Variable-stiffness self-adaptive toe joint, toe joint operation method and application thereof

Abstract

The invention discloses a variable-stiffness self-adaptive toe joint which comprises a sole plate and toes and further comprises a driving mechanism and a driven mechanism, and the driven mechanism comprises a pressing wheel. One side of each toe is connected with the sole plate through the titanium steel plate spring, the pressing wheel is located above the titanium steel plate spring and presses the titanium steel plate spring, and the driving mechanism can drive the pressing wheel to move above the titanium steel plate spring so as to adjust the rotating radius of the toes. One side of the toe is connected with the sole plate through the titanium steel plate spring, the pressing wheel is located above the titanium steel plate spring and can press the titanium steel plate spring, the driving mechanism can drive the pressing wheel to move along the titanium steel plate spring, and the bending radius when the toe is stressed is changed through different contact positions of the pressing wheel and the titanium steel plate spring; the variable stiffness self-adaptive movement of the toes in the movement process is achieved, and the walking speed, the stride height and stride of the robot in the walking process and the walking stability of the robot are improved.

Description

Technical Field

[0001] The invention relates to the field of biped robot manufacturing, and in particular to a variable-rigidity adaptive toe joint, a toe joint operation method and applications thereof. Background Art

[0002] Bipedal robots are a hot topic in the field of robotics research. After decades of development, many bipedal robots that can achieve stable walking have appeared in countries around the world. However, compared with humans, these robots still have a large gap in gait, walking speed, walking stability, etc.

[0003] In traditional bipedal robot design, the role of the foot in robot walking is often ignored. The general robot leg has 12 degrees of freedom, that is, each leg has 6 degrees of freedom. The foot is composed of the entire foot plate, which makes it difficult to achieve a walking method in which the heel touches the ground and the toes leave the ground. Even if the walking ground is only slightly uneven, it may cause irregular contact between the sole of the foot and the ground, affecting the stability of the humanoid robot. It can only achieve the whole sole of the foot to touch the ground in parallel, and its walking speed is very slow. Because each foot is a whole, the foot cannot rotate around the front of the foot when walking, especially when the stride is relatively large, which leads to accelerated movement of the knee joint, thereby increasing the swing amplitude of the leg, resulting in unstable movement.

[0004] For example, the patent publication number is CN107128398A, and the patent name is a multi-joint leg structure of a bipedal walking robot. It specifically discloses "including a foot movement mechanism, an ankle joint movement mechanism, and a leg joint movement mechanism. The toe joint is hinged to the foot through an axis, the lower leg joint bracket is hinged to the inner bracket through an axis, and the inner bracket is hinged to the ankle joint support plate. The foot movement mechanism can control the toe joint to lift the toe around the axis hinged to the foot, thereby realizing the toe lifting movement; the ankle joint movement mechanism can control the foot to swing left or right, and can also control The footplate is controlled to move forward or backward, realizing that the robot's footplate joint can move with multiple degrees of freedom; the leg joint movement mechanism can control the calf joint to lift the leg clockwise or counterclockwise, and can also control the calf to rotate around the thigh, realizing that the robot's leg joint can lift the leg and walk with multiple degrees of freedom. "Although the above technology can rotate the footplate around the toes, the distance between the toes and the footplate is fixed, and the bending range of the two is limited, which limits the robot's walking speed, the height and stride that can be crossed, and the stability of the robot when walking. Summary of the invention

[0005] The technical problem to be solved by the present invention is: how to improve the walking speed, traversable height and stride of the robot during walking, and improve the walking stability of the robot.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A variable stiffness adaptive toe joint comprises a sole plate and a toe located at the front side of the sole plate, and also comprises a driving mechanism and a driven mechanism installed on the sole plate, wherein the driven mechanism comprises a pressure wheel;

[0008] One side of the toe is connected to the sole of the foot via a titanium leaf spring, wherein the pressure wheel is located above the titanium leaf spring and presses the titanium leaf spring, and the driving mechanism can adjust the rotation radius of the toe by driving the pressure wheel to move above the titanium leaf spring.

[0009] The present application connects the toe to the sole of the foot through a titanium leaf spring on one side, and the pressure wheel is located above the titanium leaf spring and can press the titanium leaf spring. The pressure wheel can be driven to move along the titanium leaf spring through a driving mechanism. The bending radius of the toe when subjected to force is changed by the different contact positions of the pressure wheel and the titanium leaf spring on the toe, thereby realizing variable stiffness adaptive movement of the toe during movement, thereby improving the walking speed, traversable height and stride of the robot during walking, and the walking stability of the robot.

[0010] As a further solution of the present invention: let the distance between the toe and the pressure wheel be H;

[0011] The larger the H value, the larger the turning radius of the toe and the smaller the stiffness of the titanium leaf spring;

[0012] The smaller the H value is, the smaller the turning radius of the toe is, and the greater the stiffness of the titanium leaf spring is.

