Propulsive force actuated spherical tensioning robot and working method and control method thereof

Abstract

The propelling force-actuated spherical tensioning robot comprises supporting rods and inhaul cables, every two of the six supporting rods form a group, the two supporting rods in the first group are longitudinally arranged at intervals, and the two supporting rods in the second group are located on the two sides of the two supporting rods in the first group correspondingly; the two supporting rods in the third group are located between the two supporting rods in the first group and located on the two sides of the two supporting rods in the second group, the end of each supporting rod is fixedly connected with four inhaul cables, and the other ends of the four inhaul cables are fixedly connected to the ends of the adjacent supporting rods in the other two groups respectively; connecting rods are installed between the two ends of the two supporting rods in each set, and propellers are installed on the connecting rods and used for pushing the spherical tensioning robot to move. The connecting rods are installed between the two ends of the two supporting rods in each set, the propellers are installed on the connecting rods, the spherical tensioning robot is pushed to move through the propellers, the structure is simple, and the complexity of a control system is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of water spherical tensioning robots, and in particular to a propulsion-actuated spherical tensioning robot and a working method and a control method thereof. Background Art

[0002] Although the current research on typical tensile spherical robots has made significant progress in physical structure design and motion performance optimization, there are still some technical bottlenecks that need to be broken through. First, the robot's motion mechanism mainly relies on structural deformation to achieve displacement, which not only increases the time consumption of the displacement process, but also affects the motion efficiency. Second, a large number of actuators are required to drive the coordinated deformation of the rod-cable structure, which greatly increases the complexity of the control system. More noteworthy is that the structural deformation during the movement process will inevitably change the internal space volume of the robot, which directly limits the room for improvement of the robot's load capacity. Therefore, researchers began to explore tensegrity spherical robots with different drive modes and functions.

[0003] In addition, since the robot uses a rolling motion, the driving motor needs to be switched according to the robot's posture. The solution of manually judging the motor driving has low movement efficiency and slow movement speed. Therefore, an algorithm is needed that can intelligently judge the driving motor and perform precise control to ensure that the robot can move continuously and efficiently. Summary of the Invention

[0004] In order to solve the current technical problems, the main purpose of the present invention is to provide a propulsion-actuated spherical tensioning robot and its working method and control method. The two support rods of each group are respectively installed with connecting rods between the two ends, and the connecting rods are installed with propellers. The spherical tensioning robot is pushed to move by the propeller. The structure is simple and the complexity of the control system is reduced.

[0005] In order to overcome the problems existing in the prior art, the technical solution adopted by the present invention is: a propulsion-actuated spherical tensioning robot, comprising support rods and cables, the six support rods forming a group of two, the two support rods of the first group being longitudinally spaced apart, the two support rods of the second group being located on both sides of the two support rods of the first group, the two support rods of the third group being located between the two support rods of the first group and also on both sides of the two support rods of the second group, each end of the support rod being fixed with four cables, the other ends of the four cables being fixed to the ends of the other two adjacent groups of support rods; a connecting rod is installed between the two support rods of each group, and a propeller is installed on the connecting rod, which is used to push the spherical tensioning robot to move.

[0006] The two support rods in each group are parallel and equidistant, and the support rods in each group are perpendicular to each other and arranged symmetrically.

[0007] An attitude angle sensor is installed at the center of the spherical tensioning robot.

[0008] A connecting plate is installed between two support rods of one group, and the attitude angle sensor is installed on the connecting plate.

[0009] A battery and a controller are installed on the connecting plate. The battery is electrically connected to the controller for power supply. The attitude angle sensor is electrically connected to the controller. The controller is electrically connected to the six thrusters respectively.

[0010] The propeller is a ducted fan propeller or a rotor propeller.

[0011] The working method of actuating a spherical tensioning robot using the propulsion force comprises the following steps: Step 1: When the spherical tensegrity robot is in an initial position, one of the three-point support domains of the tensegrity structure based on the icosahedron of the spherical tensegrity robot supports the ground; Step 2: When the spherical tensile robot is in a stable support state, after determining the direction of movement, select the propeller in the lowest position with the same direction to operate, so that the spherical tensile robot generates torque around one side of the ground to cause the spherical tensile robot to roll; Step 3: The spherical tensioning robot enters the next triangular support domain and remains stable.

