Similarity and invariance in scaled bilateral telemanipulation

This paper addresses the issue of dynamic similarity and intensive property invariance in scaled bilateral manipulation, and offers a design methodolo gy based on these considerations. The methodology incorporates dimensional analysis techniques to define a set of necessary and sufficient conditions to preserve the dynamic similarity of any physical environment. These techn iques are utilized to demonstrate that any combination of kinematic and for ce scaling in a bilateral manipulator control structure will preserve the d ynamic similarity of any physical environment. Any combination of kinematic and force scaling, however, will nor in general maintain intensive propert y invariance between the original and scaled physical environments, and thu s will result in lost information. As such, the dimensional analysis method s are further utilized to form the basis of a constrained optimization prob lem that enables selection of a force scaling factor that minimizes the int ensive distortion of the environment. The proposed formulation is applicabl e to any physical environment, including those that are nonlinear and conta in multiple degrees of freedom. Further, the formulation does not require a n exact environmental model, provided the parameters that influence the env ironment are known. The proposed techniques are particularly relevant to bi lateral manipulation of a microscopic environment (i.e., macro-micro bilate ral manipulation), since such environments are difficult to model exactly a nd are largely influenced by nonlinear effects.