Design and experimental validation of a new three-degree-of-freedom flexible arm with simplified dynamics

Abstract This article describes the design and experimental validation of a new three-degree-of-freedom flexible arm. This arm was built with light links, has most of its mass concentrated at the tip, and uses a special mechanical configuration to approximately decouple radial tip motion from angular tip motions; i.e. the first actuator produces an azimuth movement, the second actuator produces a cenital movement and the third one produces an approximately radial movement. The compliance matrix can be used to model the oscillations of the structure. The proposed mechanism shows some advantages to control the arm: first, a lumped masses model with only one mass concentrated at the tip can be used to characterize the system, avoiding the use of distributed masses models; second, because of these simple dynamics, minimum sensing effort is required (only motor and tip measurements) and the use of complex observers is avoided because the state of the system is obtained directly. Experimental identification and validation are presented