Three-degree-of-freedom parallel mechanism capable of simulating ankle and sole movement of human body

Abstract

The invention relates to the field of humanoid robots, in particular to a three-degree-of-freedom parallel mechanism capable of simulating ankles and soles of a human body. The invention relates to a three-degree-of-freedom parallel mechanism, and aims to provide a three-degree-of-freedom parallel mechanism capable of simulating human ankle and sole movement, so that the degree of freedom of simulating human sole movement is increased on the basis of ensuring high rigidity, movement precision and bearing capacity, and the three-degree-of-freedom parallel mechanism is good in supporting performance and better in environmental adaptability. According to the technical scheme, the invention discloses a three-degree-of-freedom parallel mechanism capable of simulating ankle and sole movement of a human body. The shank is connected with a knee joint, the foot body is connected to the bottom end of the shank through a first hooke joint, the sole is connected with the foot body through a first rotating pair, the sole driving branch is connected between the foot body and the sole, and the two ankle driving branches are located on the left side and the right side of the shank and connected with the shank and the foot body respectively.

Description

Technical Field

[0001] The present invention relates to the field of humanoid robots, in particular to a three-degree-of-freedom parallel mechanism capable of simulating the movements of human ankles and soles. Background Art

[0002] With the rapid development of rehabilitation medicine, intelligent prosthetics, and humanoid robotics, the demand for simulating the movement functions of the human lower limbs is becoming increasingly urgent. The ankle-foot system is in direct contact with the ground. As the core joint for walking, steering, and balance control, its movement is highly complex: the ankle needs to achieve dual-degree-of-freedom movement of dorsiflexion / plantar flexion (swinging up and down) and inversion / eversion (tilting sideways), while the foot needs to complete pronation / supination movement around the longitudinal axis during the gait cycle to adapt to the ground contact posture. In the existing technology, although traditional serial joint mechanisms can achieve multi-degree-of-freedom movement, they have problems with insufficient rigidity and poor motion coupling, making it difficult to accurately reproduce the biomechanical characteristics of human movement. Some parallel mechanisms have the advantage of high rigidity, but due to the limited number of degrees of freedom or unreasonable configuration, the coordination and flexibility of the ankle and foot movements are insufficient. In addition, there is currently very little research on the foot of humanoid robots.

[0003] CN202411492102.X discloses a mechanical leg structure, including a calf support and a foot support and an ankle joint assembly movably connected therebetween, which can achieve two rotational degrees of freedom of the foot. However, the foot flexibility of this ankle joint mechanism is very small, and only the entire foot can move, and the ability to adapt to the environment and actively move is insufficient. CN202311220122.7 discloses a humanoid foot structure, including a forefoot and a rear foot, the front end of the rear foot and the rear end of the forefoot are pressed against each other by a leaf spring, and the rear foot is equipped with a detector that can detect the force on the foot in real time and simulate the rotation of the forefoot when it is subjected to external force. However, this foot is a passive force response, and the foot posture cannot be changed in time, and the rotation flexibility of the forefoot is reduced due to the compression of the leaf spring. In addition, the existing humanoid robot foot solutions mostly use two degrees of freedom ankle rotation, and do not involve the design of the foot, which has defects in environmental adaptability and bionic human functions. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned background technology and provide a three-degree-of-freedom parallel mechanism that can simulate the movement of the human ankle and foot, so as to increase the freedom of movement of the bionic human foot while ensuring high rigidity, movement accuracy and load-bearing capacity, and have good supporting performance and better environmental adaptability.

[0005] The technical solution provided by the present invention is:

[0006] A three-degree-of-freedom parallel mechanism that simulates the movement of a human ankle and sole is characterized by comprising a calf connected to the knee joint, a foot body connected to the bottom end of the calf via a first Hooke's hinge, a sole connected to the foot body via a first revolute pair, a sole drive branch connected between the foot body and the sole, and two ankle drive branches located on the left and right sides of the calf and respectively connecting the calf and the foot body.

