Humanoid foot-like mechanical foot for humanoid robot

Abstract

A humanoid foot-like mechanical foot for a humanoid robot, said foot comprising a foot frame (1) connected to a lower leg and other foot components of a humanoid robot, a split foot arch, an elastic buffer assembly forming a three-link with the foot arch, a heel, an elastic buffer assembly forming a three-link with the heel, a two-degree-of-freedom toe assembly (6) having an automatic reset function, and a ground contact detection sensor. By means of designing the toe assembly (6) having a pitch degree of freedom, a front sole of the robot integrally rotates relative to the foot, so that a human-like gait can be achieved. By means of designing the toe assembly (6) having a roll degree of freedom, an arch elastic buffer assembly (4), and a heel elastic buffer assembly (2), the ability of the feet of the robot to adapt to different terrains is enhanced. By means of designing a contact sensor on the feet, the ability of the feet of the robot to sense the ground is increased, thereby having the ability to achieve a static gait, enabling the robot to save more energy, create less noise, and have a more human-like straight-knee and heel-toe gait, while also having the capability to cushion foot-ground impacts and adapt to unstructured ground.

Description

A humanoid foot mechanical foot for humanoid robot TECHNICAL FIELD

[0001] The present application belongs to the field of robotics and mechanical technology, and relates to a humanoid foot mechanical foot for humanoid robot, in particular to a humanoid robot foot device supporting humanoid gait and enhancing ground adaptability. BACKGROUND

[0002] In recent years, the field of humanoid robots has developed rapidly. Compared with wheeled robots, multi-rotor robots and other foot robots, humanoid robots can more easily integrate into human society and replace humans to complete operations and transportation.

[0003] Most of the current humanoid robots adopt flat feet and do not have foot-ground contact sensors. At the same time, due to the assumption in the control algorithm that the foot-ground contact is point contact, the foot posture is unchanged, and the body height is unchanged, the current humanoid robot walking gait mostly presents the characteristics of knee flexion, continuous stepping, and the foot bottom always maintaining horizontal to the ground. Although this reduces the difficulty of control and mechanical design and reduces manufacturing costs, knee flexion causes the robot knee joint motor to always bear high load, and continuous stepping also greatly increases the energy consumption of the robot. At the same time, this unnatural gait is not friendly enough in human-machine interaction, with loud noise and the possibility of accidental touch or injury to humans.

[0004] Based on the above reasons, it is necessary to design a bionic foot device that supports straight knees, toe gait, is highly adaptable, and has foot-ground sensors, which is the demand for the development of humanoid robots. SUMMARY

[0005] To solve the problems of the prior art, the present application provides a humanoid foot mechanical foot for humanoid robot, which supports the humanoid robot to realize the humanoid straight knee and toe gait and adapt to unstructured ground.

[0006] The humanoid foot mechanical foot for humanoid robot of the present application comprises a foot frame, a heel elastic buffer assembly, a heel assembly, an arch elastic buffer assembly, an arch assembly and a toe assembly.

[0007] The front part and the rear part of the foot frame are respectively provided with the arch assembly and the heel assembly; meanwhile, the middle part and the rear end of the foot frame are respectively provided with a bearing hole and a through hole for connecting the robot calf and the ankle joint driving assembly.

[0008] The arch assembly is provided in two sets and arranged on the left and right sides of the foot frame. The middle parts of the two sets of arch assemblies are connected with the foot frame to form a rotating pair; the top parts of the arch assemblies are connected with the foot frame through the arch elastic buffer assembly, and the bottom parts of the arch assemblies are used for connecting the toe assembly.

[0009] The toe assembly comprises a toe body and a cross shaft, wherein the bottom surface of the toe body is a plane, and the front and rear opposite connecting shafts of the cross shaft are connected with the support seats fixedly installed on the toe body at the front and rear positions to form a rotating pair.

[0010] The two toe assemblies of the above structure are connected with the bottom of the arch assembly through the left and right opposite connecting shafts of the cross shaft to form a rotating pair.

[0011] The two roll degree torsional springs are sleeved on the front and rear rotating shafts of the cross shaft, and the rotation directions of the two roll degree torsional springs are opposite.