[0013] The present application can archive and record the distance between the toe and the pressure wheel, so as to facilitate the subsequent adjustment of the pressure wheel position and promptly understand the relationship between the pressure wheel position and the toe bending radius.

[0014] As a further solution of the present invention: a rotation gap is reserved between the toes and the sole of the foot.

[0015] The present application reserves a rotation gap here, which will not affect the normal bending between the toes and the sole of the foot.

[0016] As a further solution of the present invention: the titanium steel leaf spring is a plate-shaped structure made of titanium steel and can be bent, and a titanium steel plate mounting hole connected to the foot plate is opened at the end of the titanium steel leaf spring.

[0017] The titanium leaf spring of the present application adopts titanium steel that can recover its deformation. When the toes are subjected to force and the soles of the feet are bent, the titanium leaf spring can help the soles of the feet to reset, making it convenient for the foot-type robot to return to its original state after bending and walking.

[0018] As a further solution of the present invention: the driven mechanism includes pressure wheel blocks installed on both sides of the top of the sole plate, wherein the two ends of the pressure wheel can be movably connected in the two pressure wheel blocks, and the driving mechanism can drive the pressure wheel to roll back and forth along the direction of the two pressure wheel blocks.

[0019] As a further solution of the present invention: the driving mechanism includes a motor holder installed on the sole plate, wherein a motor is installed on the motor holder, and the output end of the motor is connected to a crank through a reducer, one end of the crank is connected to the end of a connecting rod, and the other end of the connecting rod is connected to one end of a pressure wheel.

[0020] As a further solution of the present invention: a pressing wheel roller groove corresponding to the pressing wheel is opened on the inner side of the pressing wheel block, and a pressing wheel center axis groove corresponding to the pressing wheel center axis is opened on the side of the pressing wheel roller groove facing away from the pressing wheel.

[0021] As a further solution of the present invention: the height of the pressure wheel center axis groove is lower than the height of the pressure wheel roller groove.

[0022] The invention also discloses an application of a variable-rigidity adaptive toe joint on a biped robot.

[0023] The present invention also discloses an operating method of a variable stiffness adaptive toe joint, comprising the following steps:

[0024] The driving mechanism is used to drive the pressure wheel on the driven mechanism to move above the titanium leaf spring;

[0025] By adjusting the distance between the toes and the pressure wheel, you can achieve toe variable stiffness adaptive movement.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The present application connects the toe to the sole through a titanium leaf spring on one side, the pressure wheel is located above the titanium leaf spring and can press the titanium leaf spring, and the driving mechanism can drive the pressure wheel to move along the titanium leaf spring. The bending radius of the toe when subjected to force is changed by the different contact positions between the pressure wheel and the titanium leaf spring on the toe, thereby realizing variable stiffness adaptive movement of the toe during movement, thereby improving the walking speed, traversable height and stride of the robot during walking, and the walking stability of the robot;

[0028] 2. The speed reduction mechanism of the variable stiffness adaptive toe joint of the present application uses a worm gear mechanism to enable self-locking when the toe is subjected to force and increase the output torque of the motor;

[0029] 3. The variable stiffness adaptive toe joint involved in the present application adopts an elastic titanium steel leaf spring as the toe structure. When the toe is subjected to external force, it will bend adaptively and automatically return to its original shape when the force is withdrawn;

[0030] 4. This application can archive the distance between the toe and the pressure wheel, so that when the pressure wheel position is adjusted later, the relationship between the pressure wheel position and the toe bending radius can be clearly understood in time. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic structural diagram of a variable stiffness adaptive toe joint according to an embodiment of the present invention;

[0032] Figure 2 It is a front view of a variable stiffness adaptive toe joint according to an embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of the structure of the toe and titanium leaf spring according to an embodiment of the present invention;

[0034] Figure 4 An exploded view of a variable stiffness adaptive toe joint according to an embodiment of the present invention;

[0035] Figure 5 A top view of a variable stiffness adaptive toe joint according to an embodiment of the present invention;

[0036] Description of reference numerals:

[0037] 1. Driving mechanism; 11. Motor; 12. Reducer; 13. Crank; 14. Connecting rod; 15. Motor holder;

[0038] 2. driven mechanism; 21. pressure wheel block; 22. pressure wheel; 23. pressure wheel center axis groove; 24. pressure wheel roller groove;

[0039] 3. Toe; 31. Titanium steel leaf spring; 32. Titanium steel plate mounting hole;

[0040] 4. Foot plate; 41. Bottom plate mounting hole. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] Example 1

[0043] Reference Figure 1 , Figure 2 and Figure 5A variable stiffness adaptive toe joint includes a driving mechanism 1, a driven mechanism 2, a toe 3 and a sole plate 4, wherein the toe 3 is installed at the front end of the sole plate 4, and the driven mechanism 2 and the driving mechanism 1 are installed on the top of the sole plate 4.

