Hip joint yaw driving mechanism of lower limb exoskeleton and lower limb exoskeleton

Abstract

The hip joint yaw driving mechanism comprises a back connecting piece, yaw driving assemblies are symmetrically arranged on the two sides of the back connecting piece, each yaw driving assembly comprises an upper-layer plate, a middle-layer plate and a lower-layer plate which are distributed up and down, and the upper-layer plates, the middle-layer plates and the lower-layer plates form a whole through connecting pieces; the upper-layer plate and the lower-layer plate are each provided with an arc-shaped guide rail, the arc-shaped guide rails are connected with the sliding blocks in a sliding mode, the sliding blocks connected with the upper-layer plate and the middle-layer plate are connected with the back plate, the back plate is provided with a rotation driving piece, the rotation driving piece is connected with a gear, and the gear is meshed with a rack structure arranged on the middle-layer plate. And the use comfort is good.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lower extremity exoskeleton, and particularly relates to a yaw driving mechanism of a hip joint of a lower extremity exoskeleton and the lower extremity exoskeleton. BACKGROUND

[0002] The statements herein are provided only to complement the background of the present application and are not necessarily indicative of the prior art.

[0003] A lower extremity exoskeleton is a wearable robot designed to provide assisted motion functions for people with lower extremity movement disorders, such as helping paraplegic patients to walk again, or providing walking assistance for the elderly. In addition, lower extremity exoskeletons can also be applied in military, industrial and other fields to enhance the load-carrying capacity and movement ability of the wearer.

[0004] In the design of lower extremity exoskeletons, simulating the motion characteristics of human hip joints is a core challenge. The exoskeleton hip joint not only needs to have similar degrees of freedom as the human hip joint, but also needs to ensure that the motion axes of these degrees of freedom intersect at a point to maximize the restoration of natural human motion patterns. This design can reduce the motion conflict between the exoskeleton and the user, provide a more comfortable assistance experience, and reduce fatigue caused by long-term use.

[0005] However, current lower extremity exoskeleton hip joint designs, especially in the implementation of yaw degrees of freedom (i.e. internal and external rotation degrees of freedom), face many technical challenges. The control of yaw degrees of freedom usually requires complex mechanical structures, most of which are directly driven by motors. Due to the problem of motor bias, the rotation axes of internal and external rotation degrees of freedom cannot pass through the center of the human hip joint, resulting in discomfort in use. A small number of structures that consider human-machine compatibility are basically remote rotation centers implemented by multiple connecting rods. The structure is complex, occupies a large space, and has insufficient rigidity. This not only increases the weight and volume of the exoskeleton, but also increases the manufacturing cost and maintenance difficulty. In order to simplify the design, some exoskeleton systems even choose to directly cancel the yaw degrees of freedom, but this will lead to limitations in simulating human motion when the exoskeleton is used, especially in scenarios that require rotation movements, such as turning around, side stepping, etc. SUMMARY

[0006] In view of the deficiencies in the prior art, the purpose of the present application is to provide a yaw driving mechanism of a hip joint of a lower extremity exoskeleton and the lower extremity exoskeleton, which reduces the complexity of the mechanism In order to achieve the above-mentioned purpose, the present application is realized by the following technical scheme: In the first aspect, an embodiment of the present invention provides a hip joint yaw drive mechanism for a lower limb exoskeleton, including a back connector, with yaw drive frames symmetrically provided on both sides of the back connector, the yaw drive frame including an upper plate, a middle plate and a lower plate distributed up and down, the upper plate, the middle plate and the lower plate forming a whole through the connector, the upper plate and the lower plate both having an arc guide rail, the arc guide rail being slidably connected to a slider, the slider connected to the upper plate and the middle plate being connected to the back plate, a rotating drive member being provided on the back plate, the rotating drive member being connected to a gear, and the gear being meshed with a rack structure provided on the middle plate.

[0007] Optionally, the upper plate is provided with an arc-shaped groove, and the portion of the upper plate located outside the arc-shaped groove forms an arc-shaped guide rail of the upper plate.

[0008] Optionally, the lower plate is provided with an arc-shaped groove, and the portion of the lower plate located outside the arc-shaped groove forms an arc-shaped guide rail of the lower plate.

[0009] Optionally, the middle plate is provided with an arc-shaped groove, and the outer groove surface of the arc-shaped groove is provided with a rack structure.

[0010] Optionally, the slider is provided with a cavity, the arc-shaped guide rail passes through the slider through the cavity, and the slider is slidably connected to the arc-shaped guide rail.

[0011] Optionally, the sides of the cavity used for matching with the arc-shaped guide rail are provided with bearings, and the bearings match with the arc-shaped guide rail.

