Control method, device, equipment and medium of continuum robot

Abstract

The present application relates to the technical field of continuum robot, and particularly relates to a control method, device, equipment and medium of a continuum robot. The method comprises: constructing a structure model of a single flexible joint; constructing a kinematics model of the continuum robot based on the structure model; wherein the kinematics model is used to represent the mapping relationship among the length variation of the driving rope, the curvature and torsion of the flexible joint, and the position of the end of the continuum robot; determining the output displacement of each driving rope by different driving motors based on the spatial coordinates of a to-be-captured space debris and the kinematics model, so as to change the length of each driving rope and make the end of the continuum robot move to a target position, thereby realizing the capture of the to-be-captured space debris by the continuum robot. The technical scheme of the present application can realize the control of the continuum robot with the characteristic of soft capture.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of continuum robot technology, and particularly relates to a control method, device, equipment and medium of a continuum robot. BACKGROUND

[0002] With the rapid development of space technology, the pace of human exploration of space is getting faster, and the space debris generated while the exploration is getting more and more, including satellites that have completed their missions, garbage generated during space missions, and debris generated by collisions between space objects, which not only seriously affects the normal service of on-orbit spacecraft, but also occupies valuable orbital resources. The main solution to this problem is to use space robots to capture space debris.

[0003] In related technologies, robots performing space tasks are mostly discrete rigid robots, which have problems such as large volume, low flexibility, and lack of adaptability when performing capture tasks. Therefore, continuum robots with compliant capture characteristics have great research significance for the development of space debris capture technology. SUMMARY

[0004] In order to realize the control of the continuum robot with compliant capture characteristics, the embodiments of the present application provide a control method, device, equipment and medium of a continuum robot.

[0005] In a first aspect, the embodiments of the present application provide a control method of a continuum robot, the continuum robot comprising a driving assembly and a plurality of flexible joints connected in sequence, each of the flexible joints comprising two support discs, two adjacent flexible joints sharing one support disc, a spring and three driving ropes being arranged between the two support discs, the spring being arranged between the three driving ropes, the driving assembly comprising a plurality of driving motors, an output shaft of each of the driving motors being connected with one of the driving ropes to drive the driving rope to stretch, and each of the driving motors being connected with a displacement sensor, the displacement sensor being used to detect a current length of the driving rope corresponding to the displacement sensor.

[0006] The method comprises:

[0007] constructing a structural model of a single flexible joint;

[0008] constructing a kinematic model of the continuum robot based on the structural model, wherein the kinematic model is used to represent a mapping relationship among a length variation of the driving rope, a curvature and a torsion of the flexible joint, and a position of an end of the continuum robot;

[0009] determine, based on the spatial coordinates of the space debris to be captured and the kinematics model, output displacements of the driving motors to the driving ropes, so as to change the lengths of the driving ropes and move the end of the continuum robot to a target position, thereby achieving capture of the space debris to be captured by the continuum robot.

[0010] In a second aspect, an embodiment of the present application further provides a control device of a continuum robot, the continuum robot comprising a driving assembly and a plurality of flexible joints connected in sequence, each flexible joint comprising two support discs, two adjacent flexible joints sharing one support disc, a spring and three driving ropes being arranged between the two support discs, the spring being arranged between the three driving ropes, the driving assembly comprising a plurality of driving motors, an output shaft of each driving motor being connected with one driving rope to drive the driving rope to stretch, and each driving motor being connected with a displacement sensor, the displacement sensor being configured to detect a current length of the driving rope corresponding to the displacement sensor.

[0011] The device comprises:

[0012] A first construction module configured to construct a structural model of a single flexible joint.

[0013] A second construction module configured to construct a kinematics model of the continuum robot based on the structural model, wherein the kinematics model is configured to represent a mapping relationship among a length variation of the driving rope, a bending degree and a twisting degree of the flexible joint, and a position of an end of the continuum robot.

