Foot end trajectory-based kinematics analysis and gait planning method for space four-footed crawling robot

Abstract

The invention relates to the field of kinematics of four-footed crawling robots, and discloses a four-footed crawling robot kinematics analysis and gait planning method based on foot end tracks. According to the method, firstly, modeling is conducted on the quadruped crawling robot, then the motion paths of the foot ends of the quadruped crawling robot are designed, inverse kinematics analysis is conducted on the quadruped crawling robot through an analytical method, the angle value of each joint is solved, and then each joint motor is controlled to reach the expected position. Then, the Walk gait and the Trot gait of the four-footed crawling robot are designed, and finally movement tracks of foot ends of the Walk gait and the Trot gait of the four-footed crawling robot are output. The method has the advantages that the analytical method is high in speed and precision, and the method is suitable for leg structure analysis of the four-footed crawling robot. Technical support is provided for autonomous decision making and path planning, and possibility is provided for application of the four-footed crawling robot in various tasks.

Description

Technical Field

[0001] The invention relates to the kinematics field of a quadruped crawling robot, in particular to a kinematics analysis and gait planning method of a quadruped crawling robot based on foot end trajectories. Background Art

[0002] In the field of robotics research, legged robots have become a focus of attention. This type of robot includes bipedal, quadrupedal, and multi-legged robots according to the number of legs. Quadrupedal robots have attracted much attention due to their unique structure. They draw on the physiological structure of most mammals on Earth and have become a hot topic in this field for their excellent static stability and load-bearing capacity.

[0003] Gait is an orderly movement pattern followed by the legs of a legged robot when walking. It reflects the precise coordination between the legs in time and space, allowing the robot to move forward in a regular and repeatable manner. Therefore, the gait planning of quadruped robots plays a vital role in the study of robot motion control. After studying the leg movement characteristics of quadrupeds in nature, we can divide the gaits of quadruped robots into many types, including crawling gait (Crawl), walking gait (Walk), diagonal trot gait (Trot), bound gait (Bound) and gallop gait (Gallop). Summary of the invention

[0004] The present invention aims to provide a kinematic analysis and gait planning method for a quadruped crawling robot based on foot-end trajectory. Firstly, the foot-end trajectory of the quadruped crawling robot is designed, and then the inverse kinematics analysis of the legs of the quadruped crawling robot is performed. Finally, the quadruped robot smoothly realizes the designed Walk gait and Trot gait.

[0005] The technical solution adopted by the present invention to achieve the above-mentioned purpose is: a kinematic analysis and gait planning method of a spatial quadruped crawling robot based on foot end trajectory, the method comprising the following steps:

[0006] S1. Modeling a quadruped crawling robot and defining geometric parameters; the quadruped crawling robot is a full-elbow robot, including a trunk and four leg structures;

[0007] S2. Analyze the mathematical expression of the cycloid, design the motion trajectory of the cycloid, and obtain the motion path of the foot end of the quadruped robot;

[0008] S3, using analytical method to perform inverse kinematics analysis on the foot end coordinates of the quadruped crawling robot, inversely solving the angle value of each joint, which is used to control the motor of each joint to reach the desired position;

[0009] S4, analyzing the Walk gait and Trot gait of the quadruped crawling robot to obtain gait control parameters;

[0010] S5. Output the foot end motion trajectory of the quadruped crawling robot to control the quadruped crawling robot to move along the trajectory in the Walk gait and the Trot gait.

[0011] The geometric parameters include the body length and width of the quadruped crawling robot, the hip joint link length h, the thigh length hu, the calf length hl, the hip joint angle α, the side swing joint angle γ and the knee joint angle β.

[0012] The motion trajectory of the foot end of the quadruped crawling robot is a cycloid, which is defined as the trajectory formed by a certain point on the boundary of a circle when a circle moves along a straight line. The mathematical formula is as follows:

[0013]

[0014] Among them, x s is the starting position of the quadruped crawling robot, x f is the end position, |x f -x s | is the distance the robot moves when completing a complete gait cycle, called the step length; h is the maximum vertical distance the robot's leg and foot leave the ground when completing a gait cycle, called the step height; z s is the starting height of the robot foot, t is the movement time, T s is the gait period, x t is the step size function with respect to time t, z t is the step height function with respect to time t, and σ is the accumulated radians.

