Flexible cable driven self-adaptive space capturing manipulator and capturing control method thereof
Through the bionic wrapping capture mechanism driven by multiple flexible cables, the flexible capture net combined with tension feedback realizes adaptive capture, which solves the problem of capturing non-cooperative targets in existing technologies, reduces costs and improves stability.
Patent Information
- Application Number
- CN202510963887.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-14
- Publication Date
- 2025-10-17
AI Technical Summary
Existing technologies are difficult to efficiently capture non-cooperative space targets with irregular shapes and unknown motion states, are costly, and lack adaptability.
It adopts a bionic wrap-around capture mechanism driven by multiple flexible cables, controls the flexible capture net by retracting and extending the flexible cables, and realizes adaptive and active stiffness adjustment in combination with tension feedback. It is suitable for capturing non-cooperative targets in complex spatial environments.
Adaptive capture of non-cooperative targets with irregular shapes and unknown motion states is achieved, which reduces the capture cost and improves the stability and adaptability of capture.
Smart Images
Figure CN120793243A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of mechanical hand, and particularly relates to a flexible cable driven adaptive space capturing mechanical hand and a capturing control method thereof. BACKGROUND
[0002] Space capturing technology is a key link of on-orbit servicing and maintenance of spacecraft. With the increasing frequency of human space activities, the number of space debris increases dramatically, and failed satellites and space junk pose a serious threat to on-orbit spacecraft. At present, there are more than tens of thousands of space debris with a diameter of more than ten centimeters in the Earth's orbit. The capturing and removal of these non-cooperative targets has become a difficult problem to be solved in the field of aerospace. Traditional space capturing mechanical hands are mainly divided into three categories: rigid mechanical hands, rope driven mechanical hands and soft mechanical hands. Each type of technology has certain limitations when dealing with space capturing tasks.
[0003] Most current space capturing technologies are aimed at capturing cooperative targets. The premise of these technologies is that the captured objects must be equipped with docking devices. However, most of the space debris do not have docking devices, which makes it difficult to effectively capture such targets. The current non-cooperative target capturing technology has significant limitations in practical applications, such as limited versatility, high single capturing cost and insufficient adaptability when facing irregularly shaped and unknown motion state non-cooperative targets. Therefore, it is necessary to propose a flexible cable driven adaptive space capturing mechanical hand and a capturing control method thereof. SUMMARY
[0004] In order to solve the above-mentioned deficiencies of the prior art, the purpose of the present application is to provide a flexible cable driven adaptive space capturing mechanical hand and a capturing control method thereof. The bionic wrapping capturing mechanism is driven by multiple flexible cables, which combines bionic flexibility with flexible cable tension control. The flexible capturing net is controlled by flexible cable winding and unwinding. The capturing opening diameter is adjusted in real time according to the size of the captured object, and the uniformity of wrapping is ensured through tension feedback. The adaptive and active stiffness adjustment of the flexible cable net is achieved, which is suitable for capturing non-cooperative targets in complex space environments.
[0005] The application provides a flexible cable driving self-adaptive space capturing manipulator, which comprises a driving assembly, a capturing assembly, a reset assembly and driving flexible cables, the capturing assemblies are uniformly distributed on the periphery of the driving assembly, the joint support of the reset assembly is connected with the support seat of the driving assembly, the driving flexible cables are cross-wound in the flexible transmission mechanism node of the capturing assembly from top to bottom, forming a self-adaptive capturing net, the driving assembly comprises a winding device, sliding rails, a transmission rod, a variable pitch chuck, a support seat and a driving motor, the winding device is connected with the output shaft of the winding motor, the sliding rails are uniformly distributed on the periphery of the support seat, the first end of the transmission rod is rotationally connected with the support rod on the periphery of the variable pitch chuck through a pin shaft, the second end of the transmission rod is rotationally connected with the bottom end of the sliding support in the capturing assembly, the driving motor and the winding motor are arranged in the support seat, and the output shaft of the driving motor is connected with the center of the variable pitch chuck; the capturing assembly comprises a fixed frame, a sliding support and a flexible transmission mechanism, the two ends of the flexible transmission mechanism are rotationally connected with the fixed frame through pin shafts, the fixed frame is connected with the second end of the sliding support through quick-change hooks, and the sliding support is slidably connected with the sliding rail through the cooperation of the first groove and the steel ball; the reset assembly comprises a compression spring, a base, a bearing sleeve, an eccentric ball push shaft, a joint and a joint support, the compression spring is sleeved on the bearing sleeve, the two ends of the compression spring are connected with the base and the eccentric ball push shaft respectively, the base is slidably connected with the eccentric ball push shaft through the cooperation of the ball and the second groove, the bearing sleeve is sleeved on the first end of the eccentric ball push shaft, and the joint support and the joint are connected with the base respectively.