[0014] A determination module configured to determine, based on spatial coordinates of space debris to be captured and the kinematics model, output displacements of the driving motors to the driving ropes, so as to change the lengths of the driving ropes and move the end of the continuum robot to a target position, thereby achieving capture of the space debris to be captured by the continuum robot.

[0015] In a third aspect, an embodiment of the present application further provides an electronic device comprising a memory and a processor, the memory storing a computer program, and the processor being configured to execute the computer program to implement the method of any of the embodiments of the present application.

[0016] In a fourth aspect, an embodiment of the present application further provides a computer readable storage medium storing a computer program, and the computer program is configured to execute the method of any of the embodiments of the present application when executed in a computer.

[0017] The embodiment of the application provides a continuum robot control method, device, equipment and medium, first, a structure model of a single flexible joint is constructed, then a kinematics model of the continuum robot is constructed based on the structure model, finally, the output displacement of each driving rope of different driving motors is determined based on the spatial coordinates of the to-be-captured space debris and the kinematics model, so that the length of each driving rope is changed to move the end of the continuum robot to a target position, so that the continuum robot captures the to-be-captured space debris. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0019] Figure 1 It is a control method flow chart of a continuum robot provided by an embodiment of the application;

[0020] Figure 2 It is a hardware architecture diagram of an electronic device provided by an embodiment of the application;

[0021] Figure 3 It is a control device structure diagram of a continuum robot provided by an embodiment of the application;

[0022] Figure 4 It is a structure schematic diagram of a continuum robot provided by an embodiment of the application;

[0023] Figure 5 It is a schematic diagram of a structure model of a single flexible joint provided by an embodiment of the application;

[0024] Figure 6 It is a relationship diagram of the rotation angle of a continuum robot and the tension of three driving ropes provided by an embodiment of the application.

[0025] Reference signs:

[0026] 1-driving assembly;

[0027] 11-driving motor;

[0028] 12-displacement sensor;

[0029] 2-flexible joint;

[0030] 21-supporting disc;

[0031] 22-spring;

[0032] 23-driving rope. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0034] Please refer to Figure 1 and Figure 4 This invention provides a control method for a continuous robot. The continuous robot includes a drive assembly 1 and multiple flexible joints 2 connected in sequence. Each flexible joint 2 includes two support disks 21. Two adjacent flexible joints 2 share one support disk 21. A spring 22 and three drive ropes 23 are arranged between the two support disks 21. The spring 22 is arranged between the three drive ropes 23. The drive assembly 1 includes multiple drive motors 11. The output shaft of each drive motor 11 is connected to a drive rope 23 to drive the drive rope 23 to stretch. The output shaft of each drive motor 11 is connected to a displacement sensor 12, which is used to detect the current length of the corresponding drive rope 23.

[0035] The method includes:

[0036] Construct a structural model of a single flexible joint 2;

[0037] Based on the structural model, a kinematic model of the continuum robot is constructed; the kinematic model is used to characterize the length change of the drive rope 23, the curvature and twist of the flexible joint 2, and the mapping relationship of the position of the end effector of the continuum robot.

[0038] Based on the spatial coordinates and kinematic model of the space debris to be captured, the output displacement of each drive motor 11 to each drive rope 23 is determined. By changing the length of each drive rope 23, the end of the continuous robot moves to the target position, thereby realizing the capture of the space debris to be captured by the continuous robot.

[0039] In this embodiment of the invention, a structural model of a single flexible joint is first constructed. Then, a kinematic model of a continuum robot with a three-layer mapping relationship is constructed based on the structural model. Finally, the output displacement of different drive motors to each drive rope is determined based on the spatial coordinates of the space debris to be captured and the kinematic model. By changing the length of each drive rope, the end of the continuum robot moves to the target position, thereby realizing the capture of the space debris to be captured by the continuum robot.

[0040] The following descriptionFigure 1 The execution mode of each step is shown.

