Investigation in online-methods estimating the oscillating frequency to improve control adaptively

Abstract

The automation industry seeks for positioning systems with high dynamics and precision. In robotics or other light-weight applications where mechatronic drives are used, the end-effector often undesirably oscillates due to a relatively low system damping. Knowing the frequency of the damped oscillation would allow, e.g. “posicast”- or “input shaping”-control methods. Thus, suppression or even elimination of such an oscillation can be achieved. When the frequency changes due to e.g. variable loads or gravitational issues, the control settings should be changed as well. Then dynamics/precision can be held among non oscillation. Having a method which adapts e.g. a shaper to the actual frequency would allow a better suppression of such an oscillation. During run time, several sensor data of a mechatronic system contains this frequency more or less incisive. Several methods which may estimate online (during run time) this frequency in “transient”- as well as “semi-steady”-state were discussed in the following.