Load-adaptive control of a single-link flexible manipulator

An adaptive control scheme for the tip position control of a single-link flexible manipulator handling unknown changing loads and its experimental verification are presented. The scheme essentially comprises a least-squares identification algorithm and a self-tuning pole-placement controller. The controller uses a novel recursive algorithm which constrains the control signal not to respond immediately to any sudden changes in the control gains due to changes in the parameter estimate vector. Another salient feature of the present work is the observation of a `ringing effect´ transient during payload release and its resolution. This was achieved by a resetting of the parameter estimate vector to its no-load value, prior to payload release. A performance comparison of the new adaptive control with a constant-gain pole placement controller as well as a standard self-tuning pole placement controller clearly demonstrates its superior ability in handling unknown changing loads