Conference Paper (international conference)
serial: Preprints of the 8th IFAC Symposium on Nonlinear Control Systems
action: The 8th IFAC Symposium on Nonlinear Control Systems, (University of Bologna, IT, 01.09.2010-03.09.2010)
project(s): GA102/08/0186, GA ČR
keywords: reduced observer, underactuated mechanical systems, walking robots
This paper provides the algorithm how to exponentially track any trajectory of the Acrobot based on the knowledge of two position variables only. Namely, it aims to design a special reduced observer for the Acrobot angular velocities based on the respective angles measurements and then to combine this observer with the earlier developed full state feedback controllers. For the Acrobot with point feet it is not an easy task to measure the angle between its stance leg and the surface. This paper suggests to measure instead of this angle a certain distance using a laser beam sensor and then to compute the stance angle from that distance. For this purpose, the optical laser distance sensor was selected, purchased and analyzed. Remarkably, the corresponding computations maintain basically the same order of precision for the computed angle as achieved for that measured distance. The stability of both the reduced observer and the overall output feedback tracking is demonstrated as well.