[0012] A control method for actuating a spherical tensioning robot using the propulsion force comprises the following steps: Step 1: Establish the initial coordinate model of the spherical tensioning robot, set the length of the support rods and the spacing between the support rods, define the coordinates of the two ends of each support rod as the support points, and the coordinates of the thrusters; Step 2: Get the attitude angle sensor data and calculate the rotation matrix; Step 3: Based on the initial coordinates and the rotation matrix, use coordinate transformation to establish the representation of each thruster and support point in the base coordinate system; according to the coordinate transformation formula, each coordinate is expressed as: ; Where: is the rotation matrix, is the initial coordinate set, is the coordinate representation in the transformed coordinate system; Step 4: Determine the thruster that needs to be started based on the thruster coordinates and the drive instruction; Step 5: Determine the gait according to the coordinates of the support points and the propeller coordinates, and specify the driving force and driving time required for the gait; Step 6: Receive motion instructions, select different control strategies according to gait, and start the corresponding thrusters.

[0013] In step 2, the rotation matrix is calculated based on the quaternion, and the collected quaternion is expressed as: ; The formula for the quaternion transformation rotation matrix is: ; Where: represents the rotation matrix; Represents the scalar part of the quaternion; Represents the x-axis imaginary part corresponding to the quaternion; Indicates the y-axis imaginary part corresponding to the quaternion; Indicates the imaginary part of the z-axis corresponding to the quaternion.

[0014] In step 5, the driving force required for each gait is: In OO gait: ; During OC gait: ; In CO gait: ; Where: G represents the total weight of the robot.

[0015] The present invention has the following beneficial effects: 1. The propulsion-actuated spherical tensioning robot proposed in the present invention has connecting rods installed between the two ends of each group of two support rods, and propellers installed on the connecting rods. The spherical tensioning robot is pushed to move by the propellers. The robot achieves a unity of simplicity and reliability in structural design. Its unique configuration features are mainly reflected in the following aspects: the structure is symmetrical and has excellent omnidirectional motion performance; the number of propellers is small and located inside the robot, the motion process is simple and stable, and the complexity of the control system is reduced.

[0016] 2. The robot innovatively employs a dynamic induction drive principle, precisely regulating the distribution of driving force to achieve a controlled shift in the system's center of mass, thereby stimulating motion. This differs from the drive principle of traditional tensile robots, resulting in two key advantages: first, the robot requires no deformation for motion, resulting in higher efficiency and greater stability; second, its unique spatial architecture design preserves more usable internal volume while ensuring optimal motion performance.

[0017] 3. The unique icosahedral configuration of the tensegrity structure of the present invention enables the robot to have good impact resistance, support and movement performance.

[0018] 4. The present invention realizes the accurate gait judgment of the robot configuration. Based on the present invention, the robot motor can be accurately driven and controlled. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 Schematic diagram of the structure of the propulsion-actuated spherical tensioning robot of the present invention Figure 2 Schematic diagram of the modeling and propeller coordinate setting of the propulsion-actuated spherical tensegrity robot of the present invention.

[0021] Figure 3 This is a diagram showing the rolling working principle of the propulsion-actuated spherical tensegrity robot of the present invention.

[0022] Figure 4 This is a gait control flow chart of the propulsion-actuated spherical tensegrity robot of the present invention.

[0023] Figure 5 OO gait force control analysis diagram of the propulsion-actuated spherical tensegrity robot of the present invention.

[0024] Reference numerals: Support rod 10 , cable 20 , connecting rod 30 , propeller 40 , connecting plate 50 , attitude angle sensor 60 . DETAILED DESCRIPTION

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0026] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0027] Example 1: See also Figure 1The present embodiment provides a propulsion-actuated spherical tensioning robot, comprising support rods 10 and cables 20, wherein the six support rods 10 are grouped in pairs, the two support rods 10 of the first group are longitudinally spaced apart, the two support rods 10 of the second group are respectively located on both sides of the two support rods 10 of the first group, the two support rods 10 of the third group are located between the two support rods 10 of the first group, and are also located on both sides of the two support rods 10 of the second group, each end of each support rod 10 is fixedly connected to four cables 20, and the other ends of the four cables 20 are respectively fixedly connected to the ends of the other two adjacent groups of support rods 10; the two support rods 10 of each group are respectively installed with a connecting rod 30 between the two ends, and a propeller 40 is installed on the connecting rod 30, and the propeller 40 is used to push the spherical tensioning robot to move.

[0028] Connecting rods are respectively installed between the two ends of each group of two support rods, and propellers are installed on the connecting rods. The spherical tensioning robot is pushed to move by the propellers, which has a simple structure and reduces the complexity of the control system.

[0029] Specifically, the propulsion-actuated spherical tensegrity robot utilizes a six-bar spherical tensegrity structure, consisting of six rigid support rods 10 and 24 flexible cables 20. The rigid rods are arranged in three groups, each perpendicular and symmetrically arranged. Within each group, two support rods 10 are parallel and equidistant. Each support rod 10 is connected to four cables 20 at each end, forming a self-stressed, self-balancing spatial icosahedron structure.

