Critical review on complete dynamic balancing of mechanisms and parallel robots

Abstract

When mechanisms and parallel manipulators move, due to the fact that the centre of mass is not fixed and angular momentum is not constant, they often produce vibrations in the base. Shaking force balancing can be achieved by making the centre of mass of mechanism be fixed, i.e. linear momentum is constant; shaking moment balancing can be achieved by making the angular momentum constant. There are generally two main ways for shaking force balancing and shaking moment balancing, i.e. 'balancing before kinematic synthesis' and 'balancing at the end of the design process'. Under the category of balancing at the end of design process, add counterweights and counter-rotations, add ADBU and add auxiliary links are mostly used principles; here a new method is proposed, i.e. balancing through reconfiguration, which can reduce the addition of mass and inertia. Fisher's method belongs to the method of balancing before kinematic synthesis. In this paper, we will discuss the advances and problems on dynamic balancing of mechanisms in detail under the above two main categories. Two main contributions of the paper can be concluded as follows: new reactionless parallel manipulators are derived and dynamic balancing through reconfiguration concept is proposed in first time.