A powered knee prosthesis based on multi-cam parallel elastic actuator

Abstract

The present invention discloses a powered knee joint prosthesis based on a multi-cam parallel elastic driver, comprising: a multi-cam parallel elastic driver, a prosthesis structure and electronic hardware; the reduction motor module drives the cam group to move, and the driven cam is switched by the cam switching device; the prosthesis structure is driven by the multi-cam parallel elastic driver; the electronic hardware is connected to the cam parallel elastic driver. The powered knee joint prosthesis provided by the present invention can increase the maximum output torque of the prosthesis and has multi-scenario applicability.

Description

Technical Field

[0001] The invention relates to the technical field of robots, and in particular to a power knee joint prosthesis based on a multi-cam parallel elastic driver. Background Art

[0002] With the development of science and technology, the number of robotic devices in the field of rehabilitation medicine is gradually increasing both at home and abroad, and powered knee prostheses have gradually entered the commercial stage.

[0003] Powered knee prostheses need to output large peak torque within a limited volume and weight. To solve this problem, the following methods are usually used:

[0004] Method 1: Use a reducer with a large reduction ratio or even a mechanical self-locking reduction device (such as a screw) to increase the output torque of the prosthesis. This method will weaken or even eliminate the reverse driving ability of the prosthesis, thereby reducing the flexibility of the movement and increasing the difficulty or cost of using the impedance controller.

[0005] Method 2: Use a combination of motor and damper to increase the maximum output torque of the prosthesis in the damping state (when the speed is opposite to the direction of the force, it is mostly a buffer deceleration state). This method is not suitable for scenarios where the prosthesis needs to use large torque to do work, such as climbing stairs.

[0006] Method 3: Use elastic bodies such as springs and torsion springs in combination with motors to form parallel elastic actuators. In this method, the elastic body is often designed for a torque curve of a specific use case (such as walking on flat ground), and lacks adaptability to multiple use scenarios. For example, a parallel elastic actuator designed for walking on flat ground is difficult to meet the needs of climbing stairs at the same time.

[0007] Method 4: Use elastic bodies such as springs and torsion springs in combination with motors to form a series elastic drive. In this method, the maximum output torque of the prosthesis still depends on the peak torque of the motor after deceleration.

[0008] Therefore, there are still defects in the existing method and further improvement is needed. Summary of the invention

[0009] The present invention aims to overcome the defects of the prior art, and the present invention adopts the following technical solutions:

[0010] The present invention provides a powered knee joint prosthesis based on a multi-cam parallel elastic driver. The powered knee joint prosthesis based on a multi-cam parallel elastic driver comprises: a multi-cam parallel elastic driver, a prosthesis structure and electronic hardware;

[0011] The multi-cam parallel elastic driver comprises: a cam group, a cam switching device, and a reduction motor module; the reduction motor module drives the cam group to move, and switches the driven cam through the cam switching device;

[0012] The prosthetic structure is connected to the multi-cam parallel elastic driver, and the prosthetic structure is driven by the multi-cam parallel elastic driver;

[0013] The electronic hardware is connected to the multi-cam parallel elastic driver and controls the multi-cam parallel elastic driver; the electronic hardware includes:

[0014] Metal proximity switch for switching designated cams;

[0015] An angle sensor, used to detect the movement angle of the prosthetic structure;

[0016] A power management circuit to output the required voltage;

[0017] Inertial navigation sensors are used for intelligent control of prosthetic components.

[0018] In some embodiments, the reduction motor module is a brushless reduction motor module.

[0019] In some embodiments, the cam assembly includes: a cam bracket, a cam 1, a cam 2, and a cam gasket;

[0020] The cam 1, cam 2 and cam gasket are arranged on the cam bracket in sequence;

[0021] The cam bracket is arranged on the reduction motor module.