[0006] Preferably, the axes of the winding device, the variable pitch chuck, the support seat, the variable pitch motor and the winding motor are located on the same axis.
[0007] Preferably, the connection between the eccentric ball push shaft and the joint support is a spherical contact pair.
[0008] Preferably, the dynamic diameter of the capturing net is adjusted, and the length L i The relationship between the length L ; In the formula, R1 is the installation radius of the driving flexible cable on the base, R2 is the radius of the connecting point of the capturing net, H is the axial height from the base to the capturing net, is the azimuth angle of the i-th driving flexible cable.
[0009] In another aspect, the application provides a capturing control method of the flexible cable driving self-adaptive space capturing manipulator, and the steps comprise: S1, obtaining the pose, size and motion speed of the object to be captured through a visual sensor, establishing a state space equation of capturing, and controlling the driving assembly to drive the capturing assembly to adjust to a capturing area; S2, capture mouth dynamic adjustment control: when approaching and capturing the to-be-captured object, according to the shape and size of the to-be-captured object, the variable-distance chuck is driven by the variable-distance motor to move the transmission rod, and then the sliding support slides along the slide rail in the radial direction, according to the relationship between the capture net contraction rate and the driving cable displacement, the driving cable is dynamically adjusted by winding and unwinding to adjust the capture mouth diameter, which is adaptive to the movement and size of the to-be-captured object; S3, driving cable tension coordination wrapping: the take-up motor drives the winding device to rotate, the driving cable and the flexible transmission mechanism are drawn in, and after the flexible transmission mechanism contacts the to-be-captured object, based on the relationship between the capture net tension and the wrapping force, the to-be-captured object is wrapped and captured softly; S4, releasing the to-be-captured object, the driving cable is relaxed, the flexible transmission structure rebounds to the original position to release the to-be-captured object, and at the same time, the compression spring of the reset component releases the stored elastic potential energy, and the capture component is reset.
[0010] Preferably, the state space equation of the capture in S1 is: ; In the formula, is the predicted state vector at k+1 time, is the state vector, , respectively, the cable driving angle, the joint angular velocity, the cable tension, is the input torque of the driving motor, A is the state transition matrix, B is the input matrix, C is the output matrix, w k is the process noise, is the cable tension, and the target function of the predicted cable control is: ; In the formula, k is the time step index, N P is the prediction time domain, is the expected value of the cable tension, and Q is the state weight matrix.
[0011] Preferably, in S2, the to-be-captured object is wrapped in a cocoon by tightening the capture net, and the relationship between the capture net contraction rate η and the driving cable displacement is: ; In the formula, L0 is the initial length of the driving cable, ΔL is the contraction amount of the driving cable, θ is the winding angle of the cable, by adjusting the parameters ΔL and dynamically adjust the capture mouth diameter of the capture net.
[0012] Preferably, in S3, based on the dynamics model of the spatial capture manipulator, the expression of the relationship between the capture net tension and the wrapping force is: ; In the formula, F c is the wrapping force of the to-be-captured object, T iTension on the i-th driving cable, Normal vector of the i-th driving cable, n is the number of driving cables.
[0013] Compared with the prior art, the beneficial effects of the present application are embodied in: 1. The cable-driven self-adaptive space capture manipulator of the present application, through the high adaptability flexible transmission structure, under the cooperation of the variable pitch chuck and the transmission rod, drives the sliding support to slide along the variable pitch guide rail, and the multiple cables drive the flexible capture net, and the opening and closing of the capture net are controlled through the winding and unwinding of the cables, the diameter of the capture opening is dynamically adjusted, and the tension of each cable is adaptively adjusted, so that the wrapping type compliant capture is realized.
