Hardware-in-the-loop testing of current cycle feedback ILC for stabilisation and tracking control of under-actuated visual servo system

ABSTRACT

This paper presents an iterative learning control (ILC) scheme augmented with the feedback control for solving the nonlinear stabilisation and tracking control problem of ball on plate system, which is a class of under-actuated visual servo system. To enhance the trajectory tracking performance and deal with the real-time challenges of ball on plate system including the nonlinearity, inter-axis coupling and uncertain dynamics, we present a feed-forward learning control scheme, which iteratively updates the control input from one trial to the next, integrated with the cascade control. The ILC update law is synthesised based on the current iteration tracking error (CITE), and the uniform convergence of the input control sequence is presented using the contraction mapping technique. From image processing standpoint, for detecting the foreground objects from a video stream, a background subtraction algorithm using frame difference technique is employed. The efficacy of the proposed scheme is tested on a laboratory scale ball on plate system using hardware-in-the-loop (HIL) testing. Experimental results substantiate that augmenting the learning control with the feedback control not only reduces the tracking error significantly but also enhances the robustness of the closed loop system against the poor lighting conditions.

Keywords:

• ILC
• ball on plate system
• under-actuated system
• trajectory tracking
• proportional velocity control

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Vimala Kumari Jonnalagadda

Vimala Kumari Jonnalagadda received the B.Tech degree in Electrical and Electronics Engineering and the M.Tech degree in Control Systems from Jawaharlal Nehru Technological University, Kakinada, India in 2011 and 2015, respectively. She worked as an Assistant Professor at St.Peter’s Engineering College, Hyderabad, India from 2015 to 2017. She is currently working towards her Ph.D degree in the School of Electrical Engineering, Vellore Institute of Technology, India. Her research interests include nonlinear control, adaptive control and hybrid systems.

Vinodh Kumar Elumalai

Vinodh Kumar Elumalai received the B.E degree in Electrical and Electronics Engineering from Madras University, the M.E degree in Control Systems from Anna University, and the Ph.D. degree in Electrical Engineering from Anna University, India in 2004, 2007 and 2014 respectively. He worked as an Assistant Professor at PSG college of Technology, Coimbatore, India from 2009 to 2014. Since 2015, he has been with the School of Electrical Engineering, Vellore Institute of Technology, India, where he is currently an Associate Professor. His research interests include robust control, adaptive control and optimal control.