[0012] Optionally, the slider is composed of two half sliders, and a cavity for the arc-shaped guide rail to pass through is formed between the two half sliders.

[0013] Optionally, the upper plate, the middle plate and the lower plate are all made of carbon fiber plates.

[0014] Optionally, an absolute encoder magnetic particle fixing frame is fixed below the gear, a magnetic particle is embedded inside the absolute encoder magnetic particle fixing frame, a magnetic encoder matching the magnetic particle is provided below the absolute encoder magnetic particle fixing frame, and the magnetic encoder is fixed to the upper surface of the slider connected to the lower plate.

[0015] In a second aspect, an embodiment of the present invention provides a lower limb exoskeleton comprising the hip joint yaw drive mechanism of the lower limb exoskeleton described in the first aspect.

[0016] The beneficial effects of the present invention are as follows: 1. In the hip joint yaw drive mechanism of the present invention, the back plate is slidably connected to the arc-shaped guide rails of the upper plate and the lower plate through a slider, and the gear connected to the rotating drive member on the back plate is engaged with the rack of the middle plate. The yaw freedom of the hip joint is achieved by sliding the back plate along the arc-shaped guide rail. This can be achieved by using guide rails, gears and racks, without the need for a complex multi-link mechanism. The structure is simple, the complexity of the mechanism is reduced, the space occupied is small, the rigidity is high, and the stability of the mechanism is improved, which is conducive to the further development and promotion of the lower limb exoskeleton. In addition, the adjustment of the center position of the rotating shaft of the yaw motion is more convenient.

[0017] 2. The upper plate, middle plate and lower plate of the hip joint yaw drive mechanism of the present invention are all made of carbon fiber plates, and arc-shaped guide rails are formed by arc grooves, so that the weight of the entire yaw drive mechanism is light, the overall inertia of the entire mechanism is reduced, the difficulty of control is lowered, and the user's comfort requirements are met. At the same time, the arc-shaped guide rails formed by the arc grooves can limit the movement of the slider, prevent the joint from exceeding the limit of human movement, and provide higher safety protection.

[0018] 3. The hip joint yaw drive mechanism of the present invention is provided with an absolute encoder magnetic particle fixing frame, magnetic particles and a magnetic encoder, which can record the joint motion data in real time, and then provide feedback information for the closed-loop control of the joint, which helps provide walking assistance for people with lower limb dysfunction. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0020] Figure 1 This is a schematic diagram of the overall structure of Example 1 of the present invention; Figure 2 This is a front view of the overall structure of Example 1 of the present invention; Figure 3 This is a top view of the overall structure of Example 1 of the present invention; Figure 4 This is a schematic diagram of the connection between the upper plate, middle plate, lower plate and back connector in Example 1 of the present invention; Figure 5 This is a schematic diagram of the assembly of the servo motor, back plate, upper slider, and lower slider in embodiment 1 of the present invention; Figure 6 This is a schematic diagram of the structure of a half slider according to embodiment 1 of the present invention; Figure 7 1 is a top view of a half slider according to embodiment 1 of the present invention; Figure 8 This is a schematic diagram of the motion trajectory of the backplane in Example 1 of the present invention; Among them, 1. Back connector, 2. Upper plate, 3. Lower plate, 4. Middle plate, 5. Servo motor, 6. Motor bracket, 7. Second connector, 8. First connector, 9. Flange, 10. Gear, 11. Absolute encoder magnetic particle fixing bracket, 12. Absolute encoder fixing bracket, 13. Inner bearing, 14. Outer bearing, 15. First screw, 16. Half slider, 17. Second screw, 18. First bearing, 19. Magnetic encoder, 20. Fixing nut, 21. Back plate. DETAILED DESCRIPTION

[0021] Example 1 This embodiment provides a hip joint yaw drive mechanism for a lower limb exoskeleton, such as Figures 1-3 As shown, it includes a back connector 1, and yaw drive frames are provided on both sides of the back connector 1. The yaw drive frames on both sides of the back connector are symmetrically arranged relative to the center line of the back connector 1. The yaw drive frame on one side is taken as an example for explanation. The yaw drive frame includes an upper plate 2, a middle plate 4 and a lower plate 3 distributed above and below. The upper plate 2, the lower plate 3 and the middle plate 4 are arranged in parallel. The inner ends of the upper plate 2, the middle plate 4 and the lower plate 3 are fixedly connected to the back connector 1. A first connector 8 is provided between the bottom surface of the upper plate 2 and the outer end of the top surface of the middle plate 4. The first connector 8 connects the upper plate 2 and the middle plate 4 into a whole. A second connector 7 is provided between the outer end of the bottom surface of the middle plate 4 and the outer end of the top surface of the lower plate 3. The second connector 7 connects the middle plate 4 and the lower plate 3 into a whole.

