Research on a Reduced-DOF Walking Robot with Parallel Mechanism that has High Homogeneity of Output Force

Abstract

It is an effective method to improve the controllability for a robot to construct it using the least number of DOF as possible. In this paper, a new lightweight walking robot is developed that uses a simple mechanism to move and work with high efficiency. This robot consists of two leg-bases with three legs each and walks by moving each leg-base alternately. These leg-bases are connected to each other through a 6-DOF mechanism. Thus, when the robot stands on three legs, or one leg-base is placed on the ground, the other leg-base can be used as a 6-DOF manipulator or active working platform. The output force, velocity, and movable range of various mechanisms for connecting the two leg-bases were analyzed using a new idea of comparison for its output characteristic. Good performance can be achieved with a serial-parallel hybrid mechanism consisting of three 6-DOF serial linked arms composed of two active and four passive joints positioned with radial symmetry about the center of each leg-base. Walking experiments with this robot that uses this mechanism as a leg-drive mechanism confirm that this mechanism has satisfactory performance despite having less DOF and can be used for 6-DOF motion base.