[0012] The pitch degree torsional spring is sleeved on the left and right rotating shafts of the cross shaft.

[0013] The bottom of the heel assembly is a plane, and the top is provided with joints in the front and rear directions.

[0014] The bottom surfaces of the toe body and the heel assembly are both paved with toe rubber pads.

[0015] The advantages of the present application are as follows:

[0016] 1. The present application is a humanoid foot mechanical foot for a humanoid robot, which is simple in structure and reasonable in design.

[0017] 2. The application is a humanoid foot mechanical foot for a humanoid robot, which adopts a passive design, and the device is free of drivers, effectively reducing power consumption during the operation of the robot, and uses aluminum alloy and other materials, so that the application has lighter weight on the basis of meeting the operation requirements, effectively enhancing the endurance and maneuverability of the humanoid robot.

[0018] 3. The application is a humanoid foot mechanical foot for a humanoid robot, which has a passive freedom in the pitch direction, so that the robot carrying the device can realize straight knee and heel-toe gait. When the foot and the ground have an included angle in the pitch direction, the two passive toes can still be in contact with the ground, ensuring the surface contact between the foot and the ground; the passive torsion spring at the toe joint ensures that the forefoot can reset without external force, and makes the contact between the forefoot and the ground better.

[0019] 4. The application is a humanoid foot mechanical foot for a humanoid robot, which has a passive freedom in the roll and pitch directions, a two-section arch, an arch elastic buffer assembly, and a heel elastic buffer assembly, which weakens the impact and vibration between the foot and the ground on the robot body, and the flexible forefoot and heel also improve the adaptability of the foot device to unstructured ground, and improve the adaptability of the humanoid robot to different scenes.

[0020] 5. The application is a humanoid foot mechanical foot for a humanoid robot, which increases a ground contact sensor on the bottom surface of the foot device, so that the switching strategy of the support leg and the swing leg of the robot can be changed from fixed timing triggering to ground contact event, so that the robot does not need to maintain stability through continuous stepping gait.

[0021] 6. The application is a humanoid foot mechanical foot for a humanoid robot, which adopts a completely passive design, avoids the introduction of motors and reducers, thereby reducing the weight and the dimension of the control problem. BRIEF DESCRIPTION OF DRAWINGS

[0022] Fig. 1 is a whole structure diagram of the humanoid foot mechanical foot of the application;

[0023] Fig. 2 is a foot frame structure diagram of the humanoid foot mechanical foot of the application;

[0024] Fig. 3 is a structure diagram of the arch assembly of the humanoid foot mechanical foot of the application;

[0025] Fig. 4 is a structure diagram of the toe assembly of the humanoid foot mechanical foot of the application;

[0026] Fig. 5 is a sectional view of the toe assembly of the humanoid foot mechanical foot of the application;

[0027] Figure 6 is a structural diagram of the heel elastic buffer assembly in the artificial foot mechanical foot of the present application

[0028] Figure 7 is a sectional view of the heel elastic buffer assembly in the artificial foot mechanical foot of the present application

[0029] Figure 8 is a structural diagram of the heel assembly in the artificial foot mechanical foot of the present application

[0030] Figure 9 is a sectional view of the heel assembly in the artificial foot mechanical foot of the present application

[0031] Figure 10 is a structural diagram of the arch elastic buffer assembly in the artificial foot mechanical foot of the present application

[0032] Figure 11 is a sectional view of the arch elastic buffer assembly in the artificial foot mechanical foot of the present application

[0033] Figure 12 is a schematic diagram of the forefoot landing process in the artificial foot mechanical foot of the present application

[0034] Figure 13 is a schematic diagram of the roll direction rotation of the foot relative to the ground in the artificial foot mechanical foot of the present application

[0035] Figure 14 is a schematic diagram of the heel landing process in the artificial foot mechanical foot of the present application

