CN-121777207-B - Stability optimization method for internal support type mobile processing robot

Abstract

The invention discloses a stability optimization method of an internal support type mobile processing robot, and belongs to the technical field of robot processing. The method optimizes stability by actively regulating and controlling the supporting force. Firstly, the contact between the roller and the inner wall of the pipe is analyzed to form a force constraint condition of a contact interface. And secondly, establishing a force balance relation of the whole mobile processing robot through dynamic and static analysis. Next, potential disturbance characterization and dynamic machining force dispersion are carried out, and a high-disturbance-resistance supporting force distribution model is constructed by combining established constraint conditions, force balance relation and supporting force output constraint. Finally, the numerical value of each supporting force is obtained through linear optimization calculation. The robot is always kept stable in the operation task under the supporting force, so that the anti-interference capability of the robot is obviously enhanced. According to the invention, the overturning and sliding risks faced by the mobile robot in the process of processing in the pipe are solved by a supporting force regulation method, and the stability of the robot is effectively ensured.

Inventors

• LI TE
• LAN TIAN
• Mao Chongbo
• LIU HAIBO
• LI XU
• BO QILE
• WANG YONGQING

Assignees

• 大连理工大学

Dates

Publication Date

20260508

Application Date

20260309

Claims (2)

1. 1. A stability optimization method of an internal bracing type mobile processing robot is characterized by comprising the steps of firstly analyzing contact of a roller and the inner wall of a pipe to form a force constraint condition of a contact interface, secondly establishing a force balance relation of the whole mobile processing robot through dynamics and statics analysis, secondly performing potential disturbance characterization and dynamic processing force dispersion, combining the established constraint condition, the force balance relation and supporting force output constraint to construct a high-disturbance-resistance supporting force distribution model, and finally obtaining numerical values of supporting forces through linear optimization calculation; the method comprises the following specific steps: Step one, establishing contact interface constraint conditions Firstly, establishing contact constraint of a single roller and the inner wall of a pipe, wherein under a quasi-static condition, the contact force between the roller and the inner wall of the pipe accords with a friction cone form, and in order to avoid complexity of nonlinear solving, the friction cone is approximated to be a rectangular pyramid, so that the contact force relation of the single roller is established: (1) Wherein, the Is a friction coefficient component; i represents the index of the supporting unit and the moving unit, k represents the index of the wheels in the moving unit; And Tangential components of the contact force in the x-direction and the y-direction, respectively; Representing the normal component of the contact force in the z-direction; an operator that is an orientation quantity norm; And Respectively representing the resistance coefficients of the roller along the x direction and the y direction; Next, establishing equivalent contact constraint of the motion unit, establishing equivalent contact point, and generating equivalent contact force Relationship to indicate contact of the rollers; (2) Wherein, the 、 And Respectively represent The components along the x, y, z three directions are noted as ; And Mapping the relation from single contact constraint to equivalent constraint of a motion unit for the resistance coefficient of the roller along the x direction and the y direction respectively; Namely, the contact interface constraint condition; Step two, establishing a stable and balanced relation of the robot First, the dynamics analysis of the processing mechanism is carried out, and the inertia force is established Cutting force The force applied to the robot body is expressed as a working force ; (3) Wherein, the Is the dynamic relationship of a processing mechanism; Then, carrying out overall mechanical modeling of the robot, and establishing an overall force balance relation under the stable state of the robot: (4) Wherein, the Is applied with force to the robot body, Supporting a branched force for each motion, which is an intermediate quantity for the force transfer representation, Is the gravity of the robot body, In order to transform the kinematic transformation relation matrix from the kinematic supporting branched chain coordinate system { c i } to the robot coordinate system { r }, For the kinematic transformation relation matrix of the machine coordinate system { a 0 } to the robot coordinate system { r }, n is the index maximum of the support unit and the motion unit, i.e ; Establishing the internal force relation of each motion supporting branched chain: (5) Wherein, the A primary force applied to each motion support branch; And Respectively the statics of the forces in the branched chain; the robot overall force balance relationship expressed by gravity, processing force, active supporting force and contact force is obtained, and is expressed as: (6) The relation between the active supporting force and the contact force in the branched chain is as follows: (7) Wherein, the Is the mechanical relationship between the contact force in the branched chain and the active supporting force; And The robot stable equilibrium relation is obtained; Step three, establishing a high-disturbance-rejection supporting force distribution model Firstly, dispersing dynamic machining force, dispersing force generated in continuous dynamic machining process into N groups of machining force to form machining force vector The corresponding contact force vector is Expressed as: (8) correspondingly, the robot force balance relation under the action of dynamic processing force is based on Is expanded into : (9) Wherein, the ; ; Representing a column vector of length N, wherein all elements are equal to 1, and Then represents an N-dimensional identity matrix; Next, potential disturbance characterization is performed, potential disturbance direction vectors acting on the robot are determined according to the disturbance source, and the disturbance direction vector sets are recorded as , wherein, J= 1~m, the magnitude of the disturbance force that the robot can resist is expressed as The disturbance forces in all directions can be described as In a force-balancing relationship, i.e. in Based on expansion into : (10) Next, a drive output force constraint is established, taking into account that the actual force drive device has an upper output force limit, denoted as Thus increasing the constraint relationship to the active supporting force: (11) Through the steps, the formed constraint conditions and balance relation 、 、 、 A high immunity support force distribution model is constructed, expressed as: (12) Wherein, the For each branched chain Is expressed as ; Step four, linear optimization calculation The linear programming method is adopted, and the calculation formula is as follows: (13) the active supporting force distribution which ensures the stability of the mobile processing robot and has the optimal disturbance resistance can be obtained through calculation, so that the stability optimization of the robot is realized.
2. 2. The method for optimizing stability of the internal bracing type mobile machining robot is characterized by comprising a measuring machining unit, a supporting unit, a moving unit and a main body shell, wherein the measuring machining unit of the robot is arranged at the front end of the main body shell and is provided with a measuring and machining device and driven by a rotary, radial and axial three-degree-of-freedom serial movement mechanism to finish machining tasks of inner wall characteristics of a cylinder, the supporting unit is arranged inside the main body shell and is used as a main body, 6 groups of supporting units are uniformly distributed in the circumferential direction at intervals of 120 degrees, each cylinder of the supporting unit is independently controlled, the supporting unit can stretch out of the inner diameter of a self-adaptive tube and adjust the output supporting force by changing input air pressure, the moving unit is provided with two pairs of rollers, at least one pair of rollers is driven by a motor, the other wheels are driven wheels, the moving unit is connected with the supporting unit through hinges and has a rotary degree of freedom, and the taper of the self-adaptive tube ensures that the rollers are attached to the inner wall.