[0041] For step 100:

[0042] As Figure 5 shown, in one embodiment of the present application, step 100 can specifically include:

[0043] For each flexible joint 2, the following is executed:

[0044] A basic coordinate system (x, y, z) is established with the center of the support disc 21 at the bottom as the origin, and the direction of the line connecting the origin to one of the threading holes as the positive direction of the x-axis; the threading hole is used to pass through the driving rope 23;

[0045] The direction perpendicular to the support disc 21 and vertically upward is the positive direction of the z-axis, and the positive direction of the y-axis perpendicular to the (x, z) plane is determined by the right-hand screw rule;

[0046] The length of the spring 22 between the two support discs 21 is defined as l; the solid angle φ ∈ (0, 2π) is defined as the angle between the projection of the flexible joint 2 on the (x, y) plane and the x-axis, and the positive direction is counterclockwise; the bending angle θ ∈ (0, π / 2) is defined as the angle between the support disc 21 at the top and the (x, y) plane; r is defined as the radius of curvature of the flexible joint 2 during bending; P is defined as an arbitrary point on the spring 22, and the spatial coordinates of P are (xp, yp, zp); S is defined as the length of the spring 22 from the origin to P, and θp ∈ (0, θ) is defined as the bending angle corresponding to P.

[0047] In combination Figure 4 and Figure 5 , the research object of the embodiment of the present application is a rope-driven three-joint continuum robot, which can be regarded as being composed of three identical joints in series, and the support discs are between the joints, and the support discs are uniformly distributed with three threading holes on the circumference, and each joint is controlled by three driving ropes passing through the threading holes. As can be seen from the structural diagram, a single joint has two degrees of freedom and can perform bending and turning motions.

[0048] For step 102:

[0049] In one embodiment of the present application, step 102 can specifically include:

[0050] The mapping relationship between the length variation of the driving rope 23 and the bending and solid angle of the flexible joint 2 is as follows:

[0051]

[0052] In the formula, L i，jrepresents the length of the jth driving rope 23 of the ith flexible joint 2, r is the radius of curvature of the flexible joint 2 in the bending motion, and θ i represents the bending degree of the ith flexible joint 2, and φ i represents the twisting degree of the ith flexible joint 2, and S i represents the length of the spring 22 from the origin to the point P in the ith flexible joint 2, i and j are respectively 1, 2, and 3;

[0053] The mapping relationship of the bending degree and the twisting degree of the flexible joint 2 to the position of the end of the continuum robot is as follows:

[0054]

[0055] In the formula, dx, dy, and dz represent the spatial coordinates of the position of the end of the continuum robot, θ i represents the bending degree of the ith flexible joint 2, and φ i represents the twisting degree of the ith flexible joint 2.

[0056] In the embodiment, the operation structure of the entire continuum robot is divided into three spaces, thereby forming three mappings, which are the mapping relationship of the length change of the driving rope 23 to the bending degree and the twisting degree of the flexible joint 2, and the mapping relationship of the bending degree and the twisting degree of the flexible joint 2 to the position of the end of the continuum robot. Therefore, by changing the driving parameters (i.e., the length of the driving rope) of the continuum robot through the driving motor, the bending degree and the twisting degree of each flexible joint are changed, the continuum robot is bent in different postures, and the end thereof reaches different positions.

[0057] For step 104:

[0058] In an embodiment of the present application, step 104 can specifically include:

[0059] The spatial coordinates of the space debris to be captured are sequentially substituted into the second formula group and the first formula group to obtain the length of the jth driving rope 23 of the ith flexible joint 2, so as to take the length of the jth driving rope 23 of the ith flexible joint 2 as the output displacement of each driving rope 23 by different driving motors 11.

[0060] In the embodiment, after the first formula group and the second formula group are obtained, the length of the jth driving rope 23 of the ith flexible joint 2 can be obtained by sequentially substituting the spatial coordinates of the space debris to be captured into the second formula group and the first formula group, thereby obtaining the output displacement of each driving rope 23 by different driving motors 11.

