Control of Robotic Manipulator using Automatic Loop-Shaping (ALS)

Abstract: H Control designs are quite effective in robust design for systems under unstructured uncertainty, unknown disturbance and measurement noise. Conventional H loop-shaping is a reasonable method for designing the robust controller. H Loop-shaping guarantees closed-loop performance and robustness to generic unstructured dynamic uncertainty, where robustness to uncertainty is incorporated through a ì-synthesis design. At present, computer aided design tools are mostly in use for loop-shaping, and moreover, it is usually based on trial and error approach. In cases, where the plant is somehow complex, proper weight selection for loop shaping may prove to be an extremely hard task for the designer. In particular, when dealing with MIMO systems, it is difficult to set the weights so as to obtain a sufficient robust stability margin and satisfy the control specifications. The remedy to this problem is the automation of weight selection. The proposed H automatic loop-shaping method blend with advantages of a classical manual loop-shaping method. The main impetus of this paper is on the automatic loop shaping for designing H control efficiently and effectively. In proposed loop-shaping procedure, the robust stability bounds are used to get the optimized weighting matrices. This methodology helps to automates loop-shaping as well as improves robustness. Proper transformation from the MIMO system to a series of equivalent SISO problems is suggested that motivates an enhanced synthesis procedure. Special consideration is given to the adjustment of design weights in order to meet prescribed bounds. The innovation of this research focuses on the development of compensators augmented with the plant by satisfying the performance and robustness properties with much little effort. In particular, it shows how the specifications in terms of maximum complementary sensitivity is related to the weighted H introduced by McFarlane and Glover [1]. Finally, the proposed method is applied on the two-link arm to illustrate the effectiveness of the design procedure, as well as performance of the proposed algorithm.