[0007] The ankle drive branch includes a first ball joint, a second electric push rod and a second Hooke's joint which are sequentially connected between the calf body and the foot body; or, the ankle drive branch includes a fourth rotational pair, a third electric push rod, a sixth rotational pair, a first connecting rod, a second ball joint, a second connecting rod and a third Hooke's joint which are sequentially connected between the calf body and the foot body, the middle part of the first connecting rod is connected to the electric push rod through the sixth rotational pair, one end of the first connecting rod is connected to the second connecting rod through the second ball joint, and the other end is connected to the calf body through the fifth rotational pair.

[0008] The calf comprises a vertically arranged calf body and a first hinge ear located at the bottom end of the calf body.

[0009] The foot body includes a laterally arranged U-shaped body, the top end of the left side wall of the U-shaped body extends forward through an extension section and is then connected to a first rotating secondary shaft with a horizontal axis and arranged in the left and right directions; the top end of the extension section is provided with two second hinged ears arranged in the front-to-back direction; the two third hinged ears are respectively arranged on the left and right sides of the rear position of the upper end of the U-shaped body; a through slot is provided on the U-shaped body which runs through the front-to-back direction with the notch facing downward, and a second rotating secondary shaft hole is provided on the right side wall of the U-shaped body which is arranged in the left and right directions and passes through the through slot.

[0010] The axial holes of the two second hinged ears are coaxial and tilted with the front higher and the rear lower, and cooperate with the cross axis of the first Hooke's hinge and the first hinged ear at the bottom end of the calf to form the first Hooke's hinge; the first rotating pair shaft rotates with the hinge hole on the sole above the sole to form the first rotating pair.

[0011] The foot drive branch includes a third rotating pair, a first electric push rod and a second rotating pair connected in sequence between the foot body and the foot; the first electric push rod includes a first push rod base connected to the foot body, a first push rod sleeve with one end fixed to the front end of the first push rod base, a first push rod with one end slidingly matched with the first push rod sleeve and the other end equipped with a third rotating pair shaft, and a first push rod motor installed on the first push rod base.

[0012] The foot drive branch includes a third rotating pair, a first electric push rod and a second rotating pair connected in sequence between the foot body and the foot; the first electric push rod includes a first push rod base connected to the foot body, a first push rod sleeve with one end fixed to the front end of the first push rod base, a first push rod with one end slidingly matched with the first push rod sleeve and the other end equipped with a third rotating pair shaft, and a first push rod motor installed on the first push rod base.

[0013] The axis of the axial hole of the first hinged ear on the calf is arranged horizontally, and the axis of the axial hole of the second hinged ear is arranged at 30° to the horizontal plane; the axes of the first rotation pair, the second rotation pair and the third rotation pair are parallel to each other and perpendicular to the axis of the axial holes of the second hinged ear and the third hinged ear.

[0014] The first ball joint includes spherical shells mounted on the left and right sides of the calf body via brackets, and a spherical body fixedly mounted on the top of a second push rod base and cooperating with the spherical shells on the calf to form the first ball joint. The second electric push rod includes a second push rod base with its top connected to the first ball joint, a second push rod sleeve vertically fixedly mounted at the bottom of the second push rod base, a second push rod slidingly engaged with the second push rod sleeve, a fifth hinged ear fixedly mounted at the bottom of the second push rod, and a second push rod motor mounted on the second push rod base. The axial hole of the fifth hinged ear, the axial hole of the third hinged ear, and the second Hooke's hinge shaft cooperate to form the second Hooke's hinge.

[0015] The third electric push rod includes a third push rod sleeve vertically mounted on the third push rod base, a third push rod slidingly matched with the third push rod sleeve, and a third push rod motor mounted on the third push rod base; the middle portion of the first connecting rod is rotationally matched with the bottom end of the third push rod through a sixth rotation pair, one end is rotationally matched with the calf body through a fifth rotation pair, and the other end is connected to the top end of the second connecting rod through a second ball joint; the bottom end of the second connecting rod is connected to the third hinge ear of the foot body through a third Hooke's hinge (5211);

[0016] A fourth rotational auxiliary shaft and a fifth rotational auxiliary shaft are fixed to the left and right sides of the calf body respectively; the fifth rotational auxiliary shaft is located below the fourth rotational auxiliary shaft and is arranged parallel to the fourth rotational auxiliary shaft;

[0017] The sixth hinged ear at the top of the third push rod base rotates with the fourth rotation pair shaft to form the fourth rotation pair; the hinge hole shaft hole at one end of the first connecting rod cooperates with the fifth rotation pair shaft to form the fifth rotation pair; the hinge hole in the middle of the first connecting rod cooperates with the sixth rotation pair shaft at the bottom end of the third push rod to form the sixth rotation pair.

