A Study of Gliding Locomotion by Leg-wheeled Robot with Reduced DOF

In the past, various leg-wheeled robots have been proposed. However, many of them don't have enough performance for practical use, because they have high number of degree of freedom(DOF). As a result, some problems maybe occurred such as decreasing of energy efficiency and increasing of body weight. To overcome the problem, we developed another type of leg-wheeled robot, which constructed with passive wheel and the idea of reduced DOF. The passive wheels can be driven indirectly by using gliding locomotion. In our previous study, we have developed a closed link type leg-wheeled robot which has 6 legs and 3 wheels by using the mentioned ideas. However, the robot has had a problem on the speed stability. In this paper, we have improved the problem by changing the number of wheels from 3 to 4 and using phase shift for pair of wheels. While general hexapod robot has 18 DOF, our robot has only 11DOF. Then we have gotten more stable speed than the latest version.