In this paper, an alternate passive leg structure is proposed for the Tricept machine tool to form a modified Tricept machine tool. The global stiffness of the modified Tricept machine tool is derived and compared with that of the Tricept machine tool. First, the configurations of the Tricept machine tool and the modified Tricept machine tool are introduced, respectively. Then, the global velocity equations are derived and the stiffness models of the two configurations are presented and analyzed. Finally, the advantages and disadvantages of the two types of passive leg structure are analyzed and discussed and stiffness simulations are conducted.

The paper developed a robust position tracking scheme with a neuro-fuzzy inverse model velocity controller of a tele-operated master-slave robot hand system for demining. And by using impedance force control and a two-posture recognition Neural Network (NN) a smooth grasping and releasing action is realized.

Control systems of robot manipulators offer many challenges in education where the students must learn robot dynamics and control structures, and understand relations between the control parameters and the systems performance. Interactive simulation is aimed at improving the understanding of and intuition for the abstract parts of the control of robot courses. This paper presents an application of interactive simulation to teach control systems of robots. The application considers a nonlinear robot arm and two control modules: position control and motion control. Students can directly manipulate graphical representation of the systems such as a choice among seven control structures, controller gains, and desired trajectories, and obtain instant feedback on the effects. These features make the interactive learning tool stimulating and of high pedagogical value.

The determination of the assembly modes of the parallel structures with three legs of type PS or SP (P and S stand for prismatic pair and spherical pair, respectively) consists of solving the direct position analysis of all the three-legged parallel manipulators which have, in each leg, one not actuated prismatic pair, one not actuated spherical pair and one or two one-dof actuated pairs of any type, placed along the leg in any order. There are two types of such structures: (i) 3PS structures and (ii) SP-2PS structures. The procedure to determine the assembly modes of the SP-2PS structures has not been presented yet, in the literature. This paper presents the analytic form determination of the assembly modes of the SP-2PS structures. In particular, the closure equations of a generic SP-2PS structure will be written and their solution will be reduced to the solution of an eight-degree univariate polynomial equation with real coefficients. Finally, the proposed algorithm will be applied to a real case. The result of this study is that the assembly modes of any SP-2PS structure are at most eight, and the end-effector poses, which solve the direct position analysis of the parallel manipulators that generate those structures, are also eight.

By using the impedance perception algorithm, which we previously proposed, the stiffness matrix that constrains the motion-force relation of a robot's end-effector is calculated in real-time. In this paper, we describe methods of extracting information concerning certain local properties of object surfaces from the stiffness matrix when the end-effector is slid on the surfaces. We develop two algorithms to deal with two classes of surfaces: flat and convex cylindrical surfaces. Since the proposed methods are designed separately from control strategies, they can be used for both autonomous and remote controlled robots. The results of preliminary experiments are presented.

The dynamic modeling and trajectory following issues are addressed for mobile modular manipulators. Simulations are performed to validate the proposed algorithms.

Autonomous mobile robot navigation systems are based on three principal kinds of techniques: map-based navigation, map-building-based navigation and mapless navigation. We propose a mapless method for trajectory description in unknown indoor environments. The method uses distance measurements from a 2D laser range finder, digitises the robot's visibility area, eliminates superfluous data and reorients their presentation with laws similar to those used in cellular automata. The landmarks are extracted and organised in a panoramic description called fresco. The frescoes which are validated by means of neighbourhood rules. The most informative frescoes are detected by means of two criteria and stored. The stored frescoes are considered as a human-like descritption of the robot's route and could be used by the robot to retrieve its route to its starting point.

The paper presents a control scheme for simultaneous control of position and force of robot manipulator in contact with an elastodynamic environment. The control makes the assumption that interaction force between the robot and environment is adequately modeled by a second-order linear model with constant coefficients, and its implementation requires the knowledge of only boundary values of the environment parameters. It is shown that, provided that robot dynamics is exactly modeled, the scheme ensures asymptotic convergence of errors along nominal trajectories characterized by constant prescribed interaction forces and constant prescribed velocities along the contact surface.

A new 3-DOF translational parallel manipulator is presented in this paper. This manipulator has decoupled motion in for x, y, and z axes, and employs only revolute joints. The structure and kinematics of the manipulator are studied. The mechanism singularity is examined and the calibration methods are presented.

Using the notation of the wave variables, this paper introduces an autoregressive predictor, which forecasts the future values of the delay based on its previous values. Using this new knowledge, the teleoperation control system can be tuned to achieve a better and more practical performance. The validity of this modeling is first verified by actual experiments and then the results are used in simulated teleoperations.