Tree climbing control method based on snake robot

Abstract

The application discloses a tree climbing control method based on a snake-shaped robot, the snake-shaped robot comprising a snake head structure and a snake body structure; static winding of the snake-shaped robot is divided into three parts; an upper layer winding part; a middle layer driving part; a lower layer winding part; climbing of the snake-shaped robot is divided into six groups of action instructions, the six groups of action instructions are executed in sequence, and climbing of a natural tree can be realized; the snake-shaped robot is used for climbing the natural tree by using a new algorithm, and adaptability of the snake-shaped robot in a three-dimensional environment is strengthened.

Description

Technical Field

[0001] This invention relates to the field of biomimetic robot control, specifically to a tree-climbing control method based on a snake-like robot. Background Technology

[0002] As is well known, snakes have degenerated limbs and move using their bones and scales. When a snake moves forward, its ribs pull on muscles, which in turn cause the scales to stand upright or lie horizontally. It then uses the friction between its belly and the ground to glide forward. Due to the unique body structure and distinctive locomotion of snakes, research into them in the field of bionic robotics has become increasingly in-depth and widespread. Bionic snakes can be applied to rescue and exploration fields to replace humans in venturing into hard-to-reach locations.

[0003] Current research on snake-like robots largely focuses on gait studies in a two-dimensional plane, such as forward gait, obstacle avoidance, and obstacle crossing. Research on gait control in three-dimensional space is scarce. In complex and variable terrains, such as earthquake or fire scenes, snake-like robots cannot navigate freely using only two-dimensional pose and gait. Therefore, conducting research on the pose and gait of snake-like robots in three-dimensional space has significant practical implications.

[0004] Focusing on the climbing ability of snake robots, this study found that most existing examples extract key points from natural trees, simplifying irregular natural trees into regular cylindrical objects, and enabling snake robots to climb through fitted control functions. Summary of the Invention

[0005] Focusing on the climbing ability of snake-like robots, and targeting rescue and exploration environments, the complex and ever-changing three-dimensional environment was simplified. Natural trees were selected for research, enabling snake-like robots to climb natural trees and enhancing their adaptability in three-dimensional environments.

[0006] A tree-climbing control method based on a snake-like robot, wherein the snake-like robot includes a snake head structure and a snake body structure;

[0007] The snake head structure includes a rear-mounted unit joint drive servo, a three-dimensional angle sensor and an OpenMV drive servo, a snake head shell, an OpenMV, and a first U-shaped frame;

[0008] The OpenMV drive servo is fixedly connected inside the snake head shell, and the OpenMV drive servo rotor extends out of the snake head shell and is fixedly connected to the three-dimensional angle sensor and OpenMV via a mounting plate. The rear unit joint drive servo is fixedly connected inside the snake head shell, and the first U-shaped frame is fixedly connected to the rotating shaft of the snake head drive servo. The OpenMV drive servo is responsible for the movement of the three-dimensional angle sensor and OpenMV on the roll axis.

[0009] The snake-body structure includes i unit joints (i=14). Each unit joint includes a front unit joint drive servo and a rear unit joint drive servo, which are installed inside the unit joint housing in an orthogonal connection manner. A second U-shaped frame and a third U-shaped frame are fixedly connected to the rotating shafts of the front unit joint drive servo and the rear unit joint drive servo, respectively. A connecting block is fixedly connected to the third U-shaped frame. The second U-shaped frame on the first unit joint is fixedly connected to the first U-shaped frame in an orthogonal connection manner. The connecting block on the i-th (i=1, 2, ..., 13) unit joint is fixedly connected to the second U-shaped frame on the adjacent (i+1)-th (i=1, 2, ..., 13) unit joint.

[0010] Multiple pressure sensors are connected to the outer wall of each connecting block;

[0011] The front unit joint drives the servo motor (i = 1, 2, ..., 14) to move around the pitch axis for vertical drive, and the rear unit joint drives the servo motor to move around the yaw axis for horizontal drive; the unit joint length l of the snake body structure is 158mm and the width q is 48mm.