[0044] For ease of understanding and description, Figure 1 The side of the midfoot sole plate 4 facing the toe 3 is the front, and the rest of the directions are based on this and similarly. It should be understood that this direction setting is only for the convenience of description and understanding, and cannot be understood as a limitation to the present invention.

[0045] Reference Figure 1 , Figure 2 and Figure 4 The driving mechanism 1 includes a motor 11, a reducer 12, a crank 13, a connecting rod 14 and a motor holder 15, wherein the motor 11 and the reducer 12 are both installed above the sole plate 4 through the motor holder 15; wherein the motor holder 15 is provided with three groups, each group is a conical structure, and the bottom can be welded or fastened to the sole plate 4 by bolts or pins, etc., the motor 11 and the reducer 12 are fixed between the three motor holders 15, the output shaft of the motor 11 is connected to the reducer 12, and the output shaft of the reducer 12 is connected to the crank 13 located on one side of the top of the sole plate 4, wherein the crank 13 is fan-shaped as a whole, and one end of the connecting rod 14 is movably connected to the tip of the fan, and the arc portion of the fan is connected to the reducer 12; and the other end of the connecting rod 14 is connected to the pressure wheel 22 located in the driven mechanism 2.

[0046] It should be noted that the reducer 12 contains a worm gear mechanism, which achieves reverse self-locking and allows movement to be transmitted in only one direction. The power is output to the crank 13 through the reducer 12, and the crank 13 drives the other end of the connecting rod 14 to perform back and forth linear motion.

[0047] In summary, the working principle here is as follows: by controlling the motor 11 to work, the motor 11 can drive the crank 13 to rotate through the reducer 12, and when the crank 13 rotates, it can drive the connecting rod 14 to perform circular motion, and then the power transmitted from the crank 13 to the connecting rod 14 pulls the pressure wheel 22 to achieve lateral movement.

[0048] The driving mechanism 1 of the present application adopts the combination of a crank connecting rod and a motor to convert circular motion into linear motion of the pressure wheel 22; and a linear cylinder or other method can also be selected to achieve the linear motion of the pressure wheel 22. The present application does not limit this method, and only provides one of the optimal implementation methods.

[0049] Reference Figure 1 , Figure 2 and Figure 4 The driven mechanism 2 includes a pressure wheel block 21, a pressure wheel 22, a pressure wheel center axis groove 23 and a pressure wheel roller groove 24;

[0050] There are two groups of pressure wheel blocks 21, which are fixed on both sides of the top of the sole plate 4 respectively, and the pressure wheel 22 is located between the two pressure wheel blocks 21, and can roll and move in the front and rear directions between the two pressure wheel blocks 21. The two groups of pressure wheel blocks 21 are arranged horizontally, and a pressure wheel roller groove 24 is opened on the inner side of each pressure wheel block 21. The pressure wheel 22 can roll and move in the pressure wheel roller groove 24. A pressure wheel center axis groove 23 is opened on the side of the pressure wheel roller groove 24 facing away from the center of the pressure wheel 22. It should be noted that the height of the pressure wheel center axis groove 23 is less than the height of the pressure wheel roller groove 24.

[0051] The pressure wheel 22 as a whole is composed of rollers of three diameters, the outermost pressure wheel roller has the largest diameter, and the innermost pressure wheel center axis roller has the smallest diameter. When the pressure wheel 22 is located between the two sets of pressure wheel blocks 21, the outermost pressure wheel roller can just press the titanium steel leaf spring 31 installed on the sole plate 4, and the middle roller is just located in the pressure wheel roller groove 24, and the innermost pressure wheel center axis roller with the smallest diameter is just located in the pressure wheel center axis groove 23; therefore, when the pressure wheel 22 is driven by the driving mechanism 1 to roll forward or backward, the pressure wheel center axis roller can roll in the pressure wheel center axis groove 23, the middle roller can roll in the pressure wheel roller groove 24, and the outermost pressure wheel roller can roll on the titanium steel leaf spring.