[0022] In some embodiments, the multi-cam parallel elastic driver further includes: a linear bearing, a linear bearing lock, an optical axis guide rail, an optical axis fixing seat, a spring, a spring guide hole, a spring bottom plate, a spring top plate and a preload adjustment screw;

[0023] The cam switching device comprises:

[0024] Roller bearings, roller shafts, roller sliders, micro reduction motors, slider push rods, slider baffles and linear bearing brackets;

[0025] The roller bearing is in contact with the cam profile of the cam set,

[0026] The roller shaft passes through the inner hole of the roller bearing and is installed on the roller slider;

[0027] The roller slider can slide in the slide groove of the linear bearing bracket, and its maximum movement range is limited by the slider baffle installed on the outside of the slide groove. The bottom middle of the roller slider has a U-shaped groove;

[0028] The slider push rod is driven by the micro motor, and the slider push rod can move the roller slider through the U-shaped groove to slide in the slide groove;

[0029] The linear bearing bracket is equipped with two linear bearings through a linear bearing lock, and the linear bearings can slide freely on the optical axis guide rail and can compress the spring installed in the spring guide hole through the spring top plate;

[0030] The bottom of the spring contacts the spring bottom plate, and the spring bottom plate contacts the top of the preload force adjusting screw installed at the bottom of the spring guide hole.

[0031] In some embodiments, the multi-cam parallel elastic driver and the prosthetic structure are connected to each other through four groups of optical axis fixing seats, threaded holes of spring guide holes and a mounting flange at the output end of the brushless reduction motor module.

[0032] In some embodiments, the prosthetic structure comprises: an active side shell, a top shell, a decorative plate, an ankle joint connecting tube, an ankle joint connecting tube clamping block and a prosthetic joint;

[0033] The active side housing is connected to the mounting flange of the motor module output end, the four sets of optical axis fixing seats and the threaded holes of the spring guide hole;

[0034] The top shell is mounted on the active side shell;

[0035] The inner bottom of the active side housing is provided with a semicircular groove, which can cooperate with the ankle joint connecting tube clamping block to clamp the ankle joint connecting tube;

[0036] The prosthetic joint is mounted on a flange at the fixed end of the motor module.

[0037] In some embodiments, a decorative panel is installed on the outside of the top shell.

[0038] In some embodiments, the cam 1 and the cam 2 are cams with different profiles;

[0039] The target torque curve of the cam 1 is designed based on the gait data of walking, standing up and sitting down on the flat ground;

[0040] The target torque curve of the cam 2 is designed based on the gait data of going up and down stairs.

[0041] In some embodiments, when the prosthesis walks, stands up, and sits down on flat ground, the cam switching device moves the roller shaft to make it contact with the cam;

[0042] When the prosthesis goes up and down the stairs, the cam switching device moves the roller shaft to make it contact with the cam 2.

[0043] In some embodiments, there are two metal proximity switches, which are respectively fixed on the housings on both sides of the roller slider;

[0044] The angle sensor is integrated in the main control circuit and is installed on the fixed end flange of the reduction motor module together with the main control circuit through the circuit housing;

[0045] The inertial navigation sensor is fixed on the housing of the main control circuit.

[0046] Technical effect of the present invention: The powered knee joint prosthesis based on a multi-cam parallel elastic driver disclosed in the present invention comprises: a multi-cam parallel elastic driver, a prosthetic structure and electronic hardware. The reduction motor module drives the cam group to move, and switches the driven cam through the cam switching device; the prosthetic structure is driven by the multi-cam parallel elastic driver; and the electronic hardware is connected to the cam parallel elastic driver. The powered knee joint prosthesis provided by the present invention increases the maximum output torque of the prosthesis through the interaction of the multi-cam parallel elastic driver, the prosthetic structure and the electronic hardware, and has applicability in multiple scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A front view of the overall structure of a powered knee joint prosthesis based on a multi-cam parallel elastic driver according to an embodiment of the present invention;

[0048] Figure 2 for Figure 1 The structural diagram of the decorative panel and the top shell is hidden in the figure;

[0049] Figure 3 It is a left view of the overall structure of a powered knee joint prosthesis based on a multi-cam parallel elastic driver according to one embodiment of the present invention;

[0050] Figure 4 A front view of a multi-cam parallel elastic driver structure according to an embodiment of the present invention;

[0051] Figure 5 A side view of a multi-cam parallel elastic driver structure according to an embodiment of the present invention;

[0052] Figure 6 A rear view of a multi-cam parallel elastic driver structure according to an embodiment of the present invention;

[0053] Figure 7 Schematic diagram of the structure of a cam switching device according to an embodiment of the present invention.

