CN1081112C - Cubical creeping and walking mechanism of intertube robot - Google Patents

Abstract

The present invention relates to a square cube type creeping walking mechanism of an inner pipe robot, which is formed by the assembly of twelve creeping elements which can axially contract and spread and eight supporting feet. The present invention forms a square cubic type, the twelve creeping elements are positioned on twelve edges of the square cubic and assembled together by the eight supporting feet which are positioned at eight vertexes of the square cubic, and a contact position of the supporting foot and a pipe wall forms a sphere shape. The present invention can realize the microminiaturization of a robot through a rate pipe with a certain curvature, an L-shaped pipe joint, a T-shaped pipe joint and a ten-shaped pipe joint with no need of a special turning device, and can be used as a sports trager of an inner pipe robot for inner pipe detection, flaw detection and maintenance operation so as to have more practicability.

Description

Cubic Peristaltic Walking Mechanism of In-Tube Robot

The invention relates to a peristaltic walking mechanism for an in-pipe robot, in particular to a cube-shaped peristaltic walking mechanism for an in-pipe robot, which can be used as a motion carrier for the in-pipe robot for inspection, flaw detection and maintenance operations, and belongs to the technical field of mechanical engineering robots.

Improving the passability of the robot in the tube is an urgent issue to be solved. Existing in-pipe robots are realized with the assistance of special turning devices through "L", "T" and "+" pipe joints and bend pipes with a certain curvature.

"Robot Technology Handbook" (translated by Zong Guanghua, Liu Haibo, Cheng Junshi, etc., edited by the Robotics Society of Japan, Science Press, 1996: p350-351.) introduces a 2-inch wheeled in-tube robot invented by the Japanese. The wheels are evenly distributed on the outer circumference of the robot and pressed tightly against the inner wall of the pipe. A DC motor drives the four driving wheels to rotate through the reduction gear, and the inner wall of the pipe produces the driving reaction force on the wheels when the wheels rotate to realize the movement in the pipe. There is a roller guide rail at the front end of the robot's head, and another DC motor can drive the rubber belt to rotate on the roller guide rail, using the driving force obtained by the friction between the rubber belt and the inner wall of the pipe and the driving force of the driving wheel to achieve "L" The bend at the pipe joint. However, at the corners of the "T" and "+" pipe joints, the rubber belt cannot touch the inner wall of the pipe, so the robot in the pipe cannot pass through the "T" and "+" pipe joints.

Kochi Suzumori and Akira Abe, Applying Flexible Microactuators to PipelineInspection Robots, Robots, Mechatronics and Manufacturing Systems, T. Takamorian and K. Tsuchiya (Editors), Elsevier Science Publishers B.V. (North-Holland), 19915-5 IMACS introduced in the 5 literature: p A kind of 2 inch wheel type in-tube robot invented by the Japanese, its motion in the tube is also realized by the driving wheels evenly distributed on the outer circumference of the robot through the reduction gear driven by the DC motor. The rubber flexible microactuators (Flexible Microactuators) in the middle of the robot can produce a certain bending deformation by pneumatic drive. The robot can pass through the bending pipe with a certain curvature and the "L", "T" and "+" through the bending of the flexible microactuators. type pipe joint, but the special turning device adopted by this robot increases the size and weight of the robot in the pipe.

The purpose of the present invention is to design and develop a new structure of the peristaltic walking mechanism of the robot in the pipe, so that it can pass through the curved pipe with a certain curvature and the "L", "T" and "+" pipe joints without a special turning device. , to realize the miniaturization of the robot, which is more practical.

In order to achieve such a purpose, the inventor uses a parallel offset shape memory alloy peristaltic mechanism designed by himself (patent application number: 99 2 26926.1) as a peristaltic element, and further develops a tube robot peristaltic walk in the shape of a regular cube. The mechanism is composed of twelve parallel offset shape memory alloy peristaltic elements capable of shrinking and relaxing in the axial direction and eight supporting feet. The appearance is in the shape of a regular cube. Twelve edges are assembled by eight support feet located at the eight vertices of the cube, and the contact between the support feet and the tube wall is spherical.

