This paper describes an efficient dynamic simulation of a humanoid robot. In the simulation, an order n formulation is used to solve the inverse dynamics and forward dynamics of a multi-body system. The formulation can deal with a tree structure and multiple contacts with the environment. In order to simulate a collision with friction between the foot and a floor, a virtual spring-damper contact model is proposed. By introducing this model, computation of contact becomes easier and faster compared with other method such as plastic contact. A simulation of ascending steep stairs is carried out in order to demonstrate the validity of the simulation. The results of the simulation are presented and discussed.

This paper presents the software system architecture with the dynamic reconfigurability for highly autonomous systems. The proposed architecture is based on multi-agent model, which is suitable for autonomous, open and distributed systems. Since an agent is too sophisticated as the minimal component that we handle, we define a unit as a simple component of an agent. We present the advanced capability to dynamically reconfigure autonomous systems because their goals and environments vary frequently. We determine the specification of units and agents in order to analyze the behavior of overall system and to implement the dynamic reconfiguration as easy and simple as possible. In this paper, we also discuss the method to guarantee the system behavior during the dynamic reconfiguration in order to operate the robotic system without a hitch at any time, especially while reconfiguring.

This paper proposes an adaptive intermittent crawl gait for quadruped robots to walk on a slope. In the proposed method, the inclination of a floor is estimated in real time by the displacement of the projection of the center of gravity from the nominal position. Depending upon the estimated inclination, the gait is changed in order to gain the longitudinal stability margin. Experiments and dynamic simulations are performed to validate the proposed method. The results are presented and discussed.

In a new stage of space development, collision and contact tasks under micro-gravity, such as docking, orbital servicing, and touchdown to a minor body, are now increasingly being considered. A hybrid motion simulation consisting of both physical and numerical models is an effective method to test the motions of a spacecraft under zero G on the ground. The authors have developed a hybrid zero G motion simulator based on a highspeed parallel link mechanism. A wide response bandwidth and high stiffness of the simulator have made it possible to simulate the contact motions with high precision. In this paper, they evaluate analytically the simulator characteristics and verify experimentally the impact of dynamics on the hybrid motion simulation by comparing it with a collision experiment under zero G in a drop-shaft facility. The results imply that the simulator is highly reliable for the impact dynamics simulation under zero G.

A new kind of motion simulation is proposed for the purpose of simulating complicated motions such as those caused by interactions between objects in special environments (e.g., those of micro-gravity). The motion simulation is based on a hybrid simulation: consisting of a combined analog-digital system. Hence it has functions of real-time numerical simulation and embedding a physical model in the simulation. In addition, the motion simulation is equipped with flexibility of modeling, effective human interface and scalability of system. Finally, as a preliminary experiment, motion caused by interactions between a chaser (space robot) and a target (nano satellite) has been simulated with a prototype of the hybrid motion simulator.