[0012] The specific method by which the snake-like robot climbs a natural tree is as follows:

[0013] The tree trunk radius *r* is detected using OpenMV. A parameter *b* is defined, where the value of *b* has an inverse linear relationship with the radius *r*. 2πb represents the vertical distance the snake robot travels around the tree in one revolution.

[0014] The number of unit joints, loop_number, required for a robot to orbit a tree once satisfies the following formula:

[0015]

[0016] The horizontally moving rear drive servo is responsible for hugging the tree, while the vertically moving front drive servo is responsible for generating the offset angle, so that the static pose of the snake robot can fit the cylindrical helix.

[0017] The parametric equation of the cylindrical helix is ​​as follows:

[0018]

[0019] The rotation angles (level_angle) of the rear-drive servo motors are all equal, satisfying the following formula:

[0020]

[0021] The vertical angle of each front-drive servo is different for different unit joints;

[0022] Define intermediate variables

[0023] When the number of unit joints (loop_number) around the tree is 6, the vertical angle of the front-drive servo motor satisfies:

[0024]

[0025]

[0026] vertical_angle3 = 0

[0027]

[0028]

[0029] vertical_angle1 represents the angle of rotation of the first front-drive servo motor;

[0030] vertical_angle2 represents the angle of the second front drive servo, vertical_angle3 represents the angle of the third front drive servo, vertical_angle4 represents the angle of the fourth front drive servo, and vertical_angle5 represents the angle of the fifth front drive servo.

[0031] The static winding of the snake-like robot is divided into three parts;

[0032] Upper surround section; middle drive section; lower surround section;

[0033] In the upper surrounding section, the number of participating unit joints is 6. When each unit joint in the upper surrounding section wraps around the natural tree using the aforementioned tree-wrapping method, its rear-mounted drive servos gradually increase the turning angle and pressure using the same coefficient of variation. The main controller continuously reads back the values ​​of each pressure sensor. When the values ​​of all pressure sensors that have detected pressure are within F... N1 and F N2 Between these moments, the rear-mounted drive servo stops rotating, at which point the upper part of the snake robot completes its encirclement of the natural tree.

[0034] The middle layer drive section involves two unit joints. During static winding, the angle changes of the front drive servo and rear drive servo of the unit joint in the middle layer drive section are the same as those of the front drive servo and rear drive servo in the upper layer surround section.

[0035] The lower wrapping section involves 6 unit joints. During static wrapping, the angle changes of the front and rear drive servos of the unit joints in the lower wrapping section are the same as those in the upper wrapping section, enabling the snake robot to interact with natural trees. The static winding of the week;

[0036] The snake-like robot's climbing action is divided into 6 sets of commands, which are executed sequentially to enable it to climb a section of a natural tree.

[0037] Action command 1 is to relieve the force of the upper surrounding part. The angle of the rear drive servo of the upper surrounding part gradually decreases from the static winding state with the same change coefficient. The main controller reads back the value of each pressure sensor of the upper surrounding part in real time. When the value becomes 0, the upper surrounding part is in contact with the natural tree trunk. The angle of the rear drive servo continues to decrease, so that the upper surrounding part and the natural tree trunk are in a larger gap. Then, action command 2 is executed.

[0038] Action command 2 straightens the middle drive section, and the front and rear drive servos of the middle drive section change from a static winding state to vertical upward, causing the upper ring section to rise. During this process, only the friction generated by the lower ring section resists gravity, and action command 3 is executed.