[0018] The axes of the fourth rotation pair, the fifth rotation pair and the sixth rotation pair in the two ankle driving branches are parallel to each other.

[0019] The beneficial effects of the present invention are:

[0020] This invention, while mimicking the motion of a human ankle, adds a single-degree-of-freedom mechanical joint to achieve the same swinging motion as a human foot. This allows for adaptability to various environments, adding a degree of flexibility to the rigid mechanical foot, making it more consistent with human foot motion and providing excellent support and environmental adaptability. Through the interaction of the three degrees of freedom of the entire foot, the position and motion of the mechanical foot can be flexibly controlled, helping the connected mechanical leg maintain balance and maintain the movement space of the ankle and foot joints during movement. This invention optimizes the structure and reduces production costs while ensuring motion accuracy, rigidity, and load-bearing capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the three-dimensional structure of Example 1 of the present invention.

[0022] Figure 2 for Figure 1 Schematic diagram of the three-dimensional structure of the calf.

[0023] Figure 3 for Figure 1 Schematic diagram of the three-dimensional structure of the foot body.

[0024] Figure 4 for Figure 1 Schematic diagram of the three-dimensional structure of the sole of the foot.

[0025] Figure 5 for Figure 1 Schematic diagram of the three-dimensional structure of the foot drive branch.

[0026] Figure 6 for Figure 1 Schematic diagram of the three-dimensional structure of the ankle-driven branch in .

[0027] Figure 7 This is a schematic diagram of the three-dimensional structure of Example 2 of the present invention.

[0028] Figure 8 for Figure 7 Schematic diagram of the three-dimensional structure of the calf.

[0029] Figure 9 for Figure 7 Schematic diagram of the three-dimensional structure of the ankle-driven branch in .

[0030] Reference numerals:

[0031] DETAILED DESCRIPTION

[0032] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0033] The present invention is further described below with reference to the embodiments shown in the accompanying drawings.

[0034] Example 1

[0035] Figure 1 The three-degree-of-freedom parallel mechanism shown here simulates the movement of the human ankle and sole, including a calf 1 connected to the knee joint at the top, a foot body 2 connected to the bottom end of the calf through a first Hooke's hinge 6, a sole 3 connected to the foot body, a sole drive branch 4 connected between the foot body and the sole, and two ankle drive branches 5 located on the left and right sides of the calf and respectively connecting the calf and the foot body.

[0036] like Figure 2 and Figure 3 As shown (the direction of the description in this article is based on the direction of the sole of the foot), the calf 1 includes a vertically arranged calf body and a first hinge ear 12 located at the bottom end of the calf body.

[0037] The foot body 2 comprises a U-shaped body arranged transversely, the top of the left side wall of the U-shaped body extends forward by an extension section and then connects to the first rotation auxiliary shaft 23 arranged in the horizontal direction and in the left and right directions; the top of the extension section is provided with two second hinge ears 21 arranged in the front-to-back direction; the two third hinge ears are respectively provided on the left and right sides of the rear position of the upper end of the foot body; the U-shaped body is provided with a through slot which runs through in the front-to-back direction and has the slot facing downwards (by Figure 3 It can be seen that: the through slot does not extend upward through the top of the left and right side walls of the U-shaped body. A second rotational countershaft hole 24 is opened on the right side wall of the U-shaped body. The axis of the second rotational countershaft hole is arranged in the left-right direction and passes through the two side groove walls of the through slot. The axis holes of the two second hinged ears are coaxial and arranged at an angle with the front higher and the back lower. They cooperate with the cross axis of the first Hooker hinge and the axis hole of the first hinged ear 12 at the bottom of the calf to form the first Hooker hinge. The upper part of the sole is provided with a hinged ear, and the hinged ear is made with a sole hinge hole 32 with a horizontal axis and arranged in the left-right direction. The first rotational countershaft and the sole hinge hole rotate together to form a first rotational pair, and the sole and the foot body are connected as a whole through the first rotational pair.