[0015] The inverse kinematics analysis is to inversely solve the angle value of each joint through the robot foot end coordinate, and the angle value of each joint includes the side swing joint rotation angle γ, the knee joint rotation angle β and the hip joint rotation angle α.

[0016] The solution formula is summarized as follows:

[0017]

[0018] Among them, (x, y) is the foot end coordinate in the OXY plane of the quadruped crawling robot's foot end top view diagram, hu is the distance between the hip joint and the knee joint, hl is the distance from the knee joint to the foot end, (x, z) is the foot end coordinate in the OZX plane of the quadruped crawling robot's side view diagram, and h is the distance between the leg base and the hip joint.

[0019] The Walk gait and Trot gait of the quadruped crawling robot are designed, including the following steps:

[0020] 1) Define the basic parameters of the robot's gait;

[0021] 2) In the Walk gait, at any time, only three legs are in the support phase and one leg is in the swing phase; in one movement cycle, the four legs of the quadruped crawling robot are lifted at the following times: The fastest movement speed;

[0022] 3) In the Trot gait, two diagonal legs move in pairs. Ideally, the diagonal legs are lifted and landed at the same time. In one movement cycle, the lifting time of the four legs is The fastest movement speed.

[0023] A quadruped crawling robot body and a controller arranged thereon;

[0024] The quadruped crawling robot body is a full elbow robot, including a trunk and four leg structures; each leg structure includes a hip joint and a hip joint connecting rod, a side swing joint and a thigh, a knee joint and a calf; and each joint is provided with a joint motor;

[0025] The controller stores a program, and when the program is loaded and executed, the method steps described above are calculated to calculate the angles of each joint and the gait parameters, and to control the motors of each joint to drive the connecting rod structures of the body to walk according to the target foot end trajectory and the planned gait.

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

[0027] (1) The present invention innovates the quadruped crawling robot model and can improve the efficiency of the robot when turning.

[0028] (2) The present invention adopts an analytical method to perform inverse kinematics analysis on the quadruped crawling robot. The analytical method is fast and accurate. Although it has the disadvantage of poor applicability, it is more suitable for inverse kinematics analysis of the specific leg structure of the quadruped crawling robot. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a flow chart of the method of the present invention;

[0030] Figure 2 This is a simplified diagram of a quadruped crawling robot from the top of its foot;

[0031] Figure 3 and Figure 4 It is a simplified side view of a quadruped crawling robot;

[0032] Figure 5 It is the Walk gait;

[0033] Figure 6 It is the Walk gait sequence diagram;

[0034] Figure 7 It is Trot gait;

[0035] Figure 8 It is the Trot gait step sequence diagram;

[0036] Fig. 9 This is a simulation diagram of the Walk gait motion process;

[0037] Fig.10 This is a simulation diagram of the Trot gait movement process; DETAILED DESCRIPTION

[0038] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation method of the present invention is described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the invention, so the present invention is not limited by the specific implementation disclosed below.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0040] like Figure 1 The flowchart of the method of the present invention is shown. The present invention proposes a kinematic analysis and gait planning method of a spatial quadruped crawling robot based on foot end trajectory. The method comprises the following steps:

[0041] (1) Modeling of a quadruped crawling robot. The quadruped crawling robot studied in the present invention is a full elbow design, including a trunk and four leg structures. Define the geometric parameters of the robot body length and width, hip joint connecting rod length h, thigh length hu, calf length hl, hip joint angle α, side swing joint angle γ and knee joint angle β.

[0042] (2) By analyzing the mathematical expression of the cycloid and designing the motion trajectory of the cycloid, the motion path of the foot of the quadruped crawling robot can be obtained.

[0043] (3) The inverse kinematics analysis of the legs of the quadruped crawling robot is performed using an analytical method. Inverse kinematics analysis is to inversely solve the angle value of each joint by the coordinates of the foot end of the quadruped crawling robot, and then control the motors of each joint to reach the desired position.