[0061] In an embodiment of the present application, the continuum robot captures the space debris to be captured in the following manner:

[0062] acquiring a profile range of the space debris to be captured;

[0063] when the profile range is smaller than a mesh opening range of a mesh arranged at the end of the continuum robot, adjusting the posture of the continuum robot by changing the length of each driving rope 23 to capture the space debris to be captured by the mesh;

[0064] when the profile range is not smaller than the mesh opening range of the mesh arranged at the end of the continuum robot, adjusting the posture of the continuum robot by changing the length of each driving rope 23 to envelope the space debris to be captured by the continuum robot.

[0065] In the embodiment, the continuum robot needs to adopt different capture strategies for space debris of different sizes. For example, for a small space debris to be captured, the continuum robot can capture the space debris by the mesh connected to the end; and for a large space debris to be captured, the continuum robot can achieve envelope capture by bending the continuum robot body.

[0066] However, when the continuum robot body is bent to achieve envelope capture, the body can generate force interaction with the partially rigid target, which can change the tension on the driving rope. If the same contact force is always maintained, the robot body can be damaged, which is not favorable.

[0067] To solve the above technical problem, in one embodiment of the present application, each driving rope 23 is further connected with a force sensor (not shown in the figure);

[0068] After the continuum robot envelopes the space debris to be captured, the above method further comprises:

[0069] determining the current force of two driving ropes 23 of each flexible joint 2 in the envelope state (see Figure 6 );

[0070] inputting the current force of the two driving ropes 23 of each flexible joint 2 into the pre-constructed dynamics model of the continuum robot to obtain the bending and twisting of each flexible joint 2;

[0071] inputting the obtained bending and twisting of each flexible joint 2 into the first formula group to obtain the length of each driving rope 23 of each flexible joint 2 to be corrected, so as to correct the current length of each driving rope 23 by the driving motor 11.

[0072] In the embodiment, the bending and twisting of each flexible joint 2 are obtained by means of the pre-constructed dynamics model of the continuum robot, so as to change the posture of the current continuum robot, and then the bending and twisting of each flexible joint 2 are input into the first formula group, so as to obtain the length of each driving rope 23 of each flexible joint 2 to be corrected, so that the current length of each driving rope 23 is corrected by using each driving motor 11, so as to realize the flexible clamping of the space debris, which is not easy to cause damage to the continuum robot.

[0073] Please continue to refer to Figure 6 In an embodiment of the present application, the dynamics model is:

[0074]

[0075]

[0076]

[0077]

[0078]

[0079] Wherein:

[0080] K1=-0.00426θ 2 -0.00277θ+0.15085,

[0081] K2=-0.05567θ 3 +0.2328θ 2 +0.006216θ-0.00406

[0082] K3=0.00172θ 3 -0.01692θ 2 +0.00200θ+0.24966,

[0083] K4=0.01921θ 4 -0.18736θ 3 +0.46984θ 2 -0.10043θ+0.01236

[0084] In the formula, m1 is the weight of the spring 22, m2 is the mass of a support disc 21, l is the length of the spring 22, EI is the stiffness of the spring 22, g is the acceleration of gravity, r is the radius of curvature of the flexible joint 2 in bending motion, F1 and F2 are the forces of two driving ropes 23 of the flexible joint 2.

[0085] In the embodiment, by constructing the above-mentioned dynamic model, the current force of two driving ropes 23 of each flexible joint 2 can be input into the dynamic model of the continuum robot constructed in advance, the curvature and torsion of each flexible joint 2 are obtained, so as to facilitate the change of the posture of the continuum robot, and then the flexible clamping of the space debris is realized, which is not easy to cause damage to the continuum robot.

[0086] As shown in Figure 2 , Figure 3 , the embodiment of the present application provides a control device of a continuum robot. The device embodiment can be realized by software, or realized by hardware or a combination of software and hardware. From the hardware layer, as shown in Figure 2 , a hardware architecture diagram of an electronic device where the control device of the continuum robot provided by the embodiment of the present application is located, in addition to the processor, the memory, the network interface, and the non-volatile memory shown in Figure 2 , the electronic device where the device in the embodiment is usually also can include other hardware, such as a forwarding chip responsible for processing messages and the like. Taking the software implementation as an example, as shown in Figure 3 , as a logically meaningful device, it is formed by the CPU of the electronic device where it is located reading the corresponding computer program in the non-volatile memory into the memory for running.