[0054] The reference numerals related to the embodiments of the present invention are as follows:

[0055] Multi-cam parallel elastic actuator 1, prosthetic structure 2, electronic hardware 3;

[0056] Cam group 11, cam switching device 12, reduction motor module 13;

[0057] Linear bearing 14, linear bearing lock 15, optical axis guide rail 16, optical axis fixing seat 17, spring 181, spring guide hole 182, spring bottom plate 183, spring top plate 184, preload adjustment screw 185;

[0058] Cam bracket 111, cam one 112, cam two 113, cam gasket 114;

[0059] Roller bearing 121, roller shaft 122, roller slider 123, micro reduction motor 124, slider push rod 125, slider baffle 126, linear bearing bracket 127;

[0060] Active side housing 21, top housing 22, decorative plate 23, ankle joint connecting tube 24, ankle joint connecting tube clamping block 25, prosthetic joint 26;

[0061] Metal proximity switch 31, angle sensor 32, power management circuit 33, inertial navigation sensor 34;

[0062] A powered knee prosthesis 100 based on a multi-cam parallel elastic actuator. DETAILED DESCRIPTION

[0063] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation of the present invention.

[0064] refer to Figures 1 to 7 As shown, a powered knee joint prosthesis 100 based on a multi-cam parallel elastic driver according to an embodiment of the present invention is schematically shown. The powered knee joint prosthesis 100 based on a multi-cam parallel elastic driver comprises: a multi-cam parallel elastic driver 1, a prosthesis structure 2 and electronic hardware 3;

[0065] The multi-cam parallel elastic driver 1 comprises: a cam group 11, a cam switching device 12, and a reduction motor module 13; the reduction motor module 13 drives the cam group 11 to move, and switches the driven cam through the cam switching device 12;

[0066] The prosthetic structure 2 is connected to the multi-cam parallel elastic driver 1, and the multi-cam parallel elastic driver 1 drives the prosthetic structure 2;

[0067] The electronic hardware 3 is connected to the multi-cam parallel elastic driver 1 and controls the multi-cam parallel elastic driver 1; the electronic hardware 3 includes:

[0068] A metal proximity switch 31, used for switching a designated cam;

[0069] An angle sensor 32, used to detect the movement angle of the prosthetic structure 2;

[0070] A power management circuit 33, used to output a required voltage;

[0071] The inertial navigation sensor 34 is used for intelligent control of the prosthetic structure 2 .

[0072] In some embodiments, the reduction motor module 13 is a brushless reduction motor module 13 .

[0073] In some embodiments, the cam group 11 includes: a cam bracket 111, a cam 1 112, a cam 2 113 and a cam gasket 114; the cam 1 112, the cam 2 113 and the cam gasket 114 are arranged on the cam bracket 111 in order; the cam bracket 111 is arranged on the reduction motor module 13.

[0074] In some embodiments, the multi-cam parallel elastic driver 1 further includes: a linear bearing 14, a linear bearing lock 15, an optical axis guide rail 16, an optical axis fixing seat 17, a spring 181, a spring guide hole 182, a spring bottom plate 183, a spring top plate 184 and a preload adjustment screw 185;

[0075] The cam switching device 12 includes: a roller bearing 121, a roller shaft 122, a roller slider 123, a micro reduction motor 124, a slider push rod 125, a slider baffle 126, and a linear bearing bracket 127;

[0076] The roller bearing 121 can contact the cam profile of the cam group 11, and the roller shaft 122 passes through the inner hole of the roller bearing 121 and is installed on the roller slider 123;

