This study presents the design and evaluation of a prototype snake-like robot that possesses an actuation system based on shape memory alloys (SMAs). The device is constructed based on a modular structure of links connected by two degrees of freedom links utilizing Cardan joints, where each degree of freedom is actuated by an agonist–antagonist mechanism using the SMA spring-shaped actuators to generate motion, which can be easily replaced once they reach a degradation point. The methodology for programming the spring shape into the SMA material is described in this work, as well as the instrumentation required for the monitoring and control of the actuators. A simplified design is presented to describe the way in which the motion is performed and the technical difficulties faced in manufacturing. Based on this information, the way in which the design is adapted to generate a feasible robotic system is described, and a mathematical model for the robot is developed to implement an independent joint controller. The feasibility of the implementation of the SMA actuators regarding the motion of the links is verified for the case of a joint, and the change in the shape of the snake robot is verified through the implementation of a set of tracking references based on a central pattern generator. The generated tracking results confirm the feasibility of the proposed mechanism in terms of performing snake gaits, as well as highlighting some of the drawbacks that should be considered in further studies.

This article presents the design and implementation of a linear actuator based on NiTi Shape Memory Alloys with temperature and position measurements based on a magnetic sensor array and a set of thermistors. The position instrumentation is contact free to avoid friction perturbations; the position signal conditioning is carried out through the calculation of the response of each magnetic sensor, selecting the closest sensor to ensure accurate results on the full range of movement. Experimental results validate the accuracy of the position sensing with a competitive behaviour.

Electric vehicles need continuous monitoring of the energy supply all the time to provide the user with accurate information about the available energy. However, an increase in the power consumed by the monitoring system may cause a significant decrease in the vehicles autonomy. This letter presents a monitoring and estimation system for an electric car with a hybrid energy supply based on supercapacitors and batteries based on an embedded system capable of monitoring the general current, the current from the battery system, the voltage in the battery system, the voltage in the supercapacitor system, estimating the value of the State of Charge from batteries and showing the measurements to the user with an OLED display. The proposed system performs similarly in the estimation but decreases the energy consumption by 99.9 % concerning laboratory systems.

En este trabajo se presenta una propuesta alternativa de control para un sistema mecánico lineal basado en resortes fabricados a partir de aleaciones con memoria de forma (AMF), dicho sistema se presenta en una configuración agonista-antagonista, la cual permite la manipulación de la posición de un elemento intermedio (PM) mediante un diferencial de fuerza generado al aumentar la temperatura de los resortes de AMF cuando se aplica corriente eléctrica a través de ellos. Para regular esta posición se ha propuesto un esquema de control conmutado que active o desactive el paso de corriente eléctrica en los resortes de tal manera que se produzca la fuerza necesaria para mover al elemento. Asimismo, se presentan los resultados de las simulaciones del sistema en lazo abierto ante señales de control variantes en el tiempo, tales como ondas senoidales, así como de la respuesta del sistema en lazo cerrado con la correspondiente ley de control conmutado.