Design and development of a power assisted lifting device (Dimeas, 2012)


The modern ways of life and the development of technology have created a need for an artificial increase of human muscle strength for handling various processes. In industry, there has been a variety of solutions with material handling machines that are widely used and allow a person to handle very heavy loads with minimal effort. Nevertheless, the main disadvantage of these systems is that they limit the flexibility of the manipulation.

This work aims to designing a lift mechanism which withdraws the limitation of conventional systems and allows a person to handle an object with direct manual manipulation, reducing the perceived weight and facilitating the operation of a heavy load. Such a system combines mechanical, electrical and automatic control components.

In the first part of the paper, the system structure is described and is designed a two degrees of freedom articulated boom crane which can be applied in industrial environment. The form of the crane is chosen such that the movement in the horizontal plane does not require an external power supply and does not affect the motion in the vertical direction.

Then, the control system is designed which is given great attention. At first, the mathematical modeling of the system is created, the control law is selected and after the detailed design of the controller, follows the simulation in Matlab environment. From the simulation results, valuable conclusions about the efficiency of the operation are obtained which are used to optimize the controller.

In order to proceed to the validity of the theoretical measurements, a small-scale experimental setup is constructed and the derived digital controller is implemented. In the context of this work is not constructed the full scale crane system, but only the lifting device. The separation of the crane functions allows the characteristics of the scaled model to be consistent with the original. The experimental measurements which are taken from the setup are compared with the corresponding theoretical and eventually the effectiveness of the system is evaluated.



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