[0036] In the figure: 1-foot frame 2-heel elastic buffer assembly 3-heel assembly 4-arch elastic buffer assembly 5-arch assembly 6-two-degree-of-freedom toe assembly 101-bearing hole 102-first light hole 103-second light hole 104-third light hole 105-fourth light hole 106-fifth light hole 201-guide rod limiting connecting piece 202-compression spring 203-sliding shaft sleeve 204-spring limiting sleeve 205-sliding guide rod 206-limiting plate 301-heel body 302-heel rubber pad 301a-frame connecting head 301b-buffer assembly hinged seat 401-limiting nut 402-buffer assembly connecting shaft 403-spring limiting sleeve 404-compression spring 405-guide rod 406-buffer assembly sliding shaft sleeve 501-arch outer frame 502-arch inner frame 503-toe pitch degree-of-freedom torsion spring 504-toe pitch degree-of-freedom torsion spring protective shell 601-cross shaft 602-toe sliding shaft sleeve 603-toe roll degree-of-freedom torsion spring protective shell 604-toe body 605-toe rubber pad DETAILED DESCRIPTION

[0037] The application will be further described in detail below in combination with the drawings.

[0038] The application is a humanoid robot's humanoid foot mechanism, which includes a foot frame 1, a heel elastic buffer assembly 2, a heel assembly 3, an arch elastic buffer assembly 4, an arch assembly 5, and a two-degree-of-freedom toe assembly 6, as shown in Fig. 1.

[0039] As shown in Fig. 2, the foot frame 1 is used to connect the humanoid robot lower leg and other foot components, wherein the part is provided with bearing holes 101 in the left and right directions for connecting the humanoid robot lower leg. The outer periphery of the lower side of the bearing hole 101 is provided with five light holes from front to back, respectively, the first light hole 102 in front of the bearing hole 101, the second light hole 103, the third light hole 104 below the bearing hole 101, the fourth light hole 105 and the fifth light hole 106 behind the bearing hole 101. Among them, the first light hole 102 is used to connect the arch assembly 5; the second light hole 103 is used to connect the arch elastic buffer assembly 4; the third light hole 104 is used to connect the heel assembly 3; the fourth light hole 105 is used to connect the heel elastic buffer assembly 2; the fifth light hole 106 is used to connect the ankle joint drive connecting rod.

[0040] As shown in Fig. 3, the arch assembly 5 is two sets, which are the same structure, composed of arch outer frame 501 and arch inner frame 502.

[0041] Among them, the arch outer frame 501 and the arch inner frame 502 are symmetrically arranged, and are both strip-shaped plate structures; the arch outer frame 501 is designed with a rectangular protrusion in the middle, the end face of which is attached to the inner wall of the middle part of the arch inner frame, and is fixed by screws; thus two U-shaped grooves are formed at the upper and lower ends of the arch assembly 5, respectively, for connecting the arch elastic buffer assembly 4 and the two-degree-of-freedom toe assembly 6.

[0042] The two sets of arch assemblies 5 of the above structure are symmetrically arranged on the left and right sides of the foot frame 1; the bolts coaxially pass through the shaft holes in the middle of the two sets of arch assemblies 5 along the transverse (left and right) direction, and the first light hole 102, and are connected with the two sets of arch assemblies 5 through the thrust bearing and the shaft sleeve, and are axially positioned by tightening the nut, so that the two sets of arch assemblies 5 and the foot frame 1 form a rotating pair.

[0043] As shown in Fig. 4 and Fig. 5, the two-degree-of-freedom toe assembly 6 includes a cross shaft 601, a toe sliding shaft sleeve 602, a toe body 604, and a toe rubber pad 605.

[0044] Among them, the toe body 604 is a rectangular plate with a smooth transition at the circumferential corners. The cross shaft 601 has a cubic structure in the middle, and the opposite pair of connecting shaft axes are arranged in the front and back directions, and are connected to the shaft holes in the front and rear support seats fixedly installed on the upper surface of the toe body 604 through the toe sliding shaft sleeve 602 to form a rotating pair. The lower surface of the toe body 604 is paved with the toe rubber pad 605 to increase the friction between the toe body 604 and the contact surface. At the same time, a sheet-shaped pressure sensor is installed between the toe body 604 and the toe rubber pad 605, which is used to obtain the contact force between the toe body 604 and the contact surface in real time.

