The technology on walking robots is high enough to be applied to various fields in unstructured environments. Simulation is an effective tool to develop the mechanism and control of robots. However, a general-purpose simulator for walking robots does not exist. This paper presents a general computational method of interactions such as friction and collision between feet and environments to simulate the whole motion of robots. Robots are modelled by skeletons composed of any number of legs with any degrees of freedom. Environments are modelled by smooth surface patches. Three types of constraints for feet are considered : no constraints, surface-and point-constraints. The constraints are automatically changed based on the interference of the foot with the environment and its reaction forces, as the walking motion proceeds. Simulation results are given to show the effectiveness using a prototype simulator under development.
We have already presented a pattern recognition system insensitive to translation and rotation by 90° using neural networks. In this paper, we propose a pattern recognition system invariant to rotation of input pattern by any number of degrees. The system consists of a fixed invariance net with many slabs and a trainable multi-layered network. To illustrate the effectiveness of the system, we apply it to a variable rotation coin recognition problem between 500 yen and 500 won coins.
The present paper is concerned with the robust stability of discrete-time plants when the characteristic matrix is known to be an element of a polytope of matrices. A lower bound of the degree of stability is presented which has a close parallelism to the continuous-time case. That is, the lower bound is expressed as the value of a two-person zero-sum game. Further the optimal solution provides a Lyapunov function common to all the elements of the polytope. Application to stability analysis of uncertain large-scale systems is discussed.
We consider an FMC system having a single numerical controlled machine with a finite buffer storage and an automatic tool changer. The automatic tool changer has a finite capacity of tool magazine. So far, tool switching times at numerical controlled machines have been assumed to be very small and neglected. However, it is found that the tool switching time in FMC systems significantly affects the system performance at high level of machine utilization. This paper considers the FMC model with an automatic device which can change tools between the tool magazine and the tool storage so that two types of materials are processed. We apply the queueing theory to analyze the performance of the FMC model. The moment generating function of waiting time is derived and numerical results for the average performance measures are presented.
This paper proposes an identification method of possibility distribution based on the data given by experts and leads to a possibility discriminant rule from the viewpoint of possibility distributions. Since the proposed method resorts to linear programming, possibility distributions defined as quadratic functions can be easily obtained. This method is used to construct fuzzy if-then rules. The possibility discriminant rule corresponds to Bayes discriminant rule based on probability distributions. To illustrate the proposed method, a discriminant problem is shown as a numerical example.