Joint coupling driven humanoid robot leg structure and control method thereof

Abstract

The invention relates to the technical field of legged robots, and aims to provide a joint coupling driven humanoid robot leg structure and a control method thereof. The whole mechanism has three degrees of freedom which are respectively the flexion and extension movement of the hip joint, the knee joint and the ankle joint, and the hip joint, the knee joint and the ankle joint can flexibly rotate and can reach the human body joint rotation angle range, so that the actions such as jumping can be realized. The invention provides the innovative design of the coupling joint, and has the advantages of enhancing the motion coordination, reducing the control complexity and reducing the energy consumption; on the basis of ensuring sufficient motor torque and proper volume, the appearance and the movement are in line with human body characteristics, and the biological performance advantages of a human body are fully exerted; the structural design is small and exquisite, a joint driving motor moves upwards, and overall light weight is achieved; a control strategy based on power limitation is provided, the Jacobian matrix is utilized to optimize the motor output torque, the system power consumption is further reduced, and the method has a wide social application scene.

Description

Technical Field

[0001] The present invention relates to the technical field of legged robots, and in particular to a leg structure of a humanoid robot and a control method thereof. Background Art

[0002] Robotics is the technical direction that my country needs to improve its core competitiveness, and humanoid robots are one of the most technically difficult types of robots. Compared with wheeled and tracked robots, humanoid robots have better ground adaptability and lower energy consumption. In addition, humanoid robots have a human-like appearance and are more easily accepted by humans.

[0003] However, the leg configuration and driving mode of humanoid robots still cannot meet human standards. The leg structure has not yet reached the range of motion of human leg joints. Therefore, the movement ability of humanoid robots is limited and they have not really entered human life. The present invention aims to propose a joint coupling driven humanoid robot leg structure and a control method thereof. The overall mechanism has three degrees of freedom, namely, the flexion and extension of the hip joint, knee joint and ankle joint. The hip, knee and ankle joints can rotate flexibly and reach the range of human joint rotation angles, so as to achieve jumping and other actions. The driving motor is moved upward to reduce the terminal inertia and realize lightweight design, thereby improving the leg swinging speed and efficiency. Summary of the invention

[0004] The design purpose of the present invention is to solve the problem that the legs of humanoid robots have weak movement ability. The number of parts required to build the legs of the robot is relatively large. In order to avoid the legs being bulky and to achieve the flexibility and stretchability of the legs of the robot, it is necessary to reduce the gaps between the parts. However, the legs of the robot are generally a connecting rod mechanism. The reduction of the gap between the parts will cause interference in the connecting rod mechanism, thereby limiting the range of motion of each joint of the leg. On the basis of ensuring that the motor torque is sufficient and the volume is appropriate, the present invention conforms to the characteristics of the human body in terms of appearance and movement, achieving anthropomorphism.

[0005] The technical solution adopted by the present invention is: to provide a leg structure, including a thigh structure, a calf structure rotatably connected to the thigh structure, and an ankle structure rotatably connected to the calf, and to design a thigh connection mechanism, a knee joint four-bar linkage mechanism, and an ankle joint four-bar linkage mechanism.

[0006] The single leg structure is mainly composed of the thigh, calf, and foot. The overall structure is as follows Figure 1As shown in the figure, the thigh and calf are made of carbon fiber plates, each consisting of two carbon fiber plates. The two layers of plates are fixed by cylindrical pins, and a certain space is reserved for the arrangement of the connecting rod mechanism. The shape design is similar to the shape of the human thigh and calf, which is close to an arc, reducing the inertia and mass of the leg. On the one hand, it is beneficial to improve the walking speed and walking stability of the robot, and on the other hand, it can reduce the energy consumption of the leg. The foot is also made of carbon fiber plates, and the shape is similar to the end of the human foot. Inspired by the biological structure of the human body, the robot's knee remains bent when standing on one leg, and the angle between the thigh and calf is about 120°, which helps to ensure that the robot's posture is non-singular and optimize the control output.

