Engineering topics

Homaifar, A.

Publications and source records attributed to Homaifar, A..

3 records

NASA NTRS1997

Aircraft Pitch Control with Fixed Order LQ Compensators

This paper considers a given set of fixed order compensators for aircraft pitch control problem. By augmenting compensator variables to the original state equations of the aircraft, a new dynamic model is considered to seek a LQ controller. While the fixed order compensators can achieve a set of desired poles in a specified region, LQ formulation provides the inherent robustness properties. The time response for ride quality is significantly improved with a set of dynamic compensators.

Green, James↗

NASA NTRS1992

Nonlinear robust controller design for multi-robot systems with unknown payloads

This work is concerned with the control problem of a multi-robot system handling a payload with unknown mass properties. Force constraints at the grasp points are considered. Robust control schemes are proposed that cope with the model uncertainty and achieve asymptotic path tracking. To deal with the force constraints, a strategy for optimally sharing the task is suggested. This strategy basically consists of two steps. The first detects the robots that need help and the second arranges that help. It is shown that the overall system is not only robust to uncertain payload parameters, but also satisfies the force constraints.

Song, Y. D.↗

NASA NTRS1992

Robust motion tracking control of robotic arms based on the generalized energy accumulation principle

Consider a rigid-link robot with the dynamic model tau = H(q;p)q''+C(q,q',p)q'+G(q;p)+Nu(t) where Nu(.) denotes a bounded external disturbance. The objective addressed herein is to find a control strategy that exhibits the following features: (1) simple to implement, (2) easy to code for program, and (3) robust to possible time-varying uncertainties.

Song, Y. D.↗