In order to achieve the goal that the robot can pass through certain curvature elbows and "L", "T" and "+" pipe joints, the walking mechanism should maintain the same shape when the twelve shape memory alloy peristaltic elements are fully contracted and fully expanded. For this reason, the size and performance of the twelve shape-memory alloy peristaltic elements used must be equal, and the structure and size of the eight supporting feet are also exactly the same. The three mounting surfaces of the supporting foot and the three shape memory alloy creeping elements should be perpendicular to each other, so as to ensure that the three shape memory alloy creeping elements installed on the same supporting foot are perpendicular to each other. The support legs are all spherical except for the contact with the three shape memory alloy peristaltic elements, that is, the contact with the pipe wall is spherical. The above structure ensures that when the four supporting legs of the robot in the tube support the inner wall of the tube, the forces applied to the inner wall of the tube are all symmetrical about the axis of the tube, which avoids instability of the robot during motion.

The unique cube-shaped walking mechanism adopted in the present invention ensures that the pose of the robot is the same no matter whether the robot moves along the outer normal direction of any one of the six faces of the walking mechanism. The key to L", "T" and "+" pipe joints.

The peristaltic element of the present invention adopts a parallel offset shape memory alloy peristaltic mechanism. This peristaltic element allows bending deformation in the radial direction, and the fixed connection between the peristaltic element and the supporting foot can ensure that when the four peristaltic elements on one end face of the robot relax. , the four peristaltic elements on the other end parallel to them can shrink to realize the peristalsis of the robot along the radial direction of the pipe.

In the present invention, the twelve peristaltic elements can also adopt other peristaltic mechanisms that do not allow bending and deformation along the radial direction of the peristaltic elements, such as cylinders. When the four peristaltic components are stretched, the four peristaltic components on the other end surface parallel to them can be contracted to realize the peristalsis of the robot along the radial direction of the pipe.

The movement strategy of the cube-type in-pipe robot peristaltic walking mechanism when walking in the pipe and passing through the pipe joint is as follows:

According to the principle of bionics, the movement mode of coelenterate is imitated. During the walking process of the peristaltic walking mechanism, the middle four of the twelve peristaltic elements parallel to the walking direction form a longitudinal muscle group, which contracts and relaxes along the walking direction. , realize the function of the coelenterate longitudinal muscle; the eight at the front and rear ends perpendicular to the walking direction form the front and rear two circular muscle groups, and each group of four is connected in series to form a ring, which contracts and relaxes perpendicular to the walking direction to realize the coelenterate Function of circular muscles in animals. When the parallel offset shape memory alloy peristaltic mechanism is used as the peristaltic element, the three groups of peristaltic elements can be controlled to contract and relax alternately by controlling the time sequence of the current flowing through each group of shape memory alloy peristaltic elements, so as to realize the movement of the peristaltic walking mechanism in the tube. Walking wriggling back and forth. The shape memory alloy peristaltic element allows a certain bending deformation, ensures the independent contraction and relaxation of the front and rear ring muscle groups, and makes the inner tube walking mechanism suitable for a curved tube with a certain curvature.

When the cylinder is used as the peristaltic element, the three groups of peristaltic elements can be controlled to contract and relax alternately by controlling the switching sequence of the directional control valves of each group of cylinders, so as to realize the forward and backward peristaltic walking of the peristaltic walking mechanism in the tube. The cylinder and the supporting foot are connected by a ball hinge, which ensures the independent contraction and relaxation of the front and rear ring muscle groups, and makes the inner tube walking mechanism suitable for curved tubes with a certain curvature.

When encountering "L", "T", and "+" type pipe joints, when it is necessary to change the direction of movement, the original longitudinal muscle group and the circular muscle group are dismantled, and the four parallel muscle groups parallel to the new movement direction are dismantled. A new longitudinal muscle group is formed to perform the function of the longitudinal muscle; the eight perpendicular to the new movement direction are formed into two new circular muscle groups before and after, which perform the function of the coelenterate circular muscle. In this way, the peristaltic walking mechanism can move forward and backward, up and down, and left and right in the pipe in any direction without adjusting the posture, and can pass through the "L", "T" and "+" pipe joints smoothly.

In order to better understand the technical solution of the present invention, a further detailed description will be given below in conjunction with the accompanying drawings and embodiments.

Fig. 1 is a schematic structural diagram of a peristaltic element used in the present invention.

The peristaltic element shown in the figure is a parallel eccentric shape memory alloy peristaltic mechanism. There is an elastic clip 4 at both ends of the peristaltic mechanism, and a shape-memory Alloy SMA helical spring 3, the two ends of SMA helical spring 3 are clamped with elastic clip 4, and a common helical spring 1 is sheathed on the outside of cylindrical sleeve 2, and its two ends stand on the step of cylindrical sleeve 2 respectively.

The cylindrical sleeve 2 can prevent the electrical contact between the SMA coil spring 3 and the ordinary coil spring 1, prevent the ordinary coil spring 1 from becoming unstable after being compressed, and ensure that the peristaltic element can withstand a certain radial force and allow a certain bending deformation.