[0045] In the two sets of toe assemblies 6, the main body part of the cross shaft 601 is located in the U-shaped slot at the bottom end of the two sets of arch assemblies 5 respectively; the other pair of connecting shafts in the left and right directions on the cross shaft 601 are connected with the shaft holes opened at the bottom end of the lateral arch frame 501 and the medial arch frame 502 through the toe sliding shaft sleeve 602 to form a rotating pair. Thus, the cross shaft 601 provides the toe assembly 6 with roll (roll) and pitch (pitch) degrees of freedom rotation.

[0046] The roll degree of freedom movement of the two sets of toe assemblies 6 is reset by two roll degree of freedom torsional springs 606; the two roll degree of freedom torsional springs 606 are sleeved on the front rotating shaft of the cross shaft 601, are located in the toe roll degree of freedom torsional spring protection shell 603 installed on the upper surface of the toe body 604, and are separated by a partition plate. One end of each of the two roll degree of freedom torsional springs 606 is located in the one-shaped groove opened at the end of the connecting shaft, and the other end is abutted against the inner side wall of the toe roll degree of freedom torsional spring protection shell 603 under the action of the pre-tightening force; and the two roll degree of freedom torsional springs rotate in opposite directions and can provide torque in opposite directions on the same axis. Under the condition of no external force, the toe body 604 bottom surface can be kept horizontal by the action of the two roll degree of freedom torsional springs 606, and torque can be provided for the roll degree of freedom rotation of the toe assembly 6.

[0047] The pitch degree of freedom of the two sets of toe assemblies 6 is realized by a pitch degree of freedom torsional spring. The pitch degree of freedom torsional spring is sleeved on the connecting shaft of the cross shaft 601 connected with the U-shaped slot of the medial arch frame 502, and is located in the toe pitch degree of freedom torsional spring protection shell 503 fixedly installed on the bottom end outer wall of the medial arch frame 502. One end of the pitch degree of freedom torsional spring 504 is located in the one-shaped groove opened at the end of the connecting shaft, and the other end is abutted against the inner side wall of the toe pitch degree of freedom torsional spring protection shell 503 under the action of the pre-tightening force. Under the condition of no external force, the toe assembly 6 can be kept in the forward limit rotating position of the pitch degree of freedom by the action of the pitch degree of freedom torsional spring 504, and torque can be provided for the pitch degree of freedom rotation of the toe assembly 6.

[0048] The top ends of the two sets of arch assemblies 5 are connected with the foot frame 1 through a set of arch elastic buffer assembly 4. As shown in FIG. 6 and FIG. 7, the arch elastic buffer assembly 4 comprises a limiting nut 401, a buffer assembly connecting shaft 402, upper and lower spring limiting sleeves 403, a compression spring 404, a guide rod 405 and a buffer assembly sliding shaft sleeve 406. The guide rod 405 is sequentially sleeved with two limiting nuts 401, the buffer assembly connecting shaft 402, the upper spring limiting sleeve 403, the compression spring 404 and the lower spring limiting sleeve 403 from top to bottom. The lower end of the guide rod 405 is designed with a joint, and a connecting hole perpendicular to the axial direction of the guide rod 405 is opened on the joint, and the buffer assembly sliding shaft sleeve 406 is installed in the connecting hole. The lower end of the guide rod 405 is in contact with the lower end limiting surface of the lower spring limiting sleeve 403. The compression spring 404 is sleeved between the upper and lower spring limiting sleeves 403, and the two ends are respectively positioned with the annular shoulder designed on the circumferential surface of the two spring limiting sleeves 403. The buffer assembly connecting shaft 402 is sleeved on the guide rod 405 through the buffer assembly sliding shaft sleeve 406, and the outer wall has two axis connecting ends perpendicular to the guide rod 405. The axial positioning between the components on the guide rod 405 and the compression spring 404 elastic adjustment are realized by tightening the double limiting nuts 401.