[0022] In this embodiment, Figure 4 As shown, the upper plate 2, the middle plate 4 and the lower plate 3 are arc-shaped plates, and their shapes are designed based on bionics and ergonomics to meet the comfort requirements of users during use. Their specific shapes are not described in detail here.

[0023] The upper plate 2 , the middle plate 4 and the lower plate 3 have the same shape, and corresponding edges are aligned with each other, that is, the corresponding edges are located on the same plane.

[0024] The hip joint yaw drive mechanism also includes a back plate 21. The bottom end of the back plate 1 is used to connect other drive mechanisms of the lower limb exoskeleton. The back plate 21 is arranged on the outside of the upper plate 2, the middle plate 4 and the lower plate 3. An upper slider is provided at the top of the inner side of the back plate 21, and a lower slider is provided at the bottom end of the inner side of the back plate 21. The upper slider is slidably connected to the arc-shaped guide rail provided on the upper plate 2, and the lower slider is slidably connected to the arc-shaped guide rail provided on the lower plate 3.

[0025] By setting the slider and the arc-shaped guide rail, the back plate can move along an arc track, thereby realizing the yaw movement of the hip joint.

[0026] A rotating drive member is fixed to the inner side surface of the back panel 21. The output shaft of the rotating drive member is connected to the gear 10. The gear is engaged with the rack structure provided on the middle plate 4. The distribution trajectory of the rack structure is exactly the same as the distribution trajectory of the arc-shaped guide rail. The rotating drive member drives the gear to rotate. Under the meshing action of the gear and the rack structure, the back panel can move along an arc-shaped trajectory.

[0027] In this embodiment, an arc groove is provided on the upper plate 2, wherein the outer groove surface of the arc groove is arranged along the target motion trajectory of the back plate 21. Accordingly, the outer arc surface of the upper plate 2 is arranged parallel to the outer groove surface of the arc groove. With this arrangement, the part outside the arc groove in the upper plate 2 forms an arc-shaped guide rail, and the circular guide rail passes through the upper slider through the cavity set therein and is slidably connected to the upper slider.

[0028] An arc groove is also provided on the lower plate 3. The shape, size and position of the arc groove correspond to the shape, size and position of the arc groove of the upper plate 2. In the lower plate, the part outside the arc groove forms an arc guide rail, which passes through the cavity of the lower slider and is slidably connected to the lower slider.

[0029] An arc groove is also provided on the middle plate 4. The shape, size and position of the arc groove correspond to the shape, size and position of the arc grooves of the upper plate 2 and the lower plate 3. In the middle plate 4, the outer arc surface of the arc groove is provided with a rack structure, which is engaged with the gear.

[0030] In this embodiment, an arc-shaped guide rail is formed in the form of an arc groove, and the arc-shaped guide rail passes through the slider. This method reduces the weight of the upper plate 2, the middle plate 4 and the lower plate 3, realizes a lightweight design, and improves the comfort requirements of the users. On the other hand, the arc groove can limit the sliding of the back plate, prevent the joints from exceeding the limit of human movement, and provide higher safety protection.

[0031] In order to further reduce the weight of the upper plate 2, the middle plate 4 and the lower plate 3, the upper plate 2, the middle plate 4 and the lower plate 3 are all made of carbon fiber plates, which are light in weight.

[0032] The first connecting member 8 adopts a first connecting plate distributed along the outer end edges of the upper plate 2 and the middle plate 4. The first connecting plate also adopts a carbon fiber plate. The top end of the first connecting plate is fixed to the upper plate 2, and the bottom end is fixed to the middle plate 4. The second connecting member 7 adopts a second connecting plate distributed along the outer end edges of the middle plate 4 and the lower plate 3. The second connecting plate also adopts a carbon fiber plate. The top end of the second connecting plate is fixed to the middle plate 4, and the bottom end is fixed to the lower plate 3.

[0033] Further, the first connecting plate and the second connecting plate are both provided with weight reduction holes for reducing the weight of the first connecting plate and the second connecting plate, and further realizing the lightweight design of the whole yaw driving mechanism.

[0034] Further, in order to make the movement of the sliding block along the circular arc guide rail more smooth, the side surface of the cavity of the sliding block for cooperating with the circular arc guide rail is provided with a bearing, the bearing is in contact with the circular arc guide rail, the sliding friction is converted into rolling friction, the friction is reduced, and the smooth movement of the sliding block is ensured.

