Browsing by Author "Tomizuka, M"

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A complete fault diagnostic system for automated vehicles operating in a platoon
(2001-07-01)
Rajamani, R
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Howell, AS
;
Chen, C
;
Hedrick, JK
;
Tomizuka, M
A "complete" fault diagnostic system is developed for automated vehicles operating as a platoon on an automated highway system. The diagnostic system is designed to monitor the complete set of sensors and actuators used by the lateral and longitudinal controllers of the vehicle, including radar sensors, magnetometers and inter-vehicle communication systems, A fault in any of the twelve sensors and three actuators is identified without requiring any additional hardware redundancy. The diagnostic system uses parity equations and several reduced-order nonlinear observers constructed from a simplified dynamic model of the vehicle. Nonlinear observer design techniques are used to guarantee asymptotically stable convergence of estimates for the nonlinear dynamic system. Different combinations of the observer estimates and the available sensor measurements are then processed to construct a bank of residues. The paper analytically shows that a fault in any one of the sensors or actuators creates a unique subset of these residues to grow so as to enable exact identification of the faulty component. Both simulation and experimental results are presented to demonstrate the effectiveness of the fault diagnostic system in the presence of various faults.
Lateral control of commercial heavy vehicles
(2000)
Chen, C
;
Tomizuka, M
;
机械工程学系
;
Department of Mechanical Engineering
Two nonlinear lateral control algorithms are designed for a tractor-semitrailer type commercial heavy vehicle. The baseline steering control algorithm is designed utilizing input-output linearization. To enhance the lateral stability and furthermore reduce tracking errors of the trailer, braking forces are independently controlled on the inner and outer wheels of the trailer. The coordinated steering and braking control algorithm is designed based on the multivariable backstepping technique. Simulations conducted using the complex model show that the trailer yaw errors under coordinated steering and independent braking force control are much smaller than those without independent braking force control.