Hardware-in-the-loop simulation experiments with a hydraulic manipulator model

Hardware-in-the-loop simulation (HILS) is a technique that allows a simulation model to interact with real-world components, that is, one part of a system can be a simulation model, when other parts of the system are the actual hardware. This paper presents the development of a hydraulic SCARA (Selective Complience Assembly Robot Arm) manipulator model with the purpose of using it in hardware-in-the-loop simulation experiments. Most of the mathematical models are semi-empirical in order to reduce the required simulation time and to perform real time simulations in small cost platforms. Two small cost acquisition boards from National instruments, installed in a PentiumIII PC, were used to connect the real time simulation to the real world. The real time simulations run in the xPC platform from Mathworks. Position control experiments, following typical robot trajectories, were made with PD controllers implemented with operational amplifiers. The results obtained in the HILS experiments were very satisfactory, considering that semi- empirical models were used.