Cad Based Trajectory Planning and Advanced Motion Control for Quadruped Locomotion Robot

The purpose of this study is to analyze a motion of the quadruped locomotion robot TITAN-VIII in the walking and design the control system using a CAD-based model. Also, such results are compared with experiments. Until now, there are many behaviour based studies of locomotion robots. Because the robot has the non-linear properties and it is difficult to build up a three dimensional model of the robot considering a slip and a collision between the foot and the floor. If a three-dimensional model of the robot is built up on a computer, it is possible to simulate the walking considering the interaction with the outside world and to analyze the states of the robot in the walking in details. Recently, softwares applied to multibody dynamics system are getting popular and familiar and motion analysis like a locomotion robot is easily done. DADS/Plant is one of them. In this study, firstly, we build up a DADS model of TITAN-VIII on DADS/Plant to realize virtual experiments with DADS CG animation. And, in order to realize a adaptive walking to fit environment, a hybrid position/force control system is designed on DADS/Plant. Next, simulations are done to verify the validity of the hybrid control system. Finally, the experiments are done to compare with the simulations. INTRODUCTION Locomotion robots are system which moves on the ground by switching the contact between the foot and the floor. The studies for such system were mainly used to be behaviour based studies. Because the robot has the non-linear properties and it is difficult to build up a three-dimensional model of the robot considering a slip and a collision between the foot and the floor. However, the research works of multibody dynamics have been done aggressively and the studies simulating the walking of human [1] and robots [2]-[4] are done. And, with the progress of the computer, softwares, for example ADAMS, DADS, are getting popular and familiar, so the model of multi-link system like the locomotion robot is getting to be built up. If a three-dimensional model of the robot which is very similar to actual robot is built up on a computer, it is shown that the efficiency of the research progresses because of being able to analyze the walking states and design the controller based on the CAD-based model, not the intuition of the designer. If we can simulate the robot in three dimension, 1)we can check the dangerous states of the robot in advance and the states that the robot collides and is broken is difficult to occur. 2) We can analyze the states of the robot in the walking in details. 3) The environment of walking is able to be changed, freely. So, we can build up the almost same states as the actual environment where the robot is active. 4) Three dimensional model becomes a platform comparing with the performance of the walkingby each control method.