1 research outputs found
Stability and Robustness of Disturbance Observer based Motion Control Systems
This paper analyzes the robustness and stability of a disturbance observer
(DOB) and a reaction torque observer (RTOB) based robust motion control
systems. Conventionally, a DOB is analyzed by using an ideal velocity
measurement that is obtained without using a low-pass-filter (LPF); however, it
is impractical due to noise constraints. An LPF of velocity measurement changes
the robustness of a DOB significantly and puts a new design constraint on the
bandwidth of a DOB. An RTOB, which is used to estimate environmental impedance,
is an application of a DOB. The stability of an RTOB based robust force control
system has not been reported yet since its oversimplified model is derived by
assuming that an RTOB has a feed-forward control structure. However, in
reality, it has a feed-back control structure; therefore, not only the
performance but also the stability is affected by the design parameters of a
RTOB. A new practical stability analysis method is proposed for a RTOB based
robust force control system. Besides that novel and practical design methods,
which improve the robustness of a DOB and the stability and performance of an
RTOB based robust force control system, are proposed by using the new analysis
methods. The validity of the proposals is verified by simulation and
experimental results