Modeling robotic manipulators powered by variable stiffness actuators: a graph-theoretic and port-hamiltonian formalism

This paper proposes a modeling method for generic compliant robotic manipulators. It is based on graph theory and the port-Hamiltonian formalism, which allows a modular approach to the interconnection of rigid bodies with compliant actuators by means of kinematic pairs. This modularity enables a simple and straight-forward adaption the model when a manipulator’s actuator morphology is changed. An example of a spatial three degree-of-freedom manipulator shows that this modeling method is more suitable for modeling changes in actuator placement than the traditional Euler–Lagrange method.