[0030] The exterior of the propulsion-actuated spherical tension robot is composed of twenty triangles formed by the ends of each support rod 10, and its contact plane depends on these stable triangular planes. These twenty triangles are divided into two different types of triangles. One is an equilateral triangle surrounded by three cables 20, called a closed triangle; the other is an isosceles triangle formed by two cables 20, called an open triangle. The movement process of the propulsion-actuated spherical tension robot is the process of continuous conversion of triangles in contact with the ground. The conversion from one triangle to another is regarded as the robot completing a gait conversion. Gait conversion can be performed when the robot structure and the two triangles are in contact with the ground. The propulsion-actuated spherical tension robot of the present invention provides a driving force for the robot to roll by installing a propeller 40 in the middle position of the two support rods 10.

[0031] In this embodiment, the two support rods 10 in each group are parallel and equidistant, and the support rods 10 in each group are perpendicular to each other and symmetrically arranged.

[0032] Furthermore, an attitude angle sensor 60 is installed at the center of the spherical tensioning robot to sense the posture of the spherical tensioning robot.

[0033] Specifically, a connecting plate 50 is installed between the two support rods 10 of one group, and the attitude angle sensor 60 is installed on the connecting plate 50 .

[0034] Furthermore, a battery and a controller are mounted on the connecting plate 50. The battery and the controller are electrically connected for power. The attitude angle sensor 60 is electrically connected to the controller, and the controller is electrically connected to each of the six thrusters 40. The battery provides power to the controller, attitude angle sensor 60, and thrusters 40.

[0035] In this embodiment, the propeller 40 is a ducted fan propeller or a rotor propeller.

[0036] Example 2: Based on Example 1, the present invention proposes a working method for actuating a spherical tensioning robot using the propulsion force, comprising the following steps: Step 1: When the spherical tensegrity robot is in an initial position, one of the three-point support domains of the tensegrity structure based on the icosahedron of the spherical tensegrity robot supports the ground.

[0037] The icosahedron-based tensegrity structure naturally forms a grounded supporting triangular facet, a specific geometric configuration that provides a stable static equilibrium state.

[0038] Step 2: When the spherical tensioning robot is in a stable support state, after determining the direction of movement, select the propeller 40 at the lowest position with the same direction to work, so that the spherical tensioning robot generates torque around one side of the ground to cause the spherical tensioning robot to roll.

[0039] Step 3: The spherical tensioning robot enters the next triangular support domain and remains stable.

[0040] For details, see Figure 2 ,Each roll of the spherical tensegrity robot is a bottom triangle transformation ,along one edge of the bottom triangle. Figure 2 The following is a schematic diagram of its three gait transitions. The relevant rod end nodes are numbered, where triangle 123 is the initial landing triangle of the robot. The following describes the basic principles of the three rolling gaits: OC Gait: The OC gait is when the robot initially lands on plane O and rolls toward plane C. Since plane O is an isosceles triangle, rolling around either side of the isosceles triangle constitutes an OC gait. When the robot is in a stable, stationary state with isosceles triangle 123 touching the ground, after determining the direction of motion, the thrusters (marked by the red arrows) operate to cause the robot to roll around side 23 until it lands on plane C of the equilateral triangle 234.

[0041] OO Gait: The OO gait involves rolling around the base of isosceles triangle 123. Therefore, the robot can only perform the OO gait in one direction when landing on the O-side of isosceles triangle 123. Once the robot is in a stable, stationary state with isosceles triangle 123 touching the ground, and after determining its direction of motion, the thrusters (marked by the red arrows) operate to roll around edge 23 until they land on the O-side of equilateral triangle 234.

[0042] CO Gait: The CO Gait involves rolling around any side of equilateral triangle 123. Therefore, the robot can perform the CO Gait in three directions when landing on the C-side of equilateral triangle 123. Once the robot is in a stable, stationary state with equilateral triangle 123 touching the ground, and after determining the direction of motion, the thrusters (marked by the red arrows) operate to roll around side 23 until landing on the O-side of isosceles triangle 234.

[0043] Example 3: Based on Example 1 or Example 2, the present invention further proposes a control method for actuating a spherical tensioning robot using the propulsion force, comprising the following steps: Step 1: Establish an initial coordinate model of the spherical tensioning robot, set the length of the support rods 10 and the spacing between the support rods 10 , define the coordinates of the two ends of each support rod 10 as support points, and the coordinates of the thruster 40 .

