In the field of human–robot interaction in industrial environments, the active control of robot based on exteroceptive sensors' measurements is a viable approach to the issue of safety enhancement. Among all possible solutions, onboard sensors have several advantages, in terms of ease of deployment and calibration, and absence of occlusions. In this paper, we present a prototype of a distributed distance sensor that can be mounted on an industrial robot. The sensor's outputs have been used as part of a newly conceived control strategy, aimed at improving human safety by means of assessing the level of danger induced by the robot. Several experiments on an ABB IRB140 industrial robot have been carried out, demonstrating the feasibility of the proposed approach in a realistic scenario.

Permanent-magnet linear synchronous motors can serve as direct-drive actuators for machine tools and production machines, whenever high dynamic performance are required. Since compliance in transmission elements is eliminated, higher control bandwidths can be achieved, when compared to traditional solutions based on conversion from rotational to linear motion. Like their rotational counterparts, these motors are, however, affected by a ripple, in the form of parasitic and undesired force pulsations. In this paper, a compensation scheme of force ripple is proposed, based on a simple and compact model of the disturbance. The compensation requires a preliminary identification stage that simply consists of a couple of controlled motions at constant and very low velocity. The compensation term is then applied in parallel to the position/velocity controller, as a function of the linear position of the motor. A robustness analysis is performed based on a convenient formulation of the closed-loop system, as well as on a Lyapunov argument. Experiments that demonstrate the effectiveness of the method are reported, even when compared to a traditional force disturbance observer.

Research interest in human-robot interaction (HRI) has been increasing in recent decades and has now reached an appealing degree of maturity, which encourages first steps toward a technology transfer from research centers to robot manufacturers. Making robots able to cooperate with humans in a safe and intuitive manner is no longer a futuristic vision but a concrete opportunity that is just around the corner. On the other hand, measuring the quality of this interaction is a novel field in robotics research and will be extremely useful for future assessments of all efforts in the direction of more effective HRI. First results exist, ranging from a simple approach, like the so-called "uncanny valley" proposed in [1], to a more scientific interpretation supported by physiological measurements [2].