[0044] (4) Analyze the Walk gait and Trot gait of the quadruped crawling robot.

[0045] (5) Output the foot motion trajectory of the quadruped crawling robot to control the quadruped crawling robot to move along the trajectory in the Walk gait and the Trot gait.

[0046] In step (2), the motion trajectory of the foot of the quadruped crawling robot can be explored by studying the trajectory of the cycloid. The cycloid, also known as the cycloid or the circular rolling line, is defined in mathematics as the trajectory formed by a certain point on the boundary of a circle when it moves along a straight line. The mathematical formula is as follows:

[0047]

[0048] Among them, x corresponds to the horizontal length of the foot end of the quadruped crawling robot, y corresponds to the longitudinal length of the foot end of the quadruped crawling robot, and t corresponds to the accumulated radians, ranging from [0, 2π]. By making corresponding transformations on this formula, we get the following relationship:

[0049]

[0050] Among them, x s is the starting position of the quadruped crawling robot, x f is the end position, |x f -x s | is the distance the robot moves when completing a complete gait cycle, called the step length; h is the maximum vertical distance the robot's leg and foot leave the ground when completing a gait cycle, called the step height; z s is the starting height of the robot foot, t is the movement time, T s is the gait period, x t is the step size function with respect to time t, z t is the step height function with respect to time t, and σ is the accumulated radians.

[0051] The step (3) uses an analytical method to perform inverse kinematics analysis on the legs of the quadruped crawling robot. Specifically, for a quadruped crawling robot, the inverse kinematics analysis is to inversely solve the angle value of each joint through the robot foot end coordinates, and then control the motors of each joint to make it reach the desired position. Inverse kinematics analysis can be divided into two categories: analytical method and numerical method. The numerical method has a wide range of applicability, but the solution speed is slow. The analytical method is fast and accurate. Although it has the disadvantage of weak applicability, it is more suitable for the specific leg structure of the quadruped crawling robot to use the analytical method for inverse kinematics analysis, so the analytical method is used for inverse kinematics analysis. Solving the angle value of each joint includes:

[0052] 1) Side swing joint rotation angle γ: In order to facilitate research and analysis, considering the symmetry of the structure of the quadruped crawling robot, the structure and geometric dimensions of the four legs are the same, and each leg has three degrees of freedom, so the left front leg is analyzed first. Figure 2 The figure shows a simplified top-down view of the foot end of a quadruped crawling robot.

[0053] Among them, γ is the rotation angle of the side swing joint of the quadruped crawling robot. It is stipulated that counterclockwise rotation around the joint is negative and clockwise rotation is positive. The foot end coordinate P in this OXY plane is (x, y), where x is a negative value and y is a positive value. The coordinate of the leg base O point is set to the origin coordinate (0, 0), and the distance between the leg base (side swing joint center) and the hip joint is set to h. There is the following relationship:

[0054]

[0055] 2) Knee joint rotation angle β: Assume that the projection length of the hip joint link AB after the quadruped crawling robot moves on the hip joint link PB before rotation is l. According to the side swing joint rotation angle γ of the quadruped crawling robot, l is calculated as follows:

[0056] l=hcosγ

[0057] like Figure 3 A schematic side view of a quadruped crawling robot.

[0058] Among them, β is the rotation angle of the knee joint, the distance between the hip joint and the knee joint is hu, the distance between the knee joint and the foot end is hl, and the coordinates of the foot end in this OZX plane are (x, z). There is the following relationship:

[0059]

[0060] By combining the above formulas, we can get:

[0061] hu 2 +2*n*hu=lxz' 2 -hl 2

[0062] From the above formula, we can get:

[0063]

[0064] According to the Pythagorean theorem, we can get lxz' 2 The calculation formula is:

[0065] lxz' 2 =(-xl) 2 +z 2

[0066] Knee joint rotation value β = arccos (n / hl), that is:

[0067]

[0068] 3) Hip joint rotation angle α: Figure 4 A schematic side view of a quadruped crawling robot.