[0049] The two sets of arch elastic buffer assemblies 4 are arranged on the left and right sides of the foot frame 1. The upper buffer assembly connecting shafts 402 are located in the U-shaped grooves at the top ends of the two sets of arch assemblies 1, and the two connecting ends of the connecting shafts are connected with the shaft holes opened at the top ends of the arch outer frame 501 and the arch inner frame 502 through the buffer assembly sliding shaft sleeve 406 to form a rotating pair. The joints at the lower ends of the two sets of arch elastic buffer assemblies 4 are sleeved on the two ends of the rotating shaft penetrating into the second light hole 103 of the foot frame 1 through the buffer assembly sliding shaft sleeve 406 to form a rotating pair. When the toe assembly 6 is subjected to the normal pressure from the ground, the two sets of arch elastic buffer assemblies 4 are compressed. The compression spring 404 absorbs the energy of impact and vibration to realize shock absorption and reduce the influence of the plantar reaction force fluctuation on the overall machine body.

[0050] As shown in FIG. 8 and FIG. 9, the heel assembly 3 comprises a heel body 301 and a heel rubber pad 302. The heel body 301 is a rectangular plate structure, and the top surface of the heel body 301 is designed with a frame connecting head 301a and a buffer assembly hinged seat 301b at the front and rear positions. The bottom surface of the heel body 301 is paved with the heel rubber pad 302, and the heel rubber pad 302 wraps the circumferential wall surface of the heel body 301. A sheet-shaped pressure sensor is also installed between the heel rubber pad 302 and the heel body 301 to realize the contact force between the heel assembly 3 and the contact surface.

[0051] The frame connecting head 301a is connected with the fourth light hole 105 in the foot frame 1 through a rotating shaft to form a rotating pair. The frame connecting head 301a is composed of two side strip plates, the bottom ends of which are connected with the top surface of the heel body 301, and the top ends of which are provided with through holes. The third light hole 104 in the foot frame 1 is disposed between the top ends of the two strip plates, and the rotating shaft passes through the through holes in the top ends of the two strip plates and the third light hole 104, and the two ends are connected with the two strip plates through shaft sleeves to form a rotating pair.

[0052] The above-mentioned buffer assembly connecting head 301b is connected with the foot frame 1 through two heel elastic buffer assemblies 2. As shown in FIGS. 10 and 11, the two heel elastic buffer assemblies 2 are the same in structure and include a guide rod limiting connecting piece 201, a compression spring 202, a sliding shaft sleeve 203, a spring limiting sleeve 204 and a sliding guide rod 205. The bottom end of the sliding guide rod 205 is designed with a joint, and the joint is provided with a connecting hole with an axis perpendicular to the sliding guide rod 205. The top end of the sliding guide rod 205 is inserted into the cylindrical guide rod limiting connecting piece 201 through a shaft sleeve. The sliding guide rod 205 is sleeved with the compression spring 202, and the upper and lower parts of the compression spring 202 are sleeved with the spring limiting sleeve 204 on the guide rod limiting connecting piece 201 and the sliding guide rod 205 respectively; meanwhile, the upper and lower ends of the compression spring 202 are matched with the circumferential shoulders of the outer walls of the guide rod limiting connecting piece 201 and the spring limiting sleeve 204 respectively. The top end of the guide rod limiting sleeve 204 is also designed with a joint, and the joint is provided with a through hole with an axis perpendicular to the guide rod.

[0053] In the above-mentioned two heel elastic buffer assemblies 2, the joints at the top ends of the guide rod limiting sleeves 204 are respectively located on the left and right sides of the foot frame 1, and the connecting holes thereon are matched with the fourth light hole in the foot frame 1 to be connected through a rotating shaft to form a rotating pair. In the two heel elastic buffer assemblies 2, the joints at the bottom ends of the guide rod limiting sleeves 204 are respectively located on the left and right sides of the buffer assembly hinged seat 301b, and the connecting holes thereon are matched with the through holes provided on the buffer assembly hinged seat 301b on the heel body 301 to be connected through a rotating shaft to form a rotating pair. Thus, the elastic buffer assemblies 2, the heel assembly 3 and the foot frame 1 together form a three-link mechanism with a variable length. When the heel assembly 3 is subjected to pressure from the ground, the heel assembly 3 rotates around the rotating shaft connected with the foot frame 3, so that the two heel elastic buffer assemblies 2 are pressed to generate elastic force to play a buffering role.

[0054] In order to reduce the overall weight of the device while ensuring the structural strength and functionality of the device, the foot frame 1, the heel elastic buffer assembly 2, the heel assembly 3, the arch elastic buffer assembly 4, the arch assembly 5 and the two-degree-of-freedom toe assembly are all optimized for weight reduction. The main materials of each component are all aluminum alloy, the connecting shaft materials of the arch and the foot frame are steel, and the shaft sleeve materials are nylon.