[0039] Action command 3 is to reduce the force on the upper surrounding section. The unit joints of the upper surrounding section surround the natural tree using the above-described tree-wrapping method. If the pressure sensor values ​​of the upper surrounding section are all detected to be within F during the wrapping process... N1 and F N2 Between these points, the rear-mounted drive servo stopped rotating, indicating that the actual natural tree trunk is thicker than the ideal trunk. If no pressure sensor readings were detected in the upper surrounding section during the circling process, and all readings were within F... N1 and F N2 The information provided indicates that the actual natural tree trunk is thinner than the ideal tree trunk. The rear-mounted drive servos gradually increase the turning angle and pressure using the same coefficient of variation. The main controller reads back the values ​​of each pressure sensor in real time. When all pressure sensor values ​​detect pressure are within F... N1 and F N2 In between, the rear drive servo stops rotating and executes action command 4;

[0040] Action command 4 is to relieve the force of the lower surrounding part. The angle of the rear drive servo of the lower surrounding part gradually decreases from the static winding state with the same change coefficient. The main controller reads back the value of each pressure sensor of the lower surrounding part in real time. When the value becomes 0, the lower surrounding part is in contact with the natural tree trunk. The angle of the rear drive servo continues to decrease, so that the lower surrounding part and the natural tree trunk are in a larger gap. Then, action command 5 is executed.

[0041] Action command 5 is the action command for the middle layer drive section to retract, and the front drive servo and rear drive servo of the middle layer drive section to return to static winding. During this process, only the friction force generated by the upper layer winding section resists gravity and executes action command 6.

[0042] Action command 6 is to reduce the force of the lower surrounding section. The unit joints of the lower surrounding section surround the natural tree using the above-described tree-wrapping method. If the pressure sensor values ​​of the lower surrounding section are all detected to be within F during the wrapping process... N1 and F N2 Between these points, the rear-mounted drive servo stopped rotating, indicating that the actual natural tree trunk is thicker than the ideal trunk. If no pressure sensor readings were detected in the lower surrounding section during the circling process, and all readings were within F... N1 and F N2 The information provided indicates that the actual natural tree trunk is thinner than the ideal tree trunk. The rear-mounted drive servos gradually increase the turning angle and pressure using the same coefficient of variation. The main controller reads back the values ​​of each pressure sensor in real time. When all pressure sensor values ​​detect pressure are within F... N1 and F N2 Between these points, the rear-mounted drive servo stops rotating.

[0043] The beneficial effects of this invention are:

[0044] A new algorithm was adopted to enable snake robots to climb natural trees, which enhanced the adaptability of snake robots in three-dimensional environments. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the overall structure of the snake-like robot;

[0046] Figure 2 This is a side view and a side unfolded view of a cylindrical helix.

[0047] Figure 3 A flowchart illustrating a snake-like robot climbing a natural tree;

[0048] Figure 4 A schematic diagram of the formula for vertical angle when loop_number = 6;

[0049] Figure 5 A schematic diagram of a snake-like robot climbing a natural tree; Detailed Implementation

[0050] Referring to the accompanying drawings, a tree-climbing control method based on a snake-like robot is provided. The snake-like robot includes a snake head structure and a snake body structure. The structure of the snake-like robot is a known structure in the prior art. This invention only briefly describes the structure here. This invention does not change the structure of the snake-like robot, but only proposes a new tree-climbing method.

[0051] The snake head structure includes a rear-mounted unit joint drive servo, a three-dimensional angle sensor and an OpenMV drive servo, a snake head shell, an OpenMV, and a first U-shaped frame;

[0052] The OpenMV drive servo is fixedly connected inside the snake head shell, and the OpenMV drive servo rotor extends out of the snake head shell and is fixedly connected to the three-dimensional angle sensor and OpenMV via a mounting plate. The rear unit joint drive servo is fixedly connected inside the snake head shell, and the first U-shaped frame is fixedly connected to the rotating shaft of the snake head drive servo. The OpenMV drive servo is responsible for the movement of the three-dimensional angle sensor and OpenMV on the roll axis.