[0069] Among them, α is the rotation angle of the hip joint, and the following relationship can be obtained:

[0070]

[0071] Depend on Figure 4 From the side view of the quadruped crawling robot, we can see that α = -(α1-α2), that is:

[0072]

[0073] So far, the inverse kinematics analysis of the quadruped crawling robot has been completed. Through the three-dimensional coordinates (x, y, z) of the foot end of the quadruped crawling robot, the rotation angles of the side swing joint γ, hip joint α and knee joint β are obtained by inverse solution. The solution formula is summarized as follows:

[0074]

[0075] The step (4) of analyzing the Walk gait and Trot gait of the quadruped crawling robot includes:

[0076] 1) In order to facilitate the description of the relevant characteristics of gait, the basic terms related to gait are described as follows:

[0077] Support phase: In the support state, the foot end of the leg is in contact with the ground and pushes the fuselage forward.

[0078] Swing phase: In the swing state, the foot of the leg leaves the ground and swings in the air.

[0079] Gait cycle: The time it takes for each leg of the robot to complete a complete gait movement.

[0080] Phase difference: the ratio of the delayed movement time of the i-th leg relative to the reference leg to the gait period.

[0081] Duty cycle: The ratio of the time a leg of the robot is in the support phase to the time of a gait cycle.

[0082] 2) Walk gait analysis: Walk gait is a static gait, that is, during the movement, three legs are always in the support phase, and at most only one leg is in the swing phase, such as Figure 5 As shown in Figure 2, the most common rotation sequence of the four legs of a quadruped reptile in the walking gait is 1→3→4→2→1. In one movement cycle, the lifting moments of the four legs of the quadruped crawling robot are 1-ρ is the time that the robot leg is in the swing phase. The gait period is set to 1s, where 1-ρ must be less than Because only in this way can the walking gait be established.

[0083] A critical form of the Walk gait is when ρ = 0.75 and That is, there is no obvious quadruped support phase. At any time, only three legs are in the support phase and one leg is in the swing phase. The duty cycle is defined as the ratio of the time a leg of the robot is in the support phase to the time of a gait cycle. Therefore, the duty cycle in the Walk gait is 0.75. This Walk gait is the fastest gait among static gaits, so the Walk gait of quadruped crawling robots is often planned according to this critical form. The Walk gait sequence is as follows: Figure 6 As shown, the white part represents the lifting of the leg in the swing phase, and the black part represents the landing of the leg in the support phase.

[0084] 2) Trot gait analysis: Trot gait is a dynamic gait suitable for running at medium and low speeds and has a relatively large range of movement speeds. Another important feature is that the Trot gait has the highest energy efficiency at medium speeds. These advantages make the Trot gait the most commonly used quadruped gait. The Trot gait is characterized by the movement of two diagonal legs in pairs, that is, leg 1 and leg 3 move in unison, and leg 2 and leg 4 move in unison. Ideally, the diagonal legs are lifted and landed at the same time. In one movement cycle, the lifting time of the four legs is like Figure 7 1-ρ is the time that the robot leg is in the swing phase, and the gait period is set to 1s, where 1-ρ must be less than Because only in this way can the Trot gait be established.

[0085] A critical state of Trot gait is when At any time, only two legs are in the swing phase and two legs are in the support phase, so the duty cycle is 0.5, which is the most ideal state in the Trot gait. Figure 8 As shown, the white part represents the lifting of the leg in the swing phase, and the black part represents the landing of the leg in the support phase.

[0086] Example:

[0087] Here, a four-legged crawling robot is taken as an example to provide a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiment. The specific implementation steps are:

[0088] (1) Define the structural parameters of the quadruped crawling robot as shown in Table 1. The quadruped crawling robot studied in the present invention is based on a full elbow design, including a trunk and four leg structures. Each leg has three degrees of freedom and is composed of a hip joint link, a thigh and a calf.

[0089] Table 1 Structural parameters of the quadruped robot

[0090]

[0091] (2) The motion path of the quadruped robot foot end is designed to be a cycloid. The mathematical relationship is expressed as follows:

[0092]

[0093] Among them, x s is the starting position of the quadruped crawling robot, x f is the end position, |x f -x s | is the distance the robot moves when completing a complete gait cycle, called the step length. h is the maximum vertical distance the robot's leg and foot leave the ground when completing a gait cycle, called the step height. s is the starting height of the robot foot, t is the movement time, T s is the gait period, x t is the step size function with respect to time t, z t is the step height function with respect to time t.