[0087] As shown in Figure 3 , the control device of the continuum robot provided by the embodiment includes a driving assembly and a plurality of flexible joints connected in sequence, each of the flexible joints includes two support discs, two adjacent flexible joints share one support disc, a spring and three driving ropes are arranged between the two support discs, the spring is arranged between the three driving ropes, the driving assembly includes a plurality of driving motors, the output shaft of each driving motor is connected with one driving rope to drive the driving rope to stretch, and each driving motor is connected with a displacement sensor, and the displacement sensor is used to detect the current length of the driving rope corresponding thereto.

[0088] The device includes:

[0089] The first construction module 300 is used for constructing a structural model of a single flexible joint.

[0090] The second construction module 302 is used for constructing a kinematics model of the continuum robot based on the structural model, and the kinematics model is used for representing the mapping relationship among the length change of the driving rope, the curvature and torsion of the flexible joint, and the position of the end of the continuum robot.

[0091] The determining module 304 is configured to determine, based on the spatial coordinates of the space debris to be captured and the kinematic model, output displacements of different driving motors to different driving ropes, so as to move the end of the continuum robot to a target position by changing the lengths of the different driving ropes, thereby realizing the capture of the space debris to be captured by the continuum robot.

[0092] In the embodiments of the present application, the first construction module 300 can be configured to perform step 100 in the above-mentioned method embodiments, the second construction module 302 can be configured to perform step 102 in the above-mentioned method embodiments, and the determining module 304 can be configured to perform step 104 in the above-mentioned method embodiments.

[0093] In an embodiment of the present application, the first construction module is configured to perform the following operations:

[0094] For each flexible joint, the following operations are performed:

[0095] A basic coordinate system (x, y, z) is established with the center of the support disc at the bottom as the origin, and the direction from the origin to one of the threading holes is defined as the positive direction of the x-axis; wherein the threading hole is used to pass through the driving rope;

[0096] The direction perpendicular to the support disc and vertically upward is defined as the positive direction of the z-axis, and the positive direction of the y-axis perpendicular to the (x, z) plane is determined by the right-hand screw rule;

[0097] The length of the spring between the two support discs is defined as l; the rotation angle φ∈(0, 2π) is defined as the angle between the projection of the flexible joint on the (x, y) plane and the x-axis, and the positive direction is counterclockwise; the bending angle θ∈(0, π / 2) is defined as the angle between the support disc at the top and the (x, y) plane; r is defined as the radius of curvature of the flexible joint during bending; P is defined as an arbitrary point on the spring, and the spatial coordinates of P are (xp, yp, zp); S is defined as the length of the spring from the origin to P, and θp∈(0, θ) is defined as the corresponding bending angle of P.

[0098] In an embodiment of the present application, the second construction module is configured to perform the following operations:

[0099] The mapping relationship between the length variation of the driving rope and the bending and rotation angles of the flexible joint is as follows:

[0100]

[0101] In the formula, L i，j represents the length of the jth driving rope of the ith flexible joint, r is the radius of curvature of the flexible joint during bending, θ idenotes the curvature of the i-th flexible joint, φi denotes the torsion of the i-th flexible joint, S i denotes the length of the spring from the origin to point P in the i-th flexible joint, i and j respectively take 1, 2, 3;

[0102] The mapping relationship of the curvature and the torsion of the flexible joint to the position of the continuum robot end is as follows second formula group:

[0103]

[0104] In the formula, dx, dy, dz denote the spatial coordinates of the position of the continuum robot end, θ i denotes the curvature of the i-th flexible joint, φ i denotes the torsion of the i-th flexible joint.