[0007] The mechanism connecting the thigh includes a base plate, a guide rail connecting plate and a triangular fixed angle code. The four lower corner pieces are used to fix the relative position of the hip joint motor connecting plate and the base plate, and the four upper corner pieces are used to fix the relative position of the guide rail connecting plate and the base plate. The two guide rail connecting plates are located on both sides of the robot's single leg and are fixed to the slider. The slider is connected to the guide rail, which is installed on a 6090 aluminum profile with a height of 2.5m, which can maximize the up and down movement of the entire device.

[0008] The motor uses Yushu Technology A1 motor, and a total of three motors are installed. Two of the motors are located in coaxial positions on both sides of the hip joint, controlling the movement of the hip joint and knee joint respectively. The other motor is located at the knee joint on the outside of the leg to control the movement of the ankle joint. The motor distribution is more beautiful.

[0009] To drive the flexion and extension of the thigh, only an A1 motor and a thigh carbon fiber plate are needed. The motor is installed on the inside of the leg. The stator housing of the motor has a threaded hole and is fixed to the inside of the hip joint motor connection plate. One end of the thigh carbon fiber plate is threadedly connected to the motor stator to achieve the movement of the hip joint.

[0010] To drive the knee joint, a four-bar linkage mechanism is needed. The A1 motor is installed on the outside of the robot's single leg. The connection between the outer thigh carbon fiber plate and the motor is different from that on the inner side. A hole is opened at one end of the outer carbon fiber plate so that the motor rotor can just pass through the hole. Figure 6 As shown, the same applies to the ankle joint swing arm. The through hole on the left side of the swing arm in the figure is assembled with the output shaft of the knee joint motor. Six threaded holes are opened and threadedly connected to the output shaft. The bearing is tightly attached to the end face of the knee joint output shaft through a retaining ring. The connecting rod of the knee joint is connected to the swing arm, and the other end of the connecting rod is connected to the carbon fiber plate of the calf. There is also a hole above the calf rotation pair, which serves as the rotation pair at the end of the connecting rod.

[0011] In addition, the present invention also constructs a four-bar linkage mechanism for the ankle joint. The motors of most humanoid robots' ankle joints are placed at the ankle joint or on the calf near the ankle joint. Considering the humanoid nature of the humanoid robot, the present invention places the third A1 motor on the outside of the knee joint of the single leg, which is more in line with the human body structure mechanism, effectively reduces the load on the ankle joint, and makes the ankle joint lighter. The knee joint is composed of an A1 motor, a motor output shaft, a swing arm, a connecting rod, a retaining spring, a bearing, and a thigh and calf carbon fiber plate, such as Figure 8 As shown, a total of four bearings and three retaining springs are used. The motor is fixed to the outside of the thigh carbon fiber plate by a cylindrical pin. In addition, other types of cylindrical pins are selected for the relative position between the thigh plates and the calf plates. The connection method of the ankle joint swing arm is the same as that of the knee joint. With the help of the end surface generated by the retaining spring and the swing arm, the circumferential fixation of the two calf carbon fiber plates can be achieved. There will also be a gap between the thigh and the calf due to the presence of the retaining spring, which can avoid friction when the calf rotates relative to the thigh.

[0012] The design at the ankle is like Figure 5 As shown, the foot support can be divided into three parts: the first and second side plates and the base (9-1, 9-2, 9-3). The first and second side plates (9-1, 9-2) can be placed between the two calf plates. The outer rings of the two bearings pass through the calf plates respectively. Each bearing uses two retaining springs to support the inner ring. The outer sides of the first and second side plates (9-1, 9-2) are in contact with the retaining springs. A sleeve in the middle passes through the ankle joint rotation axis and is located in the middle of the first and second side plates (9-1, 9-2) and contacts the inner side thereof, thereby avoiding uneven force on the foot support. One end of the fisheye connecting rod used at the ankle joint is connected to the swing arm of the knee joint, and the other end is connected to the threaded hole of the foot support. The base (9-3) is threadedly connected to the force sensor support plate, and the support plate is provided with 4 threaded holes connected to the upper part of the force sensor. The sole plate is provided with four threaded holes connected to the lower part of the force sensor. When a single leg touches the ground, the sensor can read the size of the sole contact force in real time, which is used as the basis for designing a single-leg jumping controller.