[0094] (3) The inverse kinematics equations of the quadruped crawling robot are solved by analytical methods. The angle values ​​of the hip joint, lateral swing joint and knee joint are inversely solved by the foot end coordinates of the quadruped crawling robot.

[0095] 1) Side swing joint rotation angle γ:

[0096]

[0097] Among them, (x, y) is the foot end coordinate of the quadruped crawling robot in the OXY plane of the foot end top view diagram.

[0098] Knee joint rotation angle β:

[0099]

[0100] Among them, hu is the distance between the hip joint and the knee joint, hl is the distance from the knee joint to the foot end, (x,z) is the foot end coordinates in the OZX plane of the side view diagram of the quadruped crawling robot, and h is the distance between the leg base and the hip joint.

[0101] Hip joint rotation angle α:

[0102]

[0103] Among them, hu is the distance between the hip joint and the knee joint, hl is the distance from the knee joint to the foot end, (x,z) is the foot end coordinates in the OZX plane of the side view diagram of the quadruped crawling robot, and h is the distance between the leg base and the hip joint.

[0104] (4) Design the Walk gait and Trot gait of the quadruped crawling robot.

[0105] 1) Walk gait is a static gait. A critical form is that at any time only three legs are in the support phase and one leg is in the swing phase. This Walk gait is the fastest among static gaits. In one movement cycle, the four legs of the quadruped crawling robot are lifted at the following times:

[0106] 2) Trot gait is a dynamic gait. The Trot gait is characterized by the movement of two diagonal legs in pairs. Ideally, the diagonal legs are lifted and landed at the same time. In one movement cycle, the lifting time of the four legs is

[0107] (5) Output the foot motion trajectory of the quadruped crawling robot during the Walk gait and Trot gait.

[0108] Simulation analysis:

[0109] Before planning the Walk and Trot gaits of the quadrupedal crawling robot, the present invention first presets the three-dimensional coordinates of the four foot ends of the quadrupedal crawling robot to (-0.11, 0, -0.3) to prepare for the subsequent continuous movement of the robot. The lifting moments of the four legs of the quadrupedal crawling robot in one movement cycle of the Walk gait are The lifting moments of the four legs of the quadruped crawling robot in one movement cycle of the Trot gait are Set the starting position x of the foot trajectory s =-0.11m, end point position x f =-0.21m, foot end starting height z s =-0.3m, leg lifting height h = 0.06m, the joint rotation angle corresponding to each moment of the quadruped crawling robot's leg swinging can be calculated by the inverse kinematics equation, then the quadruped crawling robot Walk gait motion process is as follows Fig. 9 The gait motion process of the quadruped crawling robot Trot is shown in Fig.10 As shown in the figure, from the visual effect, the quadruped crawling robot moves relatively smoothly during the simulation process and has strong adaptability to complex terrain.

[0110] The advantages of the present invention are as follows: (1) The present invention innovates the model of the quadruped crawling robot by setting the side swing joint of the left front leg of the robot to rotate 90 degrees counterclockwise, i.e., γ 左前 = -pi / 2, set the side swing joint of the right front leg to rotate 90 degrees clockwise, γ 右前 =pi / 2, set the side swing joint of the left hind leg to rotate 90 degrees clockwise, γ 左后 =pi / 2, set the side swing joint of the right hind leg to rotate 90 degrees counterclockwise, γ 右后 =-pi / 2. The quadruped robot can achieve a 90-degree turn to the left, improving the robot's motion efficiency when turning. (2) The present invention uses an analytical method to perform inverse kinematics analysis on the quadruped crawling robot. The analytical method is fast and accurate. Although it has the disadvantage of weak applicability, it is more suitable for the specific leg structure of the quadruped crawling robot to perform inverse kinematics analysis using the analytical method.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A kinematic analysis and gait planning method for a spatial quadruped crawling robot based on foot end trajectory, characterized in that: The method comprises the following steps: S1. Modeling a quadruped crawling robot and defining geometric parameters; the quadruped crawling robot is a full-elbow robot, including a trunk and four leg structures; S2. Analyze the mathematical expression of the cycloid, design the motion trajectory of the cycloid, and obtain the motion path of the foot end of the quadruped robot; S3, using analytical method to perform inverse kinematics analysis on the foot end coordinates of the quadruped crawling robot, inversely solving the angle value of each joint, which is used to control the motor of each joint to reach the desired position; S4, analyzing the Walk gait and Trot gait of the quadruped crawling robot to obtain gait control parameters; S5. Output the foot end motion trajectory of the quadruped crawling robot to control the quadruped crawling robot to move along the trajectory in the Walk gait and the Trot gait.