[0053] The snake-body structure includes i unit joints (i=14). Each unit joint includes a front unit joint drive servo and a rear unit joint drive servo, which are installed inside the unit joint housing in an orthogonal connection manner. A second U-shaped frame and a third U-shaped frame are fixedly connected to the rotating shafts of the front unit joint drive servo and the rear unit joint drive servo, respectively. A connecting block is fixedly connected to the third U-shaped frame. The second U-shaped frame on the first unit joint is fixedly connected to the first U-shaped frame in an orthogonal connection manner. The connecting block on the i-th (i=1, 2, ..., 13) unit joint is fixedly connected to the second U-shaped frame on the adjacent (i+1)-th (i=1, 2, ..., 13) unit joint.

[0054] Multiple pressure sensors are connected to the outer wall of each connecting block;

[0055] The front unit joint drives the servo motor (i = 1, 2, ..., 14) to move around the pitch axis for vertical drive, and the rear unit joint drives the servo motor to move around the yaw axis for horizontal drive; the unit joint length l of the snake body structure is 158mm and the width q is 48mm.

[0056] The specific method by which the snake-like robot climbs a natural tree is as follows:

[0057] The tree trunk radius r is detected using OpenMV. A parameter b is defined, and the value of b has an inverse linear relationship with the radius r. 2πb represents the vertical distance of the snake robot's rotation around the tree. The number of unit joints, loop_number, of the snake robot in one rotation around the tree satisfies the following formula:

[0058]

[0059] The unit joint length *l* of the snake robot is 158 mm, while the maximum diameter of a common natural tree is approximately 300 mm. Six unit joints are sufficient to circle the tree once, so the value of *loop_number* (the number of unit joints required for one loop) ranges from 3 to 6. This article uses a *loop_number* of 6 as an example.

[0060] The horizontally moving rear drive servo is responsible for hugging the tree, while the vertically moving front drive servo is responsible for generating the offset angle, so that the static pose of the snake robot can fit the cylindrical helix.

[0061] The parametric equation of the cylindrical helix is ​​as follows:

[0062]

[0063] The rotation angles (level_angle) of the rear-drive servo motors are all equal, satisfying the following formula:

[0064]

[0065] The vertical angle of each front-drive servo is different for different unit joints;

[0066] Define intermediate variables

[0067] When the number of unit joints (loop_number) around the tree is 6, the vertical angle of the front-drive servo motor satisfies:

[0068]

[0069]

[0070] vertical_angle3 = 0

[0071]

[0072]

[0073] vertical_angle1 represents the angle of rotation of the first front-drive servo motor;

[0074] vertical_angle2 represents the angle of the second front-drive servo, vertical_angle3 represents the angle of the third front-drive servo, vertical_angle4 represents the angle of the fourth front-drive servo, and vertical_angle5 represents the angle of the fifth front-drive servo.

[0075] Figure 4 A schematic diagram of the formula for the vertical angle of the front drive servo motor when the number of unit joints loop_number = 6 for one revolution around the tree.

[0076] Using the above formula, the rotation angles of the front and rear drive servos of each unit joint when the snake robot circles the tree can be obtained, thus achieving the fit between the snake robot and the natural tree trunk. At this time, no pressure is generated that would prevent the snake robot from overcoming its own weight.

[0077] The critical pressure F can be calculated from the total mass of the snake-like robot and the coefficient of friction. N1 The ultimate pressure F can be obtained from the maximum torque value when the servo motor is stalled. N2 ;

[0078] The static winding of the snake-like robot is divided into three parts;

[0079] Upper surround section; middle drive section; lower surround section;

[0080] In the upper surrounding section, the number of participating unit joints is 6. When each unit joint in the upper surrounding section wraps around the natural tree using the aforementioned tree-wrapping method, its rear-mounted drive servos gradually increase the turning angle and pressure using the same coefficient of variation. The main controller continuously reads back the values ​​of each pressure sensor. When the values ​​of all pressure sensors that have detected pressure are within F... N1 and F N2 Between these moments, the servo motors stop rotating, at which point the upper part of the snake robot completes its encirclement of the natural tree.