[0014] 2. The cable-driven self-adaptive space capture manipulator of the present application, the reset assembly adopts an eccentric spherical contact pair, so that the joint presents a surface contact state at the initial position, ensuring high stability. Before a certain torque value is reached, the joint maintains a statically indeterminate stable state, improving the stability of the manipulator during movement. BRIEF DESCRIPTION OF DRAWINGS
[0015] Figure 1 It is a front view of the cable-driven self-adaptive space capture manipulator of the present application; Figure 2 It is a half-sectional view of the cable-driven self-adaptive space capture manipulator of the present application; Figure 3 It is a structure diagram of the cable-driven self-adaptive space capture manipulator of the present application in a capture state; Figure 4 It is a structure diagram of the driving assembly in the cable-driven self-adaptive space capture manipulator of the present application; Figure 5 It is a structure diagram of the capture assembly in the cable-driven self-adaptive space capture manipulator of the present application; Figure 6 It is a structure diagram of the reset assembly in the cable-driven self-adaptive space capture manipulator of the present application; Figure 7 It is a sectional view of the reset assembly in the cable-driven self-adaptive space capture manipulator of the present application; Figure 8 It is a dynamic contraction diagram of the cable-driven self-adaptive space capture manipulator of the present application; Figure 9 It is a driving simulation diagram of the cable-driven self-adaptive space capture manipulator of the present application; Figure 10 It is a cable movement and mechanics diagram of the cable-driven self-adaptive space capture manipulator of the present application; Figure 11 It is a driving force response diagram of the cable-driven self-adaptive space capture manipulator of the present application.
[0016] Reference signs: 1, drive assembly; 11, winding device; 12, slide rail; 13, transmission rod; 14, variable pitch chuck; 15, support seat; 16, variable pitch motor; 17, take-up motor; 18, steel ball; 2, capture assembly; 21, fixed frame; 22, sliding support; 23, flexible transmission structure; 24, pin shaft; 3, reset assembly; 31, compression spring; 32, base; 33, bearing sleeve; 34, eccentric ball push shaft; 35, joint; 36, joint support; 37, ball; 4, drive cable; 5, captured object. DETAILED DESCRIPTION
[0017] Hereinafter, the embodiments of the present application will be described with reference to the accompanying drawings.
[0018] The flexible cable drive self-adaptive space capture manipulator of the present application, as shown in Figure 1 , includes a drive assembly 1, a capture assembly 2, a reset assembly 3, and a drive cable 4. Multiple capture assemblies 2 are evenly distributed around the drive assembly 1. The joint support 36 of the reset assembly 3 is connected to the support seat 15 at the bottom of the drive assembly 1. Multiple drive cables 4 are wound in the flexible transmission mechanism 23 node of the capture assembly 2 from top to bottom, forming a self-adaptive capture net.
[0019] As shown in Figure 2 and Figure 3 , the drive assembly 1 includes a winding device 11, a slide rail 12, a transmission rod 13, a variable pitch chuck 14, a support seat 15, a drive motor 16, and a take-up motor 17. The winding device 11 is connected to the output shaft of the take-up motor 17. Multiple slide rails 12 are evenly distributed around the support seat 15. The first end of the transmission rod 13 is rotatably connected to the support rod around the variable pitch chuck 14 through a pin shaft. The second end of the transmission rod 13 is rotatably connected to the bottom end of the sliding support 22 in the capture assembly 2. The drive motor 16 and the take-up motor 17 are arranged in the support seat 15. The output shaft of the drive motor 16 is connected to the center of the variable pitch chuck 14. The axes of the winding device 11, the variable pitch chuck 14, the support seat 15, the variable pitch motor 16, and the take-up motor 17 are all located on the same axis.
[0020] As shown in Figure 4 , the capture assembly 2 includes a fixed frame 21, a sliding support 22, and a flexible transmission mechanism 23. The two ends of the flexible transmission mechanism 23 are rotatably connected to the fixed frame 21 through pin shafts 24. The fixed frame 21 is connected to the second end of the sliding support 22 through quick-change hooks. The sliding support 22 is slidably connected to the slide rail 12 through the steel ball 18 in the first groove.
