Application of a novel 6-DOF parallel robot with redundant actuation for earthquake simulation

In this paper a novel orthogonal 6-DOF (Degree Of Freedom) parallel robot with redundant actuation is studied as an earthquake motion simulator. Taking the practical simulation of earthquake waves into consideration, we firstly analyze the general characteristics of natural earthquakes. Complexity and variety of seismic waves, 3-dimension and multi-DOF movement and strong devastating force are regarded as their three obvious features in this article. Based on the characteristics of this novel orthogonal 6-DOF parallel mechanism with redundant actuation and the features of earthquakes, the feasibility of using this parallel robot as an earthquake motion simulator is analyzed. In order to simulate earthquake motion by using the parallel robot, its unambiguous kinematics and dynamics models are derived in details. The control system of the proposed earthquake simulator is developed based on the PXIbus development platform. A typical three-direction earthquake motion, the El Centro earthquake, is simulated on the end-effector of the parallel robot using its mathematical models and control system. Three main motion parameters of simulated seismic waves, displacements, velocities and accelerations are measured respectively. The experimental results show that this equipment is appropriate for using as an earthquake simulator.