Design of Torque Balancing Mechanisms

Machines are often subjected to periodic loads, related both to the characteristics of the payload or to the kinematic chains used for motion generation, such as linkages or cam follower mechanisms. The load fluctuation can cause several inconveniences to the proper functioning of the machines, like shaking forces and moments, vibrations, severe speed fluctuations. Speed fluctuations are a main source of concern since, generally, mechanisms design and optimization is performed considering a constant main shaft speed and a departure from ideal behavior gets worse increasing machine speed. The simpler approach used to mitigate this fact consists in adopting a large flywheel and/or a massive motor, even to drive small loads. More sophisticated procedures add appropriate balancer mechanisms to the machine. This paper, starting from a review of the available literature, presents a theoretical framework to the problem of input torque balancing and defines a methodology for the synthesis of balancing mechanisms.