A new global isotropy index (GII) is proposed to quantify the configuration independent isotropy of a robot's Jacobian or mass matrix. A new discrete global optimization algorithm is also proposed to optimize either the GII or some local measure without placing any conditions on the objective function. The algorithm is used to establish design guidelines and a globally optimal architecture for a planar haptic interface from both a kinematic and dynamic perspective and to choose the optimum geometry for a 6-DOF Stewart Platform. The algorithm demonstrates consistent effort reductons of up to six orders of magnitude over global searching with low sensitivity to initial conditions.

This paper concerns the modeling and control of a mobile manipulator which consists of a robotic arm mounted upon a mobile platform. The equations of motion are derived using the Lagrange-d'Alembert formulation for the nonholonomic model of the mobile manipulator. The dynamic model which considers slip of the platform's tires is developed using the Newton-Euler method and incorporates Dugoff's tire friction model. Then, the tracking problem is investigated by using a well known nonlinear control method for the nonholonomic model. The adverse effect of the wheel slip on the tracking of commanded motion is discussed in the simulation. For the dynamic model, a variable structure control approach is employed to minimize the harmful effect of the wheel slip on the tracking performance. The simulation results demonstrate the effectiveness of the proposed control algorithm.

This paper contains the result of a computer simulation of the dynamic performance of a manipulator. Provision is made in the program developed to represent the manipulator in either a redundant or non-redundant form. The models derived are used in simulation studies to evaluate the dynamic behaviour of the process when subjected to different control strategies for a range of operational tasks. The dynamic manipulator model presented is derived from the laws of Newtonian and Lagrangian Mechanics.

The paper addresses the robust adaptive control problem of robot manipulators. The dynamic equations of robot manipulators and their fundamental properties that facilitate analysis and control system design are first reviewed. Then the direct, indirect, and combined direct and indirect adaptive control approaches of robot manipulators are presented. After that, a number of variable structure adaptive control approaches which combines features of the robust design based on variable structure systems with parameter adaptive control, are studied. After that, a new combined adaptive and variable structure adaptive control approach is proposed for the tracking control of robot manipulators under the uncertainty environment. This is a robust, high-performance adaptive control scheme that combines the advantages and overcomes the disadvantages of both types of techniques. Finally, the extensive comparing simulation results are presented to demonstrate the theory study.

In this paper, we are introducing a system which is able to recognize polyhedral objects in an indoor environment. Our system is intended to be implemented on autonomous mobile platforms in order to enable the localization or research of a precise item. The algorithm is based on the use of geometric quasi-invariants associated to every object. These geometric quasi-invariants correspond to the ratio of the lengths as well as the angle formed by the pair of segments which are in relationship and which are constituting the object. We present some experimental results gained on one of our platforms in our laboratory.

A new systematic exploration method is addressed that permits a mobile robot to effectively acquire the information on an unknown environment without wasting time. The algorithm is composed of following three modules: the first is the decomposition of a workspace into several sub-nodes by employing the concept of Quadtree. These nodes are chosen as sub-goals to be reached successively. The second is that controls the robot to follow the boundaries of objects in the environment in order to reach each sub-goal avoiding the situation of the robot entering a local minima. Here we utilize the imaginary distance forces exerted by objects. The third is the node conditions for estimating the map quality for each node, which enables the robot to remove sufficiently informed nodes from the Quadtree. Two conditions are defined for the estimation of the map quality; entropy and maximum level of Quadtree. The proposed approaches were successfully implemented to our mobile robot equipped with sonar sensors for constructing a sonar map of an unknown environment in a real world.

This paper focuses on overcoming the problem of tracking control in structurally flexible redundant manipulators by utilizing their self-motion capabilities. In the proposed algorithm, the self-motion is evaluated in order to nullify the dominant modal force of flexural motion that is induced by a rigid body motion.

The flexure motions of manipulators, which are induced by joint motion, cause undesired inaccuracy in end-effector tracking. In-plath planning states, joint trajectories are so designed as not to excite but to damp out the flexure motions. The self-motion, inherent in redundant manipulators, can alter joint motion, influencing the flexure motion (by exciting and damping the flexure modes), while not affecting end-effector motion at all. Therefore, the self-motion can be utilized to regulate flexibility and effectively reduce the end-effector tracking error.

The effectiveness and applicability of the proposed algorithm have been demonstrated through numerical simulation with three-link planar robotic manipulators possessing flexible links.

In this paper a method for the reduction of the uncertainties in robotised assembly process is presented. The generated assembly strategies are based on the determination of the contact points. The assembly task is divided in two main subtasks, the initial and the main. To reduce the uncertainty of the process a deliberate misalignment of the peg is used.

This paper is focused on the determination of the position and the forces at the contact points between the peg and hole under uncertainty. The available data are the force signal retrieved from the force sensor, the geometry of the assembly parts and the geometry of the robot. The analysis presented in this paper is a part of a knowledge-based system, which generates assembly strategies under the presence of uncertainties.

An analytical procedure is proposed for determining the workspace boundary of general telescopic manipulators. The algorithm has been developed by using the Theory of Envelopes providing an algebraic formulation. An analysis of the workspace of telescopic chain has been carried out to emphasize on a general topology and to investigate the effect of link parameters and telescopic stroke.