A method for optimizing structural parameters of space manipulator based on operability

Abstract

The invention provides a space mechanical arm structure parameter optimization method based on operability. The method comprises the following steps that (1) the freedom degree layout of a space mechanical arm and an initial parameter of an arm rod are determined; (2) the mechanical arm direct kinematics is applied, and the reachable work space of the space mechanical arm is determined by a numerical value method; (3) an upper half circle part is taken from a symmetrical surface of the reachable work space, and is divided into c*c sub regions, c is a positive integer, then, flexible posture probability coefficients are respectively calculated for each sub region, and a flexible work space chart of the whole reachable work space is obtained; (4) in the reachable work space, M work points are randomly selected, the respective corresponding flexible posture probability coefficients are calculated, in addition, the number m of work points greater than alpha in the posture probability coefficients is counted, and the mechanical arm operability is obtained; (5) the reciprocal number of the operability is used as an adaptability degree function, and the parameters of each arm rod of the space mechanical arm are optimized by a genetic algorithm.

Description

technical field [0001] The invention relates to a structural design method of a six-degree-of-freedom or redundant space manipulator. Background technique [0002] Since the 1950s, a variety of spacecraft, such as satellites, space shuttles, space stations, and various probes have been launched into space, and it has become essential for the on-orbit maintenance and recovery of these spacecraft work. If some in-orbit spacecraft that are out of service or malfunctioning are recovered, maintained, and reused by space manipulators, a lot of human resources and funds can be saved. In order to make the manipulator have better flexibility and operability, meet the requirements of performing multiple tasks in space, and at the same time make the manipulator have better versatility, and further reduce the cost of the entire space mission, the optimal design of the manipulator is particularly important. important. Most space manipulators are manipulators with six degrees of freedo...

AI Technical Summary

Problems solved by technology

GCI is a performance index based on the Jacobian matrix condition number distributed over the entire manipulator workspace. It can measure the kinematic reversibility of the manipulator over the entire workspace. However, when the condition number of the global condition index is a non-smooth curve, Its calculated value will deviate from the actual value; in addition, for six degrees of freedom or redundant manipulators, the global condition index is not easy to obtain

[0004] The above methods all design the manipulator based on the reversible criterion of manipulator kinematics and the workspace criterion, which cannot reflect the flexibility of the manipulator in the workspace; while the condition number criterion is a local performance index and cannot be used as the global design index of the manipulator; Although the global condition index can measure the kinematic reversibility of the manipulator in the entire workspace, it is more convenient to use this index on the manipulator with few degrees of freedom. For six degrees of freedom or redundant manipulators, it is difficult to obtain its expression, so it is necessary to study the optimal design method of multi-configuration manipulator based on flexibility

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