[0055] The application is used for the humanoid robot, and the mechanical foot of the humanoid foot is connected with the robot calf through a bearing to form a rotating pair, and the fifth light hole is connected with the robot ankle driving connecting rod through a rotating shaft to complete the connection with the robot calf. In the application, the limiting plate 206 is arranged at the rear side of the heel body 301, and the inclination angle of the limiting plate 206 is the same as that of the two strip-shaped plates in the hinge seat 301b of the buffer assembly, and the limiting plate 206 is arranged in the groove at the rear side of the two strip-shaped plates and in contact with the inner wall of the groove of the two strip-shaped plates, as shown in FIG. 2. Meanwhile, the buffer rubber pad is arranged on the limiting plate 206 between the two strip-shaped plates, and the buffer rubber pad is used to contact with the foot frame 1 during the movement of the robot, limit the downward displacement of the rear part of the foot frame 1, and prevent the sliding shaft sleeve 203 on the two sets of heel elastic buffer assemblies 2 from being pulled out during the movement of the robot. The limiting plate 206 can reinforce the structure of the two strip-shaped plates and prevent the two strip-shaped plates from being bent downward due to excessive force during the movement of the robot.

[0056] The application is used for the movement mode of the mechanical foot of the humanoid robot as follows:

[0057] (1) As shown in FIG. 1, when the bottom surfaces of the heel assembly 2 and the toe assembly 6 of the mechanical foot of the humanoid foot contact the ground at the same time, the arch elastic buffer assembly 4 and the heel elastic buffer assembly 2 provide support force for the arch assembly 5 and the heel assembly 3, so that the robot can be supported by the mechanical foot of the humanoid foot.

[0058] (2) As shown in FIG. 12, when the bottom surface of the toe assembly 6 contacts the ground and has a certain rotation angle in the pitch direction relative to the ground, the toe assembly 6 can rotate in the pitch direction to ensure that the bottom surface is as close to the ground as possible, so that the humanoid robot can realize the action of the bottom surface of the toe assembly 6 contacting the ground. When the arch assembly 5 is not perpendicular to the ground, the impact on the toe assembly 6 can be absorbed by the arch elastic buffer assembly 4. After the bottom surface of the toe assembly 6 is separated from the ground, the toe assembly 6 will be reset under the action of the torsional spring.

[0059] (3) As shown in FIG. 13, when the mechanical foot of the humanoid foot has a certain rotation angle in the roll direction relative to the ground, the bottom surfaces of the two toe assemblies 6 will be subjected to different ground reaction forces, and the two arch assemblies 5 will rotate different angles around the connecting points of the foot frame 1 under the combined action of the ground reaction force and the arch elastic buffer assembly 4. The two toe assemblies 6 will rotate a certain angle around the respective cross shaft axes to ensure that the bottom surfaces of the toe assemblies 6 are close to the ground.

[0060] (4) As shown in Fig. 14, when the foot device only the heel touches the ground and has a certain angle of rotation in the pitch direction relative to the ground, the heel assembly 3 can rotate a certain angle in the pitch direction under the joint action of the ground reaction force and the heel elastic buffer assembly 2, which can make the heel bottom surface as much as possible to be in contact with the ground, and on the other hand, the heel elastic buffer assembly 2 can absorb the vibration and impact of the heel assembly 3 touching the ground.

[0061] (5) When the different bottom surfaces of the humanoid foot mechanical foot touch the ground with different sizes of force, the sheet-shaped pressure sensor of the foot bottom can provide the robot with data of whether the ground is touched and the size of the ground reaction force.

[0062] (6) When the humanoid robot applying the humanoid foot mechanical foot walks, the humanoid foot mechanical foot will switch between the states described in (1), (2) and (4) alternately, and interspersed with the state described in (3), so as to complete the straight knee and toe gait.