[0013] Compared with the existing technology, the present invention has the following beneficial effects: the appearance design of the present invention is more humanoid, giving full play to the biological performance advantages of the human body; the innovative design of the coupling joint can enhance movement coordination and reduce energy consumption; the position of the joint motor is moved upward to achieve overall lightweight, providing a basis for the stability design of the controller; the joint movement range conforms to the human body structure; a control strategy based on power limitation is proposed; the Jacobian matrix is ​​used to optimize the motor output torque, further reducing the system power consumption; and it has a wide range of social application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Overall schematic diagram of a motor-driven humanoid robot with a single leg;

[0015] Figure 2 Single leg lateral view;

[0016] Figure 3 Schematic diagram of thigh assembly connection;

[0017] Figure 4 Schematic diagram of the connection of the lower leg assembly;

[0018] Figure 5 Schematic diagram of foot end assembly connection;

[0019] Figure 6 Knee and ankle joint swing arm structure diagram;

[0020] Figure 7 Single leg hip connection diagram;

[0021] Figure 8 Schematic diagram of the connection at the knee of a single leg;

[0022] Fig. 9 Schematic diagram of the connection at the ankle of a single leg;

[0023] Figure 10-1 Schematic diagram of the single-leg mechanism;

[0024] Figure 10-2 Schematic diagram of the joint reference coordinate system;

[0025] Figure 11-1 Schematic diagram of the four-bar linkage of the knee joint;

[0026] Figure 11-2 Schematic diagram of the four-bar linkage of the ankle joint;

[0027] Fig.12 Single-leg hopping control flow chart;

[0028] In the figure: a thigh component (1), a calf component (2), a foot component (3), a leg connector (4), an inner thigh carbon fiber plate (5), an outer thigh carbon fiber plate (6), an inner calf carbon fiber plate (7), an outer calf carbon fiber plate (8), a foot support (9), a first and second side plates and a base (9-1, 9-2, 9-3), a sensor connecting plate (10), a force sensor (11), a foot sole plate (12), a first and second A1 motor connecting plate (13-1, 1 3-2), a knee joint control motor (14), a knee joint motor output shaft (15), a knee joint swing arm (16), a knee joint connecting rod (17), a hip joint control motor (18), a bearing (19), a retaining spring (20), an ankle joint control motor (21), an ankle joint motor output shaft (22), a motor carrying platform (23), an ankle joint swing arm (24), an ankle joint connecting rod (25), a connecting rod fastening sleeve (26), an ankle rotating shaft (27), and a foot end fastening sleeve (28). DETAILED DESCRIPTION

[0029] The present invention will be further described in conjunction with the accompanying drawings.

[0030] The problem to be solved by the present invention is to design a structural design and jumping control method for a single leg of a motor-driven humanoid robot, ensuring that the robot's legs conform to the biological structure of human legs in terms of appearance and movement, ensuring that the single leg can reach the joint rotation angle required for jumping, while improving the robustness of control.

[0031] The technical solution adopted by the present invention to solve the technical problem is:

[0032] A motor-driven humanoid robot single-leg structure design, the overall appearance is as follows Figure 1 The side view is shown in Figure 2 As shown, it is characterized in that: its overall structure consists of a thigh component (1), a calf component (2) and a foot component (3), the thigh component (1) is connected to a leg connector (4), the leg connector (4) is overlapped on the aluminum profile frame, and the leg connector (4) and the aluminum profile are connected by a guide rail and a slider, so that the whole leg completes the jumping movement in the vertical direction of the ground. The thigh component (1) and the calf component (2) use two carbon fiber plates, which serve as the outer side and inner side of the thigh and calf respectively. The two layers of carbon fiber plates are fixed together by cylindrical pins, and a space is left in the middle to place the connecting rod mechanism. The design of the appearance is similar to the shape of the human thigh and calf, which is similar to an arc. The foot component (3) also uses a carbon fiber plate. In the standing state, the robot's single leg remains bent, and the angle between the thigh and the calf is 120°.

