We proposed new arm-wheel hybrid robot "Souki-II" which consists of a body, a pair of large bore wheels which sandwich the body and rotates around the same axis from the body, articulated hand attached to the body, and free caster attached around the wrist of the hand. Souki-II showed high terrain adaptive motion by using the large bore wheels and free caster of the hand. We also showed that the mobility can be enhanced when multiple units are connected together. Souki-II can also take the mode of a manipulator. For the joint mechanism of the Souki-II, we introduced a unit actuator system and a cover member with spiral groove to pass the electric harness and to assist in heat dissipation. From the experiments of the constructed models, we could demonstrate the innovative performance of the proposed Souki-II system.

A reconfigurable planetary rover system (RPRS) is presented, including the parent body and some child robots. The child robot composed with the arm part and the wheel part has two moving modes: locomotion mode and manipulation mode. According to the mechanical characteristics, we proposed the two methods for the motion planning of swerving locomotion. The results of experiments showed that the robot can achieve turn during locomotion by adjusting the arm's attitude. But the child robot's radius of left-hand turning motion during locomotion is bigger much than the radius of right-hand turning motion during locomotion and the effect is not obvious. The method of spot turning is presented by use of the difference between radial frictional force and tangential frictional force of ground and direction wheel, which is important for robot for autonomous locomotion.

We propose a new planetary rover system called "SMC-Rover". This system consists of one main body and some detachable units, which can work as child rover, and also become driving units of the main body. Each detachable unit, consisting of a single manipulator mounted on a wheel, is called "Uni-Rover". This paper discusses a new method of trajectory modelling and steering control optimization for the Uni-Rover, using the relation between arm posture and turning radius. The validity of the presented method is verified by computer simulations and experiments with an actual mechanical model. Thus, effective arm-posture-based steering method is introduced.