[0021] As shown in Figures 5 to 7As shown, the reset assembly 3 includes a compression spring 31, a base 32, a bearing sleeve 33, an eccentric ball push shaft 34, a joint 35 and a joint bracket 36, the compression spring 31 is sleeved on the bearing sleeve 33, and the two ends of the compression spring 31 are connected with the base 32 and the eccentric ball push shaft 34 respectively, the base 32 is slidably connected with the second groove of the eccentric ball push shaft 34 through the ball 37, the bearing sleeve 33 is sleeved on the first end of the eccentric ball push shaft 34, the joint bracket 36 and the joint 35 are connected with the base 32 respectively, and the connection between the eccentric ball push shaft 34 and the joint bracket 36 is a spherical contact pair.
[0022] By driving the geometric mapping model of the length of the flexible cable-diameter of the capture port, the length L of the i-th driving flexible cable is obtained i The relationship with the capture port diameter D is: ; In the formula, R1 is the installation radius of the driving flexible cable at the base, R2 is the connection point radius of the capture ring, H is the axial height from the base to the capture ring, is the azimuth angle of the i-th driving flexible cable.
[0023] In the second aspect of the present application, the capture control method of the flexible cable driving self-adaptive space capture manipulator, the steps include: S1, the pose, size and motion speed of the to-be-captured object are obtained through a visual sensor, and a state space equation of capture is established, specifically: ; In the formula, is the predicted state vector at k+1 time, is the state vector, , respectively, the flexible cable driving angle, the joint angular velocity, the flexible cable tension, is the input torque of the driving motor, A is the state transition matrix, B is the input matrix, C is the output matrix, w k is the process noise, is the flexible cable tension, and the target function of the predicted flexible cable control is: ; In the formula, k is the time step index, N P is the prediction time domain, is the expected value of the flexible cable tension, and Q is the state weight matrix.
[0024] S2, capture port dynamic adjustment control: when approaching and capturing the to-be-captured object 5, the variable pitch chuck 14 drives the transmission rod 13 to move under the drive of the variable pitch motor 16, and then drives the sliding bracket 22 to slide radially along the slide rail 12, according to the relationship between the capture net contraction rate η and the driving flexible cable displacement, specifically: ; In the formula, L0 is the initial length of the driving cable, ΔL is the contraction amount of the driving cable, and θ is the winding angle of the cable.
[0025] By adjusting ΔL and The diameter of the capture opening of the capture net is dynamically adjusted, and the motion and size of the captured object are adaptively adjusted.
[0026] S3, driving cable tension cooperation wrapping: the take-up motor 17 drives the winding device 11 to rotate, the driving cable 4 and the flexible transmission mechanism 23 are drawn inward, and the flexible transmission mechanism 23 contacts the captured object 5, based on the relationship between the capture net tension and the wrapping force, the wrapping type compliant capture of the captured object 5 is completed.
[0027] Based on the dynamics model of the spatial capture manipulator, the relationship between the capture net tension and the wrapping force is: ; In the formula, F c is the wrapping force of the captured object, T i is the tension on the i-th driving cable, is the normal vector of the i-th driving cable, and n is the number of driving cables.
[0028] S4, releasing the captured object 5, the driving cable 4 is relaxed, the flexible transmission structure 23 rebounds to the original position to release the captured object, and the compression spring 31 of the reset assembly 3 releases the stored elastic potential energy, and the capture assembly 2 is reset.
[0029] The cable-driven adaptive spatial capture manipulator of the present application is based on the dynamic simulation experiment and result analysis of ABAQUS, specifically: As Figure 8 and Figure 9 shown, the dynamic contraction process of the spatial capture manipulator, verifies the consistency of its motion characteristics and design expectations. Although the spatial capture manipulator has a large motion elasticity, resulting in lower motion accuracy than traditional grippers, two parameters are defined based on simulation data to roughly evaluate its contraction motion behavior: *d*~C~ is the minimum inscribed circle diameter of the capture space in the top view (the center coincides with the geometric center of the spatial capture manipulator), which is used to represent the real-time capture aperture.
[0030] *h*~C~ is the position range of the node, with the height of the lower edge of the node in the initial state as the reference.
