder, and the other end of the second normally closed switch valve is connected with the lower cavity of the hydraulic cylinder; the oil port of the system oil cylinder accumulator is connected with one end of the first normally open switch valve and one end of the second normally open switch valve respectively, the other end of the first normally open switch valve is connected with the lower cavity of the hydraulic cylinder, and the other end of the second normally open switch valve is connected with the upper cavity of the hydraulic cylinder; The upper end of the hydraulic integrated block is also provided with an adapter connecting seat, the adapter connecting seat is used to connect with the lower extremity of the disabled person; the motor energy storage accumulator, the gravity recovery accumulator, the system oil cylinder accumulator and the adapter connecting seat are placed on the top of the hydraulic integrated block; The motor pump includes a motor and two plunger pumps, the power output end of the motor is provided with an eccentric shaft, the eccentric shaft is connected with the rotor swash plate of the plunger pump, and the power output end of the motor drives each of the two plunger pumps to run once in a rotation cycle; The integrated topology foot includes an ankle skeleton, a front palm, a heel and a support shaft, the middle part of the ankle skeleton is rotationally connected with the hydraulic integrated block through the support shaft, an angle sensor is arranged on the support shaft, the front end of the ankle skeleton is hinged with the telescopic end of the hydraulic cylinder, the rear end of the front palm is connected with the ankle skeleton, and the front end of the heel is connected with the ankle skeleton.

2. The electro-hydrostatic active ankle prosthesis according to claim 1, characterized in that The integrated topology foot is made of carbon fiber.

3. The electro-hydrostatic active ankle prosthesis of claim 1, characterized in that: The hydraulic cylinder is a double-rod hydraulic cylinder.

4. The electro-hydrostatic active ankle prosthesis of claim 1, wherein: It also includes a control board and a driving board, and the control board and the driving board are integrated on the hydraulic integrated block.

5. A method of walking with an electro-hydrostatically active ankle prosthesis according to one of claims 1 to 4, characterized in that: Comprise the following stages: Passive plantar flexion stage: the first and second normally open valves are both open, the first and second normally closed valves are both closed, the upper chamber of the hydraulic cylinder and the lower chamber of the hydraulic cylinder are connected through the first and second normally open valves, the pressure of the upper chamber of the hydraulic cylinder and the lower chamber of the hydraulic cylinder is equal, the hydraulic cylinder is in a suspended state, the opening degree of the first normally open valve is controlled by PWM-PFM, the flow damping of the hydraulic oil is adjusted, so that the electro-hydraulic active ankle prosthesis can absorb the impact of landing, at this time, the oil output by the motor pump directly charges the motor energy accumulator; Passive dorsiflexion stage: the first normally open valve is open, the second normally open valve is not open, the first and second normally closed valves are closed, the human body gravity works on the electro-hydraulic active ankle prosthesis, the hydraulic oil in the system oil cylinder accumulator enters the lower chamber of the hydraulic cylinder through the first normally open valve, the hydraulic oil energy of the upper chamber of the hydraulic cylinder is recovered to the gravity recovery accumulator, at the same time, the motor energy accumulator continues to charge; Active plantar flexion stage: the first normally closed valve and the first normally open valve are open, the second normally closed valve and the second normally open valve are not open, the hydraulic oil output by the motor pump, the hydraulic oil in the gravity recovery accumulator and the hydraulic oil in the motor energy accumulator all enter the upper chamber of the hydraulic cylinder through the first normally closed valve, the hydraulic oil in the lower chamber of the hydraulic cylinder enters the system oil cylinder accumulator through the first normally open valve; Active dorsiflexion stage: the second normally open valve and the second normally closed valve are open, the first normally closed valve and the first normally open valve are not open; the hydraulic oil of the motor pump enters the lower chamber of the hydraulic cylinder through the second normally closed valve, the hydraulic oil of the upper chamber of the hydraulic cylinder flows back to the system oil cylinder accumulator through the second normally open valve.

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