Department: Mechanical & Aerospace Engineering
Research Institute Affiliation: Center for Control Systems and Dynamics (CCSD)
Faculty Advisor(s): Miroslav Krstic

Primary Student
Name: Nikolaos Bekiaris Liberis
Email: nbekiari@ucsd.edu
Phone: 858-822-1936
Grad Year: 2013

State-dependent delays are common in real world. For example, in control over networks, it makes sense to send control signals less frequently when the state is small and more frequently when the state is large. In control of mobile robots the magnitude of the delay depends on the distance of the robot from the operator interface. In milling processes, speed-dependent delays arise due to the deformation of the cutting tool. The reaction time of a driver depends on the speed of the vehicle, the physical situation of the driver, etc. In engine cooling systems the delay in the distribution of the coolant among the consumers depends on the coolant flow. We present a methodology for compensating state-dependent input delays for nonlinear systems which are, in the absence of the input delay, forward-complete and globally stabilizable. We design a predictor-based compensator which uses predictions of future values of the state on appropriate prediction horizons that depend on the current values of the state. Due to a fundamental restriction on the allowable magnitude of the delay function's gradient (the control signal never reaches the plant if the delay rate is larger than one), we obtain only a regional stability result. We give an estimate of the region of attraction for our control scheme based on the construction of a strict, time-varying Lyapunov functional.

Related Links:

  1. http://flyingv.ucsd.edu/nikos/index.htm

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