Biomechanics and Ergonomics

The development of efficient artificial hands, both for use in robots and for prosthetic replacements, remains a complex challenge for design and control engineering. In the past, simulation tools have been used to evaluate the functionality of robotic grippers and anthropomorphic hands and to define grasping metrics for motion planning. However, these simulation tools are limited to consider the actual functionality of hand designs in daily life activities, since aspects as the friction, the deformation, the joints stiffness or the dynamic response of actuators or the control system, are difficult to incorporate into analytical metrics. Therefore, the experimental evaluation of prototypes of artificial hands is essential to move towards more efficient solutions. From the analysis of the literature and from the previous developments of the research team, is deduced the need for standardized equipment, protocols and metrics that permit the experimental evaluation of different prototypes of artificial hands, whether they are robotic or prosthetic hands, and the definition of quality metrics or indices compared to the human hand. In this project it is assumed that this experimental evaluation must be structured to analyse separately the three main factors that affect the functionality of an artificial hand: 1) the mechanical design (topology, materials) that affect to the attainable stable grip postures 2) the dynamic performance of their actuators and mechanical transmission, which condition the dynamic response as grasp forces and opening/closing times 3) the control system, affecting to the proprioception, sensitivity, responsiveness or versatility for different tasks. It is also assumed that the experimental metrics that allow evaluating hand prototypes according to these three factors must be based on the comparison with the performance of the human hand. Therefore, the project has three main objectives:
To develop test equipment and protocols (benchmarks) that allow for the experimental evaluation of any artificial hand compared to the human hand, using metrics defined at the three levels above-mentioned (mechanical design, actuators performance, control system).
To obtain an improved design of a robotic hand for service applications, using the methodologies developed in objective 1 at its three levels.
To obtain an improved design of a low-cost motorized transradial hand prosthesis, using the methodologies developed in objective 1 at its three levels.