[0077] The roller slider 123 can slide in the slide groove of the linear bearing bracket 127, and its maximum movement range is limited by the slider baffle 126 installed on the outside of the slide groove. The roller slider 123 has a U-shaped groove in the middle of the bottom;

[0078] The slider push rod 125 is driven by the micro motor, and the slider push rod 125 can move the roller slider 123 in the slide groove through the U-shaped groove;

[0079] The linear bearing bracket 127 is equipped with two linear bearings 14 through the linear bearing lock 15. The linear bearing 14 can slide freely on the optical axis guide rail 16 and can compress the spring 181 installed in the spring guide hole 182 through the spring top plate 184;

[0080] The bottom of the spring 181 contacts the spring bottom plate 183 , and the spring bottom plate 183 contacts the top of the preload adjustment screw 185 installed at the bottom of the spring guide hole 182 .

[0081] In some embodiments, the multi-cam parallel elastic driver 1 and the prosthetic structure 2 are connected to each other through four groups of optical axis fixing seats 17, threaded holes of spring guide holes 182 and a mounting flange at the output end of the brushless reduction motor module 13.

[0082] In some embodiments, the prosthetic structure 2 includes: an active side shell 21, a top shell 22, a decorative plate 23, an ankle joint connecting tube 24, an ankle joint connecting tube clamping block 25 and a prosthetic joint 26;

[0083] The active side housing 21 is connected to the mounting flange of the motor module output end, the four sets of optical axis fixing seats 17 and the threaded holes of the spring guide holes 182; the top housing 22 is installed on the active side housing 21;

[0084] The inner bottom of the active side housing 21 is provided with a semicircular groove, which can cooperate with the ankle joint connecting tube clamping block 25 to clamp the ankle joint connecting tube 24; the prosthetic joint 26 is installed on the flange of the fixed end of the motor module.

[0085] In some embodiments, a decorative panel 23 is installed on the outside of the top shell 22 .

[0086] In some embodiments, the cam 1 112 and the cam 2 113 are cams with different profiles;

[0087] The target torque curve of the cam 1 112 is designed based on the gait data of walking on flat ground, standing up and sitting down; the target torque curve of the cam 2 113 is designed based on the gait data of going up and down stairs.

[0088] In some embodiments, when the prosthesis walks, stands up, and sits down on flat ground, the cam switching device 12 moves the roller shaft 122 to make it contact with the cam 1 112;

[0089] When the prosthesis goes up or down stairs, the cam switching device 12 moves the roller shaft 122 to make it contact with the cam 2 113 .

[0090] In some embodiments, there are two metal proximity switches 31, which are respectively fixed on the outer casing on both sides of the roller slider 123; the angle sensor 32 is integrated in the main control circuit, and is installed on the fixed end flange of the reduction motor module 13 together with the main control circuit through the circuit casing; the inertial navigation sensor 34 is fixed on the outer casing of the main control circuit.

[0091] The powered knee joint prosthesis based on a multi-cam parallel elastic driver disclosed in an embodiment of the present invention comprises: a multi-cam parallel elastic driver, a prosthesis structure and electronic hardware. The reduction motor module drives the cam group to move, and switches the driven cam through the cam switching device; the prosthesis structure is driven by the multi-cam parallel elastic driver; and the electronic hardware is connected to the cam parallel elastic driver. The powered knee joint prosthesis provided by the present invention increases the maximum output torque of the prosthesis through the interaction of the multi-cam parallel elastic driver, the prosthesis structure and the electronic hardware, and has multi-scenario applicability. The powered knee joint prosthesis based on a multi-cam parallel elastic driver disclosed in the present invention increases the maximum output torque of the prosthesis through the multi-cam parallel elastic driver, and has good reverse driving ability and multi-scenario applicability. Good reverse driving ability makes the control of the prosthesis easier and more flexible, fewer reduction mechanisms reduce the energy loss and noise of the transmission, and the motor can be force-controlled without adding a torque sensor, thereby reducing costs.

