Robust Adaptive Nonlinear Control Under Extended Matching Conditions

Coordinated Science Laboratory was formerly known as Control Systems LaboratoryNational Science Foundation / ECS 87-15811Air Force Office of Scientific Research / AFOSR 90-001

Adaptive Feedback Linearization: Stability and Robustness

Coordinated Science Laboratory was formerly known as Control Systems LaboratoryNational Science Foundation / NSF ECS 87-15811U of I OnlyRestricted to UIUC communit

Adaptive Feedback Linearization: Stability and Robustness

Coordinated Science Laboratory was formerly known as Control Systems LaboratoryNational Science Foundation / NSF ECS 87-15811U of I OnlyRestricted to UIUC communit

Adaptive Feedback Linearization: Stability and Robustness

Coordinated Science Laboratory was formerly known as Control Systems LaboratoryNational Science Foundation / NSF ECS 87-15811U of I OnlyRestricted to UIUC communit

Adaptive control of nonlinear systems

In the last few years, adaptive control of nonlinear systems has emerged as an important area of research, with possible applications in areas as diverse as robotic systems, electric motors, chemical processes, and automotive suspensions. Many of the existing results employ design methods and proof techniques borrowed from the adaptive linear control literature. As a consequence, they impose linear growth constraints on the nonlinearities in order to guarantee global stability. Such constraints bypass the true nonlinear problem and exclude many practically important systems. Furthermore, most existing results are based on the often unrealistic assumption of full-state feedback.In this thesis we construct fundamentally new systematic procedures for adaptive nonlinear control design, which yield global results without imposing any type of growth constraints on the nonlinearities and without requiring full-state feedback. This is achieved by identifying a set of basic tools from nonlinear and adaptive control and interlacing them in an intricate fashion to produce new design tools, which are used as building blocks in our design procedures.Each of these new procedures is applicable to nonlinear systems which can be expressed in a special canonical form. Since models of nonlinear systems are often derived from physical principles and given in specific coordinates, it may not always be obvious whether or not the nonlinear system at hand can be transformed into one of these canonical forms. Using differential geometric conditions, we derive coordinate-free characterizations for many of these forms, thereby identifying the classes of systems to which the corresponding design procedures are applicable.U of I OnlyETDs are only available to UIUC Users without author permissio

Analysis, Design, And Evaluation Of AVCS For Heavy-duty Vehicles: Phase 1 Report

This report addresses the problem of automation of heavy-duty vehicles. After a brief description of the dynamic model used in the design and simulations, the authors develop nonlinear controllers with adaptation, first for speed control and then for vehicle follower longitudinal control. Both autonomous operation as well as intervehicle communication are considered, and the performance of the controllers in several different scenarios through simulation are evaluated

Longitudinal Control of Commercial Heavy Vehicles: Experimental Implementation

The report describes the results of the project funded under MOU 314.The main result is the experimental implementation of various longitudinal control algorithms that were developed under MOU124 and MOU 240. In order to conduct these experiments, in collaboration with Professor Tomizuka’s group and PATH Personnel, we first outfitted a Class-8 tractor-trailer commercial heavy-duty vehicle on loan from Freightliner Corporation with the necessary sensors and actuators for fully automated operation. These sensors and actuators included the vehicle speed sensors, air-brake pressure sensors, air-brake actuators, and the throttle actuator. Then, a series of open-loop and closed-loop experiments were carried out at Crow’s Landing test field. In the open-loop experiments, we identified and collected important parameters for vehicle dynamics such as the working ranges for the brake and fuel actuators, the vehicle speed signals, and the air-brake pressure signals. These parameters enabled us to evaluate the vehicle dynamics and adjust the control algorithms accordingly, tuning their parameters off-line in preparation for the closed-loop experiments. In addition, because of the noise levels present in the sensor data, we designed low-pass filters to smooth out the speed signal and the brake/fuel command signal

Analysis, Design And Evaluation Of Avcs For Heavy-duty Vehicles

In this report, the authors develop two new nonlinear spacing policies, variable time headway and variable separation error gain, designed to all but eliminate the undesirable side effect of large steady-state intervehicle spacings. This disadvantage is pronounced in heavy-duty vehicles, which require larger time headways due to their low actuation-to- weight ratio. The first policy significantly reduces the transient errors and allows for the use of much smaller spacings in autonomous platoon operation, while the second one results in smoother and more robust longitudinal control