On the stability of macro–mini robotic systems for physical human–robot interaction.

This paper addresses the stability of macro–mini robotic systems in a context of physical human–robot interaction (pHRI). A simple model including a one-degree-of-freedom (one-dof) macro robot and a one-dof mini robot is investigated using a state-space representation in order to assess the controllability and stability of the system. In this work, the stability of the system is analysed in more detail regarding two perspectives of the interaction process, namely the human force input and the human position input. Moreover, physical limits and the frequency response of the macro–mini system are also examined. Therefrom, this study derives a general formula for the constraints of the virtual mass and the virtual damping. Possible choices of these parameters in certain ranges are graphically and visually demonstrated. Simulations are carried out in order to demonstrate the stability and the behaviour of the system with different input signals. The conclusions of the analysis can be used in the design of multi-dof macro–mini systems. An example of a 12-dof macro–mini system is briefly described to illustrate potential applications. • The dynamic modelling of macro–mini robotic systems. • A stability analysis of macro–mini robotic systems. • Proposed controller design for macro–mini robotic systems. • Simulation results that demonstrate the stability. • Design guidelines for the selection of the rendered mass and damping. [ABSTRACT FROM AUTHOR]