Method for robot to climb multi-step pole column object, storage medium and equipment

Abstract

The application discloses a motion method of a robot for climbing a multi-step rod column object, a storage medium and equipment, and belongs to the field of super-redundant robot motion planning. In order to solve the problem that a snake robot is easily blocked by steps when climbing a multi-step rod column object, the back spine curve of the snake robot is divided into J1, J2 and J3 segments, the J2 segment is connected with the J1 and J3 segments in a continuous and smooth manner, the parameters of the J2 segment cylindrical spiral line are adopted to be polynomial interpolation, the motion of the snake robot is controlled through the segmented back spine curve, the segmented back spine curve is changed in a spring-like stretching and contracting manner with time, the motion of the snake robot is controlled, steps of a rod are crossed, and movement on the surface of a multi-step rod is realized. 2 The segmented back spine curve is continuously and smoothly connected; the segmented back spine curve of the snake robot is constructed based on a segmented spiral line, the parameters of the J2 segment cylindrical spiral line are adopted to be polynomial interpolation, and the motion of the snake robot is controlled through the segmented back spine curve; the segmented back spine curve is changed in a spring-like stretching and contracting manner with time, the motion of the snake robot is controlled, steps of a rod are crossed, and movement on the surface of a multi-step rod is realized. The application is suitable for the field of snake robot motion planning.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of super-redundant robot motion planning, and particularly relates to a motion method for a robot to climb a multi-step pole column object, a storage medium and equipment. BACKGROUND

[0002] With the application of snake robots in the fields of pipelines, post-disaster assistance and rescue, the motion ability of snake robots to adapt to complex environments becomes increasingly important. For the climbing motion of snake robots on pole column objects, a back curve motion planning method is now mostly used to discretize the entire cylindrical helix to generate a motion gait for rolling and climbing the pole column object. In combination with an adaptive control method, the rolling climbing on the surfaces of pole column objects with constant diameters and gradually changing diameters can be well achieved. The gait of this method can adjust the envelope diameter of the links of the snake robot on the pole column object as a whole by adjusting the diameter of the cylindrical helix, but cannot control the local motion of the links of the robot, so the rolling and climbing motion of the robot on the pole column object with multiple steps will be stuck at the steps and cannot proceed, thereby limiting the motion ability of the snake robot in complex unstructured environments. SUMMARY

[0003] The application provides a motion method for a robot to climb a multi-step pole column object to solve the problem that the existing snake robot is easily blocked by steps when climbing a multi-step pole column object.

[0004] A motion method for a robot to climb a multi-step pole column object comprises the following steps:

[0005] Step 1: The back curve of the snake robot is divided into three segments: J1 segment, J2 segment and J3 segment.

[0006] The J1 segment and the J3 segment are designed as cylindrical helixes, the radii of the cylindrical helixes of the J1 segment and the J3 segment are r1 and r3 respectively, and the pitch parameters are p1 and p3 respectively; it is assumed that the parameter q of the parameter curve equation of the J1 segment is in the range of [q0, q1], and the parameter q of the J3 segment is in the range of [q2, q3].

[0007] For the J2 segment curve, a cylindrical helix variant based on a standard cylindrical helix is designed; the value range of the parameter q of the J2 segment curve equation is [q1, q2], the radius is r2, and the pitch parameter is p2. c ;

[0008] The J2 segment is continuously and smoothly connected with the J1 segment and the J3 segment. 2 The parameters r2 and p2 of the J2 segment cylindrical helix are polynomial interpolation. c r2(q) = a1q 5 +a2q 4 +a3q 3 +a4q 2+a5q+a6, wherein a1-a6 are polynomial coefficients; the r2(q) expression needs to satisfy the following equation group constraints

[0009]

[0010] for the parameter p c The p c1 (q) = b1q 3 +b2q 2 +b3q+b4 and p c2 (q) = k1q 3 +k2q 2 +k3q+k4, b1, b2, b3, b4 and k1, k2, k3, k4 are polynomial coefficients; the parameter p c of the J2 segment satisfies the following equation:

[0011]

[0012]

[0013] wherein q c is the parameter that divides the J2 segment into two segments on the q parameter;

[0014] Step two, based on the coefficients a1, a2, a3, a4, a5, a6 and b1, b2, b3, b4 and k1, k2, k3, k4, determine the parameter expression of J2 as

[0015]

[0016] wherein x, y, z are the x-axis, y-axis, z-axis coordinate values of the J2 segment curve at the q parameter in the Cartesian coordinate system;

[0017] If q c < q c , then h1 = b1, h2 = b2, h3 = b3, h4 = b4, otherwise h1 = k1, h2 = k2, h3 = k3, h4 = k4;

[0018] Step three, let the back curve design satisfy the arc length constraint to solve q2, and then solve the values of a1, a2, a3, a4, a5, a6 and b1, b2, b3, b4 and k1, k2, k3, k4, determine the segmented back curve parameter equation of the snake robot;

[0019] Step four, discretize the determined segmented back curve, and then obtain the joint angle required for the pole climbing gait; by controlling the change of the back curve parameter to control the motion of the snake robot.