[0092] The following describes the power knee joint prosthesis 100 based on the multi-cam parallel elastic drive from the structural features of the embodiment of the present invention, mainly including the mechanical structure, gait cycle and output torque of the knee joint prosthesis, energy conversion, and reverse driving capability:

[0093] 1. Mechanical structure

[0094] The main feature of the powered knee joint prosthesis based on the multi-cam parallel elastic drive is the use of a multi-cam parallel elastic drive. The multi-cam parallel elastic drive is composed of a multi-cam spring structure and a reduction motor in parallel. The output torque of the prosthesis is the combined force of the multi-cam spring structure and the reduction motor output. The difference between the multi-cam spring structure and the traditional cam spring structure is that the former uses multiple cams and adds a cam switching device. The traditional cam spring mechanism is composed of structures such as cams, rollers and springs. The profile radius of the cam changes continuously with the angle. Therefore, at each given cam rotation angle, the cam profile has a certain radius and slope. At the same time, the roller moves closely against the cam profile surface and is connected to the spring. Therefore, the radius of the cam determines the compression of the spring, and then determines the pressure between the roller and the cam. The slope of the cam profile determines how much of this pressure will be used to generate torque. At this time, the force and radius that generate torque can be determined. Therefore, in the cam spring structure, the cam will generate a certain torque at each determined angle. The relationship between torque and angle can be called the target torque curve of the cam. According to the target torque curve, the shape of the cam profile can be calculated by mathematical formula1. The cam switching device is a device in which a motor changes the position of a roller through a transmission mechanism so that the roller can contact different cams, thereby switching the cam in action.

[0095] 2. Gait cycle and output torque of knee prosthesis

[0096] The walking process of a person is a cyclical movement. Each cycle is called a gait cycle. The gait cycle starts with the first contact of the heel with the ground and ends when the heel leaves the ground and contacts the ground for the second time. In a gait cycle, the output torque of the knee joint often has a short peak value, and most of the time in this cycle, the output torque will be much lower than this peak value. Since the angle and torque of the joint are regular in the gait cycle, we can establish the torque relationship corresponding to the joint at various angles, and then we can find that the joint only needs to output a large torque at certain angles. Healthy adults often have similar gaits for walking on flat ground, climbing stairs, and descending stairs, but there are obvious differences between these three gaits, so the torque relationship corresponding to the joint at various angles is different in different walking scenarios.

[0097] 3. Energy conversion

[0098] From the above introduction to the cam spring structure, it can be seen that when the cam drives the roller to compress the spring, the external force is converted into elastic potential energy, and when the cam radius decreases, the elastic potential energy of the spring can do work externally. In addition, the profile of the cam can be designed according to the relationship between the joint angle and torque in the gait cycle, so that it can absorb energy in a specified angle range and release energy in a specified angle range. Therefore, the powered knee joint prosthesis based on a multi-cam parallel elastic drive can make the reduction motor output additional torque when the output torque of the prosthesis is small, and store the additional energy through the cam spring mechanism; when the prosthesis requires a larger output torque, the output torque is increased by releasing elastic potential energy, thereby meeting the larger torque peak demand in the gait cycle.

[0099] 4. Reverse drive capability

[0100] Reverse driving capability refers to the ability of a prosthesis to be driven by an external force when an external force acts on the prosthesis. The reverse driving capability is mainly affected by factors such as mechanical efficiency, electromagnetic resistance, and mechanical structure. In some prostheses that use a large reduction ratio gearbox, the mechanical efficiency and resistance are amplified by the gearbox, making it difficult for the prosthesis to be driven by an external force, resulting in reduced reverse driving capability. Even in some structures with mechanical self-locking, the reverse driving capability is completely lost. The reduction or loss of reverse driving capability in a prosthesis is usually accompanied by the following problems: the prosthesis requires additional force sensors to control the motor torque, the compliance is reduced, the noise is increased, it is difficult to utilize the inertia brought to the prosthesis by the movement of the hip joint during walking, and the negative energy in the gait cycle is more difficult to absorb and utilize.