[0031] By extracting the simulation data, we get Figure 10 According to the trend of *d*~C~, the driving process is divided into three stages: pre-tightening, contraction and impedance.
[0032] (1) Pre-tightening stage: the lower nodes start to move, and *d*~C~ and *h*~C~ tend to be stable.
[0033] (2) Contraction phase: dC decreases significantly with an obvious linear trend, and hC converges rapidly and stabilizes within a certain bandwidth.
[0034] (3) Impedance phase: the expanding cable undergoes adaptive deformation, and the configuration stabilizes, and the system enters a force balance state (the driving force is mainly converted into cable deformation rather than structural motion). At this time, the system begins to resist the tension of the expanding cable, and dC stabilizes again, and hC oscillates up and down within its stable bandwidth. The entire motion system remains in a tension state, and the global stiffness is significantly improved.
[0035] In the later stage of the simulation, the rebound speed of the space capturing manipulator is observed with time as the independent variable. The results show that dC recovers to the pre-tightening value within 200 ms, with a diameter reduction of about 15%, indicating high recovery efficiency; but hC is still in a converging state, and the capturing space height decreases by about 35%. This shows that the space capturing manipulator needs to operate stably in the contraction phase and maintain basic controllability in the recovery phase.
[0036] As shown in Figure 10 , the maximum principal stress fitting curve and oscillation band of the two groups of driving cables 4 in the simulation are shown. The original data takes the average stress value of each cable group, and a seventh-degree polynomial is used for fitting. Due to high stiffness and complex contact action, the sphincter cable stress is low but the vibration range is large; the principal stress of the expanding cable increases rapidly and stably at the beginning, and the growth rate slows down significantly and the vibration intensifies after entering the impedance phase, the system is highly tensioned, and the stiffness is significantly increased. In the later stage, the sphincter cable stress drops sharply to a very low level, while the elastic potential energy of the expanding driving cable 4 is quickly released and eventually stabilizes. The simulation results show that the motion and mechanical properties of the space capturing manipulator meet the design expectations.
[0037] By adjusting the Young's modulus of the two groups of driving cables 4, the driving force response surface shown in Figure 11 is obtained. Due to the lightweight characteristics of the space capturing manipulator, the overall driving force demand is low, and the Young's modulus of the expanding driving cable 4 has a significant impact. Low driving force is beneficial to reduce power demand, but excessively elastic expanding driving cable 4 may weaken the final aperture size after contraction. Therefore, appropriate modulus value needs to be selected to balance performance and energy efficiency.
[0038] The present invention is a cable-driven adaptive space capturing manipulator and its capturing control method, which adopts a multi-cable collaborative driving bionic wrapping capturing mechanism, combines bionic flexibility with cable tension collaborative control, controls the flexible capturing net through cable winding and unwinding, adjusts the capturing port diameter in real time according to the size of the captured object, and ensures the uniformity of wrapping through tension feedback, realizes the adaptive and active stiffness adjustment of the cable net, and is suitable for capturing non-cooperative targets in complex space environment.
[0039] The above embodiments are only used to describe the preferred embodiments of the present application, and not intended to limit the scope of the present application, and various changes and modifications of the present application made by those skilled in the art without departing from the spirit of the present application should fall within the scope of the present application defined by the claims.
Claims
1. A flexible cable-driven adaptive space capture manipulator, characterized by: It includes a driving component, a capturing component, a resetting component and a driving flexible rope. Multiple capturing components are distributed around the driving component. The joint bracket of the resetting component is connected to the support seat of the driving component. Multiple driving flexible ropes are cross-wound from top to bottom in the flexible transmission mechanism nodes of the capturing component to form an adaptive capturing net. The driving assembly includes a reel, a slide rail, a transmission rod, a variable pitch disc, a support base and a driving motor. The reel is connected to the output shaft of the take-up motor. A plurality of slide rails are evenly distributed along the circumference of the support base. The first end of the transmission rod is rotatably connected to the support rod on the circumference of the variable pitch disc through a pin shaft. The second end of the transmission rod is rotatably connected to the bottom end of the sliding bracket in the capture assembly. The driving motor and the take-up motor are arranged in the support base. The output shaft of the drive motor is connected to the center of the variable pitch disc. The capture assembly includes a fixed frame, a sliding frame and a flexible transmission mechanism. The two ends of the flexible transmission mechanism are rotatably connected to the fixed frame through pins. The fixed frame is connected to the second end of the sliding frame through a quick-change hook. The sliding frame is slidably connected to the slide rail through the first groove and the steel ball. The reset assembly includes a compression spring, a base, a bearing sleeve, an eccentric ball push shaft, an articulated joint and a joint bracket. The compression spring is sleeved on the bearing sleeve. The two ends of the compression spring are respectively connected to the base and the eccentric ball push shaft. The base is slidingly connected to the eccentric ball push shaft through the ball bearing and the second groove. The bearing sleeve is sleeved on the first end of the eccentric ball push shaft, and the joint bracket and the articulated joint are respectively connected to the base.
