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On the explicit robust force control via disturbance observer

Journal Article


Abstract


  • This paper analyzes the robustness and stability of disturbance observer (DOb)-based explicit force control systems. Conventional analysis methods, which only consider ideal robustness, are impractical due to the design constraints of a DOb, e.g., bandwidth limitations. This paper shows that not only the stability but also the robustness of a DOb-based explicit force control system changes by environmental impedance variations. The robustness of a DOb-based explicit force control system is clarified by deriving new sensitivity functions. Implicit and explicit environmental impedance estimation methods are considered by analyzing the dynamics of a force sensor and a reaction force observer (RFOb), respectively. It is shown that the stability and performance of an explicit force control system can be improved by using an explicit environmental impedance estimation method, i.e., an RFOb, intrinsically. However, an RFOb is more sensitive than a force sensor to external disturbances, and the stability of the explicit force control system drastically changes by the design parameters of a DOb and an RFOb. Force-sensor- and RFOb-based explicit robust force control systems are compared in terms of stability, robustness, and performance in detail. The validity of the proposals is verified by simulation and experimental results.

Publication Date


  • 2015

Geographic Focus


Citation


  • Sariyildiz, E. & Ohnishi, K. (2015). On the explicit robust force control via disturbance observer. IEEE Transactions on Industrial Electronics, 62 (3), 1581-1589.

Scopus Eid


  • 2-s2.0-84923171458

Number Of Pages


  • 8

Start Page


  • 1581

End Page


  • 1589

Volume


  • 62

Issue


  • 3

Abstract


  • This paper analyzes the robustness and stability of disturbance observer (DOb)-based explicit force control systems. Conventional analysis methods, which only consider ideal robustness, are impractical due to the design constraints of a DOb, e.g., bandwidth limitations. This paper shows that not only the stability but also the robustness of a DOb-based explicit force control system changes by environmental impedance variations. The robustness of a DOb-based explicit force control system is clarified by deriving new sensitivity functions. Implicit and explicit environmental impedance estimation methods are considered by analyzing the dynamics of a force sensor and a reaction force observer (RFOb), respectively. It is shown that the stability and performance of an explicit force control system can be improved by using an explicit environmental impedance estimation method, i.e., an RFOb, intrinsically. However, an RFOb is more sensitive than a force sensor to external disturbances, and the stability of the explicit force control system drastically changes by the design parameters of a DOb and an RFOb. Force-sensor- and RFOb-based explicit robust force control systems are compared in terms of stability, robustness, and performance in detail. The validity of the proposals is verified by simulation and experimental results.

Publication Date


  • 2015

Geographic Focus


Citation


  • Sariyildiz, E. & Ohnishi, K. (2015). On the explicit robust force control via disturbance observer. IEEE Transactions on Industrial Electronics, 62 (3), 1581-1589.

Scopus Eid


  • 2-s2.0-84923171458

Number Of Pages


  • 8

Start Page


  • 1581

End Page


  • 1589

Volume


  • 62

Issue


  • 3