[0101] The powered knee joint prosthesis 100 based on the multi-cam parallel elastic driver provided by the present invention is described in detail below in conjunction with specific embodiments.

[0102] Embodiment 1:

[0103] Figure 1 , which is a schematic diagram of the overall structure of a powered knee prosthesis 100 based on a multi-cam parallel elastic driver according to an embodiment of the present invention.

[0104] The present invention mainly consists of the following parts: a multi-cam parallel elastic driver 1, a prosthetic structure 2 and electronic hardware 3.

[0105] refer to Figures 1 to 7As shown, the multi-cam parallel elastic driver 1 is composed of a brushless reduction motor module 13, a cam bracket 111, a cam 1 112, a cam 2 113, a cam gasket 114, a roller bearing 121, a roller shaft 122, a roller slider 123, a micro reduction motor 124, a slider push rod 125, a slider baffle 126, a linear bearing bracket 127, a linear bearing 14, a linear bearing lock 15, an optical axis guide rail 16, an optical axis fixing seat 17, a spring 181, a spring guide hole 182, a spring bottom plate 183, a spring top plate 184 and a preload adjustment screw 185. The cam bracket 111 is mounted on the fixed end flange of the brushless reduction motor module 13, and the cam 1 112, the cam gasket 114 and the cam 2 113 are mounted on the cam bracket 111 in sequence. The roller bearing 121 can contact the cam profile, and the roller shaft 122 passes through the inner hole, and the roller shaft 122 is mounted on the roller slider 123. The roller slider 123 can slide in the slide groove of the linear bearing bracket 127, and its maximum range of motion is limited by the slider baffle 126 installed on the outside of the slide groove. There is a U-shaped groove in the middle of the bottom of the roller slider 123, and the slider push rod 125 driven by the micro motor can slide the slider in the slide groove through the U-shaped groove. At the same time, the linear bearing bracket 127 is equipped with two linear bearings 14 through the linear bearing lock 15. The linear bearings 14 can slide freely on the optical axis guide rail 16 and can compress the spring 181 installed in the spring guide hole 182 through the spring top plate 184. The bottom of the spring 181 contacts the spring bottom plate 183, and the spring bottom plate 183 contacts the top of the preload adjustment screw 185 installed at the bottom of the spring guide hole 182. The multi-cam parallel elastic driver 1 and the prosthetic structure 2 can be connected to each other through four groups of optical axis fixing seats 17, the threaded holes of the spring guide hole 182, and the mounting flange at the output end of the brushless reduction motor module 13.

[0106] The prosthetic structural part 2 includes an active side shell 21, a top shell 22, a decorative plate 23, an ankle joint connection tube 24, an ankle joint connection tube clamping block 25 and a prosthetic joint 26. Among them, the active side shell 21 is connected to the mounting flange of the output end of the brushless motor module brushless reduction motor module 13, four sets of optical axis fixing seats 17 and threaded holes of the spring guide hole 182. The top shell 22 is installed on the active side shell 21, and the decorative plate 23 is installed on the outside. The inner bottom of the active side shell 21 has a semicircular groove, which can cooperate with the ankle joint connection tube clamping block 25 to clamp the ankle joint connection tube 24. The prosthetic joint 26 is installed on the flange of the fixed end of the brushless motor module brushless reduction motor module 13.

[0107] The electronic hardware 3 of the prosthesis mainly includes two metal proximity switches 31, an angle sensor 32, an inertial navigation sensor 34, a power management circuit 33, a main control circuit and a corresponding installation housing. The two metal proximity switches 31 are respectively fixed on the housings on both sides of the stick roller slider 123, and are used to switch the specified cam. The angle sensor 32 is integrated in the main control circuit, and is installed on the fixed end flange of the brushless motor module 13 through the circuit housing together with the main control circuit, and detects the movement angle of the prosthesis by cooperating with the radial magnet on the active side housing 21 fixed to the output end of the brushless motor module 13. The power management circuit 33 is installed on the other side of the brushless motor module 13 through the housing, and is used to output the voltage required by the motor and different devices. The inertial navigation sensor 34 is fixed on the housing of the main control circuit for intelligent control of the prosthesis.