[0063] When the humanoid robot applying the humanoid foot mechanical foot walks on unstructured ground, the pressure of the three contact surfaces on the bottom of the humanoid foot mechanical foot is not uniformly distributed, and under the joint action of the non-uniform pressure and the elastic assembly, the bottom surfaces of the two toe assemblies 6 and the heel assembly 3 will each rotate a certain angle and finally reach a balanced state, and the characteristic of this balanced state is that the three bottom surfaces will respectively maintain surface contact with the ground as much as possible, thereby ensuring the friction between the foot and the ground in the case of unstructured ground.

Claims

1. A humanoid foot mechanism for a humanoid robot, characterized by: The foot frame, the heel elastic buffer assembly, the heel assembly, the arch elastic buffer assembly, the arch assembly and the toe assembly are included. The front and rear parts of the foot frame are respectively provided with the arch assembly and the heel assembly; meanwhile, the middle and rear ends of the foot frame are respectively provided with bearing holes and through holes for connecting the robot shank and the ankle joint driving assembly. The arch assembly is provided with two sets, which are arranged on the left and right sides of the foot frame; the middle parts of the two sets of arch assemblies are connected with the foot frame to form rotating pairs; the top parts of the arch assemblies are connected with the foot frame through the arch elastic buffer assembly; and the bottom parts of the arch assemblies are used for connecting the toe assembly. The toe assembly includes a toe body and a cross shaft; the bottom surface of the toe body is a plane; the front and rear opposite connecting shafts of the cross shaft are connected with the support seats fixedly installed on the toe body to form rotating pairs; when the toe assembly is subjected to normal pressure from the ground, the arch elastic buffer assembly is compressed; and the impact and vibration energy is absorbed by the compression spring. The two toe assemblies are connected with the bottom parts of the arch assemblies through the left and right opposite connecting shafts of the cross shaft to form rotating pairs; the cross shaft provides the toe assembly with roll and pitch freedom degrees; and the two roll freedom degree torsional springs and one pitch freedom degree torsional spring are used to respectively realize the reset of the roll and pitch freedom degree rotation. The two roll freedom degree torsional springs are sleeved on the rotating shafts in the front and rear directions of the cross shaft, and the rotating directions of the two roll freedom degree torsional springs are opposite; in the absence of external force, the two roll freedom degree torsional springs are used to make the bottom surface of the toe body horizontal and provide the reset of the roll freedom degree rotation of the toe assembly with torque. The pitch freedom degree torsional spring is sleeved on the rotating shaft in the left and right directions of the cross shaft; in the absence of external force, the pitch freedom degree torsional spring is used to make the toe assembly in the forward limit rotating position of the pitch freedom degree and provide the reset of the pitch freedom degree rotation of the toe assembly with torque. The bottom part of the heel assembly is a plane, and the top part is provided with joints in the front and rear directions; the front joint is connected with the foot frame to form a rotating pair, and the rear joint is connected with the foot frame through the heel elastic buffer assembly; when the heel assembly is subjected to pressure from the ground, the heel assembly rotates around the rotating shaft connected with the foot frame, so that the two heel elastic buffer assemblies are compressed to generate elastic force and play a buffering role.

2. The anthropomorphic foot mechanism for a humanoid robot of claim 1, wherein: Five light holes are formed in the periphery of the bearing hole from front to rear, which are respectively a first light hole in front of the bearing hole, a second light hole below the bearing hole, a third light hole below the bearing hole, a fourth light hole and a fifth light hole behind the bearing hole; the first light hole is used for connecting the arch assembly; the second light hole is used for connecting the arch elastic buffer assembly; the third light hole is used for connecting the heel assembly; the fourth light hole is used for connecting the heel elastic buffer assembly; and the fifth light hole is used for connecting the ankle joint driving connecting rod.

3. The anthropomorphic foot mechanism for a humanoid robot of claim 1, wherein: The toe body and the heel assembly are both provided with toe rubber pads; and sheet-shaped pressure sensors are installed between the toe body and the toe rubber pad and between the heel assembly and the rubber pad.

4. The anthropomorphic foot mechanism for a humanoid robot of claim 1, wherein: Two roll freedom torsion springs are located in the toe roll freedom torsion spring protection shell mounted on the toe body, and are separated by a partition plate; one end of each roll freedom torsion spring is placed in a one-word groove opened at the end of the connecting shaft, and the other end is in contact with the inner wall of the toe roll freedom torsion spring protection shell under the action of the pre-tightening force.

