Parallel mechanism multi-objective optimization design method considering parameter nondeterminacy

Abstract

The invention discloses a parallel mechanism multi-objective optimization design method considering parameter nondeterminacy. The parallel mechanism multi-objective optimization design method comprises the following steps that 1, an analysis mapping model among optimization objectives, constraint conditions and design parameters of a parallel mechanism is constructed; 2, the design parameters obtained after disturbance are regarded as random variables, a probability factor is calculated with the help of Monte Carlo simulation, an analysis mapping model of the probability factor is constructed,probability factor analysis mapping models of all the constraint conditions are fit through a least square method, precision evaluation is carried out on the probability factor analysis mapping models of all the constraint conditions, and the model with highest precision is adopted as the probability factor analysis mapping model of all the constraint conditions, and on this basis, the probability factors larger than or equal to 1 of probability factors are set as the constraint conditions of all parameters; 3, solving is carried out through an objective optimum matching method, and an optimum design parameter is obtained. According to the method, the mechanism optimizing speed is increased.

Description

technical field [0001] The invention relates to an optimal design method, in particular to a multi-objective optimal design method for a parallel mechanism considering parameter uncertainty. Background technique [0002] With the rapid development of aviation, aerospace, medical treatment, and high-end equipment manufacturing, the demand for parallel mechanisms is increasing. Due to the diversity of topological structures of parallel mechanisms and the complexity of design tasks, the optimal design of such mechanisms has been a long-standing challenge in the field of mechanism academia. The reason for this is that the optimization difficulties of parallel mechanisms are mainly manifested in the following aspects: [0003] (1) Diversification of optimization design objectives. [0004] The optimal design of parallel mechanisms is mostly a multi-objective optimal design that comprehensively considers the kinematics, statics and dynamics of the mechanism. It can be generaliz...

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Problems solved by technology

Due to the diversity of topological structures of parallel mechanisms and the complexity of design tasks, the optimal design of such mechanisms has been a long-standing challenge in the field of mechanism academia.

Existing optimization designs usually use a single objective as the optimization function and other objectives as constraints. At present, there is still a lack of multi-objective optimization methods that consider the mutual coupling and competition constraints between objectives.

[0005] (2) Uncertainty of design parameters

[0006] The parallel mechanism consists of multiple kinematic branch chains connecting the static platform and the dynamic platform. The topological structure is relatively complex. At the same time, most of the parts constituting the branch chains are non-standard structures with irregular shapes, resulting in a large number of design parameters for determining the size and cross section of the mechanism.

The design parameters of the mechanism will inevitably have deviations during manufacturing and assembly, which directly leads to uncertainty in the specific values ​​of the design parameters, seriously affecting the performance of the mechanism, and making the actual performance of the mechanism deviate from the theoretical design performance.

At present, there is still a lack of methods to properly solve the problem of design parameter uncertainty.

[0007] (3) The calculation time is longer

At present, there is still no method to ensure the optimization accuracy and shorten the optimization time.

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