A two-channel bilateral controller is proposed for teleoperation systems, which takes into account both the free space motion and the constrained motion. Specifically, the force-position (F-P) architecture is applied during the constrained motion, while the position-position (P-P) architecture is applied during the free space motion. Perfect transparency can be achieved in theory. In addition, the controller is robust to model uncertainties and disturbances, and it does not need to switch the control modes of the master and the slave controllers during the transition between the free space motion and the constrained motion. Experiments are conducted to demonstrate the effectiveness of the proposed bilateral controller.

In the basic impedance control structure, it is usually required to know the environment stiffness/impedance for precise force tracking. In addition, the performance may be degraded when the random external disturbances exist. By incorporating a PI-type compensator to the basic impedance control structure, this paper presents a combined impedance/direct control scheme for control of robot manipulators, which is characterized by high disturbance rejection, robustness to uncertainties, and simple structure for application. Moreover, it does not require to switch the control modes during the transition between the free space motion and the constrained motion. Therefore, the proposed controller combines the advantages of both the direct control and the impedance control. Computer simulations are performed to demonstrate the superiority of the proposed control scheme over the impedance control.

In this paper, a study of a wheeled mobile robot (WMR) with omni-directional mobility and rover-like climbing ability is presented. Various rovers with robust locomotion design had been developed. However, the rover locomotion design with omni-directional mobility has not been addressed commonly. Shrimp suspension system and parallel bogies were employed as robot locomotion. It adapts to the terrain profile passively and it has better climbing capability than other rovers. To achieve a singularityless motion, the kinematic model of a wheeled mobile robot (WMR), including a platform equipped with six omni-directional wheels (ODWs), is formulated. The contents of this study are the design principle, kinematics, and motion studies. Also, experimental results have been employed to verify the model developed.

A mapping algorithm is essential to teleoperate a robot hand. Joint-to-joint mapping, pose mapping and point-to-point mapping are three commonly used methods for telemanipulation. However, these methods might not produce satisfactory performance if the robot hand is non-anthropomorphic. This paper introduces a method for mapping based on the relative positions between fingertips. An algorithm particularly for a three-fingered non-anthropomorphic robot hand is presented. The principle of the method is to find suitable parameters in the hand frame, to transform them to the robot frame, and then to compute the robot fingertip positions according to the transformed parameters. The mapping results and the comparisons with the traditional methods validate the advantages of the proposed method.

This paper presents the process of a motion control system design and implementation for a teleminulation system. The robotic manipulator/hand is a nonlinear system with coupled effects among the joints. By applying the frequency response method, the nonlinear system is modeled as decoupled linear ones, in which each joint is controlled independently. The experimental results show the feasibility of the modeling process. Based on the obtained transfer function of each joint, the digital PID controllers are designed. The motion control system for the telemanipulation system is then implemented using the software package MATLAB, Simulink, Real Time Workshop, xPC Target and a C/C++ compiler, and the hardware I/O boards, amplifiers, etc. The presented developing procedure shows a convenient way to implement a real time robotic control system.

An investigation was initiated on the study of the kinematic mapping between human hand and the non-anthropomorphic robot hand. To account for the significant dissimilarities between them, a "virtual circle mapping" method has been developed based on the fingertips' relative positions. The principle of the method is to find suitable parameters in the hand frame, transform them to the robot frame, and then compute the robot fingertip positions according to the transformed parameters. The preliminary results and the comparison with the point-to-point mapping results are presented and analyzed. The generalization of the relative-position based mapping idea is also discussed.