[0035] Specifically, as shown in the drawings, Figures 6-7 The upper sliding block and the lower sliding block are both assembled by two upper and lower distributed half sliding blocks 16, and a cavity for the circular arc guide rail to pass through is formed between the two half sliding blocks 16.

[0036] The two side edges of the half sliding block 16 are provided with a plurality of first screws 15 passing through between the two side edges in the tangential direction of the circular arc guide rail, preferably, eight first screws 15 are arranged on each side, and a fixed nut 20 is screwed on the first screw 15 to fix the two half sliding blocks 16, and preferably, a hexagonal nut is used as the fixed nut.

[0037] The outer periphery of the part of the first screw 15 between the two plate sliding blocks is sleeved with a plurality of first bearings 18, preferably, three first bearings 18 are sleeved on the outer periphery of the first screw 15, and the outer ring of the first bearing 18 is in contact with the arc surface of the circular arc guide rail.

[0038] A plurality of second screws 17 are arranged in the radial direction of the circular arc guide rail and pass through the two half sliding blocks, preferably, three second screws 17 pass through the half sliding blocks, the second screws 17 avoid the positions of the first screws 15, and the second screws 17 are screwed with fixed nuts after passing through the back plate 21 to realize the fixation of the sliding block and the back plate 21. Preferably, a hexagonal nut is used as the fixed nut.

[0039] The bottom surface of the upper half sliding block and the top surface of the lower half sliding block are provided with grooves corresponding to the second screws 17, the second screws 17 are located in the grooves, and the outer periphery of the part of the second screw 17 located in the groove is sleeved with a plurality of second bearings, preferably, four second bearings are arranged, the two second bearings in the middle are inner bearings 13, and the two second bearings at the ends are outer bearings 14. The second bearings of the upper half sliding block cooperate with the top surface of the circular arc guide rail, and the second bearings of the lower half sliding block cooperate with the bottom surface of the circular arc guide rail.

[0040] Through the arrangement of the bearings, the friction between the sliding block and the circular arc guide rail is reduced, and the movement of the sliding block is more smooth.

[0041] As shown in the drawings, Figure 5As shown, the rotating driving member adopts a servo motor 5, which is fixed between the upper layer plate 2 and the middle layer plate 4, so that the distance between the upper layer plate 2 and the middle layer plate 4 is greater than the distance between the middle layer plate 4 and the lower layer plate 3.

[0042] The servo motor 5 is fixed on a motor support 6, which is fixed on the inner side of the back plate 21.

[0043] The output shaft of the servo motor 5 is connected with a gear 10 through a flange 9, and the gear 10 extends into the arc-shaped slot of the middle layer plate 4 and is engaged with the rack structure.

[0044] A below of the gear 10 is provided with an absolute value encoder magnetic particle fixing frame 11, which is connected with the lower end surface of the gear 10.

[0045] An embedded magnetic particle is arranged in the absolute value encoder magnetic particle fixing frame 11 at an eccentric position.

[0046] A magnetic encoder 19 is arranged below the absolute value encoder magnetic particle fixing frame 11, and the magnetic encoder 19 is fixedly connected with a magnetic encoder fixing frame 12, which is fixed on the upper surface of the lower sliding block.

[0047] The magnetic encoder 19 can be obtained by using existing equipment, and can cooperate with the magnetic particle to detect the number of rotations of the output shaft of the servo motor 5.

[0048] When the servo motor 5 rotates, the magnetic particle connected therewith is driven to rotate, and the magnetic encoder 19 can detect the rotating position and the number of rotations of the magnetic particle.

[0049] The magnetic encoder 19 is connected with a control system, and can transmit the detected information to the control system. In an embodiment, the control system has a power-off memory function, that is, when power-off, the current record data is saved, and the last record value is output when power-on next time. The power-off memory function of the control system can be realized by using existing technology, and will not be described in detail here.

[0050] A rectangular opening is arranged on the back connecting member 1, which is used for connecting a test platform.

[0051] The yaw driving assembly on the other side has the same structure, which will not be repeated here.

[0052] The working principle of the hip joint yaw driving mechanism of the lower limb exoskeleton of the embodiment is as follows: The servo motors 5 of the two yaw driving assemblies work independently to drive the respective yaw driving assemblies to move, the servo motor 5 drives the gear 10 to rotate, and under the meshing action of the gear 10 and the rack structure, the servo motor 5 and the back plate 21 can move along the circular arc guide rail under the action of the sliding block to realize the yaw movement, as shown in Figure 8 As shown in the figure, the back plate 21 can be considered to rotate around the center of the circular arc guide rail, converting the curved sliding joint into a rotating joint around a virtual axis, and the virtual axis is vertically arranged. By adjusting the radius of the circular arc guide rail, the position of the virtual axis can be changed. In this way, the three joint axes at the hip joint can be more easily intersected at a point without the need to use a complex mechanism.

