Analysis On Reconfiguration Principle Of Generalized Parallel Mechanisms And Modal Control Theory

Compared with serial mechanisms,parallel mechanisms possess the characteristics of high stiffness,high precision and high bearing capacity.As a result,parallel mechanisms have been widely used in many fields such as isolation,precision pointing and motion simulation.Decoupling research of parallel mechanism is of great significance.Generally speaking,decoupling research is divided into the structure optimization design and control strategy.In this paper,the generalized parallel mechanism which is described by composite hyperboloids is studied.The research varies from the decoupling design and optimization,control strategy and experimental verification etc.The specific content is presented as follows:The discourse upon the generalized parallel mechanism configuration classification,decoupling method based on definition and description of composite hyperboloids is presented.Compound Decoupling Algorithm(CDA)is carried out based on the decoupling condition,which is used to solve the adjusting mode as generalized parallel mechanism perform the translation and rotation motion along the Z axis.The lower hinge point adjustment path is given to meet the decoupling condition.Based on CDA,the mechanism of reconfigurable mechanism and the idea of global low coupling are put forward,which provides the basis for the design of global low-coupling generalized parallel mechanism.Based on Particle Swarm Optimization(PSO),the structure optimization design of global low-coupling generalized parallel mechanism is performed.The optimized structure of the generalized parallel mechanism acquires the lowest condition number within the limit of preset parameters.Furthermore,the global coupling numerical evaluation of the generalized parallel mechanism is carried out.The decoupling effectiveness of the reconfigurable mechanism is proved thereafter.The decoupling control of the generalized parallel mechanism is studied.Firstly,modal analysis of the generalized parallel mechanism is carried out.Through simulation analysis,the joint effects of mechanism configuration,workspace and modal control on mechanism decoupling are investigated.The decoupling effectiveness analysis of modal control is demonstrated to provide the guideline for application of the modal control.To prove the low coupling characteristic of the generalized parallel mechanism,the experimental prototype is built.The experimental result and analysis of generalized parallel mechanism in time domain and frequency domain characteristics of different positions and the influence of non-configurable and configurable generalized parallel mechanism is presented.As can be seen from the experimental result,the low coupling performance of the generalized parallel mechanism is verified and the effectiveness of the CDA is proved.