[0038] like Figure 4 and Figure 5As shown, the foot drive branch 4 includes a third rotation pair, a first electric push rod and a second rotation pair connected in sequence between the foot body and the foot body. The rear part of the foot body is provided with a foot lower hinge hole 31 parallel to the foot upper hinge hole 32 and located below the foot upper hinge hole. The first electric push rod includes a first push rod base 42 connected to the foot body through the third rotation pair, a first push rod sleeve 44 fixed at one end to the front end of the first push rod base, a first push rod 45 with one end slidingly matched with the first push rod sleeve and the other end equipped with a third rotation pair shaft 46, and a first push rod motor 41 installed on the first push rod base. The shaft hole on the fourth hinge ear 43 provided at the rear end of the first push rod base 42 is coaxially arranged with the second rotation pair shaft hole 24 at the rear end of the foot body, and the shaft hole of the fourth hinge ear, the second rotation pair shaft hole and the plug-fitting shaft together form a second rotation pair. The other end of the first push rod extending forward is horizontally fixed with the third rotation pair shaft 46, which is also rotated together with the hinge hole 31 under the sole to form a third rotation pair. Obviously, after the first electric push rod is energized, the sole can be driven to swing around the horizontal axis.

[0039] like Figure 6 As shown, the ankle drive branch 5 includes a first ball joint, a second electric push rod, and a second Hooke's joint 517, which are sequentially connected between the calf and the foot. The first ball joint includes a spherical shell 11 mounted on the left or right side of the calf via a bracket, and a sphere 513 fixedly mounted on the top of a second push rod base 512, which cooperates with the spherical shell on the calf 1 to form the first ball joint. The second electric push rod includes a second push rod base with the sphere 513 mounted on the top, a second push rod sleeve 514 vertically fixed to the bottom of the second push rod base, a second push rod motor 511, a second push rod 515 slidingly engaged with the second push rod sleeve, and a fifth hinge lug 516 fixed to the bottom of the second push rod. The third hinge lug 22, the second Hooke's joint axis, and the axial hole of the fifth hinge lug 516 cooperate to form the second Hooke's joint 517. The second push rod motor is parallel to the axis of the second push rod sleeve and mounted opposite the sphere. The second push rod motor drives the second push rod to telescopic movement along the axis of the second push rod sleeve.

[0040] In this embodiment, the axis of the shaft hole of the first hinged ear 12 on the calf is arranged horizontally, and the axis of the shaft hole of the second hinged ear 21 on the foot body is arranged at an angle of 30° to the horizontal plane; the axes of the first rotational pair, the second rotational pair and the third rotational pair are parallel to each other and perpendicular to the axis of the shaft holes of the second hinged ear and the third hinged ear 22.

[0041] Example 2

[0042] like Figure 7 As shown, the difference between this embodiment and embodiment 1 is only the structure of the ankle driving branch, and the rest are the same.

[0043] like Figure 8As shown, the difference between this embodiment and embodiment 1 is that the structures of the two ankle driving branches 5 are different; the ball shell 11 is removed from each ankle driving branch and a fourth rotation pair and a first connecting rod 527 are added.

[0044] Depend on Figure 9 It can be seen that the ankle drive branch 5 includes a fourth rotation pair, a third electric push rod, a sixth rotation pair 526, a first connecting rod 527, a second ball joint 529, a second connecting rod 5210 and a third Hooke's joint 5211, which are sequentially connected between the calf body and the foot body; the middle part of the first connecting rod 527 is connected to the third push rod 525 of the electric push rod through the sixth rotation pair 526, one end of the first connecting rod is connected to the calf body through the fifth rotation pair, and the other end is connected to the top of the second connecting rod 5210 through the second ball joint 529; the bottom end of the second connecting rod is connected to the third hinge ear 22 of the foot body through the third Hooke's joint 5211.

