A cable layout method for a continuum robot

Abstract

The present disclosure discloses a cable layout method for a continuum robot, comprising the following steps: S100: pulling out the b end of the first drive cable from the original cable through hole on the metal ring; S200: removing the a end of the second drive cable from the second lead screw module, and pulling out the b end from the original cable through hole on the metal ring; S300: connecting the middle part of the first drive cable with the a end of the second drive cable, and passing the b end of the first drive cable and the b end of the second drive cable through the cable through hole after the layout is optimized. The present disclosure optimizes the layout of the cables, so that the original need to calculate the length change of all the drive cables is simplified to only need to calculate the length change of half of the drive cables, thereby simplifying motion control and improving calculation efficiency.

Description

Technical Field

[0001] The present disclosure belongs to the field of robot technology, and in particular relates to a cable layout method for a continuum robot. Background Art

[0002] As a novel biomimetic robot, continuum robots have attracted increasing attention in the past two decades due to their unique flexibility and adaptability to narrow spaces. Compared with traditional rigid-link robots, continuum robots can better adapt to confined and unstructured spaces by flexibly changing their own shapes. Thanks to these characteristics, continuum robots are widely used in minimally invasive surgery, nuclear reactor maintenance, and post-earthquake search and rescue. In recent years, continuum robots have been used as a novel solution for inspection and maintenance in the field of aerospace engineering, which has aroused widespread interest from all walks of life.

[0003] However, although its external wire drive method greatly miniaturizes the size of the robot body, making it easier for it to invade narrow, unstructured confined spaces, it causes the drive system at the end to become quite large. Generally speaking, a section of a robot arm joint usually requires 3 to 4 cables to drive, which means that with the same number of degrees of freedom, this type of wire-driven continuum robot has more drive motors than traditional industrial robots, so its control is more complex and more expensive. At present, the structural optimization of continuum robots is mostly focused on the joint configuration of the robot body, and there is little optimization of the drive system. Although the layout of the drive module can be optimized to a certain extent, such as the ring layout and the rectangular layout, it can optimize the size of the drive system to make it more compact, but these layout schemes only physically optimize its geometric size and do not essentially reduce the complexity of its control. In fact, the core issue of optimizing its drive system is to optimize the number of drive modules. There are schemes that reduce the number of drive motors by sharing cables with multiple joints. Although this approach does not sacrifice some workspace, it reduces the motion stability of the robot arm. However, for some restricted environments, such as the combustion chamber of an aircraft engine, the continuum robot is not required to have a large enough workspace, which means that we can reduce some redundant degrees of freedom and still be able to complete the corresponding task requirements. However, simply reducing the drive cables will cause the continuum robot to become unstable.

[0004] Therefore, technicians in this field are committed to proposing a cable layout method for a wire-driven continuum robot, which simplifies motion control by optimizing the cable layout without affecting its motion stability, thereby optimizing the drive system. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention aims to provide a cable layout method for a wire-driven continuum robot, which simplifies the motion control of the robot arm by optimizing the cable layout.

[0006] To achieve the above objectives, the present disclosure provides the following technical solutions:

[0007] A cable layout method for a continuum robot, the continuum robot comprising a continuum mechanical arm, the continuum mechanical arm comprising a plurality of metal rings, each of which is provided with a plurality of groups of cable through holes; the continuum robot further comprising a plurality of lead screw modules, each of which is provided with a wire locker for locking the a end of a drive cable, the b end of the drive cable passing through the cable through hole to transmit traction to the metal ring so that the continuum mechanical arm performs bending motion, characterized in that the method comprises the following steps:

[0008] S100: Pull out the end b of the first driving cable from the original cable through hole on the metal ring;

[0009] S200: Remove the end a of the second drive cable from the second lead screw module, and pull the end b out of the original cable through hole on the metal ring;

[0010] S300: Connect the middle portion of the first drive cable to the end a of the second drive cable, and pass the end b of the first drive cable and the end b of the second drive cable through the cable through hole after the layout is optimized.

[0011] Preferably, in step S300, end a of the second driving cable is connected to the middle portion of the first driving cable via a connector.

[0012] Preferably, the connecting member comprises a locking sleeve, a socket is provided on the locking sleeve, and a screw is provided in the socket.

[0013] Preferably, in step S300, optimizing the layout of the cable through holes includes: symmetrically arranging the cable through holes on the metal ring.