Description

Stability optimization method for internal support type mobile processing robot Technical Field The invention belongs to the technical field of robot processing, and relates to a stability optimization method of an internal support type mobile processing robot, which is used for guaranteeing high-quality and reliable in-pipe processing of the mobile robot. Background The mobile processing robot is used as important operation equipment for in-situ processing, and is widely applied to the fields of ships, aerospace, nuclear industry and the like. With the continuous improvement of engineering demands, the internal processing tasks aiming at narrow and limited structures such as pipelines, containers and the like are increasingly increased, and the application scene of the internal processing tasks is gradually expanding to more complex and harsh environments such as small diameter, deep cavities and the like. Unlike conventional stationary processing equipment, mobile processing robots do not have a stable external base, and their operational stability is mainly dependent on the force-moment equilibrium relationship established between the robot itself and the environment. In the actual machining process, various factors such as cutting force, inertia force, external environment disturbance and the like are mutually overlapped, so that the original stress balance state is extremely easy to damage, and the destabilization phenomena such as robot overturning or sliding and the like are caused, so that the machining precision is reduced, the operation is failed, even workpieces are damaged, and the reliability and the safety of the machining process are seriously influenced. Aiming at complex working conditions such as cylindrical or conical structure, pipe diameter change, local geometric deformation and the like in an in-pipe working environment, the mobile processing robot generally adopts an internal support type structural design with reducing capacity. However, such highly compliant structures further exacerbate stability problems under process loads. Therefore, there is a need to develop stability modeling and optimization research for internal bracing type mobile processing robots to improve the safety and operation reliability of the internal bracing type mobile processing robots under complex in-pipe processing conditions. In recent years, related research work has been carried out on the problem of the processing stability of mobile robots. Patent CN118444565A discloses a four-foot robot stability criterion method based on critical stability margin, which is used for robot stability determination, but is only applicable to robots based on planar support. Patent CN114839878a discloses a bipedal robot walking stability optimization method based on improved PPO algorithm, which realizes walking stability, and adopts neural network with high cost and poor generalization capability, and is difficult to be applied to industrial environment and robots with other configurations. Both of the above methods are not applicable to an internal bracing type mobile processing robot. Patent CN120619943a discloses a municipal drainage pipeline local polishing robot and a method thereof, wherein a hydraulic push rod is arranged at the upper part of the robot, and the wall of the pipe is tightly pushed to resist the processing force and moment in the processing process. The method can be applied to an internal bracing type mobile processing robot, but the stability enhancement mode is non-task oriented, and is difficult to conduct pertinence enhancement according to specific processing tasks and potential instability directions, so that more conservative processing parameters have to be adopted in practical application, and the performance of the processing performance of the robot is limited. Disclosure of Invention The invention aims to solve the problem of processing stability of an internal bracing type mobile processing robot in the current pipeline and container operation, and provides a method for optimizing the stability of the internal bracing type mobile processing robot. The invention discloses an internal bracing type mobile machining robot with controllable supporting force, which comprises a measuring and machining unit, a supporting unit, a moving unit and a main body shell. The measuring and processing unit of the robot is arranged at the front end of the main body shell, is provided with a measuring and processing device, is driven by a rotary, radial and axial three-degree-of-freedom serial motion mechanism and is used for completing the processing task of the inner wall characteristics of the cylinder. The support units are arranged in the main body shell and are taken as a main body, 6 groups of support units are circumferentially and uniformly distributed in front and back rows at intervals of 120 degrees, and each cylinder of each support unit is independently controlled and can extend out of the in