[0108] The powered knee joint prosthesis 100 based on a multi-cam parallel elastic driver provided in an embodiment of the present invention is a powered knee joint prosthesis with a brand-new structure. It can absorb external forces or excess energy of the motor within a suitable joint angle range in five usage scenarios, namely, walking on flat ground, climbing stairs, descending stairs, standing up, and sitting down, and convert it into elastic potential energy for storage. The stored energy can be released with a suitable force within a suitable joint angle range, ultimately achieving the purpose of increasing the peak torque of the prosthesis and reducing the power consumption of the prosthesis.

[0109] In the multi-cam parallel elastic actuator 1, there are two cams with different profiles. The target torque curve of the first cam cam 1 112 is designed based on the gait data of walking on the ground, standing up and sitting down (angle-torque relationship of the knee joint), and the target torque curve of the second cam cam 2 113 is designed based on the gait data of going up and down stairs (angle-torque relationship of the knee joint). When the prosthesis is walking on the ground, standing up and sitting down, the cam switcher cam switching device 12 will move the roller so that the roller shaft 122 contacts the first cam cam 1 112; when the prosthesis is going up and down stairs, the cam switcher cam switching device 12 will move the roller so that the roller shaft 122 contacts the second cam cam 2 113, thereby achieving adaptability to a variety of usage scenarios.

[0110] To improve the adaptability to multiple scenarios, the embodiments of the present invention also adopt the following two methods.

[0111] 1. Method 1: Angle difference merging method:

[0112] Combine usage scenarios with different angle ranges corresponding to the force, such as walking on flat ground with a main range of motion of the knee joint of 0 to 60 degrees, and for standing up and sitting down, the corresponding angle when the knee joint outputs a larger torque is 60 to 90 degrees. The 0 to 60 degree flat ground walking data and the 60 to 90 degree standing up and sitting down data are spliced, and the spliced ​​data are used to calculate the best target torque at each angle using the optimization algorithm and control model, and finally generate the target torque curve of the cam. The resulting cam 112 will be applicable to these three usage scenarios at the same time.

[0113] 2. Method 2: Similarity merging method:

[0114] Combine some usage scenarios similar to "the torque relationship corresponding to the joint at each angle": first, calculate the angle-torque relationship of each gait data, fit or average the angle-torque curve; then, select the appropriate angle resolution for sampling to obtain a set of torque values ​​for each gait; finally, calculate the correlation coefficient of the torque values ​​in pairs (because the different angle ranges will cause the data length of the torque value to differ, for the shorter data, use the corresponding value of the longer data to fill in the missing part and then calculate), set the threshold, and combine the gait data with the correlation coefficient greater than the threshold to calculate the cam target torque together. For example, when designing the cam 113, the gait data of going up and down stairs was considered at the same time.

[0115] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0116] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features.

[0117] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0118] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0119] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0120] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

[0121] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A powered knee joint prosthesis based on a multi-cam parallel elastic drive, characterized in that: include: Multi-cam parallel elastic actuators, prosthetic structures, and electronic hardware; The multi-cam parallel elastic drive includes: a cam group, a cam switching device, and a speed reducer. Motor module; The reduction motor module drives the cam group to move, and the cam switching device The driven cam is switched; The prosthetic structure is connected to the multi-cam parallel elastic driver and is connected to the multi-cam parallel elastic driver. The cam parallel elastic driver drives the prosthetic structure; The electronic hardware is connected to the multi-cam parallel elastic driver and controls the multi-cam Wheel parallel elastic drive; The electronic hardware includes: Metal proximity switch for switching designated cams; An angle sensor, used to detect the movement angle of the prosthetic structure; A power management circuit to output the required voltage; Inertial navigation sensors are used for intelligent control of prosthetic components.