2. The method for kinematic analysis and gait planning of a quadruped crawling robot based on foot end trajectory according to claim 1 is characterized in that: The geometric parameters include the body length and width of the quadruped crawling robot, the hip joint link length h, the thigh length hu, the calf length hl, the hip joint angle α, the side swing joint angle γ and the knee joint angle β.

3. The method for kinematic analysis and gait planning of a quadruped crawling robot based on foot end trajectory according to claim 1, characterized in that: The motion trajectory of the foot end of the quadruped crawling robot is a cycloid, which is defined as the trajectory formed by a certain point on the boundary of a circle when a circle moves along a straight line. The mathematical formula is as follows: Among them, x s is the starting position of the quadruped crawling robot, x f is the end position, |x f -x s | is the distance the robot moves when completing a complete gait cycle, called the step length; h is the maximum vertical distance the robot's leg and foot leave the ground when completing a gait cycle, called the step height; z s is the starting height of the robot foot, t is the movement time, T s is the gait period, x t is the step size function with respect to time t, z t is the step height function with respect to time t, and σ is the accumulated radians.

4. The method for kinematic analysis and gait planning of a quadruped crawling robot based on foot end trajectory according to claim 1 is characterized in that: The inverse kinematics analysis is to inversely solve the angle value of each joint through the robot foot end coordinate, and the angle value of each joint includes the side swing joint rotation angle γ, the knee joint rotation angle β and the hip joint rotation angle α.

5. The method for kinematic analysis and gait planning of a quadruped crawling robot based on foot end trajectory according to claim 4 is characterized in that: The solution formula is summarized as follows: Among them, (x, y) is the foot end coordinate in the OXY plane of the quadruped crawling robot's foot end top view diagram, hu is the distance between the hip joint and the knee joint, hl is the distance from the knee joint to the foot end, (x, z) is the foot end coordinate in the OZX plane of the quadruped crawling robot's side view diagram, and h is the distance between the leg base and the hip joint.

6. The method for kinematic analysis and gait planning of a quadruped crawling robot based on foot end trajectory according to claim 1, characterized in that: The Walk gait and Trot gait of the quadruped crawling robot are designed, including the following steps: 1) Define the basic parameters of the robot's gait; 2) In the Walk gait, at any time, only three legs are in the support phase and one leg is in the swing phase; in one movement cycle, the four legs of the quadruped crawling robot are lifted at the following times: The fastest movement speed; 3) In the Trot gait, two diagonal legs move in pairs. Ideally, the diagonal legs are lifted and landed at the same time. In one movement cycle, the lifting time of the four legs is The fastest movement speed.

7. The kinematic analysis and gait planning system of a quadruped crawling robot based on foot end trajectory according to claim 1 is characterized in that: A quadruped crawling robot body and a controller arranged thereon; The quadruped crawling robot body is a full elbow robot, including a trunk and four leg structures; each leg structure includes a hip joint and a hip joint connecting rod, a side swing joint and a thigh, a knee joint and a calf; and each joint is provided with a joint motor; The controller stores a program, and when the program is loaded and executed, the method steps described in any one of claims 1 to 6 are calculated to calculate the angles and gait parameters of each joint, control the motors of each joint to drive the connecting rod structures of the body, and walk according to the target foot trajectory and planned gait.

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