A compatibility study of static balancing in reconfigurable mechanisms

Reconfigurable mechanisms are a group of mechanisms that can change their topology or mobility while in operation. This property can add flexibility of the use of the mechanisms in constrained environments. Some situations require these mechanisms to be statically balanced. One example is a statically balanced lower-limb rehabilitation device, allowing patients who suffer from lower-limb paralysis to exercise without the need for a therapist to guide them. This mechanism by Tseng et al. [1] is one of the very few examples of a statically balanced reconfigurable mechanism. From literature it is known that there is no general way to statically balance these mechanisms. This paper aims to create an overview of the methods that can be applied by making a classification of reconfigurable mechanisms based on the intrinsic properties, then reviewing each group of this overview to find a generalised static balancing method. Only two mechanism groups show high compatibility with static balancing. One of these groups could be balanced using a single spring. The other shows the property that if one operation mode is balanced, no additional springs are needed for the other mode. Applying these techniques could reduce the overall complexity of the mechanism.