Robust Optimization Design Of Compliant Mechanisms

Compliant mechanism is a mechanism using the elastic deformations to realizethe required functions. Due to the use of flexible joints instead traditional motion pairof rigid body, compliant mechanism has many advantages over rigid body such as lesscomponents, small in vibration, non-lubrication, non-abrasion. Compliant mechanismhas been widely used in Micro Electro Mechanical Systems (MEMS), the bionic,aerospace and other fields recently. However, the performance of the mechanism willbe affected by the deviation which exists in manufacturing, assembly and theenvironment in engineering practice to some extent. On the basis of fully using thecompliant design theory and robust design theory, this paper takes uncertainties intoaccount to carry out the exploration and research in the process of structuraldesign.The main works are as follows:1. Pseudo-Rigid-Body Model (PRBM) method is first used to obtain the model ofcompliant slider mechanism, its displacement and driving torque also can be analyzed.Then, the Principle of Virtual Work is used to solve the relationship between force anddeformation which exits in PRBM and then draw parameters relational expression ofgeneral four-bar mechanism. Finally, taking Young’s bistable mechanism as anexample to find the input torque changes with the body angle. In addition, two stablepositions of Young’s bistable mechanism are obtained based on the relationship that thetorque is the first order derivative of the potential energy.2. Taking compliant constant force mechanism and Young bistable mechanism asresearch object is possible to set up their deterministic optimization model and robustoptimization model respectively. Particle swarm optimization algorithm and MonteCarlo (Monte Carlo) simulation method are used to obtain mechanism and outputproperties such as force, potential energy and variance of compliant mechanism. Bycomparing the results of two design agencies under the influence of uncertainties, theeffectiveness of the design method is proved in this paper.