Stabilizing robot force control through low pass filtering with low cut off frequency

Addressing the problem of dynamic instability in robot force control, the authors reveal that for an arbitrary linear time invariant process which is open loop stable, closed loop stability of proportional feedback control can be guaranteed by adding low pass filtering with a sufficiently low cutoff frequency in the loop, even if the control is implemented in continuous time or discrete time. As a consequence, the dynamic instabilities caused either by flexibility or insufficient sampling rate in robot force control can all be eliminated through simple low pass filtering. The analysis also shows that the filtering does not lead to slow response