Research On Full Compliant Mechanisms And Application In Earthworm-like Robot

Full compliant mechanisms are new class of mechanisms that transfer their motion, force and energy via elastic deformation. These kinds of mechanisms have good prospects in areas such as micro and small bio-robot due to their advantages such as high precision in motion, no rigid connection, integrated manufacturing, elimination of friction and wear. This paper applies full compliant mechanisms to micro bio-robot design.In the first section, this paper studies the basic theories, characteristic, classification and the design methods of full compliant mechanisms systematically. Present studies in earthworm-like micro moving robot are discussed then. This paper researches the applying full compliant mechanisms to earthworm-like micro robot design.In the second section, this paper studies the present motion planning of earthworm-like micro robot and then brings forward a new motion planning on the basis of the earthworm's biology motion principle. This motion planning is on the basis of the friction between the robot and the working plane. In the moving planning the earthworm-like micro robot consists of flexible units which are the most important part in the whole robot design. This paper chooses piezoelectric ceramic as the driver of the robot because of its small size. However, the deformation of the piezoelectric ceramic is just in nano-scale. Above all, the design of flexible units with motion amplification capability is essential.In the third section, this paper researches on the topology optimization of full compliant motion amplification mechanisms. A mathematical model is established for optimal topology design of compliant motion amplification mechanisms using SIMP artificial material density method based on the theory of topological optimization technology of continuum structures. The rate of output displacement and input displacement is employed as the objection function. The iterative formulation is deduced using the optimal criteria method. A filtering scheme is used to obtain checkerboard-free and mesh-independent designs. Numerical examples are presented for demonstration of the effectiveness of the proposed approaches. The effect of different parameters on the factor of motion amplification has also been analyzed. The matlab software is used for the optimization calculation. Numerical examples are presented for demonstration of the effectiveness of the proposed approaches.In the forth section, this paper designs the flexible units of the robot according to the design method of topology optimization of foil compliant motion amplification mechanisms. Then the flexible units' topology shape is obtained. The topology shape is imported into ANSYS software through AutoCAD drawing software. This paper analyzes the displacement output with different displacement input conditions to testify the effect of motion amplification. The maximum mises stresses in the mechanism are also discussed with different displacements input conditions. It can ensure that the mechanism avoid failure when in working. The effect of flexible hinges' size on the Mechanical properties has been discussed. The carrying capacity of flexible unit has also been analyzed.In the last section, the flexible units designed are connected to form assembly robot. Geometric modeling of the robot has been carried out in ADAMS software. The flexible hinges in the flexible unit are replaced by the rigid hinges and torsion spring. The piezoelectric ceramics are substituted by springs which have the same stiffness as the piezoelectric ceramics. What's more, a fixed flat plane is set. The ADAMS software simulates the contact between the robot and the plane by means of the 'Contact' model the software contained itself. The 'Coulomb' model is use to simulate the friction. Then the morion simulation of the robot is given and being analyzed. The Simulation results are presented for demonstration of the effectiveness of the robot motion planning.