Ángel Gaspar González Rodríguez

A new articulated leg for mobile robots

Purpose – The paper aims to present a new mechanical scheme for a leg to be included in legged vehicles that simplifies the control actuations along the stride.Design/methodology/approach – The scheme includes three four‐bar links grouped in two mechanisms. The first one decouples the vertical and horizontal foot movements. The second one produces a constant horizontal foot velocity when the corresponding motor is given a constant speed. A hybrid robot with wheels at the end of the hind legs has been simulated and constructed to validate the leg performance.Findings – The gait control requires only five commands for the electronic cards to control the leg. Decoupling vertical and horizontal movements allows a more adequate selection of actuators, a reduction of energy consumption, and higher load capacity and robot velocity. Additional mechanical benefits, such as improved robustness and lower inertia, are obtained. The hind legs can also be articulated, allowing the robot to overcome an obstacle and to c...

Design and validation of a novel actuator with adaptable compliance for application in human‐like robotics

Purpose – The purpose of this paper is to propose a novel actuator with adaptable compliance for robotic applications.Design/methodology/approach – In order to achieve limb actuation similar to that of human muscles, a novel actuator with adaptable compliance is proposed. Three principal design paradigms currently exist in the development of artificial muscles that have been adopted at several research centres, universities and commercial organizations around the world. The first approach consists of using compliant actuator systems such as pneumatic actuators. The second approach undertakes the development of electroactive polymers that deform when a voltage is applied. The third approach involves electromechanical devices typically comprising an electrical actuator and an elastic element in combination. The proposed actuator extends on the third approach. It comprises an electrical DC motor in serial configuration and a novel elastic device exhibiting variable stiffness.Findings – The novel elastic devi...

Electrical maps of induction machines

The study of circular maps of induction machines is one of the classical subjects dealt with in literature about electrical machines and it is fairly interesting from a didactical point of view as well as from its practical applications. This paper presents a new and general method that allows for, among other things, the analytical way of obtaining center coordinates and the radius of any of the geometrical maps (impedance, admittance, current, voltage, and power) of induction machines. To reach this goal, a two-port model associated to any of the equivalent induction machines is used.