This paper proposes a shared control scheme which aims to achieve a stable control of the speed and turn of a bipedal robot during a delayed bilateral teleoperation. The strategy allows to get a delay-dependent damping value that must be injected to assure a bounded response of the hybrid system, while simultaneously, the human operator receives a force feedback that help him to decrease the synchronism error. Furthermore, a test where a human operator handles the walking of a simulated bipedal robot, to follow a curve path in front of varying time delay, is performed and analyzed.

This paper addresses the problem of trajectory tracking control in mobile robots under velocity limitations. Following the results reported in ref. [1], the problem of trajectory tracking considering control actions constraint is focused and the zero convergence of the tracking errors is demonstrated. In this work, the original methodology is expanded considering a controller that depends not only on the position but also on the velocity. A simple scheme is obtained, which can be easily implemented in others controllers of the literature. Experimental results are presented and discussed, demonstrating the good performance of the controller.

This paper is a continuation of a previous work of authors, Scaglia et al. [G. J. E. Scaglia, L. M. Quintero, V. Mut and F. Di Sciascio, “Numerical methods based controller design for mobile robots,” Robotica27(2), 269–279 (2009)]. A method is presented to choose the controller parameters such that, the values of the control actions do not exceed the maximum allowable and the tracking errors tend to zero. In addition, the analysis of the controller design parameters is included. The experimental results (laboratory experiments and a real world application) demonstrate the efficiency of the controller.

A brain–computer interface (BCI) is a system for commanding a device by means of brain signals without having to move any muscle. One kind of BCI is based on Steady-State Visual Evoked Potentials (SSVEP), which are evoked visual cortex responses elicited by a twinkling light source. Stimuli can produce visual fatigue; however, it has been well established that high-frequency SSVEP (>30 Hz) does not. In this paper, a mobile robot is remotely navigated into an office environment by means of an asynchronous high-frequency SSVEP-based BCI along with the image of a video camera. This BCI uses only three electroencephalographic channels and a simple processing signal method. The robot velocity control and the avoidance obstacle algorithms are also herein described. Seven volunteers were able to drive the mobile robot towards two different places. They had to evade desks and shelves, pass through a doorway and navigate in a corridor. The system was designed so as to allow the subject to move about without restrictions, since he/she had full robot movement's control. It was concluded that the developed system allows for remote mobile robot navigation in real indoor environments using brain signals. The proposed system is easy to use and does not require any special training. The user's visual fatigue is reduced because high-frequency stimulation is employed and, furthermore, the user gazes at the stimulus only when a command must be sent to the robot.

In this work, a vision-based control interface for commanding a robotic wheelchair is presented. The interface estimates the orientation angles of the user's head and it translates these parameters in command of maneuvers for different devices. The performance of the proposed interface is evaluated both in static experiments as well as when it is applied in commanding the robotic wheelchair. The interface calculates the orientation angles and it translates the parameters as the reference inputs to the robotic wheelchair. Control architecture based on the dynamic model of the wheelchair is implemented in order to achieve safety navigation. Experimental results of the interface performance and the wheelchair navigation are presented.

This work proposes a teleoperation architecture for mobile robots in partially unknown environments under the presence of variable time delay. The system is provided with artificial intelligence represented by a probabilistic path planner that, in combination with a prediction module, assists the operator while guaranteeing a collision-free motion. For this purpose, a certain level of autonomy is given to the system. The structure was tested in indoor environments for different kinds of operators. A maximum time delay of 2s was successfully coped with.

This paper proposes a prediction system and a command fusion to help the human operator in a teleoperation system of a mobile robot with time-varying delay and force feedback. The command fusion is used to join a remote controller and the delayed user's commands. Besides, a predictor is proposed since the future trajectory of the mobile robot is not known a priori being it decided online by the user. The command fusion and predictor are designed based on the time delay and the current context measured through the crash probability. Finally, the proposed scheme is tested from teleoperation experiments considering time-varying delay as well as force feedback.

A novel approach for trajectory tracking of a mobile-robots formation by using linear algebra theory and numerical methods is presented in this paper. The formation controller design is based on the formation states concept and the dynamic model of a unicycle-like nonholonomic mobile robot. The proposed control law designed is decentralized and scalable. Simulations and experimental results confirm the feasibility and the effectiveness of the proposed controller and the advantages of using the dynamic model of the mobile robot. By using this new strategy, the formation of mobile robots is able to change its configuration (shape and size) and follow different trajectories in a precise way, minimizing the tracking and formation errors.

This paper proposes a control scheme for the teleoperation of a mobile robot in presence of time delay. Our proposal uses a compensation of the time delay based on a human operator's model and a simple 3D augmented reality scheme; both are related through a prediction system. Unlike other strategies, the proposed scheme has a model of the human operator inside it, including his decision so that human and robot “push in the same direction.” The stability of the teleoperation system adding the proposed control scheme is proven concluding how the time delay changes the convergence rate and the convergence ball size. Finally, to illustrate the performance and stability of the proposed control structure, several teleoperation experiments in presence of various delays are shown.

This paper presents the design of four controllers for a mobile robot such that the system may follow a preestablished trajectory. To reach this aim, the kinematic model of a mobile robot is approximated using numerical methods. Then, from such approximation, the control actions to get a minimal tracking error are calculated. Both simulation and experimental results on a PIONEER 2DX mobile robot are presented, showing a good performance of the four proposed mobile robot controllers. Also, an application of the proposed controllers to a leader robot following problem is shown; in it, the relative position between robots is obtained through a laser.

A new approach for navigation of mobile robots in dynamic environments by using Linear Algebra Theory, Numerical Methods, and a modification of the Force Field Method is presented in this paper. The controller design is based on the dynamic model of a unicycle-like nonholonomic mobile robot. Previous studies very often ignore the dynamics of mobile robots and suffer from algorithmic singularities. Simulation and experimentation results confirm the feasibility and the effectiveness of the proposed controller and the advantages of the dynamic model use. By using this new strategy, the robot is able to adapt its behavior at the available knowing level and it can navigate in a safe way, minimizing the tracking error.

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.

In this paper, development and implementation are presented of a client software package for remote process control. The proposed software is based on a client-server model under an Intranet architecture. The architecture is proposed for a telecontrol system of a real process, which includes the possibility of integrating I/O devices with data networks based on open protocols such as TCP/IP. This protocol allows the implementation of control systems using a low-cost alternative. Also, the Smith predictor is revised for remote control applications over an Ethernet network. Some experiences on a laboratory pasteurization plant are addressed to show both developed controllers and architecture performance.

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, 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.

In this paper we propose a tracking adaptive impedance controller for robots with visual feedback. It is based on a generalized impedance concept where the sensed distance is introduced as a fictitious force to the control in order to avoid obstacles in restricted motion tasks. The controller is designed to compensate for full non-linear robot dynamics. Robot parameters adjustment is introduced to reduce the sensibility of the controller design to dynamic uncertainties of the robot and the manipulated load. It is proved that the vision control errors are ultimately bounded in the image coordinate system. Simulations are carried out to evaluate the controller performance.