[0033] The fixing method of the thigh component (1) is as follows: Figure 3 As shown, the inner thigh carbon fiber plate (5) and the outer thigh carbon fiber plate (6) are fixed together by cylindrical pins, and the position of the cylindrical pins ensures that there will be no interference when the knee joint moves. The fixing method of the calf component (2) is as follows Figure 4 As shown in FIG. 1 , similar to the thigh component (1), the carbon fiber plate (7) on the inner side of the calf and the carbon fiber plate (8) on the outer side of the calf are fixed together, and the fixed position of the cylindrical pin ensures that there is no interference in the movement of the ankle joint. Figure 5 As shown, it is mainly composed of a foot support (9), a sensor connecting plate (10), a force sensor (11), and a foot sole (12), wherein the foot support (9) is a special-shaped structural member, which is divided into a first side plate and a second side plate (9-1, 9-2) and a base (9-3), and the upper and lower planes of the sensor have threaded holes. The sensor connecting plate (10) has a total of 8 threaded holes, which serve as a bridge to connect the upper surface of the force sensor (10) and the foot support (9). The lower surface of the sensor is connected to the foot sole by screws.

[0034] The connection diagram of the single leg hip is as follows Figure 7As shown, the outermost part is two A1 motor connection plates (13), which are vertically fixed to the flat plate through angle pieces to form a part of the leg connection piece (4), the knee joint control motor (14) and the hip joint control motor (18) are respectively fixed to the inner side of the two A1 motor connection plates (13), the knee joint motor output shaft (15) is connected to the rotor of the knee joint control motor (14), the knee joint swing arm (16) passes through the knee joint motor output shaft (15), and the output shaft (15) and the knee joint swing arm (16) are both provided with 6 threaded holes to achieve the fixation of the knee joint swing arm (16) on the output shaft (15), the inner thigh carbon fiber plate (5) is directly connected to the hip joint control motor (18), and the inner thigh carbon fiber plate (5) and the outer thigh carbon fiber plate (6) realize flexible rotation through bearings (19) and retaining springs (20), which can effectively reduce friction loss. The hip part uses two standard bearings and two retaining springs.

[0035] The connection diagram at the knee is as follows Figure 8 As shown, two calf carbon fiber plates are located on the inner side of two thigh carbon fiber plates, an ankle joint control motor (21) is built on the outer side of the thigh at the knee and fixed to a motor mounting platform (23), the motor mounting platform (23) is directly fixed to the outer side of the thigh carbon fiber plate (6), the special-shaped surface of the ankle joint motor output shaft (22) is directly connected to the rotor of the ankle joint control motor (21), and the output shaft passes through the outer side of the thigh carbon fiber plate (6), the outer side of the calf carbon fiber plate (8), the ankle joint swing arm (24), the inner side of the calf carbon fiber plate (7), and the inner side of the thigh carbon fiber plate (5) in sequence. The rotational movement of the carbon fiber plate uses bearings and retaining springs, the retaining springs are clamped on the output shaft, and the bearing contacts the retaining spring and the side plane of the swing arm, thereby ensuring the positioning of the bearing. A total of four standard bearings, three retaining springs, and three cylindrical pins are used.

[0036] The connection diagram of the ankle of a single leg is as follows Fig. 9 As shown, the four retaining ring grooves of the ankle shaft (27) clamp the retaining rings to fix the inner and outer carbon fiber plates (7, 8) of the calf, the inner rings of the two bearings pass through the ankle shaft (27), and the outer rings pass through the first and second side plates (9-1, 9-2), and the foot end fastening sleeve (28) is assembled to the middle position of the ankle shaft (27) to fix the positions of the two bearings and support the first and second side plates (9-1, 9-2) at the same time, thereby reducing the deformation amount caused by the force on the foot end support (9).

[0037] A single-leg jumping control method for a joint-coupled driven humanoid robot is characterized by: using the robot's forward kinematics to obtain the expression of the end position with respect to the hip joint, knee joint and ankle joint, considering the peak power of the motor, adding the power limit of the joint motor, and controlling the torque output of the joint motor to achieve optimal jumping performance.