[0045] The left and right sides of the calf body are respectively fixed with a fourth rotation sub-axis 13, and the sixth hinge ear 522 arranged at the top of the third push rod base 523 rotates with the fourth rotation sub-axis to form a fourth rotation pair; each third electric push rod includes a third push rod base, a third push rod sleeve 524 installed on the third push rod base and a third push rod motor 521, and a third push rod 525 slidingly matched with the third push rod sleeve; the fifth rotation sub-axis hole 528 at one end of the first connecting rod 527 is connected to the fifth rotation sub-axis 14 on the calf body (the fifth rotation sub-axis is located below the fourth rotation sub-axis and parallel to the fourth rotation sub-axis). The hinge hole in the middle of the first connecting rod rotates with the sixth rotational secondary shaft at the bottom end of the third push rod (the sixth rotational secondary shaft is fixed at the bottom end of the third push rod and is perpendicular to the third push rod; the hinge hole in the middle of the first connecting rod rotates with the sixth rotational secondary shaft to form the sixth rotational secondary 526), ​​and the other end is connected to the second connecting rod 5210 through the second ball joint 529; the third push rod motor is parallel to the axis of the third push rod sleeve and is installed in the opposite direction to the sixth hinge ear. The third push rod motor drives the third push rod to extend and retract along the third push rod sleeve, thereby pushing the first connecting rod and the second connecting rod to move.

[0046] In this embodiment, the axes of the fourth rotational pair, the fifth rotational pair, and the sixth rotational pair in the two ankle driving branches are parallel to each other.

[0047] Working principle:

[0048] This three-degree-of-freedom parallel mechanism can realize the two rotational degrees of freedom and functions required for bionic human ankle movement, as well as one degree of freedom of bionic human foot movement that cooperates with the synchronous movement of the ankle joint. In the foot drive branch, the push rod is driven by a motor to perform linear reciprocating motion, thereby realizing one forward and backward rotational degree of freedom of the foot. The two ankle drive branches in Example 1 can directly realize the two rotational degrees of freedom of the entire foot by driving the two push rods to extend and retract in the same direction and speed or at a differential speed by a motor; the two ankle drive branches in Example 2 can indirectly realize the two rotational degrees of freedom of the entire foot by driving the two push rods to push in the same direction and speed or at a differential speed by a motor. When the two ankle rotations and one foot rotation cooperate with each other, precise movement control of the foot can be realized. When combined with other components to form a robot, the balance of the body movement can be ensured, and the functions of bionic human ankle joint and foot movement can be realized.

Claims

1. A three-degree-of-freedom parallel mechanism that simulates the motion of a human ankle and foot, characterized by: The three-degree-of-freedom parallel mechanism comprises a calf (1) with a top end connected to a knee joint, a foot body (2) connected to the bottom end of the calf via a first Hooke's joint (6), a sole (3) connected to the foot body via a first revolute pair, a sole drive branch (4) connected between the foot body and the sole, and two ankle drive branches (5) located on the left and right sides of the calf and respectively connected to the calf and the foot body; The ankle driving branch (5) comprises a first ball joint, a second electric push rod and a second Hooke's joint (517) connected in sequence between the calf and the foot body; or, The ankle drive branch (5) includes a fourth rotation pair, a third electric push rod, a sixth rotation pair (526), ​​a first connecting rod (527), a second ball joint (529), a second connecting rod (5210) and a third Hooke's joint (5211) connected in sequence between the calf body and the foot body, the middle part of the first connecting rod is connected to the electric push rod through the sixth rotation pair, one end of the first connecting rod is connected to the second connecting rod through the second ball joint, and the other end is connected to the calf body through the fifth rotation pair.

2. The three-degree-of-freedom parallel mechanism according to claim 1 that simulates the motion of the human ankle and foot, characterized in that: The calf comprises a vertically arranged calf body and a first hinge ear (12) located at the bottom end of the calf body.

3. The three-degree-of-freedom parallel mechanism according to claim 2 that simulates the motion of the human ankle and foot, characterized in that: The foot body (2) comprises a U-shaped body arranged transversely, wherein the top end of the left side wall of the U-shaped body extends forward through an extension section and then connects to a first rotation sub-shaft (23) with a horizontal axis and arranged in the left and right directions; the top end of the extension section is provided with two second hinged ears (21) arranged in the front-to-back direction; two third hinged ears (22) are respectively arranged on the left and right sides of the rear position of the upper end of the foot body; a through slot is provided on the U-shaped body, which passes through in the front-to-back direction and has a notch facing downwards, and a second rotation sub-shaft hole (24) is provided on the right side wall of the U-shaped body, which is arranged in the left and right directions and passes through the through slot.