[0020] Further, by controlling the change of the back spine curve parameters to control the process of the snake robot movement, by changing the parameters r1, r3 and p c of the boundary value p2 to control the segmented back spine curve J1 segment, J3 segment and J2 segment respectively.

[0021] Further, the specific process of controlling the snake robot movement by controlling the change of the back spine curve parameters includes the following steps:

[0022] (1) increase r3, the robot module corresponding to J3 segment is released from the cylinder;

[0023] (2) increase p2, the robot module corresponding to J2 and J3 segment is lifted, and the robot module corresponding to J1 segment remains to hold the cylinder;

[0024] (3) reduce r3, the robot module corresponding to J3 segment is contracted and tightly holds the cylinder;

[0025] (4) increase r1, the robot module corresponding to J1 segment is released from the cylinder;

[0026] (5) reduce p1, the robot module corresponding to J1 and J2 segment is lifted, and the robot module corresponding to J3 segment remains to hold the cylinder;

[0027] (6) reduce r1, the robot module corresponding to J1 segment is contracted, and finally the robot tightly holds the entire cylinder;

[0028] Steps (1)-(6) are a complete pole climbing gait cycle, and the snake robot continuously moves on the surface of the cylinder by continuously repeating the above steps.

[0029] Further, the first order derivative r2'(q) and the second order derivative r2"(q) of r2(q) with respect to the parameter q are 0.

[0030] Further, the parameter q c =(q1+q2) / 2 divides the J2 segment into two segments.

[0031] Further, the back spine curve satisfies the arc length constraint, that is, the arc length is equal to the full length of the snake robot, and the length of each back spine curve is fixed.

[0032] Further, when the back spine curve satisfies the arc length constraint, there are

[0033]

[0034] where M is the arc length of J2 segment; x'(q), y'(q), z'(q) represent the derivative of the curve q of J2 segment, and d represents the differential operator.

[0035] A computer storage medium, the storage medium has at least one instruction, the at least one instruction is loaded and executed by the processor to realize the motion method of the robot climbing multi-step pole column object.

[0036] A motion device for a robot to climb a multi-step pole column object, the device comprises a processor and a memory, the memory has at least one instruction stored therein, the at least one instruction is loaded and executed by the processor to realize the motion method of the robot climbing a multi-step pole column object.

[0037] The present application has the following advantages due to the above technical scheme:

[0038] 1. The present application solves the problem that the existing method of a snake robot cannot climb across multiple steps by constructing a segmented dorsal curve to control the snake robot to climb a multi-step pole column object.

[0039] 2. The present application controls the motion of a snake robot through a segmented dorsal curve, each segment of the dorsal curve can be independently controlled, greatly improving the flexibility of the motion of the snake robot.

[0040] 3. The present application can be constructed through a spatial curve, which has lower development difficulty compared to the existing parameterized gait method, and the parameter setting and adjustment are intuitive and simple. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 is a schematic diagram of the segmented dorsal curve of the method described in the present application.

[0042] Figure 2 is a front view of Figure 1

[0043] Figure 3 is a side view of Figure 1

[0044] Figure 4 is a schematic diagram of the effect of parameter adjustment (r1 increase) of the segmented dorsal curve on the shape change of the dorsal curve.

[0045] Figure 5 is a schematic diagram of the effect of parameter adjustment (r2 increase) of the segmented dorsal curve on the shape change of the dorsal curve.

[0046] Figure 6 is a schematic diagram of the effect of parameter adjustment (p2 increase) of the segmented dorsal curve on the shape change of the dorsal curve.

[0047] Figure 7 is a simulation process diagram of controlling the motion of a snake robot through parameter adjustment of the segmented dorsal curve.