[0038] Establish a single-leg forward kinematics model, the mechanism diagram is as follows Figure 10-1 As shown, the single leg is simplified into a three-link mechanism, θ 1 ,θ 2 ,θ 3 are the rotation angles of the hip, knee and ankle respectively, and the hip joint, knee joint, ankle joint and ankle end are set as the origin O base , O 1 , O 2 , O 3 , establish the corresponding coordinate system, such as Figure 10-2 As shown, the coordinate system at the hip joint is the base coordinate system. By establishing the DH parameter table, the transformation matrix of the ankle joint coordinate system relative to the hip joint coordinate system can be obtained as follows:

[0039]

[0040] in It is expressed as:

[0041]

[0042] Therefore, the position of the end of the single leg relative to the base coordinate system is obtained as follows:

[0043]

[0044] The rotation angle of each joint has a certain relationship with the rotation angle of its corresponding motor. For the hip joint, since the hip joint control motor (18) is directly connected to the inner thigh carbon fiber plate (5) for driving, the rotation angle at the hip joint and the corresponding motor rotation angle α are obtained. 1 The relationship is:

[0045] θ 1 =α 1

[0046] For the knee joint, the motor is connected to the knee joint swing arm (16), and forms a four-bar linkage with the thigh and calf. Since the length of the calf is equal to the length of the connecting rod, the four-bar linkage forms a parallelogram, such as Figure 11-1 As shown in the figure, the knee joint angle is the rotation angle of the motor at the knee joint, which is expressed as:

[0047] θ 2 =α 2

[0048] The ankle joint is also driven by a four-bar mechanism. The ankle assembly can be transformed into a virtual rod, and the motor swing arm is connected to the two ends of the calf, forming an "eight-shaped" structure. Figure 11-2The figure shows a simplified diagram of the ankle joint linkage mechanism. Since the ankle joint motor is fixed to the thigh board, if the knee joint motor is driven and the ankle joint motor remains stationary, it can be found that the ankle joint rotation angle will change. The motor is fixed to the thigh and connected to the ankle through the swing arm and the connecting rod to control the ankle joint movement. If the ankle joint motor is not driven, the angle between the swing arm and the thigh remains unchanged, and the angle of knee joint rotation is α 2 , assuming that the knee joint rotates before and after, the ankle joint angle is θ 3 becomes θ 3 ', according to the geometric relationship, the change of angle θ 31 About α 2 When the knee joint is not driven, the ankle joint motor is controlled to drive. The rotation angle of the ankle joint can be finally calculated by trigonometric functions and the triangular cosine theorem:

[0049]

[0050] According to the single-leg model coordinate system established previously, α 1 , α 2 , α 3 The defined directions are consistent, and the motor swing arm rotation directions are Figure 10-1 Clockwise in the viewing angle, α 2 As θ increases gradually, 31 will continue to increase, and when α 3 When θ increases, 32 Will follow α 2 decreases with the increase of 31 ,θ 32 The two change in opposite directions, so they need to be synthesized by subtraction to obtain the final ankle joint angle:

[0051]

[0052] The motion characteristics of a robot's single leg include two motion phases: the support phase and the flight phase. The constraints of the support phase and the flight phase are different, and the state variables of the system's motion phase equation will also change. Therefore, the dynamic models of the support phase and the flight phase are also different. The generalized coordinates are defined as q 0 =[x yθ 1 θ 2 θ 3 ] T , the Lagrangian function of the system is L = TU. When the single leg is in the support phase, the sole of the foot is in contact with the ground, and the Cartesian coordinates (xy) are constants. Therefore, the generalized coordinates of the system of the jumping robot in the support phase are q = [θ 1 θ 2 θ 3 ] T , the Euler-Lagrangian dynamics equation of the support phase can be written as:

[0053]

[0054] The above dynamic equation can be transformed into matrix form:

[0055]

[0056] Where: Q = [τ 1 τ 2 τ 3 ] T is the generalized driving torque, M is the inertia matrix of the robot support phase, are the centrifugal force and the Kohlberg force terms, H(q) are the gravity and spring force terms, S is the selection matrix of the active joint torque, τ is the joint torque vector, λ is the force vector at the foot end; J is the Jacobian matrix.

[0057] During the flight phase, the robot is not subject to any other forces except gravity, and the dynamic equation of its dynamic model is:

[0058]

[0059] A power-limited top-level jump control strategy is designed to dynamically adjust the motor's output torque by real-time monitoring of the motor's operating status to prevent the motor from operating beyond its rated peak power. When the motor's actual output power approaches or exceeds its maximum allowable value, the system will automatically reduce the output torque to limit power output and protect the motor from damage. If the motor operates within a safe range, it will continue to maintain maximum torque output to achieve optimal performance.

