Dynamics and speed control of a flexible four-bar mechanism

Mechanisms are designed and used to make a particular movement in a certain time. However the mechanism is designed as the crank velocity is constant; it fluctuates because of the inertias and the elasticity of the links. It is necessary to eliminate these fluctuations that the mechanism works properly.In this study, first a DC motor and a four-bar mechanism with rigid links are modeled. Then the equation of motion of the system is derived. After the solution of the equation of motion, the fluctuation of the crank velocity is obtained. To analyze the effect of the elasticity, the equation of motion is obtain and solved by accepting the connecting rod as elastic. The results are compared with the mechanism has rigid link to show the effect of the elasticity.One way to fix the crank velocity is to control the voltage of the motor. For this purpose, moving sliding mode control (MSMC) is applied to the mechanisms which have rigid links and elastic links.Further the performance of the control method is experimentally studied. A real-time working experimental setup is prepared to control the crank velocity of the mechanism which has rigid and elastic links by conventional SMC and MSMC methods.The obtained results are compared by the figures and the tables.