Load Lifting in the Exoskeleton with Gravity Compensation

Abstract

Purpose of research. Currently, exoskeletons are getting widespread use. They enhance human capabilities in terms of ease of movement, carrying loads and different types of activities that require considerable effort. Especially effective are those exoskeletons that make it possible to make complex types of movement of both for the lower and upper limbs, which significantly expands the capabilities of a person when performing loading and unloading operations. Relatively recently, they have started the development of exoskeletons which use the elements of gravity compensation. Therfore, the study of energy costs in the process of load lifting and the study of gravitational compensators influence on the magnitude of moments made by the electric drives of the femoral and knee joints, is relevant and is revealed in this paper.Methods. Methods of system analysis, design of biotechnical systems, control theory, theory of mechanisms and machines, methods of mathematical modeling of dynamic systems, methods of optimal planning and design were used to solve the problems. Mathematical packages Matlab/Simulink were used to make software products.Results. The study shows that the use of gravity compensators can significantly reduce the load on electrodrives. The movement of load is due to the operation of engines located in the area of ankle, knee and thigh joints. Since the movement of the exoskeleton occurs in the sagittal plane during load lifting, the position of the exoskeleton links in space is determined by four independent parameters.Conclusion. The mathematical model of load lifting by a man in an exoskeleton has been developed. Mathematical modeling of the process of load lifting with the help of exoskeleton electric drives has been made. A special attention is paid to the study of gravitational compensators influence on the magnitude of moments created by the electric drives of femoral and knee joints. It shows that the use of gravity compensators can significantly reduce the load on electric drives. Also, the study of energy costs in the process of load lifting has been conducted.