One of the frequent problems in the stabilized gimbal system is the rejection of disturbances associated with moving components. Very often such disturbances have non-linear characteristics. In a typical gimbal system, each gimbal and platform are connected by a mutual bearing which induces inevitable friction. Particularly, the non-linear Coulomb friction causes position errors as well as slow responses that lead to unfavorable performance. In this paper, a modified PID controller that is augmented by Coulomb friction estimator is presented. Through constantly estimating the Coulomb friction torque, it is applied to the output of the existing PID controller. The effectiveness of the proposed controller is evaluated through a series of experiments.
[1]
Carlos Canudas de Wit,et al.
A survey of models, analysis tools and compensation methods for the control of machines with friction
,
1994,
Autom..
[2]
Young-Youp Cha.
The Comparison Experiment of Rotation Range of RC Servo Motors According to change of a Periods
,
2011
.
[3]
Craig D. Walrath,et al.
Adaptive bearing friction compensation based on recent knowledge of dynamic friction
,
1984,
Autom..
[4]
L. Ljung.
Prediction error estimation methods
,
2002
.
[5]
Carlos Canudas de Wit,et al.
A new model for control of systems with friction
,
1995,
IEEE Trans. Autom. Control..
[6]
Bernard Friedland,et al.
On adaptive friction compensation
,
1992
.