[0048] Figure 8 is a multi-step pole climbing simulation process.​​

[0049] Figure 9 is a discontinuous bar climbing simulation process. DETAILED DESCRIPTION DETAILED DESCRIPTION

[0051] The embodiment is a motion method for a robot to climb a multi-step pole object, comprising the following steps:

[0052] Step one, divide the back curve of the snake robot into three segments. The J1 segment and the J3 segment are designed as standard cylindrical helixes. The J2 segment is used to smoothly connect the J1 segment and the J3 segment.

[0053] The radius of the cylindrical helix of the J1 segment and the J3 segment is r1 and r3 respectively, and the pitch of J1 and J3 is the same, so the corresponding pitch parameter p1 = p3. Assume that the parameter q of the parameter curve equation of the J1 segment is q ∈ [q0, q1], and the q of the J3 segment is q ∈ [q2, q3].

[0054] For the J2 segment curve, in order to facilitate the realization of the climbing gait, the J2 segment is designed to have an appearance close to the cylindrical helix (similar to the cylindrical helix), that is, a variant of the cylindrical helix, which is modified based on the standard cylindrical helix (the modification includes the modification of r2(q) and the value range of q in equation (4)). The value range of the parameter q of the J2 segment curve equation is [q1, q2], the radius is r2, and the pitch parameter is p2. c .

[0055] In order to ensure that the J2 segment and the J1 and J3 segments C 2 are continuously and smoothly connected, for the J2 segment cylindrical helix parameters r2, p c Polynomial interpolation is adopted. Assume that r2(q) = a1q 5 +a2q 4 +a3q 3 +a4q 2 +a5q+a6, where a1-a6 are polynomial coefficients; the first derivative r2'(q) and the second derivative r2"(q) of r2(q) with respect to the parameter q are both constrained, and the cylindrical helix radius needs to be at least twice continuously differentiable at the general parameters q = q1 and q = q2 in the J1 segment and the J3 segment. Considering that the radius r1 and r3 of the back curve of the J1 segment and the J3 segment are numbers independent of the general parameter q, the first derivative r2'(q) and the second derivative r2"(q) of r2(q) with respect to the parameter q are 0, and the expression of r2(q) needs to satisfy the following equation set constraints

[0056]

[0057] Here r1, r3 and q1 are known numbers, and q2 is an unknown number. Thus, the coefficients a1, a2, a3, a4, a5 and a6 represented by q2 can be solved. Since the pitch parameters p of the J1 section and the J3 section are equal, in order to control p c The J2 section is made to stretch and shrink, and in the present embodiment, it is assumed that q c = (q1+q2) / 2, and the J2 section is divided into two sections in terms of the q parameter.

[0058] The J1 section and the J3 section can actually be designed as planar circular arcs or cylindrical helical lines, and the rod object is gripped and released by making the diameter large and small. The J2 section can actually be designed as a cylindrical helical line, and the stretching and shrinking motion is realized by changing the axis length of the J2 section, thereby pushing the corresponding robot modules of the snake robot J1 section and the J3 section to move, and realizing the overall movement of the snake robot.

[0059] Similarly, the parameter p c is constructed by using a cubic polynomial interpolation. c1 (q) = b1q 3 +b2q 2 +b3q+b4 and p c2 (q) = k1q 3 +k2q 2 +k3q+k4, and the parameter p c of the J2 section satisfies the following equation:

[0060]

[0061]

[0062] Then, the coefficients b1, b2, b3 and b4 represented by q2 and k1, k2, k3 and k4 can also be solved.

[0063] Step two, based on the coefficients a1, a2, a3, a4, a5, a6 and b1, b2, b3, b4 and k1, k2, k3, k4, the parameter expression of the J2 section is determined as

[0064]

[0065] where x, y, z are the x-axis, y-axis, z-axis coordinate values of the J2 section curve at the parameter q in the Cartesian coordinate system.

[0066] If q c < q1, then h1 = b1, h2 = b2, h3 = b3, and h4 = b4, otherwise h1 = k1, h2 = k2, h3 = k3, and h4 = k4.

[0067] Step three, the back spine curve design needs to meet the arc length constraint, that is, the arc length is equal to the full length of the snake robot, and the length of each back spine curve is fixed, so there are

[0068]

[0069] Wherein, M is the arc length of J2 segment; x'(q), y'(q), z'(q)) represents the derivative of J2 segment curve at q, d represents the differential operator.

[0070] Through steps one, two and three, the segmented back spine curve parameter equation of the snake robot can be determined.

[0071] Step four, the determined segmented back spine curve is discretized to obtain the joint angle required for the pole climbing gait.

