Desarrollo de un prototipo de órtesis para el apoyo funcional de una extremidad superior izquierda sana para el levantamiento de pesos.

Abstract

The objective of this degree work was to implement an orthosis prototype for the functional support of a healthy left upper extremity for weight lifting, being a prototype that is easy to use and adjustable to a body of average height. The prototype called Strong Arm V1 consists of four blocks that allow increasing the functionality of one of the test subject's arms when lifting a heavy object. The first block is responsible for acquiring electrical signals from the user's left biceps muscle through electrodes attached to the skin. These signals are captured by the MYOWARE sensor and after a conditioning process, the myoelectric signals are entered into the controller. The second block is made up of the mechanical parts that make up the physical structure of the orthosis prototype. Among these parts is the electric-type linear actuator driven by the torque of a DC motor. Said actuator exerts a maximum force of 900 N, so it is estimated that the prototype will be able to lift weights of up to 30Kg. The third block consists of the control system that is responsible for processing the received myoelectric signals and generating the respective command signals for the correct operation of the actuator. The fourth and last block is the power electronics that is responsible for interconnecting the control system and the actuator. Additionally, in this block is the signal conditioning of a QTR2A sensor configured as “end of travel” for the linear displacement actuator. Several tests carried out, with the orthosis prototype and different weights in each of the scenarios, effectively indicated that the device is capable of lifting up to 30kg. Several tests were carried out with a group of 8 subjects aged between 18 and 29 years, 5 women and 3 men. The results and measurements obtained showed that the prototype is capable of maintaining the physical improvement index (IM-F) above 60% for an average weight of 15 Kg. In addition, the Strong Arm V1 presented a speed improvement index (IM -V) in lifting 15 kg of weight by 44.0% on average. It is recommended to expand the use of the Strong Arm V1 in supervised physical therapies for muscle and motor recovery of affected upper limbs.