5. The anthropomorphic foot mechanism for a humanoid robot of claim 1, wherein: The pitch freedom torsion spring is located in the toe pitch freedom torsion spring protection shell fixedly installed on the inner wall of the arch assembly; one end of the pitch freedom torsion spring is placed in a one-word groove opened at the end of the connecting shaft, and the other end is in contact with the inner wall of the toe pitch freedom torsion spring protection shell under the action of the pre-tightening force.

6. The anthropomorphic foot mechanism for a humanoid robot of claim 1, wherein: The arch elastic buffer assembly comprises a limiting nut, a buffer assembly connecting shaft, two spring limiting sleeves, a compression spring, and a guide rod and a buffer assembly sliding sleeve; the guide rod is sequentially sleeved from top to bottom with two limiting nuts, a buffer assembly connecting shaft, an upper spring limiting sleeve, a compression spring, and a lower spring limiting sleeve; the buffer assembly connecting shaft is used to realize connection with the arch assembly; a joint is designed at the lower end of the guide rod to realize connection with the foot frame.

7. The anthropomorphic foot mechanism for a humanoid robot of claim 1, wherein: The heel elastic buffer assembly comprises a guide rod limiting connector, a compression spring, a spring limiting sleeve, and a sliding guide rod; the bottom end of the sliding guide rod is designed with a joint for connecting the heel body; the top end of the sliding guide rod is inserted into the cylindrical guide rod limiting connector; the compression spring is sleeved on the sliding guide rod, and the upper and lower ends of the compression spring are respectively matched with the guide rod limiting connector and the outer wall circumferential shoulder of the spring limiting sleeve; the top end of the guide rod limiting sleeve is also designed with a joint for connecting the foot frame.

8. The anthropomorphic foot mechanism for a humanoid robot of claim 1, wherein: A limiting plate is designed at the rear side of the heel body, and a buffer rubber pad is laid on the limiting plate, which is used to contact the foot frame during the movement of the robot and limit the downward displacement of the rear part of the foot frame.

9. The anthropomorphic foot mechanism for a humanoid robot of claim 1, wherein: The movement mode is as follows: (1) When the bottom surfaces of the heel assembly and the toe assembly touch the ground at the same time, the arch elastic buffer assembly and the heel elastic buffer assembly provide support force for the arch assembly and the heel assembly, so that the robot can be supported by the foot device; (2) When only the bottom surface of the toe assembly touches the ground and has a turning angle in the pitch direction relative to the ground, the toe assembly rotates around the pitch direction to ensure the adhesion of the bottom surface to the ground and realize the forefoot palm movement; when the arch assembly is not perpendicular to the ground, the impact on the forefoot palm is absorbed by the arch elastic buffer assembly; after the forefoot palm leaves the ground, the toe assembly is reset under the action of the pitch freedom torsion spring; (3) When the whole has a turning angle in the roll direction relative to the ground, the bottom surfaces of the two toe assemblies are subjected to different sizes of ground reaction force, and the two arch assemblies rotate around the foot frame connecting point under the combined action of the ground reaction force and the arch elastic buffer assembly; the two toe assemblies will rotate around their respective cross shaft axes to ensure that the bottom surface of the forefoot palm adheres to the ground. (4) When only the heel touches the ground and has a turning angle in the pitch direction relative to the ground, the heel assembly rotates around the pitch direction under the joint action of the ground reaction force and the heel elastic buffer assembly, ensuring the fit between the heel bottom surface and the ground and allowing the heel elastic buffer assembly to absorb the vibration and impact of the heel assembly when it touches the ground; (5) When touching the ground with different forces at different bottom surfaces, the sheet-shaped pressure sensor provides data on whether the ground is touched and the size of the ground reaction force; (6) When walking, the states described in (1), (2), and (4) are alternately switched, and the state described in (3) is interposed, thereby completing the straight-knee, heel-toe gait; when walking on unstructured ground, the bottom surfaces of the two toe assemblies and the bottom surface of the heel assembly will each rotate by a certain angle and eventually reach a balanced state.

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