[0081] The middle layer drive section involves two unit joints. During static winding, the angle changes of the front drive servo and rear drive servo of the unit joint in the middle layer drive section are the same as those of the front drive servo and rear drive servo in the upper layer surround section.

[0082] The lower wrapping section involves 6 unit joints. During static wrapping, the angle changes of the front and rear drive servos of the unit joints in the lower wrapping section are the same as those in the upper wrapping section, enabling the snake robot to interact with natural trees. The static winding of the week.

[0083] The snake-like robot consists of 6 sets of action commands, namely gait movements. The 6 sets of action commands are executed in sequence, enabling it to climb a section of a natural tree.

[0084] Action command 1 is to relieve the force of the upper surrounding part. The angle of the rear drive servo of the upper surrounding part gradually decreases from the static winding state with the same change coefficient. The main controller reads back the value of each pressure sensor of the upper surrounding part in real time. When the value becomes 0, the upper surrounding part is in contact with the natural tree trunk. The angle of the rear drive servo continues to decrease, so that the upper surrounding part and the natural tree trunk are in a larger gap. Then, action command 2 is executed.

[0085] Action command 2 straightens the middle drive section, and the front and rear drive servos of the middle drive section change from a static winding state to vertical upward, causing the upper ring section to rise. During this process, only the friction generated by the lower ring section resists gravity, and action command 3 is executed.

[0086] Action command 3 is to reduce the force on the upper surrounding section. The unit joints of the upper surrounding section surround the natural tree using the above-described tree-wrapping method. If the pressure sensor values ​​of the upper surrounding section are all detected to be within F during the wrapping process... N1 and F N2 Between these points, the rear-mounted drive servo stopped rotating, indicating that the actual natural tree trunk is thicker than the ideal trunk. If no pressure sensor readings were detected in the upper surrounding section during the circling process, and all readings were within F... N1 and F N2 The information provided indicates that the actual natural tree trunk is thinner than the ideal tree trunk. The rear-mounted drive servos gradually increase the turning angle and pressure using the same coefficient of variation. The main controller reads back the values ​​of each pressure sensor in real time. When all pressure sensor values ​​detect pressure are within F... N1 and F N2 In between, the rear drive servo stops rotating and executes action command 4;

[0087] Action command 4 is to relieve the force of the lower surrounding part. The angle of the rear drive servo of the lower surrounding part gradually decreases from the static winding state with the same change coefficient. The main controller reads back the value of each pressure sensor of the lower surrounding part in real time. When the value becomes 0, the lower surrounding part is in contact with the natural tree trunk. The angle of the rear drive servo continues to decrease, so that the lower surrounding part and the natural tree trunk are in a larger gap. Then, action command 5 is executed.

[0088] Action command 5 is the action command for the middle layer drive section to retract, and the front drive servo and rear drive servo of the middle layer drive section to return to static winding. During this process, only the friction force generated by the upper layer winding section resists gravity and executes action command 6.

[0089] Action command 6 is to reduce the force of the lower surrounding section. The unit joints of the lower surrounding section surround the natural tree using the above-described tree-wrapping method. If the pressure sensor values ​​of the lower surrounding section are all detected to be within F during the wrapping process... N1 and F N2 Between these points, the rear-mounted drive servo stopped rotating, indicating that the actual natural tree trunk is thicker than the ideal trunk. If no pressure sensor readings were detected in the lower surrounding section during the circling process, and all readings were within F... N1 and F N2The information provided indicates that the actual natural tree trunk is thinner than the ideal tree trunk. The rear-mounted drive servos gradually increase the turning angle and pressure using the same coefficient of variation. The main controller reads back the values ​​of each pressure sensor in real time. When all pressure sensor values ​​detect pressure are within F... N1 and F N2 Between these points, the rear-mounted drive servo stops rotating.