[0072] According to step three, q2 is solved, and then a1, a2, a3, a4, a5, a6 and b1, b2, b3, b4 and k1, k2, k3, k4 are solved. Finally, the segmented back spine curve of the spring-like pole climbing gait is as shown in Figures 1 to 3 .

[0073] When the spring-like segmented back spine curve design is completed, the spring-like back spine curve is discretized by using the discretization formula, and then the spring-like pole climbing gait is obtained, and the spring-like pole climbing gait controls the movement of the snake robot through the change of the spring-like back spine curve, that is, the movement of the snake robot is controlled through the change of the back spine curve parameters.

[0074] The present application controls the segmented back spine curve J1 segment, J3 segment and J2 segment by changing the boundary value p2 of the parameters r1, r3 and p c . Figures 4-6 . Figures 4-6 The segmented back spine curve parameter r1 increases, r2 increases, and p2 increases, respectively.

[0075] Assuming that the initial state of the snake robot is to hold the cylinder, the specific movement process of controlling the movement of the snake robot by changing the back spine curve parameters is as shown in Figure 7 , wherein stage a) represents the opening of J3 segment, stage b) represents the lifting of J3 segment, stage c) represents the contraction of J3 segment, stage d) represents the opening of J1 segment, stage e) represents the lifting of J1 segment, and stage f) represents the contraction of J1 segment.

[0076] The specific process of controlling the movement of the snake robot by changing the back spine curve parameters includes the following steps:

[0077] (1) increase r3, the robot module corresponding to J3 section releases from the cylinder.

[0078] (2) increase p2, the robot module corresponding to J2 and J3 sections is lifted, and the robot module corresponding to J1 section keeps holding the cylinder.

[0079] (3) decrease r3, the robot module corresponding to J3 section is contracted and tightly holds the cylinder.

[0080] (4) increase r1, the robot module corresponding to J1 section releases from the cylinder.

[0081] (5) decrease p1, the robot module corresponding to J1 and J2 sections is lifted, and the robot module corresponding to J3 section keeps holding the cylinder.

[0082] (6) decrease r1, the robot module corresponding to J1 section is contracted, and finally the robot tightly holds the whole cylinder.

[0083] Steps (1)-(6) are a complete pole climbing gait cycle, and the continuous movement of the snake robot on the surface of the cylinder is realized by constantly repeating the above steps. Similarly, the above steps can also realize Figure 8 climbing of a multi-step pole surface, Figure 9 climbing of a discontinuous pole surface. Specific implementation method two:

[0085] The embodiment is a computer storage medium, and the storage medium stores at least one instruction. The at least one instruction is loaded and executed by a processor to realize the motion method of the robot climbing a multi-step pole object.

[0086] It should be understood that the instructions include a computer program product, software or computerized method corresponding to any method described in the present application; the instructions can be used to program a computer system or other electronic device. The computer storage medium can include a readable medium having instructions stored thereon, and can include but is not limited to a magnetic storage medium, an optical storage medium, a magneto-optical storage medium, a read-only memory (ROM), a random access memory (RAM), an erasable programmable memory (such as an EPROM and an EEPROM), and a flash memory layer, or other types of media suitable for storing electronic instructions. Specific implementation method three:

[0088] The embodiment is a motion device of a robot climbing a multi-step pole object, and the device includes a processor and a memory. It should be understood that the device includes any device described in the present application, including a processor and a memory. The device can also include other units, modules, etc. that display, interact, process, control, etc. through signals or instructions, and other functions;

[0089] The memory stores at least one instruction, which is loaded and executed by the processor to implement the motion method of the robot climbing a multi-step pole column object.

[0090] The above examples of the present application are only to illustrate the calculation model and calculation process of the present application, and are not limited to the embodiments of the present application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art, and it is impossible to enumerate all the embodiments here. Any obvious changes or variations derived from the technical solutions of the present application are still within the protection scope of the present application.

