Forward kinematic positioning method of manipulator based on asymmetric variable structure

Abstract

The invention relates to a motion arm forward kinetics positioning method based on an asymmetric variable structure. The method comprises steps that 1, parameter initialization is carried out in an operation space scope; 2, motion expansion of a motion arm composed of multiple asymmetric single modules connected in parallel is carried out to form translation rotation superposition operation of the multiple asymmetric single modules; 3, a relationship between parameters Li and thetai is designed; 4, according to a forward kinetics constraint equation, a transcendental equation is acquired through expansion, and a compact polynomial equation is acquired through utilizing angle parameter transformation; 5, according to an algebraic cancellation method, a final polynomial equation is solved through utilizing a parameter iteration mode; 6, key nodes of an angular expression are calculated; 7, according to a motion tail end pose vector expression of the variable geometric truss motion arm, and the desired position X and the direction n are calculated; and 8, primary positioning of a target pose is realized. Compared with the prior art, the method is advantaged in that measurement precision and empirical value stability of a system can be improved.

Description

technical field [0001] The invention relates to a variable structure space kinematics analysis method, in particular to a forward kinematics positioning method of an operating arm based on an asymmetrical variable structure. Background technique [0002] The space manipulator has the characteristics of adapting to the space operation environment. It adopts an asymmetric variable structure to replace astronauts to complete space operations, which has the advantages of safer, more dexterous and more accurate than the symmetrical structure. In the space-based background, using the concept of modular design, the movement of the manipulator arm formed by the parallel connection of multiple asymmetric single modules is expanded into the superposition operation of translation and rotation of multiple asymmetric single modules. The forward kinematics of the key asymmetric single module can obtain the internal triangular topological relationship of the variable structure by analyzing...

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Problems solved by technology

However, as the kinematic positioning method of these symmetrical variable-structure parallel manipulator arms, it is necessary to fix the end and bottom of the variable-structure single module, and the end and the bottom are required to have symmetry. The bottom of the manipulator platform is installed on the satellite to be positioned. Due to the symmetry The degree of freedom of the structure itself is limited, resulting in insufficient positioning accuracy. Therefore, the forward kinematic positioning problem of asymmetric variable structure needs further study

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