Modelling, Control and Experimentation for Vibration Suppression of Single Link Flexible Manipulator

Abstract

The use of robotic arms in various sectors has been increased over a decade. Attempts to improve their performance and design are being made since many years. The size and weight of these arms have been a matter of concern in their design and application. By reducing the cross-sectional area, the weight of the arm reduces considerably but, the rigidity of the arm has to be compromised since the workspace of the arm cannot be altered. Many researchers have suggested various methods to develop these flexible robotic arms. Due to the non-linearity of the system and the complexity of deriving a solution, only discrete forms of modelling like FEM, lumped parameter method, assumed mode method have gained worldwide recognition. Some of these methods do not produce accurate results even for single arm manipulator system while others produce inaccurate results when the number of arms increases. Therefore, a suitable mathematical technique is yet to be developed which will produce accurate results. A rotary flexible link has been modelled in the present work using a conventional method of modelling (lumped parameter model) and is compared with the Rayleigh beam model developed considering the rotary inertia acting on the flexible link. The Rayleigh beam model is developed using bond graph notation. Both the models are validated with experimental results of rotary flexible link. Modern control theories have been discussed and applied on both the dynamic models. The results obtained are compared with experimentation and final conclusion has been stated in detail. Adequate results have been obtained from the Rayleigh beam theory. This model can be refined further for more accuracy. The model can be extended for multi-link flexible manipulators.