[0105] In an embodiment of the present application, the determining module is configured to perform the following operations:

[0106] Substitute the spatial coordinates of the space debris to be captured into the second formula group and the first formula group in turn to obtain the length of the j-th driving rope of the i-th flexible joint, and take the length of the j-th driving rope of the i-th flexible joint as the output displacement of each driving rope by different driving motors.

[0107] In an embodiment of the present application, the continuum robot captures the space debris to be captured by the following method:

[0108] Obtain the contour range of the space debris to be captured;

[0109] When the contour range is smaller than the mesh opening range of the capture net arranged at the end of the continuum robot, adjust the posture of the continuum robot by changing the length of each driving rope to capture the space debris to be captured by the capture net;

[0110] When the contour range is not smaller than the mesh opening range of the capture net arranged at the end of the continuum robot, adjust the posture of the continuum robot by changing the length of each driving rope to envelope the space debris to be captured by the continuum robot.

[0111] In an embodiment of the present application, each driving rope is further connected with a force sensor;

[0112] After the space debris to be captured is enveloped by the continuum robot, the method further comprises:

[0113] determining current forces of two of the driving ropes of each of the flexible joints in the enveloped state;

[0114] inputting the current forces of the two of the driving ropes of each of the flexible joints into a pre-constructed dynamics model of the continuum robot to obtain curvatures and torsions of each of the flexible joints;

[0115] inputting the obtained curvatures and torsions of each of the flexible joints into the first formula set to obtain lengths of the driving ropes of each of the flexible joints to be corrected, so as to correct the current lengths of the driving ropes by the driving motors.

[0116] In an embodiment of the present application, the dynamics model is:

[0117]

[0118]

[0119]

[0120]

[0121]

[0122] wherein:

[0123] K1=-0.00426θ 2 -0.00277θ+0.15085,

[0124] K2=-0.05567θ 3 +0.2328θ 2 +0.006216θ-0.00406

[0125] K3=0.00172θ 3 -0.01692θ 2 +0.00200θ+0.24966,

[0126] K4=0.01921θ 4 -0.18736θ 3 +0.46984θ 2 -0.10043θ+0.01236

[0127] In the formula, m1 is a weight of the spring, m2 is a mass of one of the support discs, l is a length of the spring, EI is a stiffness of the spring, g is a gravitational acceleration, r is a radius of curvature of the flexible joint in bending motion, and F1 and F2 are forces of the two of the driving ropes of the flexible joint.

[0128] It can be understood that the structure of the embodiment of the present application does not constitute a specific limitation of the control device of the continuum robot. In other embodiments of the present application, the control device of the continuum robot can include more or fewer components than the illustration, or combine certain components, or split certain components, or different component arrangement. The components illustrated can be implemented in hardware, software, or a combination of software and hardware.

[0129] The information interaction, execution process and the like between the modules in the device are based on the same concept as the method embodiments of the present application, and the specific content can be referred to the description in the method embodiments of the present application, which will not be described here.

[0130] The embodiment of the present application also provides an electronic device including a memory and a processor, the memory stores a computer program, and the processor implements the control method of the continuum robot in any embodiment of the present application when executing the computer program.

[0131] The embodiment of the present application also provides a computer readable storage medium, the computer readable storage medium stores a computer program, and the computer program makes the processor execute the control method of the continuum robot in any embodiment of the present application when the processor executes the computer program.

[0132] Specifically, a system or device equipped with a storage medium can be provided, and the storage medium stores software program codes for realizing the functions of any one of the above embodiments, and the computer (or CPU or MPU) of the system or device reads and executes the program codes stored in the storage medium.

[0133] In this case, the program codes read from the storage medium can realize the functions of any one of the above embodiments, and therefore the program codes and the storage medium storing the program codes constitute a part of the present application.

[0134] The storage medium for providing the program codes includes a floppy disk, a hard disk, a magneto-optical disk, an optical disk (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), a magnetic tape, a non-volatile memory card, and a ROM. Alternatively, the program codes can be downloaded from a server computer through a communication network.

