Design and Optimization of Hydraulically Actuated Hexapod Robot COMET-IV

Abstract

The development of COMET-III resulted in a completely self-contained drive system that closely approximated a practical robot. However, various problems emerged in the course of research and development. In general, there was significant scope for improvement in terms of adaptability to terrain and speed of movement. For example, owing to an insufficient amount of oil and poor durability, sustained tripod walking could not be achieved, and the achieved walking speed was slow; the possible range of motion of the legs, which lacked the ability to move sideways or diagonally, was small, and the robot could not move omnidirectionally. In particular, the preeminence of legged robots as locomotive robots is ascribed to their superior capability of discrete walking in specific environments (such as minefields) and outstanding ability in general to adapt to the terrain. These capabilities enable legged robots to easily move over difficult and uneven terrain—even in environments wherein crawler robots and wheeled robots are incapable of motion. Therefore, there is an urgent need to overcome the fatal flaws in COMET-III—for example, in terms of terrain adaptability and speed of movement.