Fig. 2 is a schematic diagram of a regular cube structure of the present invention.

It can be seen from the figure that the cube-shaped peristaltic walking mechanism of the robot in the tube is assembled by twelve parallel offset shape memory alloy peristaltic elements (numbered from 1# to 12#) that can contract and relax along the axis and eight supporting feet 5, The appearance is in the shape of a regular cube, and twelve shape memory alloy peristaltic elements are located at the twelve edges of the regular cube, and are assembled into one body by eight supporting feet 5 at the eight vertices of the regular cube.

When the walking direction of the robot is consistent with the normal direction of the plane where the four creeping elements 1#, 2#, 3#, and 4# are located in the creeping walking mechanism, the four creeping elements 5#, 6#, 7#, and 8# are composed of For the longitudinal muscle group, four peristaltic elements 1#, 2#, 3#, and 4# form a circular muscle group, and four peristaltic elements 9#, 10#, 11#, and 12# form another circular muscle group. When the robot needs to move to the normal direction of the plane where the four peristaltic elements of 1#, 5#, 9#, and 8# are located, the above-mentioned peristaltic elements in the longitudinal muscle group and the circular muscle group are disassembled, and the 2#, 4 #, 12#, 10# four peristaltic elements form a new longitudinal muscle group, 1#, 5#, 9#, 8# four peristaltic elements form a new circular muscle group, 6#, 3#, 7#, 11# four peristaltic elements form another new circular muscle group.

The process of controlling the peristaltic walking mechanism to wriggle and walk in the tube is actually the process of controlling the contraction and relaxation of the twelve peristaltic elements according to a certain time sequence.

The contraction and relaxation of the shape memory alloy peristaltic element is realized by causing the shape memory alloy helical spring to undergo a cold-heat cycle. The present invention uses electricity to heat the shape memory alloy helical spring to shrink the shape memory alloy peristaltic element, and uses a single-chip microcomputer to control the timing of energization. and the strength of the current. The shape memory alloy peristaltic element is stretched by naturally cooling the shape memory alloy helical spring.

Fig. 3 is a control circuit diagram of the peristaltic traveling mechanism in the present invention in all directions peristaltic travel in the pipe.

In the figure, the output from the single-chip microcomputer PIC16C711 enters the twelve transistors, which are twelve-way PWM signals implemented by software. The transistors play the role of switching and amplification, and the duty ratio of the PWM signal is controlled by controlling the duty cycle of the shape memory alloy coil spring SMA. The intensity of the average current, the intensity of the average current is divided into three levels, and the heat generated by them respectively causes the shape memory alloy coil spring to undergo martensitic reverse phase transformation when it is heated up, maintains the high-temperature austenite state at a constant temperature, and generates martensitic phase when the temperature is lowered. Change, make the shape memory alloy peristaltic element in the contraction state, maintain the contraction state and the relaxation state respectively. By controlling the time sequence of twelve PWM signals to control the time sequence of contraction and relaxation of twelve shape memory alloy peristaltic elements, the peristaltic walking mechanism can realize omnidirectional peristaltic walking in the tube.

When using the parallel offset shape memory alloy peristaltic mechanism as the peristaltic element, the peristaltic elements belonging to the same group are heated and stopped at the same time during the movement, so that they are in step with each other during the movement. When the cylinder is used as the peristaltic element, the directional control valves of the cylinders belonging to the same group are switched at the same time during the movement, so that they are in step with each other during the movement.

Claims (3)

1. A cube-shaped peristaltic walking mechanism of a robot in a tube, which is characterized in that it is assembled from twelve peristaltic elements capable of shrinking and relaxing in the axial direction and eight supporting feet (5), and is in the shape of a regular cube, with twelve peristaltic elements The elements are located at the twelve edges of the regular cube, and are assembled into one body by eight supporting feet (5) at the eight apexes of the regular cube, and the contact between the supporting feet (5) and the pipe wall is spherical. 2. The cube-shaped peristaltic walking mechanism of the in-tube robot as claimed in claim 1, characterized in that the peristaltic element used is a parallel offset shape memory alloy peristaltic mechanism that allows bending deformation in the radial direction, and the peristaltic element is fixed to the supporting feet connect. 3. The cube-shaped peristaltic walking mechanism of the in-pipe robot as claimed in claim 1, characterized in that the peristaltic element used is a cylinder that does not allow bending deformation in the radial direction, and the peristaltic element is connected to the supporting foot by a ball joint.

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