[0044] Step 2: Get the attitude angle sensor data and calculate the rotation matrix.

[0045] Specifically, the rotation matrix is calculated based on the quaternion, and the collected quaternion is expressed as: ; The formula for the quaternion transformation rotation matrix is: ; Where: represents the rotation matrix; Represents the scalar part of the quaternion; Represents the x-axis imaginary part corresponding to the quaternion; Indicates the y-axis imaginary part corresponding to the quaternion; Indicates the imaginary part of the z-axis corresponding to the quaternion.

[0046] Step 3: Based on the initial coordinates and the rotation matrix, coordinate transformation is used to establish the representation of each thruster 40 and support point in the base coordinate system.

[0047] Specifically, according to the coordinate conversion formula, each coordinate is expressed as: ; Where: is the rotation matrix, is the initial coordinate set, is the coordinate representation in the converted coordinate system.

[0048] Step 4: Determine the propeller 40 that needs to be started based on the coordinates of the propeller 40 and the driving instruction.

[0049] Specifically, under the action of the attitude angle sensor, the coordinates of the robot's propeller 40 and the coordinates of each endpoint are all in an absolute coordinate system with the north direction as the y-axis, the east direction as the x-axis, and the vertical direction as the z-axis. When the instruction is to the north direction, and because the propeller 40 is thrust-actuated, the robot will drive the propeller 40 with the smallest y coordinate and the smallest z coordinate. Similarly, when the instruction is to the south direction, the robot will drive the propeller 40 with the largest y coordinate and the smallest z coordinate. When the instruction is to the east direction, the robot will drive the propeller 40 with the smallest x coordinate and the smallest z coordinate. When the instruction is to the west direction, the robot will drive the propeller 40 with the largest x coordinate and the smallest z coordinate. In this way, the robot's movement along the absolute direction is achieved.

[0050] Step 5: Determine the gait according to the coordinates of the support point and the coordinates of the propeller 40, and specify the driving force and driving time required for the gait.

[0051] Specifically, first determine whether the landing triangle is an equilateral triangle based on the coordinates. If it is an equilateral triangle, then the landing triangle must then switch from an equilateral triangle to an isosceles triangle gait; if it is an isosceles triangle, then determine the next gait based on the positional relationship between the propeller 40 and the landing triangle. If the propeller 40 is located on the midline of the isosceles triangle, then according to the robot model, the next gait is to switch from an isosceles triangle to another isosceles triangle gait, that is, the 00 gait; otherwise, the next gait is to switch from an isosceles triangle to an equilateral triangle, that is, the OC gait.

[0052] Step 6: Receive motion instructions, select different control strategies according to gait, and start the corresponding propeller 40.

[0053] After obtaining the robot's driving gait, the next step is to conduct a theoretical analysis of each gait to obtain the precise driving force required for the robot's gait switching.

[0054] Take the "OO" gait conversion as an example: Figure 5 The force in the direction of the arrow shown in the figure is used to rotate the robot along the edge line so that it can land on triangle 124. Without considering the deformation of the tensegrity body, if the friction between the two grounding nodes 1 and 2 is large enough, assuming that they are fixed to the ground, the robot is a spherical entity, so the OO gait is the robot rotating around the edge line. According to the ideal parameters of the six-bar tensegrity structure, the robot rod spacing is set to half the rod length. If the rod spacing is , the rod length is , the total weight of the robot is G.

[0055] When the robot rotates, the driving force arm is the distance from the direction of the force to the triangular rolling edge of the robot's bottom, recorded as H; the resistance arm is the distance from the projection of the center of gravity on the ground to the rolling edge, with point O being the center of gravity of the robot. It can be calculated based on the characteristics of the six-bar structure: ； ； According to the torque balance condition, when When , the robot can perform rolling motion, and the magnitude of the driving force is obtained as: ; According to the same principle, the driving force of OC gait is: ; The calculation formula of CO gait is: .

[0056] The robot system proposed in this invention achieves the unity of simplicity and reliability in structural design. Its unique configuration features are mainly reflected in the following aspects: symmetrical structure, excellent omnidirectional motion performance; a small number of thrusters located inside the robot, simple and stable motion process, and can adapt to extreme environments and special tasks.

[0057] The robot innovatively employs a dynamic induction drive principle, precisely regulating the distribution of driving force to achieve a controlled shift in the system's center of mass, thereby stimulating motion. This differs from the drive principle of traditional tensile robots, resulting in two key advantages: First, the robot requires no deformation for motion, resulting in higher efficiency and greater stability; second, its unique spatial architecture design preserves more usable internal volume while ensuring optimal motion performance.