[0014] Compared with the prior art, the beneficial effects brought about by the present disclosure are: the present disclosure can reduce the number of drive modules of the continuum robot arm by optimizing the layout of the drive cables, and compared with the traditional cable layout method, it will not sacrifice the degrees of freedom of the continuum robot arm, and at the same time can better overcome the influence of the self-weight on the robot arm, and has universality for the cable layout of the continuum robot. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a flow chart of a cable layout method of a wire-driven continuum robot provided by one embodiment of the present disclosure;

[0016] Figure 2is a schematic structural diagram of a continuum robot provided by another embodiment of the present disclosure;

[0017] Figure 3 yes Figure 2 Schematic diagram of the continuum robotic arm structure;

[0018] Figure 4 It is an optimized schematic diagram of the drive cable;

[0019] Figure 5(a) is a schematic diagram of the cable layout before optimization;

[0020] Figure 5(b) is a schematic diagram of the optimized cable layout;

[0021] Figure 6 is an enlarged schematic diagram of the cable through-hole layout of FIG5( b );

[0022] Figure 7 are the performance test results of two cable layouts of the continuum robot. DETAILED DESCRIPTION

[0023] The following will refer to the attached Figures 1 to 7 Specific embodiments of the present disclosure are described in detail. Although specific embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0024] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned throughout the specification and claims, "including" or "comprising" is an open term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present disclosure, but the description is based on the general principles of the specification and is not used to limit the scope of the present disclosure. The scope of protection of the present disclosure shall be determined by the attached claims.

[0025] To facilitate understanding of the embodiments of the present disclosure, further explanation will be given below using specific embodiments as examples in conjunction with the accompanying drawings, and each of the accompanying drawings does not constitute a limitation on the embodiments of the present disclosure.

[0026] In one embodiment, if Figure 1 As shown, the present disclosure provides a cable layout method for a continuum robot, wherein the continuum robot is as follows Figure 2As shown, it specifically includes an optical platform 3, on which the optical platform 3 is provided with Figure 3 The L-shaped fixing plate 12 shown in the figure has a continuum robot 4 arranged on it, and the continuum robot 4 includes a robot body 13, and the robot body includes a plurality of metal rings 15, and each metal ring 15 is provided with a plurality of cable through holes; the optical platform 3 is also provided with a plurality of lead screw modules 6, each lead screw module is provided with a slider, and the slider is provided with a wire locker for locking the a end of the drive cable, and the b end of the drive cable passes through the cable through hole via the pulley group 5, and the drive cable transmits traction to the metal ring under the action of the driver 9 so that the continuum robot performs bending motion, characterized in that the method comprises the following steps:

[0027] S100: Pull out the end b of the first driving cable from the original cable through hole on the metal ring;

[0028] S200: Remove the end a of the second drive cable from the second lead screw module, and pull the end b out of the original cable through hole on the metal ring;

[0029] S300: Figure 4 As shown, the middle part of the first drive cable 21 is connected to the end a of the second drive cable 22, and the end b of the first drive cable 21 and the end b of the second drive cable 22 are passed through the cable through hole after the layout is optimized.

[0030] This embodiment optimizes the layout of the existing drive cables, that is, the original method of controlling one drive cable by one screw module (as shown in Figure 5 (a), cable 1 is driven by screw module A, cable 2 is driven by screw module B, cable 3 is driven by screw module C, and cable 4 is driven by screw module D) is optimized to a method of controlling two drive cables by one screw module (as shown in Figure 5 (b), cable 1 and cable 2 are driven by screw module A, and cable 3 and cable 4 are driven by screw module B). Compared with the existing drive method, the optimized drive method can save half of the screw modules, so that the original need to calculate the length change of all drive cables is simplified to only need to calculate the length change of half of the drive cables, thereby simplifying motion control and improving calculation efficiency. At the same time, the number of drive cables used to control the continuum robot arm remains unchanged, so it will not affect the motion stability of the robot arm. In addition, since the optimized layout saves half of the screw modules, the number of drive cables can be increased, thereby strengthening the control of the robot arm.

[0031] In another embodiment, in step S300, end a of the second driving cable is connected to the middle portion of the first driving cable via a connector.

[0032] In this embodiment, the connecting piece includes a locking sleeve 24, a socket is provided on the locking sleeve 24, and a screw 23 is provided in the socket. It should be noted that before the end a of the first drive cable is locked with the lead screw module, the end a of the first drive cable is first passed through the locking sleeve and connected to the wire locker, so that the locking sleeve is pre-set in the middle of the first drive cable.

[0033] In another embodiment, in step S300, optimizing the layout of the cable through holes includes: symmetrically arranging the cable through holes on the metal ring.

