Desenvolvimento de uma centrífuga humana movida a exercício para treinamento de pilotos e pesquisas aeroespaciais

Abstract

The human body is adapted to live at an approximate gravitational acceleration of 9.81 m/s², this being equivalent to 1G. Physiological problems can occur if the body is subjected to the effects of a greater or lesser acceleration than this value. The degree of these physiological problems directly depends on the body axis affected, the intensity of acceleration and the length of time it is applied. Current equipment that can apply harmful acceleration forces includes rockets and fighter jet aircraft. Human centrifuges can be used in order to improve the resistance of the human body to this G-force, and also to develop research in this area. These devices perform a circular motion about one axis, producing an inertial reaction to the centripetal acceleration that is used to simulate G-force. Human centrifuges have been used in aerospace physiology since the middle of the 20th century. Pilot training and national research in this area are deficient in Brazil, however, as the country is lacking in this type of equipment. Thus, with this in mind, a human centrifuge was built at the Microgravity Centre/FENG PUCRS. The equipment, called the Albuquerque centrifuge, was built within a low cost budget and has good mobility in comparison to other conventional centrifuge models. The main elements of the Albuquerque centrifuge are: a base, a circular platform around the base, wheels supported on the platform, and an arm with a radius of 2.5 m situated above these wheels. There is also a central axis that connects the base and the arm, allowing the rotational movement of the arm. A subject will be positioned in a chair at one end of the arm, whilst a system of counterweights will be used at the opposite end to balance the equipment load. The base has a pyramid format and acts as the support for the arm structure. The circular platform around the base supports the two wheels that extend down from the arm, and these serve to distribute the load on both sides on the axis. The system axes were constructed using 1045 steel and the other structures using 1020 steel. The structure of the centrifuge is able to support the weight of a volunteer up to 120 kg. The total weight of the equipment itself is estimated to be about 300 kg. The movement of the Albuquerque centrifuge is generated by means of human-powered equipment, without the use of any form of mechanical or electrical motor. This equipment comprises of two devices that simulate the pedaling of a bicycle, one being located externally to the centrifuge, and the other being fitted internally and positioned at one end of the arm. Thus, the volunteer can also perform physical exercise whilst being under the influence of simulated gravity. Having tested the system without the presence a person onboard, that is to say, using external traction only, it is concluded that the equipment is capable of achieving an acceleration close to +3Gz.