Traditional upper limb rehabilitation exercises are primarily aimed at regaining the strength or range of motion of the patients' injured area. An alternative option that has been presented in the last years is the use of haptic interfaces, which have shown their potential as tools that support rehabilitation therapies. This article presents a haptic system of rehabilitation for fine upper limb movements, whose main characteristic is that users of the system can interact in a visual and tactile fashion with virtual objects mixed with real scenarios, thereby achieving an augmented reality environment. The system was tested in two stages, both with subjects who had a degree of disability in upper limbs. The data collected were followed trajectories, follow-up errors and the muscular activity obtained by means of electromyography; the collected information enabled the analysis, in a quantitative way, of the degree of progress of the patients. In addition, the assessments made by physiotherapists were considered, concluding that the proposed system can be used as a viable complementary tool for conventional rehabilitation therapies.

This paper presents the control design for a multi-agent system (MAS) of land-based mobile robots on wheels formation, that also implements a PI control for the fastest with no-overshoot response at each agent's velocity. Regarding the robot formation tracking control design, a mathematical model constructed from a geometric approach is applied. In addition, the formation's asymptotic stability is guaranteed in the light of Lyapunov's theory. When discussing the agents' velocity control, the mentioned Proportional-Integral PI algorithm is designed by using different methodologies which include σ-stability, λ tuning, and Haalman's tuning techniques. Finally, the theoretical results are confirmed by simulations.