[0090] By executing six sets of action commands sequentially, the snake-like robot climbs a section of a natural tree. By repeating these six sets of commands, it can climb the entire natural tree. If action commands 4, 2, 6, 1, 5, and 3 are executed sequentially, the snake-like robot will climb downwards.

[0091] Figure 3 This is a side view and a unfolded view of a cylindrical helix. The unfolded view of the cylindrical helix has a slope of... The straight line represents the snake robot, while the side view of the snake robot is a centrally symmetrical, approximately inverted S-shaped image.

Claims

1. A tree-climbing control method based on a snake-like robot, wherein the snake-like robot includes a snake head structure and a snake body structure; The snake head structure includes a rear-mounted unit joint drive servo, a three-dimensional angle sensor and an OpenMV drive servo, a snake head shell, an OpenMV, and a first U-shaped frame; The OpenMV drive servo is fixedly connected inside the snake head shell, and the OpenMV drive servo rotor extends out of the snake head shell and is fixedly connected to the three-dimensional angle sensor and OpenMV via a mounting plate. The rear unit joint drive servo is fixedly connected inside the snake head shell, and the first U-shaped frame is fixedly connected to the rotating shaft of the snake head drive servo. The OpenMV drive servo is responsible for the movement of the three-dimensional angle sensor and OpenMV on the roll axis. The snake-body structure includes i unit joints (i=14). Each unit joint includes a front unit joint drive servo and a rear unit joint drive servo, which are installed inside the unit joint housing in an orthogonal connection manner. A second U-shaped frame and a third U-shaped frame are fixedly connected to the rotating shafts of the front unit joint drive servo and the rear unit joint drive servo, respectively. A connecting block is fixedly connected to the third U-shaped frame. The second U-shaped frame on the first unit joint is fixedly connected to the first U-shaped frame in an orthogonal connection manner. The connecting block on the i-th (i=1, 2, ..., 13) unit joint is fixedly connected to the second U-shaped frame on the adjacent (i+1)-th (i=1, 2, ..., 13) unit joint. Multiple pressure sensors are connected to the outer wall of each connecting block; The front unit joint drives the servo motor (i = 1, 2, ..., 14) to move around the pitch axis for vertical drive, while the rear unit joint drives the servo motor around the yaw axis for horizontal drive. Its features are: The specific method for the snake-like robot to climb natural trees is as follows: The tree trunk radius *r* is detected using OpenMV. A parameter *b* is defined, where the value of *b* has an inverse linear relationship with the radius *r*. 2πb represents the vertical distance the snake robot makes while circling the tree. The number of joints per unit length *loop_number* for the snake robot to circle the tree in one revolution satisfies the following formula: The horizontally moving rear drive servo is responsible for hugging the tree, while the vertically moving front drive servo is responsible for generating the offset angle, so that the static pose of the snake robot can fit the cylindrical helix. The parametric equation of the cylindrical helix is ​​as follows: The rotation angle (level_angle) of the rear-drive servo motors are all equal, satisfying the following formula: The vertical angle of each front-drive servo is different for different unit joints; Define intermediate variables When the number of unit joints lop_number around the tree is 6, the vertical_angle of the front drive servo motor satisfies: vertical_angle3 = 0 vertical_angle1 represents the angle of rotation of the first front-drive servo motor; vertical_angle2 represents the angle of rotation of the second front-drive servo motor; vertical_angle3 represents the angle of rotation of the third front-drive servo motor; vertical_angle4 represents the angle of rotation of the fourth front-drive servo motor; vertical_angle5 represents the angle of the fifth front-drive servo motor; The static winding of the snake-like robot is divided into three parts; Upper surround section; middle drive section; lower surround section; In the upper surrounding section, the number of participating unit joints is 6. When each unit joint in the upper surrounding section wraps around the natural tree using the aforementioned tree-wrapping method, its rear-mounted drive servos gradually increase the turning angle and pressure using the same coefficient of variation. The main controller continuously reads back the values ​​of each pressure sensor. When the values ​​of all pressure sensors that have detected pressure are within F... N1 and F N2 Between these moments, the rear-mounted drive servo stops rotating, at which point the upper part of the snake robot completes