José F. Postigo

Bilateral teleoperation through the Internet

This paper proposes a stable control structure for the bilateral teleoperation of robots through Internet. The problem is motivated by the increasing use of the Internet as a communication channel. Internet has a time-varying delay which depends on factors such as congestion, bandwidth and distance. In this work, we propose a control structure for the teleoperation of a manipulator robot with force feedback. Such a control structure includes state controllers (placed on the local and remote sites) and a time-delay compensation, which modifies the delayed position command generated by the human operator using the force that he feels in such a delayed moment and the current force between the slave and the remote environment. In addition, the proposed control scheme is designed considering a model of the communication channel. Finally, experiments of bilateral teleoperation of robots through Intranet and Internet are shown to test the performance and stability of the designed teleoperation system.

Supervisory control for a telerobotic system: a hybrid control approach

A supervisory controller for a robotic teleoperation system is presented in this paper. The low-level control structure was designed to control both the position and the interaction force between the remote manipulator and its environment. Hybrid systems theory is applied to design the supervisory control in order to detect when force and position thresholds are overcome and when the communication between the local and the remote stations are interrupted or returned. On the occurrence of such events, the controller modifies the references sent from the local station to the remote robot in order to improve performance and operation safety. Simulations as well as experimental results show the performance of the hybrid system incorporating the designed supervisory controller.

Bilateral teleoperation of mobile robots

A control structure for the bilateral teleoperation of mobile robots, with tactile feedback and visual information of the interaction force is proposed in this paper. Also an impedance controller is implemented in the mobile robot structure that guarantees the linear velocity be within a desired fixed range without saturation in the actuators. To illustrate the performance of the proposed control structure, experiments on a Pioneer 2 mobile robot teleoperated with a commercial joystick with force feedback are shown.

Teleoperation of an Industrial Manipulator Through a TCP/IP Channel Using EEG Signals

This paper presents an industrial manipulator teleoperated via TCP/IP using a brain computer interface (BCI). Through a BCI based on event related potentials (ERD and ERS), the operator is capable to select a position on the manipulators workspace, that should be reached by the manipulator. A pose controller is executed on a remote PC and when new references are received, the controller calculates the necessary control actions so that the manipulator reaches the desired position. A bio-feedback link is closed through the operator watching to a visual interface, allowing him/her to visualize the manipulators workspace and the movements being executed. Besides the application of the BCI, the paper also shows how versatile it is, stressing features like its easy integration with robotic devices, its low cost and the short training time it requires

Stability analysis for a teleoperation system with time delay and force feedback

The stability analysis of a two-degree-of freedom teleoperation system, considering the remote station as a non-linear system, is presented. The non-linearity arises in the remote robots model. Force and position data are backfed from the local to the remote station. The time delay between both stations is fixed and known. A model of the human operator is incorporated into the dynamics of the local station, while a model of the environment is incorporated into the dynamics of the remote station. The analysis, based on operator theory, ensures that system signals remain within a small bounded region. The validity of the theoretical results are verified by simulation.

Teleoperation of mobile robots with time-varying delay

This paper proposes a stable control structure for the bilateral teleoperation of mobile robots. The proposed control structure includes a time-delay compensation placed on both the local and remote sites of the teleoperation system. To illustrate the performance and stability of the proposed control structure, experiences on a Pioneer 2DX mobile robot teleoperated through a commercial joystick with visual feedback, are shown.

Bilateral teleoperation of mobile robots with delay

This paper proposes a stable control structure for the bilateral teleoperation of mobile robots. The proposed control structure includes a time delay compensation placed on both the local and remote sites of the teleoperation system. To illustrate the performance and stability of the proposed control structure, experiences on a Pioneer 2DX mobile robot teleoperated through a commercial joystick with visual feedback are shown.

Stable Teleoperation of Mobile Robots

This paper proposes a stable control scheme for bilateral teleoperation of mobile robots in presence of obstacles and time-varying delay. The proposed control scheme is composed by a velocity controller on board the mobile robot and a time-delay compensation placed on both the local and remote sites of the teleoperation system. Finally, experiments on a mobile robot teleoperated by a human operator with visual feedback through Internet are shown

Hand controller for bilateral teleoperation of robots

Teleoperation, one of the oldest areas of robotics, has experienced considerable growth in the last two decades. Main causes for this trend are the need for increased safety levels for human operators and lower production costs. In this work, a three d.o.f. local manipulator (two d.o.f. for force and one d.o.f. for torque) is developed. This hand controller, intended for robot or mobile teleoperation systems, has force reflection in two axes and torque reflection in the third axis. using a robotic hand developed at INAUT as a remote device, laboratory experiments on each axis (one at a time) have shown good results. An impedance controller at the remote system allows one to carry out interactive tasks with the environment such as polishing, insertion and grinding, where it is necessary to control and accommodate the interaction forces and torques in order to avoid hazards for both the manipulated objects and the remote robot.

BILATERAL TELEOPERATION OF MOBILE ROBOTS THROUGH INTERNET

Abstract This paper addresses a stable control structure for the bilateral teleoperation of mobile robots with visual feedback in presence of time-varying delay. The proposed control structure uses estimated parameters of the human operator and a fictitious force which is calculated using data fusion from ultrasonic sensors and optical flow field from panoramic images. To illustrate the performance and stability of the proposed control structure, several teleoperation experiments between Argentina and Brazil linked via Internet are shown.