4. The three-degree-of-freedom parallel mechanism according to claim 3 that simulates the motion of the human ankle and foot, characterized in that: The axial holes of the two second hinged ears are coaxial and tilted with the front higher and the rear lower, and cooperate with the cross axis of the first Hooke's hinge and the first hinged ear at the bottom end of the calf to form the first Hooke's hinge (6); the first rotation pair shaft rotates with the upper hinge hole (32) above the sole of the foot (3) to form the first rotation pair.

5. The three-degree-of-freedom parallel mechanism capable of simulating the motion of a human ankle and foot according to claim 4, characterized in that: The foot drive branch (4) includes a third rotation pair, a first electric push rod and a second rotation pair connected in sequence between the foot body and the foot; the first electric push rod includes a first push rod base (42) connected to the foot body, a first push rod sleeve (44) fixed at one end to the front end of the first push rod base, a first push rod (45) with one end slidingly engaged with the first push rod sleeve and the other end equipped with a third rotation pair shaft (46), and a first push rod motor (41) installed on the first push rod base.

6. The three-degree-of-freedom parallel mechanism according to claim 5 that simulates the motion of the human ankle and foot, characterized in that: The axis of the shaft hole of the first hinged ear (12) on the calf is arranged horizontally, and the axis of the shaft hole of the second hinged ear (21) is arranged at 30 degrees to the horizontal plane; the axes of the first rotation pair, the second rotation pair and the third rotation pair are parallel to each other and perpendicular to the axis of the shaft holes of the second hinged ear and the third hinged ear (22).

7. The three-degree-of-freedom parallel mechanism capable of simulating the motion of a human ankle and foot according to claim 6, characterized in that: The first ball joint comprises a ball shell (11) mounted on the left and right sides of the calf body via a bracket, and a ball (513) fixedly mounted on the top of the second push rod base (512) and cooperating with the ball shell (11) on the calf to form the first ball joint; The second electric push rod comprises a second push rod base (512) with a top end connected to a first ball joint, a second push rod sleeve (514) vertically fixed to the bottom end of the second push rod base, a second push rod (515) slidingly engaged with the second push rod sleeve, a fifth hinge ear (516) fixedly mounted on the bottom end of the second push rod, and a second push rod motor (511) mounted on the second push rod base; The axial hole of the fifth hinged ear, the axial hole of the third hinged ear (22) and the second Hooke's hinge shaft cooperate to form a second Hooke's hinge.

8. The three-degree-of-freedom parallel mechanism capable of simulating the motion of a human ankle and foot according to claim 7, characterized in that: The third electric push rod includes a third push rod sleeve (524) vertically mounted on a third push rod base (523), a third push rod (525) slidingly engaged with the third push rod sleeve, and a third push rod motor (521) mounted on the third push rod base; the middle portion of the first connecting rod (527) is rotationally engaged with the bottom end of the third push rod through a sixth rotation pair (526), ​​one end is rotationally engaged with the calf body through a fifth rotation pair, and the other end is connected to the top end of the second connecting rod (5210) through a second ball joint (529); the bottom end of the second connecting rod is connected to the third hinge ear (22) of the foot body through a third Hooke's joint (5211); A fourth secondary rotation shaft (13) and a fifth secondary rotation shaft (14) located below and parallel to the fourth secondary rotation shaft are fixed to the left and right sides of the calf body respectively; The sixth hinged ear (522) at the top of the third push rod base rotates with the fourth rotation pair shaft to form a fourth rotation pair; the fifth rotation pair shaft hole (528) at one end of the first connecting rod cooperates with the fifth rotation pair shaft to form a fifth rotation pair; the hinged hole in the middle of the first connecting rod cooperates with the sixth rotation pair shaft at the bottom end of the third push rod to form a sixth rotation pair (526).

9. The three-degree-of-freedom parallel mechanism capable of simulating the motion of a human ankle and foot according to claim 8, characterized in that: The axes of the fourth rotation pair, the fifth rotation pair and the sixth rotation pair in the two ankle driving branches are parallel to each other.

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