its encirclement of the natural tree; The middle layer drive section involves two unit joints. During static winding, the angle changes of the front drive servo and rear drive servo of the unit joint in the middle layer drive section are the same as those of the front drive servo and rear drive servo in the upper layer surround section. The lower wrapping section involves 6 unit joints. During static wrapping, the angle changes of the front and rear drive servos of the unit joints in the lower wrapping section are the same as those in the upper wrapping section, enabling the snake robot to interact with natural trees. The static winding of the week; The snake-like robot's climbing action is divided into 6 sets of commands, which are executed sequentially to enable it to climb a section of a natural tree. Action command 1 is to relieve the force of the upper surrounding part. The angle of the rear drive servo of the upper surrounding part gradually decreases from the static winding state with the same change coefficient. The main controller reads back the value of each pressure sensor of the upper surrounding part in real time. When the value becomes 0, the upper surrounding part is in contact with the natural tree trunk. The angle of the rear drive servo continues to decrease, so that the upper surrounding part and the natural tree trunk are in a larger gap. Then, action command 2 is executed. Action command 2 straightens the middle drive section, and the front and rear drive servos of the middle drive section change from a static winding state to vertical upward, causing the upper ring section to rise. During this process, only the friction generated by the lower ring section resists gravity, and action command 3 is executed. Action command 3 is to reduce the force on the upper surrounding section. The unit joints of the upper surrounding section surround the natural tree using the above-described tree-wrapping method. If the pressure sensor values ​​of the upper surrounding section are all detected to be within F during the wrapping process... N1 and F N2 Between these points, the rear-mounted drive servo stopped rotating, indicating that the actual natural tree trunk is thicker than the ideal trunk. If no pressure sensor readings were detected in the upper surrounding section during the circling process, and all readings were within F... N1 and F N2 The information provided indicates that the actual natural tree trunk is thinner than the ideal tree trunk. The rear-mounted drive servos gradually increase the turning angle and pressure using the same coefficient of variation. The main controller reads back the values ​​of each pressure sensor in real time. When all pressure sensor values ​​detect pressure are within F... N1 and F N2 In between, the rear drive servo stops rotating and executes action command 4; Action command 4 is to relieve the force of the lower surrounding part. The angle of the rear drive servo of the lower surrounding part gradually decreases from the static winding state with the same change coefficient. The main controller reads back the value of each pressure sensor of the lower surrounding part in real time. When the value becomes 0, the lower surrounding part is in contact with the natural tree trunk. The angle of the rear drive servo continues to decrease, so that the lower surrounding part and the natural tree trunk are in a larger gap. Then, action command 5 is executed. Action command 5 is the action command for the middle layer drive section to retract, and the front drive servo and rear drive servo of the middle layer drive section to return to static winding. During this process, only the friction force generated by the upper layer winding section resists gravity and executes action command 6. Action command 6 is to reduce the force of the lower surrounding section. The unit joints of the lower surrounding section surround the natural tree using the above-described tree-wrapping method. If the pressure sensor values ​​of the lower surrounding section are all detected to be within F during the wrapping process... N1 and F N2 Between these points, the rear-mounted drive servo stopped rotating, indicating that the actual natural tree trunk is thicker than the ideal trunk. If no pressure sensor readings were detected in the lower surrounding section during the circling process, and all readings were within F... N1 and F N2 The information provided indicates that the actual natural tree trunk is thinner than the ideal tree trunk. The rear-mounted drive servos gradually increase the turning angle and pressure using the same coefficient of variation. The main controller reads back the values ​​of each pressure sensor in real time. When all pressure sensor values ​​detect pressure are within F... N1 and F N2 Between these points, the rear-mounted drive servo stops rotating.

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