Numerical Analysis of Controlling Base Disturbance in Long Reach Manipulators Using Eddy Current Damping

The dynamics of Long Reach Manipulators (LRM) produce undesirable vibrations creating disturbances in the mounting base. Such disturbances hamper proper mission tasks and hence controlling them has been and is an active area of research. This paper presents a numerical study incorporating eddy current (EC) damping for controlling the base disturbance of LRM applications. The LRM system has been idealized as a Double Pendulum. A short link augmented on the rigid link swings as a secondary pendulum so that the magnet, housed in it, continuously intercepts the coils mounted on the rigid link causing eddy currents and the consequent damping effect. The disturbances - in terms of the damping of oscillations, and angular displacement of the flexibly mounted base link, and damping of the angular displacement of the rigid link - are compared considering the absence and presence of EC damping. A parametric analysis involving the ratio of the lengths of the secondary link to the rigid link is also investigated. The results indicate the suitability of the damping arrangement in controlling the disturbances. Based on these results, mechanisms can be suitably developed for actual applications.