System and method for feedback control

US8831755B2 · kind B2 · utility

Assignee

• SOCOVAR S.E.C. · CA

Inventor

• David Bensoussan · Altendorf, CH

Key dates

• Filing date: Aug 25, 2011
• Grant date: Sep 9, 2014
• Expiry date: Apr 5, 2033

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02P90/02
• WIPO field: Control
• WIPO sector: Instruments

Abstract

A system and method for controlling a plant having a minimum phase transfer function P(s) and given an input signal u, the plant having an output y and a plant frequency range comprising a transfer function J(s) comprising the product of a high gain filter J1(s) having a gain k1 sufficient thatwhen |ω|≦ω1 and |1+J(ω)|>1/M for all ω wherein ω1 is selected to obtain a desired time response, and a low pass filter J2(s) selected such that |1+J(ω)|>1/M for all ω and J(s) is strictly proper, wherein ε<1 and M>1 and ε and M are selected to meet a desired sensitivity requirement. An error signal e is calculated comprising the difference between the system input signal u and the plant output signal y, and the error signal modified according to the transfer function C(s)=P−1(s)J1(s)J2(s) and inputting the error signal into the plant. The system and method can be extended to unstable invertible plants. A global sensitivity bound M≧1 could also be achieved for plants including right half planes zeros. The system and method are shown applied to a read-write head positioning actuator of a hard disk drive, but can be applied equally to other systems such as electrical systems, mechanical systems,…