Dynamic optimisation of a mechanical manipulator

Abstract: In this paper, a method for the dynamic optimization of a mechanical manipulator is proposed. A mechanical manipulator is, in general, a device able to load, to unload or to move objects automatically and rapidly, acting by its own or as a module of more complex mechanisms (parallel manipulators, pallets chargers, dischargers, etc.). This kind of manipulator executes the desired movement by virtue of a conjugate cams transmission, which assures a pre-fixed trajectory during the whole position cycle of the end-effector. If the accuracy at the end of motion is always very high, backlash effects and elasticity in the kinematic chain can cause excessive vibration phenomena and, consequently, overstress effects, which can damage the cam and roller surfaces in brief time. This paper, after a framing of the problem, suggests a motion profile which appears particularly suitable to improve the dynamic behaviour caused by system compliances (mainly backlash).