This paper presents a computationally simple stereo vision method for detecting useful features of obstacles on the ground relevant to a mobile robot's navigation in an indoor environment. Enhanced time efficiency and reliability is achieved by introducing a geometrical image transformation and a frame-wise iterative edge image comparison scheme. The image transformation used in this paper relates each constant disparity value to an oblique plane at an elevation from the floor. The stereo correspondence method is devised by implementing a frame-wise AND operation based upon edge orientation and a subsequent pixel wise intensity correlation checking. This method is efficient in terms of computation time and capable of identifying isodisparity points, so that the height information of all the obstacle points above the floor can be determined. The obtained disparities are recorded on a local map to give complete obstacle features for mobile robot's path planning. Through a series of experiments performed under various environmental conditions, it is found that the proposed method can effectively be applied for locating obstacles of various heights in indoor navigation of mobile robots.

In the problem of automatically controlling a wheeled vehicle so that a given reference point on the vehicle follows a prescribed path, several factors determine how the task can be accomplished; they are the shape of the path, the initial orientation angle, the steering angle limit and the position of the reference point on the vehicle. If the required steering angle exceeds the limit set by the steering mechanism or the required orientation angle is discontinuous at any point along the path, then the path cannot be followed. This paper investigates this motion feasibility problem, taking steering angle limit into consideration. First of all, we determine the dependence of the continuity of the orientation angle, steering angle and their derivatives on the continuity of the reference path and its derivatives, then discuss .the relationship between the steering angle limit and the feasible deviation angle intervals. Furthermore, we analyze in detail two typical motions, namely straight line motion and circular motion; some simulation results have been given based on a practical vehicle dimension.

A nonlinear feedback control based on inverse dynamics is proposed for robots with flexible joints during constrained motion task execution. Based on constrained system formalism, the presented control scheme achieves simultaneous, independent control of both position and contact force at the robot end-effector. The method can be directly applied to robot control, or it can be used as the basis for developing other advanced control strategies. In this paper, a. feedforward controller is considered. Issues related to the practical application of the full inverse dynamics and feedforward control algorithms, such as evaluation of feedback variables, the use of predictors to eliminate the time delay of digital control, and the design of robust controllers, are discussed. The results of extensive numerical simulation are used to show the effectiveness of the proposed controllers and to compare their performances. It is shown that it is possible to achieve high precision tracking if the appropriate predictors are used to eliminate the effect of computational delay of the digital controller. Applying a straightforward approach for robustness of the proposed controllers has additionally improved the trajectory tracking accuracy.

In the field of multifingered mechanisms the control/command problem is mainly a problem o1 coordination. The problem is not only to coordinate joints of a chains but also to coordinate the different chains together.

This paper presents a general and efficient method for implementing the control/command of such systems, taking into account the force distribution problem. To solve this problem it is necessary to pay great attention to dynamic effects. To do this, we broke down the Inverse Dynamic Model (I.D.M.) problem into two main levels; One level is devoted to I.D.M. computation; it can be called the Finger Level (F.L.). As we wanted to divide up the work to be done as much as possible, we subdivided the Finger Level according to the number o1 kinematic chains. In addition, we considered a second level, the Coordinator. This level has to control all the chains using the Fingers-to-Object-Interaction Model (F.O.LM.).

Next, we will also introduce new grasping systems: Polyvalent Gripper Systems (P.G.S). There are a new solution to multicomponent assembly problems. As they can be equipped with several multifingered mechanisms, they can also use the control/command scheme.

This paper presents a new formulation as well as numerical solution for the problem of finding a point-to-point trajectory with maximum load carrying capacities for flexible manipulators. For rigid manipulators, the major limiting factor in determining the maximum allowable load (mass and mass moment of inertia) is the joint actuator capacity, while the flexibility exhibited by light weight robots or by robots operating at a higher speed dictates the need for an additional constraint to be imposed for situations where precision tracking is required, that is, the allowable deformation at the end effector. The Lagrangian assumed mode method was used to model the manipulator and load dynamics, including both joint and deflection motions. An Iterative Linear Programming (ILP) method is then used to determine the maximum allowable load of elastic robot subject to both constraints, while a general computational procedure for the multiple-link case given arbitrary trajectories is presented in detail. Symbolic derivation and simulation by using a PC-based symbolic language MATHEMATICA® was carried out for a two-link planer robot and the results further confirm the necessity of the dual constraints.

Rough joint flexibility is the dominant source of compliance in today's commercial robots in future robots containing light weight flexible arms link flexibility may become most important. Hence this paper stresses link flexibility rather than joint flexibility.

The paper presents an approach to automatic synthesis of program for robots in a flexible manufacturing cell (FMC). The system of program generation consists of two layers: Task-Level Programming Layer and Program Interpretation and Verification Layer. The first layer uses robot-independent planning techniques to create a work plan for robots (set of elementary actions) and program for each elementary action. The second layer uses robot-dependent planning methods to plan robot's trajectories and calculate the robot's motion times. A simulation model of whole FMC, which is created based on a description of FMC and program for robots, makes possible evaluation of efficiency of FMC work.