[0053] Specifically, the trajectory of the back plate movement is a circular motion, as shown by the circular dashed line in Figure 8 The center of the circular trajectory is the rotation center of the back plate 21, and only by changing the radius of the circular arc guide rail can the position of the rotation center be changed. The position of the rotation center represents the rotation axis of the internal rotation / external rotation degree of freedom of the hip joint, so that the rotation axis of the internal rotation / external rotation degree of freedom of the hip joint passes through the center of the human hip joint, and intersects with the other two axes (extension / flexion, abduction / adduction) at the center point of the human hip joint.

[0054] The hip joint yaw driving mechanism of the embodiment, the back plate is slidably connected to the upper plate 2 and the lower plate 3 through the sliding block and the circular arc guide rail, the gear 10 connected to the servo motor 5 on the back plate 21 is engaged with the rack of the middle plate 4, and the yaw degree of freedom of the hip joint is realized by the sliding mode of the back plate along the circular arc guide rail. By using the guide rail, the gear and the rack, the complex multi-link mechanism, the gear transmission system and the complex bearing arrangement are not needed, the complexity of the mechanism is reduced, the stability of the mechanism is improved, and the further development and promotion of the lower limb exoskeleton are facilitated.

[0055] Embodiment 2 The embodiment provides a lower limb exoskeleton provided with the lower limb exoskeleton hip joint yaw driving mechanism of embodiment 1, and the remaining structure of the lower limb exoskeleton can adopt the prior art, which is not described in detail here.

[0056] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A hip joint yaw drive mechanism for a lower limb exoskeleton, characterized in that: It includes a back connecting piece, and yaw drive components are symmetrically provided on both sides of the back connecting piece. The yaw drive component includes an upper plate, a middle plate and a lower plate distributed up and down. The upper plate, the middle plate and the lower plate form a whole through the connecting piece. The upper plate and the lower plate both have arc guide rails, and the arc guide rails are slidably connected to the slider. The slider connected to the upper plate and the middle plate is connected to the back plate. A rotating drive component is provided on the back plate, and the rotating drive component is connected to the gear. The gear is engaged with the rack structure arranged on the middle plate.

2. The hip joint yaw drive mechanism of a lower limb exoskeleton according to claim 1, characterized in that: The upper plate is provided with an arc groove, and the portion of the upper plate located outside the arc groove forms an arc guide rail of the upper plate.

3. The hip joint yaw drive mechanism of a lower limb exoskeleton according to claim 1, characterized in that: The lower plate is provided with an arc groove, and the portion of the lower plate located outside the arc groove forms an arc guide rail of the lower plate.

4. The hip joint yaw drive mechanism of a lower limb exoskeleton according to claim 1, characterized in that: The middle plate is provided with an arc-shaped groove, and the outer groove surface of the arc-shaped groove is provided with a rack structure.

5. The hip joint yaw drive mechanism of a lower limb exoskeleton according to claim 1, characterized in that: The slider is provided with a cavity, the arc-shaped guide rail passes through the slider through the cavity, and the slider is slidably connected to the arc-shaped guide rail.

6. The hip joint yaw drive mechanism of a lower limb exoskeleton according to claim 5, characterized in that: The sides of the cavity used for matching with the arc-shaped guide rail are all provided with bearings, and the bearings match with the arc-shaped guide rail.

7. The hip joint yaw drive mechanism of a lower limb exoskeleton according to claim 1, characterized in that: The slider is composed of two half sliders, and a cavity for the arc-shaped guide rail to pass through is formed between the two half sliders.

8. The hip joint yaw drive mechanism of a lower limb exoskeleton according to claim 1, characterized in that: The upper plate, the middle plate and the lower plate are all made of carbon fiber plates.

9. The hip joint yaw drive mechanism of a lower limb exoskeleton according to claim 1, characterized in that: An absolute encoder magnetic particle fixing frame is fixed below the gear, and a magnetic particle is embedded inside the absolute encoder magnetic particle fixing frame. A magnetic encoder matching the magnetic particle is provided below the absolute encoder magnetic particle fixing frame, and the magnetic encoder fixes the upper surface of the slider connected to the lower plate.

10. A lower limb exoskeleton, characterized in that: A hip joint yaw drive mechanism comprising a lower limb exoskeleton according to any one of claims 1 to 9.

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