2. The cable-driven adaptive spatial capture manipulator according to claim 1, characterized in that: The axes of the wire reel, the pitch-changing disc, the support seat, the pitch-changing motor and the wire-rewinding motor are all located on the same axis.
3. The cable-driven adaptive spatial capture manipulator according to claim 1, characterized in that: The connection between the eccentric ball push shaft and the joint bracket is a spherical contact pair.
4. The cable-driven adaptive spatial capture manipulator according to claim 1, characterized in that: Dynamic diameter adjustment of the capture net, the length L of the i-th driving cable i The relationship with the capture net diameter D is: ； Where R1 is the installation radius of the driving cable on the base, R2 is the radius of the connection point of the capture net, and H is the axial height from the base to the capture net. is the azimuth angle of the i-th driving cable.
5. A capture control method of a flexible cable-driven adaptive spatial capture manipulator according to any one of claims 1 to 4, characterized in that: It includes the following steps: S1. Use the visual sensor to obtain the position, size, and speed of the object to be captured, establish the capture state space equation, and control the drive component to drive the capture component to adjust to the capture area; S2. Dynamic adjustment and control of the capture aperture: When approaching and capturing an object, the variable pitch disc, driven by a variable pitch motor, drives the transmission rod to move, which in turn drives the sliding bracket to slide radially along the slide rail. Based on the relationship between the capture net's contraction rate and the displacement of the driving flexible cable, the capture aperture is dynamically adjusted by retracting and extending the driving flexible cable to adapt to the movement and size of the object. S3. Drive the flexible rope tension to coordinate wrapping: The take-up motor drives the reel to rotate, driving the flexible rope and the flexible transmission mechanism to retract inward. After the flexible transmission mechanism contacts the object to be captured, the object is captured in a flexible and wrapping manner based on the relationship between the capture net tension and the wrapping force. S4, releasing the object to be captured, driving the soft rope to relax, and the flexible transmission structure rebounds to the original position to release the object to be captured. At the same time, the compression spring of the reset component releases the stored elastic potential energy, and the capture component is reset.
6. The capture control method according to claim 5, characterized in that: The state space equation captured in S1 is: ； Where, is the predicted state vector at time k+1, is the state vector, , respectively, the cable driving angle, joint angular velocity, and cable tension, is the input torque of the driving motor, A is the state transfer matrix, B is the input matrix, C is the output matrix, w k is the process noise, is the cable tension, and the objective function of the predicted cable control is: ； Where k is the time step index, N P For the prediction time domain, is the expected value of the cable tension, and Q is the state weight matrix.
7. The capture control method according to claim 5, characterized in that: In S2, the capture net is stretched to wrap the captured object in a cocoon-like manner. The relationship between the capture net contraction rate η and the displacement of the driving cable is: ； Where L0 is the initial length of the driving cable, ΔL is the contraction amount of the driving cable, and θ is the winding angle of the cable. By adjusting ΔL and Parameters dynamically adjust the capture opening diameter of the capture net.
8. The capture control method according to claim 5, characterized in that: Based on the dynamic model of the space capture manipulator in S3, the expression of the relationship between the capture net tension and the wrapping force is obtained as follows: ； Where, F c is the wrapping force of the object to be captured, T i is the tension on the i-th driving cable, is the normal vector of the i-th driving cable, and n is the number of driving cables.