Serpentine tracked robots -i. e., articulated multi-tracked vehicles -are designed to move on rough terrains and used for a variety of purposes, including search and rescue operations, planetary exploration and environmental investigations. The steerability of such vehicles depends on its posture and interaction between the vehicle and the ground. In previous research, kinematic models with slip information were derived for articulated multi-tracked vehicles. Such kinematic models, however, do not allow for the slippage of the vehicle that occurs when moving at a high speed or on a slippery surface. In this paper, we derive a dynamic model on which the frictional force is acting between the track shoes of each track of the vehicle and the ground for the slippery conditions. The frictional model neglecting static friction is given by a formula for the friction coefficient function proposed in the field of Teramechanics in order to mainly analyze slip behavior. The model is also used to analyze the steering properties, or steerability of the vehicles.

Home oxygen therapy (HOT) is a medical treatment for patients suffering from severe lung diseases. Although walking outdoors is recommended for patients to maintain physical strength, patients always have to carry a portable oxygen supplier which is not sufficiently light weight for this purpose. Our ultimate goal is to develop a mobile robot to carry an oxygen tank and follow a patient in an urban outdoor environment. We have proposed a mobile robot with a tether interface to detect the relative position of the foregoing patient. In this paper, we improve mobile platform mechanisms and active wheels to maximize the step height which can be negotiated, and to allocate sufficient space in the main body to carry an actual oxygen tank. The following control algorithm is also improved and its effectiveness is demonstrated in an outdoor experiment.

In this paper we propose a new robust force and position control method for property-unknown objects grasping. The proposed control method is capable of selecting the force control or position control, and smooth and quick switching according to the amount of the external force. The proposed method was applied to adaptive grasping by three-fingered hand which has 12 DOF, and the experimental results revealed that the smooth collision process and the stable grasping is realized even if the precise surface position, the mass and the stiffness are unknown. In addition a new algorithm determines the grasp force according to the "slip" measured with the tactile sensor and the viscoelastic media on the fingertip. This algorithm works at starting and stationary state, so the friction and mass unknown object grasping is realized by the effectual force.