Casimir based fast computation for hydraulic robot optimizations

This paper presents a fast computation method of hydraulic robot dynamics and shows the effectiveness in design optimization that needs a lot of repetitive simulation. First, an exact simplification of the conventional representation of hydraulic robots with external forces is presented based on the Casimir functions. Second, a further exact simplification is given via an integration by parts of the Hamiltonian function as a structural property and a new representation of the hydraulic robots is proposed. The new representation allows us to define a back fluidmotive force (back-FMF) as a hydraulic version of the well-known back electromotive force (back-EMF). Third, the proposed representation and the conventional representation are compared with each other with respect to computational cost and the effectiveness of the proposed representation is confirmed.