[0034] In this embodiment, the optimized cable through-hole layout is shown in FIG. 5( b ) and FIG. Figure 6 As shown ( Figure 6 5(b) is an enlarged view of the cable through hole layout. The cable through holes are arranged in an inner circle and an outer circle, and each group of cable through holes is relative to the symmetry axis 1 (i.e. Figure 6 25) and the axis of symmetry 2 (i.e. Figure 6 The metal ring is symmetrically arranged with the mark 26 shown, and the cables passing through any through hole in each group of cable through holes are also symmetrically arranged. For example, all the cable through holes on the metal ring are divided into group 1, group 2, group 3 and group 4, and there are 4 cables passing through the cable through holes, which are respectively recorded as cable 1, cable 2, cable 3 and cable 4. Among them, cable 1 passes through group 1, cable 2 passes through group 2, cable 3 passes through group 3, and cable 4 passes through group 4. At this time, it is necessary to arrange cable 1 and cable 2 symmetrically along the symmetry axis 1 ( Figure 6 In the embodiment, cable 1 is passed through the cable through hole 28 in group 1, and cable 2 is passed through the cable through hole 27 in group 2. This is merely exemplary, i.e., cable 1 and cable 2 only need to be passed through the symmetrical cable through holes in group 1 and group 2, respectively. The same is true for cables 3 and 4.

[0035] Furthermore, it is necessary to arrange the cables 2 and 3 symmetrically along the symmetry axis 2 (i.e. Figure 6 As shown in , cable 2 is passed through cable through-hole 27 in group 2, and cable 3 is passed through cable through-hole 29 in group 3. This is also exemplary, that is, cable 2 and cable 3 only need to be passed through symmetrical cable through-holes in group 2 and group 3 respectively).

[0036] Below, this disclosure takes a single-segment continuum robot arm as an example, and performs 0° to 90° bending tests on the cable layout before and after optimization to evaluate the motion performance of the two methods. The test results are as follows: Figure 7As shown. Among them, the O-shaped solid line curve is the theoretical arm shape result, the square dotted line curve is the arm shape result under the traditional cable layout, and the triangular dot-dash line curve is the arm shape result after the cable layout is optimized. From the comparison results, it can be seen that the arm shape result after the cable layout is optimized is closer to the theoretical arm shape result than the arm shape result of the traditional cable layout, and its arm shape is less affected by its own gravity (as mentioned above, the continuum robot arm before optimization is controlled by 4 cables, each cable is controlled by 1 motor, assuming that the length of the robot arm is L, the optimized layout is that two cables are driven by 1 motor, then the original 4 cables only need 2 motors to drive after optimization, and there are 2 motors left at this time. We can set 4 more cables at the position of L / 2 of the robot arm. Compared with the layout before optimization, the drooping offset of the middle position of the robot arm can be made smaller by the tension of the cable). Therefore, in comparison, the cable layout method proposed in the present disclosure can make the continuum robot have better motion performance than the traditional cable layout method.

[0037] It is not difficult to see from the above embodiments that the cable layout method of the wire-driven continuum robot proposed in the present invention does not sacrifice the degree of freedom of the continuum robot arm compared to the traditional cable layout method, and can better overcome the influence of its own weight on the robot arm. It is universal for the cable layout of the continuum robot, and the cable layout method is free and flexible, which is universal for the cable layout of the continuum robot.

Claims

1. A cable layout method for a continuum robot, the continuum robot comprising a continuum robot arm, the continuum robot arm comprising a plurality of metal rings, each metal ring being provided with a plurality of cable through holes; the continuum robot further comprising a plurality of lead screw modules, the plurality of lead screw modules comprising lead screw module A, lead screw module B, lead screw module C and lead screw module D, each lead screw module being provided with a wire locker for locking end a of a drive cable, end b of the drive cable passing through the cable through hole to transmit traction to the metal ring so that the continuum robot arm performs bending motion, characterized in that: The method comprises the following steps: S100: Pull out the end b of the first driving cable from the original cable through hole on the metal ring; S200: removing the end a of the second drive cable from the second screw module, namely the screw module B, and pulling the end b out of the original cable through hole on the metal ring; S300: Connecting the middle portion of the first drive cable to the end a of the second drive cable, and passing the end b of the first drive cable and the end b of the second drive cable through the cable through hole after the layout is optimized; Optimizing the layout of the cable through holes includes: symmetrically arranging the cable through holes on the metal ring; specifically, the cable through holes are arranged according to an inner circle and an outer circle, and each group of cable through holes is symmetrically arranged relative to a symmetry axis 1 and a symmetry axis 2, and the cables passing through any through holes in each group of cable through holes are also symmetrically arranged.

2. The method according to claim 1, wherein: In step S300, the end a of the second driving cable is connected to the middle portion of the first driving cable via a connector.

3. The method according to claim 2, wherein: The connecting piece comprises a locking sleeve, a plug hole is arranged on the locking sleeve, and a screw is arranged in the plug hole.

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