This paper presents a new algorithm for realtime collision avoidance of two mobile robots based on a heuristic risk evaluation. The main idea of this algorithm is to express the collision avoidance problem of mobile robots in terms of the velocity vector modification. A distance function obtained from the state information of two neighboring robots is introduced to evaluate the risk of collision. According to the encounter situation of robots resulting from the risk evaluation, the desired velocity vectors are determined for each robot. The robots can avoid collision from each other by following their desired velocity vectors. In a simulation study, the proposed algorithm is applied to various colliding situations of two robots and achieves acceptable performance. The feasibility and the effectiveness of our method are also discussed through the simulation results.
A new control strategy called a generalized energy dissipative control is proposed for the control of linear large space structures with proportional damping. The control strategy consists of two feedback control loops : an optimal stiffness control loop and a generalized direct velocity feedback loop for the augmentation of damping. The validity of the proposed control stategy is shown through numerical simulation of flexible mode control of symmetric elastic panels attached to a space-craft.
In this paper, a physical model is presented for describing the behavior of fish in a water tank. The system equation includes several nonlinear terms representing the main causes for fish motion, which are introduced under the physical consideration. The model parameters are estimated by applying the least squares algorithm. It is observed from a water tank experiment that, in the case of small school, an individual acts as a leader and the others as followers. The parameter values estimated reflect the role of each individual in the school. Three models are proposed as an appropriate functional form of the interactive force. The best form is determined by examining a simulation result for the behavior of fish school encountered by a leader net.
In this paper, we propose an algorithm to decompose a geometric programming problem into a set of subproblems. Each of the subproblems is constructed with some column vectors that are chosen from the n×m exponent matrix of the given problem to satisfy each of the following : (1) the convex hull of the selected n+1 vectors contains zero vector as an interior point; (2) every column vector of the exponent matrix must be included in some set which consists of n+1 vectors that satisfy the condition (1). The present paper represents a systematic choice algorithm of the column vectors. As the selection method is a pivoting method, the complexity of computation is very small. At last some examples are dealt with to show the efficiency of this algorithm.