2. The power knee joint prosthesis based on multi-cam parallel elastic actuator according to claim 1 Limb, characterized in that The reduction motor module is a brushless reduction motor module.

3. The power knee joint prosthesis based on multi-cam parallel elastic actuator according to claim 1 Limb, characterized in that The cam assembly comprises: Cam bracket, cam one, cam two and cam spacer; The cam 1, cam 2 and cam gasket are arranged on the cam bracket in sequence; The cam bracket is arranged on the reduction motor module.

4. The power knee joint prosthesis based on multi-cam parallel elastic actuator according to claim 1 Limb, characterized in that The multi-cam parallel elastic driver also includes: Linear bearings, linear bearing locks, optical axis guide rails, optical axis fixing seats, springs, spring guide holes, spring bottom plates, spring top plates and preload adjustment screws; The cam switching device comprises: Roller bearings, roller shafts, roller sliders, micro reduction motors, slider push rods, slider baffles and linear bearing brackets; The roller bearing is in contact with the cam profile of the cam set, The roller shaft passes through the inner hole of the roller bearing and is installed on the roller slider; The roller slider can slide in the slide groove of the linear bearing bracket and is installed outside the slide groove. The slider baffle on the side limits its maximum range of motion, and there is a U-shaped groove in the middle of the bottom of the roller slider; The slider push rod is driven by the micro reduction motor, and the slider push rod can be moved through the U-shaped groove The movable roller slider slides in the slide groove; The linear bearing bracket is equipped with two linear bearings through a linear bearing lock. The bearing can slide freely on the optical axis guide rail and can compress the spring installed in the spring guide hole through the spring top plate; The bottom of the spring contacts the spring bottom plate, and the spring bottom plate contacts the bottom of the spring guide hole. The top of the preload adjustment screw makes contact.

5. The power knee joint prosthesis based on multi-cam parallel elastic actuator according to claim 4 Limb, characterized in that The multi-cam parallel elastic driver and the prosthetic structure are connected to each other through four groups of optical axis fixing seats, threaded holes of spring guide holes and a mounting flange at the output end of the brushless reduction motor module.

6. The power knee joint prosthesis based on multi-cam parallel elastic actuator according to claim 1 Limb, characterized in that The prosthetic structure comprises: Active side housing, top housing, decorative panel, ankle joint connecting pipe, ankle joint connecting pipe clamping block and Prosthetic joints; The active side housing and the mounting flange of the motor module output end, four sets of optical axis fixing seats and springs Threaded hole connection of spring guide hole; The top shell is mounted on the active side shell; The inner bottom of the active side housing is provided with a semicircular groove, which can cooperate with the ankle joint connecting tube clamping block to clamp the ankle joint connecting tube; The prosthetic joint is mounted on a flange at the fixed end of the motor module.

7. The power knee joint prosthesis based on multi-cam parallel elastic actuator according to claim 6 Limb, characterized in that A decorative panel is installed on the outside of the top shell.

8. The powered knee joint prosthesis based on multi-cam parallel elastic actuator according to claim 3, characterized in that: The cam 1 and the cam 2 are cams with different profiles; The target torque curve of the cam is obtained by gait data of walking on the ground, standing up and sitting down. Line design; The target torque curve of the cam 2 is designed based on the gait data of going up and down stairs.

9. The powered knee joint prosthesis based on multi-cam parallel elastic actuator according to claim 4, characterized in that: When the prosthesis walks, stands up or sits down on the flat ground, the cam switching device moves the roller shaft to make it contact with the cam; When the prosthesis is going up and down stairs, the cam switching device will move the roller shaft to make the prosthesis go up and down stairs. It contacts the cam 2.

10. The power knee joint prosthesis based on multi-cam parallel elastic actuator according to claim 4 Limb, characterized in that There are two metal proximity switches, which are respectively fixed on the housings on both sides of the roller slider; The angle sensor is integrated in the main control circuit and is connected to the main control circuit through an external circuit. The shell is mounted on the fixed end flange of the reduction motor module; The inertial navigation sensor is fixed on the housing of the main control circuit.

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