[0135] In addition, it should be clear that not only the program codes read by the computer can be executed, but also part or all of the actual operations can be completed by the operating system and the like operating on the computer based on the instructions of the program codes, so as to realize the functions of any one of the above embodiments.

[0136] Further, it is understood that the programs while being read by the storage media are written into the memory provided in the extension board inserted into the computer or the memory provided in the extension module connected to the computer, and then the CPU or the like mounted on the extension board or the extension module is caused to perform part or all of the actual operations based on the instructions of the program codes, thereby realizing the functions of any of the above-described embodiments.

[0137] It is noted that the terms such as first and second are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply there is any such actual relationship or order between these entities or operations. Also, the terms "include", "contain" or any other variants thereof are intended to cover the non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment. Without more limitations, the element defined by the statement "including a" does not exclude the presence of other identical elements in the process, method, article or equipment including the element.

[0138] It is understood by those skilled in the art that all or part of the steps of the above-mentioned method embodiments can be completed by program instruction related hardware, the aforementioned program can be stored in a computer readable storage medium, and the program executes the steps including the above-mentioned method embodiments when executed; and the aforementioned storage medium includes ROM, RAM, magnetic disc or optical disc and various storage medium capable of storing program codes.

[0139] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit it; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the above embodiments, or make equivalent replacement to part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A control method of a continuum robot, characterized by, The continuum robot comprises a driving assembly and a plurality of flexible joints connected in sequence, each flexible joint comprises two support discs, two adjacent flexible joints share one support disc, a spring and three driving ropes are arranged between the two support discs, the spring is arranged between the three driving ropes, the driving assembly comprises a plurality of driving motors, the output shaft of each driving motor is connected with one driving rope to drive the driving rope to stretch, each driving motor is connected with a displacement sensor, and the displacement sensor is used to detect the current length of the driving rope corresponding to the displacement sensor; The method comprises: constructing a structural model of a single flexible joint; based on the structural model, a kinematic model of the continuum robot is constructed; wherein the kinematic model is used to represent the mapping relationship between the length change of the driving rope, the curvature and torsion of the flexible joint, and the position of the end of the continuum robot; based on the spatial coordinates of the space debris to be captured and the kinematic model, the output displacement of each driving rope by different driving motors is determined, so that the length of each driving rope is changed to move the end of the continuum robot to a target position, thereby realizing the capture of the space debris to be captured by the continuum robot; the construction of the structural model of a single flexible joint comprises: for each flexible joint, the following is performed: a basic coordinate system (x, y, z) is established with the center of the support disc at the bottom as the origin, and the direction of the line connecting the origin to one of the threading holes is defined as the positive direction of the x-axis; wherein the threading hole is used to pass through the driving rope; the direction perpendicular to the support disc and vertically upward is defined as the positive direction of the z-axis, and the positive direction of the y-axis perpendicular to the (x, z) plane is determined by the right-hand screw rule; the length of the spring between the two support discs is defined as l; the torsion φ∈(0, 2π) is defined as the angle between the projection of the flexible joint on the (x, y) plane and the x-axis, and the positive direction is counterclockwise; the curvature θ∈(0, π / 2) is defined as the angle between the support disc at the top and the (x, y) plane; r is defined as the radius of curvature of the flexible joint in bending motion; P is defined as any point on the spring, and the spatial coordinates of P are (xp, yp, zp); S is defined as the length of the spring from the origin to P, and θp∈(0, θ) is defined as the curvature corresponding to P. the construction of the kinematic model of the continuum robot based on the structural model comprises: the mapping relationship between the length change of the driving rope and the curvature and torsion of the flexible joint is as follows: φ' i = φ i + (i-1) x π / 6 wherein L i，j represents the length of the jth driving rope of the ith flexible joint, r is the radius of curvature of the flexible joint when bending, θ i represents the bending of the ith flexible joint, φ i represents the rotation of the ith flexible joint, S i represents the length of the spring from the origin to point P in the ith flexible joint, i and j are 1, 2, 3, respectively. the mapping relationship between the curvature and torsion of the flexible joint and the position of the end of the continuum robot is as follows: wherein dx, dy, dz represent the spatial coordinates of the position of the end of the continuum robot, θ i represents the curvature of the i-th flexible joint, φ i represents the torsion of the i-th flexible joint.