Claims

1. A method for a robot to climb a multi-step column object, characterized in that, Includes the following steps: Step 1: Divide the spine curve of the snake robot into 3 segments: J1 segment, J2 segment, and J3 segment; Segments J1 and J3 are designed as cylindrical helices, with radii r1 and r3 respectively, and pitch parameters p1 and p3 respectively; it is assumed that the parameter q∈[q0,q1] of the parametric curve equation of segment J1, and q∈[q2,q3] in segment J3; For the J2 segment curve, it is designed as a variant of the cylindrical helix based on the standard cylindrical helix; the parameter q of the J2 segment curve equation takes values ​​in the range [q1, q2], the radius is r2, and the pitch parameter is p. c ; J2 segment and J1, J3 segment C 2 For a continuous smooth connection, the parameters r2 and p of the cylindrical helix segment J2 are... c Polynomial interpolation is used; r2(q)=a1q 5 +a2q 4 +a3q 3 +a4q 2 +a5q+a6, where a1-a6 are polynomial coefficients; the expression for r2(q) needs to satisfy the following system of equations. For parameter p c Construct p using cubic polynomial interpolation c1 (q)=b1q 3 +b2q 2 +b3q+b4 and p c2 (q)=k1q 3 +k2q 2 +k3q+k4, b1, b2, b3, b4 and k1, k2, k3, k4 are polynomial coefficients; the parameter p of segment J2 c Satisfy the following equation: Where, q c The parameter that divides segment J2 into two segments based on the q parameter; Step 2: Based on the coefficients a1, a2, a3, a4, a5, a6, b1, b2, b3, b4, and k1, k2, k3, k4, determine the parametric expression of J2 as follows: Where x, y, z are the x-axis, y-axis, and z-axis coordinates of the J2 segment curve at parameter q in the Cartesian coordinate system; If q c If h1 = b1, h2 = b2, h3 = b3, h4 = b4; otherwise h1 = k1, h2 = k2, h3 = k3, h4 = k4.​ Step 3: Solve q2 to satisfy the arc length constraint of the spine curve design, and then solve for the values ​​of a1, a2, a3, a4, a5, a6, b1, b2, b3, b4, and k1, k2, k3, k4 to determine the parametric equations of the segmented spine curve of the snake robot. Step 4: Discretize the determined segmented spine curves to obtain the joint angles required for pole climbing gait; control the movement of the snake robot by controlling the changes in the spine curve parameters.

2. The method for a robot to climb a multi-step column object according to claim 1, characterized in that, In controlling the movement of a snake-like robot by varying the parameters of its spine curve, the parameters r1, r3, and p are changed. c The boundary value p2 is used to control the segmented spine curves J1, J3 and J2 respectively.

3. The method for a robot to climb a multi-step column object according to claim 2, characterized in that, The specific process of controlling the movement of a snake-like robot by controlling the changes in the spine curve parameters includes the following steps: (1) Increase r3, and the robot module corresponding to segment J3 is released from the cylinder; (2) Increase p2, corresponding to the robot modules of segments J2 and J3 being raised, while the robot module corresponding to segment J1 remains tightly gripping the cylinder; (3) Decrease r3, and the robot module corresponding to segment J3 will shrink and tightly hug the cylinder; (4) Increase r1, and the robot module corresponding to segment J1 is released from the cylinder; (5) Decrease p1, the robot modules corresponding to segments J1 and J2 are lifted, and the robot module corresponding to segment J3 remains holding the cylinder; (6) Decrease r1, and the robot module corresponding to segment J1 shrinks, so that the robot tightly hugs the entire cylinder. Steps (1)-(6) constitute a complete pole-climbing gait cycle. By continuously repeating the above steps, the snake robot can move continuously on the cylindrical surface.

4. The method for a robot to climb a multi-step column object according to claim 3, characterized in that, The first derivative r2(q) with respect to parameter q, r2'(q), and the second derivative r2""(q) are both 0.

5. A method for a robot to climb a multi-step column object according to claim 1, 2, 3 or 4, characterized in that, The parameter q that divides segment J2 into two segments based on the q parameter. c = (q1+q2) / 2.

6. The method for a robot to climb a multi-step column object according to claim 5, characterized in that, The spine curve satisfies the arc length constraint, that is, the arc length is equal to the total length of the snake robot, and the length of each spine curve segment is fixed.

7. The method for a robot to climb a multi-step column object according to claim 6, characterized in that, When the ridge curve satisfies the arc length constraint, we have Where M is the arc length of segment J2; x'(q),y'(q),z'(q)) represent the derivatives at point q on the curve of segment J2, and d represents the differential operator.

8. A computer storage medium, characterized in that, The storage medium stores at least one instruction, which is loaded and executed by a processor to implement a method for a robot to climb a multi-step column object as described in any one of claims 1 to 7.

9. A motion device for robots to climb multi-step pillar objects, characterized in that, The device includes a processor and a memory, the memory storing at least one instruction, which is loaded and executed by the processor to implement a method for a robot to climb a multi-step column object as described in any one of claims 1 to 7.

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