CML Colloquium: Passivity-based and Model-based Control Approaches for Bilateral Teleoperation Systems
10 May 2016
CML Colloquium 10 May 2016, 15:00, Room F334, Informatikum
Professor Dr. Ya-Jun Pan, Department of Mechanical Engineering, Dalhousie University, Halifax, Canada
Bilateral Teleoperation is the manipulation of a remote system where system state information is relayed to the remote site and forces are fed back to the operator in order to improve awareness of the remote environment. When delays are introduced into the bilateral teleoperation communication channels, the interacting systems become inherently unstable. These instabilities are both undesirable for the functioning of the teleoperation scheme and unsafe for people interacting with the system. Two approaches developed in recent years are introduced in this presentation.
Firstly, a Power Based Time Domain Passivity Control (PTDPC) is proposed and then experimentally evaluated for use in bilaterally teleoperated schemes. The new passivity observer (PO) monitors the current power behavior and decides the activation of the passivity controller (PC). The PC output is distributed along the time index and a sudden big force change is alleviated. Applications of the approach to haptic interfaces are simulated. A haptic steering wheel interface was constructed to interact with a virtual environment. Furthermore, this steering interface was used in conjunction with a robotic vehicle modified for teleoperation. In both experiments PTDPC is shown to improve the stability and transparency of the teleoperated system. Secondly, a novel control scheme for asymmetric bilateral teleoperation systems is developed based on linear models of the hardware, with considerations in the existence of communication time delays. The master and slave manipulators were modeled as linear single degree of freedom systems. The human user force was modeled based on the band limited availability of human motion, and the environmental force was modeled as a spring and damper type function. An impedance matching approach was applied to the master side dynamics, while a static error feedback gain was used to stabilize the slave side dynamics. A Lyapunov functional based on the error dynamics of the system is proposed with consideration for the minimum and maximum level of delays existing in the system. LMI techniques are used with Jensen’s inequality to determine the static feedback control gain. The experimental results with comparisons to simulation results are demonstrated to show the effectiveness of the proposed approach.
Dr. Ya-Jun Pan is currently a Professor in the Department of Mechanical Engineering at Dalhousie University, Canada. She received the B.E. degree in Mechanical Engineering from Yanshan University in 1996, the M.E. degree in Mechanical Engineering from Zhejiang University in 1999 and the Ph.D degree in Electrical and Computer Engineering from the National University of Singapore in 2003. She held post-doctoral positions of CNRS in the Laboratoire d’Automatique de Grenoble (Current Name: GPISA-Lab), France and the Department of Electrical and Computer Engineering at the University of Alberta, Canada, in 2003 and 2004 respectively.
Her research interests are focused on robust nonlinear control, networked control systems, intelligent transportation systems and collaborative multiple autonomous ground/underwater vehicles. She is currently an Associate Editor of the IEEE/ASME Transactions on Mechatronics (2015-Present), International Journal of Advanced Robotics Systems (2014-Present), the International Journal of Information and Systems Sciences (2009-Present) and the Conference Editorial Board of the IEEE Robotics and Automation Society for ICRA 2016. She has been the Associate Editor for the Journal of Franklin Institute (2007-2013). She is a Senior Member of the Institute of Electrical and Electronics Engineers (IEEE), a Member of the American Society of Mechanical Engineers (ASME) and a Registered Professional Engineer in the Province of Nova Scotia, Canada.