[0060] The specific real-time steps are as follows: First, define the peak parameters to determine the peak power P of each motor. m and peak torque T m , and obtain the real-time speed ω of each joint motor in real time; then calculate the real-time power and calculate the instantaneous output power of the motor

[0061] P=T·ω

[0062] The units of output power P, torque T, and speed ω are W, N·m, and rad / s respectively; then compare the power and make adjustments if P>P m , then adjust the output torque to

[0063]

[0064] If P<P m , then keep T=T m unchanged, and finally the calculated T adjust or T m It is sent as a new control signal to the motor driver, which continuously monitors the working status of the motor and repeats the above steps as needed.

[0065] A control strategy optimization method for effectively reducing energy consumption is characterized by: using the Jacobian matrix to solve and optimize to obtain the output torque of each joint, so that the motor output torque is reduced while keeping the jumping height unchanged as much as possible, thereby reducing energy consumption.

[0066] Each column of the Jacobian matrix J corresponds to the effect of a small change in a single joint on the position and posture of the end effector. In mathematical expression, let is the velocity vector in the joint space, is the velocity vector in the terminal working space, then the relationship between the two can be expressed by the Jacobian matrix J as

[0067]

[0068] in is a vector composed of joint angles. Through the Jacobian matrix, the speed of the end effector can be directly inferred from the speed of the joint. From the differential idea, we can know that each element of the Jacobian matrix is ​​the partial derivative of the position vector of the end workspace to the position vector of each joint space. According to the derived end expression, the speed Jacobian matrix of a single leg can be obtained as:

[0069]

[0070] Figure 10-2 The x shown 0 ,y 0 is the base coordinate system of the single-legged robot. The foot end workspace is limited to one plane. Due to the constraints of the overall frame and the guide rail, the robot remains in the x plane throughout the jumping process. 0 In the direction. At the moment of jumping, the external force on the ankle is only x 0 Force F in the direction x , according to the Newton-Euler equation, the end force F x The relationship between and the joint torque τ can be expressed by the transpose of the force Jacobian matrix:

[0071] τ=J(q) T F

[0072] in

[0073]

[0074] The velocity Jacobian matrix is ​​a matrix about the joint angles, which changes with the changes in the joint angles during the jumping process. The time from squatting to the sole of the foot leaving the ground is quite short. At this time, the independent variable of the Jacobian matrix can be approximated as the joint angle when the robot squats. The corresponding Jacobian matrix can be calculated using the leg length information and the joint angle information when the robot squats. Substituting it into the above formula can obtain the torque output.

[0075] To minimize the total power consumption, it is necessary to select a suitable ground contact reaction force to make the output torque more evenly distributed on each joint and reduce the burden on the motor of a single joint. 1 , τ 2 , τ 3 They are the torques of the three joint motors, μ is the average output torque of the three joint motors, and to achieve a uniform distribution effect, the difference between the output torques of the three motors and μ is sufficient; from the impulse theorem, the greater the ground reaction force, the greater the bounce speed, and the energy consumption is relatively low. To ensure the minimum energy consumption, add 1 / F x At the same time, the joint torque must be as small as possible, so add So the optimal problem can be described as follows:

[0076]

[0077] τ 1 , τ 2 , τ 3 Limited to the peak torque range, the final solved motor output torque is the motor output when the energy consumption is lowest.