2. The method of claim 1, wherein, the determination of the output displacement of each driving rope by different driving motors based on the spatial coordinates of the space debris to be captured and the kinematic model comprises: The space coordinates of the space debris to be captured are sequentially substituted into the second formula set and the first formula set to obtain the length of the jth driving rope of the ith flexible joint, and the length of the jth driving rope of the ith flexible joint is taken as the output displacement of the different driving motors to each driving rope.

3. The method of claim 2, wherein, The continuum robot captures the space debris to be captured in particular by the following manner: Obtaining a contour range of the space debris to be captured; When the contour range is smaller than the mesh opening range of the capturing net arranged at the end of the continuum robot, adjusting the posture of the continuum robot by changing the length of each driving rope to capture the space debris to be captured by the capturing net; When the contour range is not smaller than the mesh opening range of the capturing net arranged at the end of the continuum robot, adjusting the posture of the continuum robot by changing the length of each driving rope to envelope the space debris to be captured by the continuum robot.

4. The method of claim 2, wherein, Each driving rope is further connected with a force sensor; After the space debris to be captured is enveloped by the continuum robot, the method further comprises: Determining the current force of two driving ropes of each flexible joint in the enveloping state; Inputting the current force of the two driving ropes of each flexible joint into a pre-constructed dynamic model of the continuum robot to obtain the bending and twisting of each flexible joint; Inputting the obtained bending and twisting of each flexible joint into the first formula set to obtain the length of each driving rope of each flexible joint to be corrected, so as to correct the current length of each driving rope by each driving motor.

5. The method of claim 4, wherein, The dynamic model is: Wherein: K1 = -0.00426θ 2 -0.00277θ + 0.15085, K2 = -0.05567θ 3 + 0.2328θ 2 + 0.006216θ - 0.00406 K3 = 0.00172θ 3 -0.01692θ 2 +0.00200θ + 0.24966, K4 = 0.01921 θ 4 -0.18736 θ 3 +0.46984 θ 2 -0.10043 θ + 0.01236 In the formula, m1 is the weight of the spring, m2 is the mass of one support disc, l is the length of the spring, EI is the stiffness of the spring, g is the acceleration of gravity, r is the curvature radius of the flexible joint in bending motion, and F1 and F2 are the forces of the two driving ropes of the flexible joint.

6. A control device of a continuum robot characterized by comprising: The continuum robot comprises a driving assembly and a plurality of sequentially connected flexible joints, each flexible joint comprises two support discs, two adjacent flexible joints share one support disc, a spring and three driving ropes are arranged between the two support discs, the spring is arranged between the three driving ropes, the driving assembly comprises a plurality of driving motors, the output shaft of each driving motor is connected with one driving rope to drive the driving rope to stretch, the output shaft of each driving motor is connected with a displacement sensor, and the displacement sensor is used to detect the current length of the driving rope corresponding thereto. The device comprises: A first construction module for constructing a structural model of a single flexible joint; a second construction module, configured to construct a kinematics model of the continuum robot based on the structure model, wherein the kinematics model is configured to represent a mapping relationship among a length variation of the driving ropes, a bending and twisting of the flexible joints, and a position of an end of the continuum robot; a determination module, configured to determine, based on a space coordinate of a space debris to be captured and the kinematics model, an output displacement of each of the driving ropes by different driving motors, so as to move the end of the continuum robot to a target position by changing the length of each of the driving ropes, thereby realizing capturing of the space debris to be captured by the continuum robot.

7. An electronic device, comprising: A computer program product, comprising a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the method according to any one of claims 1-5.

8. A computer-readable storage medium, characterized in that, A computer program product, comprising a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the method according to any one of claims 1-5.

Images