[0052] Reference Figure 1 and Figure 3 The rear end of the toe 3 is provided with an integrated titanium steel leaf spring 31, the bottom of the toe 3 is horizontal, the top is arc-shaped, and a certain bending gap is left between the toe 3 and the sole plate 4 to prevent the bending between the toe 3 and the sole plate 4 from being affected; the titanium steel leaf spring 31 is arranged at the rear end root of the toe 3, the titanium steel leaf spring has a certain elasticity, is made of titanium steel material and can be bent, and the overall deformation can be restored. A titanium steel plate mounting hole 32 is opened on the side of the titanium steel leaf spring 31 away from the toe 3, and the titanium steel plate mounting hole 32 can be directly fixed in the bottom plate mounting hole 41 on the sole plate 4 by a threaded connection such as a bolt;

[0053] Let the distance between the toe 3 and the pressure wheel 22 be H; the larger the H value, the larger the rotation radius of the toe 3, and the smaller the stiffness of the titanium steel leaf spring 31; the smaller the H value, the smaller the rotation radius of the toe 3, and the larger the stiffness of the titanium steel leaf spring 31. By changing the bending radius of the toe 3 when it is stressed by the different contact positions of the pressure wheel 22 and the titanium steel leaf spring 31, the variable stiffness adaptive movement of the toe during the movement is realized, and the adjustment of the variable stiffness means the rotation radius of the toe 3 relative to the sole 4, which means the adjustment of the walking speed, the height that can be crossed and the stride of the robot during walking.

[0054] Reference Figure 1 The sole plate 4 is a plate-shaped structure as a whole, and its bottom is flush with the bottom of the toe 3.

[0055] Example 2

[0056] The present invention also discloses a bipedal walking robot, the bipedal walking robot adopts the variable stiffness adaptive toe joints in Example 1. When walking, the bending radius of the toe joints when subjected to force can be adjusted in real time as needed, thereby realizing variable stiffness adaptive movement of the toes during movement.

[0057] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A variable stiffness adaptive toe joint, comprising a sole plate (4) and a toe (3) located on the front side of the sole plate (4), characterized in that: It also includes a driving mechanism (1) and a driven mechanism (2) mounted on the sole plate (4), wherein the driven mechanism (2) includes a pressure wheel (22); One side of the toe (3) is connected to the sole (4) via a titanium steel leaf spring (31), wherein the pressure wheel (22) is located above the titanium steel leaf spring (31) and presses the titanium steel leaf spring (31), and the driving mechanism (1) can adjust the rotation radius of the toe (3) by driving the pressure wheel (22) to move above the titanium steel leaf spring (31).

2. The variable stiffness adaptive toe joint according to claim 1, characterized in that: The distance between the toe (3) and the pressing wheel (22) is H; The larger the H value is, the larger the rotation radius of the toe (3) is, and the smaller the stiffness of the titanium leaf spring (31) is; The smaller the H value is, the smaller the rotation radius of the toe (3) is, and the greater the stiffness of the titanium steel leaf spring (31) is.

3. The variable stiffness adaptive toe joint according to claim 1, characterized in that: A rotation gap is reserved between the toes (3) and the sole (4).

4. The variable stiffness adaptive toe joint according to claim 1, characterized in that: The titanium steel leaf spring (31) is a plate-shaped structure made of titanium steel and can be bent. A titanium steel plate mounting hole (32) connected to the foot plate (4) is provided at the end of the titanium steel leaf spring (31).

5. The variable stiffness adaptive toe joint according to claim 1, characterized in that: The driven mechanism (2) comprises pressure wheel blocks (21) mounted on both sides of the top of the foot plate (4), wherein the two ends of the pressure wheel (22) can be movably connected in the two pressure wheel blocks (21), and the driving mechanism (1) can drive the pressure wheel (22) to roll back and forth along the direction of the two pressure wheel blocks (21).

6. The variable stiffness adaptive toe joint according to claim 5, characterized in that: The driving mechanism (1) comprises a motor holder (15) mounted on the sole plate (4), wherein a motor (11) is mounted on the motor holder (15), an output end of the motor (11) is connected to a crank (13) via a reducer (12), one end of the crank (13) is connected to the end of a connecting rod (14), and the other end of the connecting rod (14) is connected to one end of a pressure wheel (22).

7. The variable stiffness adaptive toe joint according to claim 5, characterized in that: A pressing wheel roller groove (24) corresponding to the pressing wheel (22) is provided on the inner side of the pressing wheel block (21), and a pressing wheel center axis groove (23) corresponding to the pressing wheel center axis is provided on the side of the pressing wheel roller groove (24) facing away from the pressing wheel (22).

8. The variable stiffness adaptive toe joint according to claim 7, characterized in that: The height of the pressing wheel central axis groove (23) is lower than the height of the pressing wheel roller groove (24).

9. Application of the variable stiffness adaptive toe joint as claimed in any one of claims 1 to 8 in a biped robot.

10. The method for operating a variable stiffness adaptive toe joint according to any one of claims 1 to 8, characterized in that: The steps include: The driving mechanism is used to drive the pressure wheel on the driven mechanism to move above the titanium leaf spring; By adjusting the distance between the toes and the pressure wheel, the toes can achieve variable stiffness adaptive movement.

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