[0058] The unique icosahedral configuration of the tensegrity structure of the present invention enables the robot to have good impact resistance, support and movement performance.

[0059] The present invention realizes accurate gait judgment of the robot configuration. Based on the present invention, the robot motor can be accurately driven and controlled.

[0060] Although the specific embodiments of the present invention are described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and are not intended to limit the scope of the present invention. Any modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A propulsion-actuated spherical tensioning robot, comprising support rods (10) and cables (20), wherein six support rods (10) are arranged in groups of two, the two support rods (10) of the first group are longitudinally spaced apart, the two support rods (10) of the second group are respectively located on both sides of the two support rods (10) of the first group, the two support rods (10) of the third group are located between the two support rods (10) of the first group, and are also located on both sides of the two support rods (10) of the second group, each support rod (10) is fixedly connected to four cables (20) at its end, and the other ends of the four cables (20) are respectively fixedly connected to the ends of the other two groups of adjacent support rods (10); characterized in that: A connecting rod (30) is respectively installed between the two ends of each group of two support rods (10), and a propeller (40) is installed on the connecting rod (30). The propeller (40) is used to propel the spherical tensioning robot to move.

2. The propulsion-actuated spherical tensioning robot according to claim 1, characterized in that: The two support rods (10) in each group are parallel and equidistant, and the support rods (10) in each group are perpendicular to each other and arranged symmetrically.

3. The propulsion-actuated spherical tensioning robot according to claim 1 or 2, characterized in that: An attitude angle sensor (60) is installed at the center of the spherical tensioning robot.

4. The propulsion-actuated spherical tensioning robot according to claim 3, characterized in that: A connecting plate (50) is installed between two support rods (10) of one group, and an attitude angle sensor (60) is installed on the connecting plate (50).

5. The propulsion-actuated spherical tensioning robot according to claim 4, characterized in that: A battery and a controller are installed on the connecting plate (50), the battery and the controller are electrically connected to supply power, the attitude angle sensor (60) is electrically connected to the controller, and the controller is electrically connected to the six thrusters (40) respectively.

6. The propulsion-actuated spherical tensioning robot according to claim 5, characterized in that: The propeller (40) is a ducted fan propeller or a rotor propeller.

7. A method for operating a propulsion-actuated spherical tensioning robot according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: When the spherical tensegrity robot is in an initial position, a tensegrity structure based on the icosahedron of the spherical tensegrity robot is supported on the ground by one of its three-point support domains; Step 2: When the spherical tensioning robot is in a stable support state, after determining the direction of movement, select one of the lowest position propellers (40) with the same direction to work, so that the spherical tensioning robot generates torque around one side of the ground to cause the spherical tensioning robot to roll; Step 3: The spherical tensioning robot enters the next triangular support domain and remains stable.

8. A control method for a spherical tensioning robot actuated by a propulsion force according to claim 5, characterized in that: The following steps are involved: Step 1: Establish an initial coordinate model of the spherical tensioning robot, set the length of the support rod (10) and the spacing between the support rods (10), define the coordinates of the two ends of each support rod (10) as support points, and the coordinates of the propeller (40); Step 2: Get the attitude angle sensor data and calculate the rotation matrix; Step 3: Based on the initial coordinates and the rotation matrix, coordinate transformation is used to establish the representation of each propeller (40) and support point in the base coordinate system; According to the coordinate transformation formula, each coordinate is expressed as: ； Where: is the rotation matrix, is the initial coordinate set, is the coordinate representation in the transformed coordinate system; Step 4: Determine the propeller (40) that needs to be started according to the propeller (40) coordinates and the driving instruction; Step 5: judging the gait according to the coordinates of the support point and the coordinates of the propeller (40), and specifying the driving force and driving time required for the gait; Step 6: Receive motion instructions, select different control strategies according to gait, and start corresponding propellers (40).

9. The control method of the propulsion-actuated spherical tensioning robot according to claim 8, characterized in that: In step 2, the rotation matrix is calculated based on the quaternion, and the collected quaternion is expressed as: ； The formula for the quaternion transformation rotation matrix is: ； Where: represents the rotation matrix; Represents the scalar part of the quaternion; Represents the x-axis imaginary part corresponding to the quaternion; Indicates the y-axis imaginary part corresponding to the quaternion; Indicates the imaginary part of the z-axis corresponding to the quaternion.

10. The control method of the propulsion-actuated spherical tension robot according to claim 9, characterized in that: In step 5, the driving force required for each gait is: In OO gait: ; During OC gait: ; In CO gait: ; Where: G represents the total weight of the robot.

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