Claims

1. A humanoid robot leg driven by joint coupling, characterized in that: The overall structure is composed of a thigh component (1), a calf component (2), a foot end component (3) and a leg connecting member (4). The leg connecting member (4) is overlapped on the aluminum profile frame to limit the degree of freedom so that the whole leg can complete the jumping movement in the vertical direction of the ground. Among them, the fixing method of the thigh component (1) is shown in FIG3 , and the inner thigh carbon fiber plate (5) and the outer thigh carbon fiber plate (6) are fixed together by a cylindrical pin, and the position of the cylindrical pin ensures that there is no interference when the knee joint moves; the fixing method of the calf component (2) is shown in FIG4 , and the inner calf carbon fiber plate (7) and the outer calf carbon fiber plate (8) are fixed together like the thigh component (1), and the fixing position of the cylindrical pin ensures that there is no interference when the ankle joint moves; the exploded schematic diagram of the foot end component (3) is shown in FIG5 , which is mainly composed of a foot end support (9), a sensor connecting plate (10), and a force sensor (11) , a foot sole (12), wherein the foot end support (9) is a special-shaped structural member, which is divided into a first and a second side plate (9-1, 9-2) and a base (9-3), the upper and lower planes of the sensor have threaded holes, and the sensor connecting plate (10) has a total of 8 threaded holes, which serve as a bridge to connect the upper surface of the force sensor (10) and the foot end support (9); the lower surface of the sensor is connected to the foot sole by screws; the leg connecting member (4) is formed by two sides of carbon fiber plates vertically fixed to the bottom plate, the carbon fiber plates on both sides connect the guide rails and the slider, and finally are installed on the aluminum profile frame, so that the whole leg can complete the jumping movement in the vertical direction of the ground; The connection at the hip of a single leg, the knee joint control motor (14) and the hip joint control motor (18) are respectively fixed on the inner sides of two A1 motor connection plates (13), the knee joint motor output shaft (15) is connected to the rotor of the knee joint control motor (14), the knee joint swing arm (16) is fixed to the output shaft (15) by threads, the inner thigh carbon fiber plate (5) is directly connected to the hip joint control motor (18), and the inner thigh carbon fiber plate (5) and the outer thigh carbon fiber plate (6) realize flexible rotational movement through bearings (19) and retaining springs (20); The two calf carbon fiber plates at the knee are located on the inner side of the two thigh carbon fiber plates. The ankle joint control motor (21) is built on the outer side of the thigh at the knee and fixed to the motor mounting platform (23). The motor mounting platform (23) is directly fixed to the outer side of the thigh carbon fiber plate (6). The special-shaped surface of the ankle joint motor output shaft (22) is directly connected to the rotor of the ankle joint control motor (21). The output shaft passes through the outer side of the thigh carbon fiber plate (6), the outer side of the calf carbon fiber plate (8), the ankle joint swing arm (24), the inner side of the calf carbon fiber plate (7), and the inner side of the thigh carbon fiber plate (5) in sequence. The rotational movement of the carbon fiber plates uses bearings and retaining springs to ensure the positioning of the bearings. The circlip of the ankle shaft (27) at the ankle of a single leg fixes the carbon fiber plates (7, 8) on the inner and outer sides of the calf, the inner rings of the two bearings pass through the ankle shaft (27), and the outer rings pass through the first and second side plates (9-1, 9-2), and the foot end fastening sleeve (28) is assembled to the middle position of the ankle shaft (27) to fix the positions of the two bearings and support the first and second side plates (9-1, 9-2) at the same time, thereby reducing the deformation amount caused by the force of the foot end support (9).

2. The joint-coupled driven humanoid robot leg according to claim 1, characterized in that: On the basis of ensuring that the motor torque is sufficient and the volume is appropriate, the leg assembly is processed into an arc, which conforms to the biological characteristics of the human body in terms of appearance and movement, achieving anthropomorphism; the overall mechanism has a total of three degrees of freedom, namely the flexion and extension of the hip joint, knee joint and ankle joint, and the hip, knee and ankle joints have been verified to be able to rotate flexibly and be within the flexion and extension angle range of the human joint, so as to achieve movements with large joint angles such as jumping; except for the foot end support (9) and the swing arm and shaft that need to be machined, other parts only need to be wire cut or use standard parts, which is convenient to process and has low cost consumption, and the assembly between the parts is threaded connection, which is simple to assemble and easy to disassemble.

3. A control method for the legs of a humanoid robot driven by joint coupling, characterized in that: The robot forward kinematics is used to obtain the expression of the end position about the hip joint, knee joint and ankle joint, and then the rotation angle of the three motors is controlled; The single-leg forward kinematics model is established to obtain the position of the end of the single leg relative to the base coordinate system: The rotation angle of each joint is related to the rotation angle of its corresponding motor. In particular, the ankle joint rotation angle is coupled, and its size is related to the rotation angle of the knee and ankle joint motors. According to the four-bar mechanism of the model, the relationship between the hip joint θ1, knee joint θ2, ankle joint θ3 and their corresponding motor rotation angles α1, α2, α3 is obtained as follows: θ1=α1 θ2=α2 Define the generalized coordinates as q0 = [x yθ1θ2θ3] T , the Lagrangian function of the system is L = TU; when the single leg is in the support phase, the sole of the foot is in contact with the ground, and the Cartesian coordinates (xy) are constants; therefore, the generalized coordinates of the system of the jumping robot in the support phase are q = [θ1θ2θ3] T , the Euler-Lagrangian dynamic equation of the support phase can be written as: The above dynamic equation can be converted into matrix form: Where: Q = [τ1τ2τ3] T is the generalized driving torque, M is the inertia matrix of the robot support phase, are the centrifugal force and the force term of Koch, H(q) is the gravity and spring force term, S is the selection matrix of the active joint torque, τ is the joint torque vector, λ is the force vector at the foot end; J is the Jacobian matrix; During the flight phase, the robot is not subject to any other forces except gravity, and the dynamic equation of its dynamic model is: A top-level jump control strategy with limited power dynamically adjusts the output torque of the motor by real-time monitoring of the motor working status to prevent the motor from working beyond its rated peak power. First, the peak parameters are defined to determine the peak power P of each motor. m and peak torque T m , and obtain the real-time speed ω of each joint motor in real time; then calculate the real-time power, and calculate the instantaneous output power of the motor according to the following formula P=T·ω Then compare the power and make adjustments if P>P m , then adjust the output torque to If P<P m , then keep T=T m unchanged, and finally the calculated T adjust or T m Sent to the motor driver as a new control signal; A control strategy optimization method for effectively reducing energy consumption, characterized in that: the output torque of each joint is obtained by solving the optimization using the Jacobian matrix, so that the jump height is kept unchanged as much as possible when the motor output torque is reduced, thereby reducing energy consumption; According to the terminal expression derived from forward kinematics, the velocity Jacobian matrix of a single leg can be obtained as: Due to the constraints of the overall frame and the guide rail, the robot remains in the vertical direction throughout the jumping process; at the moment of jumping, the external force on the ankle is only the force F perpendicular to the ground. x , the external forces in other directions are zero; according to the Newton-Euler equation, the end force F x The relationship between and the joint torque τ can be expressed by the transpose of the force Jacobian matrix: τ=J(q) T F in The time from squatting to leaving the ground with a single leg is quite short. At this time, the independent variable of the Jacobian matrix can be approximated as the joint angle of the robot when squatting. The corresponding Jacobian matrix can be obtained by using the leg length information and the joint angle information of the robot when squatting. Substituting it into the above formula can obtain the torque output; In order to minimize energy consumption, the motor output torque needs to be evenly distributed on each joint. Let τ1, τ2, and τ3 be the motor torques of the three joints, and μ be the average of the motor output torques of the three joints. To achieve the desired effect, the difference between the three motor output torques and μ is sufficient. According to the impulse theorem, the greater the ground reaction force, the greater the bounce speed, and the lower the energy consumption. To minimize energy consumption, add 1 / F x At the same time, the joint torque must be as small as possible, so add Item; so the optimal problem can be described as follows: τ1, τ2, and τ3 are limited within the peak torque range, and the final solved motor output torque is the motor output when the energy consumption is the lowest.

4. The joint-coupled driven humanoid robot leg according to claim 1, characterized in that: The installed hip and knee joint control motors are located in coaxial positions on both sides of the hip joint, controlling the movements of the hip and knee joints respectively. The ankle joint control motor is located at the knee joint on the outside of the leg, controlling the movement of the ankle joint. The distribution of the motors has shifted to give full play to the excellent anthropomorphic characteristics of the single leg. Inspired by the biological structure of the human body, the robot's knee remains bent when standing on one leg, and the angle between the thigh and calf is approximately 120°, which helps to ensure that the robot's posture is not singular and optimize the control output.

5. The joint coupling driven humanoid robot leg control method according to claim 3, characterized in that: An innovative design of coupled joints is proposed, which has the advantages of improving movement efficiency, enhancing movement coordination, reducing control complexity and lowering energy consumption; the driving motors of the knee and ankle joints are moved upward, which effectively reduces the terminal inertia of the single leg and achieves overall lightweight, thereby significantly improving the speed and efficiency of leg swinging; a control strategy based on power limitation is proposed, and the Jacobian matrix is ​​used to optimize the motor output torque, which can further reduce the system power consumption.

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