Systems & Control Labs College Department B C Chang

Research Interests _ BC Chang

Funded Projects

Dr. Chang's research interests include control of nonlinear systems with uncertainties, controller configuration for actuator/sensor failures, real-time microcomputer control, sensors/actuators and their interface with computers, image data acquisition and processing. He has contributed to the development of H-infinity control theory and its application to the design of controllers for systems with uncertainties. He was a recipient of the IEEE Control Society Best Paper Award in 1985 for his contribution in optimal disturbance reduction in linear multivariable systems. He has been involved in funded research projects sponsored by NSF, AFOSR, Flight Dynamics Laboratory of Wright-Patterson Air Force Base, NASA Langley Research Center, Army Research Laboratory, The Boeing Company, and Ben Franklin Partnership Program of the Commonwealth of Pennsylvania.

Ongoing Research

Dr. Chang's ongoing research project with the Army Research Laboratory is on real-time embedded solutions for digital signal processing using the Texas Instruments DSP microprocessors TMS320C2000 and TMS320C6000. This research involves sophisticated sensor suites, actuators, wireless digital communication, autonomous decision making, guidance, and control for flying munitions systems. The DSP microprocessor, virtually an embedded computer, is used to process and analyze the signals received from wireless communication and the data from the accelerometers, magnetometers, gyros, global positioning systems, video cameras, etc. The microprocessor also serves as a decision/control unit that is capable of making autonomous decision and performing robust feedback controls. The actuators include those that can actuate the surface controls or the thrusts of the flying vehicles ?dc motors, brushless dc motors, hydraulic actuators, and pneumatic actuators, etc.

The design and implementation of the sensing/communication/decision/control system is constrained by the limited space available in the flying munitions systems. All components are required to be small in physical size and all electronic devices to consume less power. They also need to stand the shock up to 3000G and function normally after the shock. In addition, the supersonic speed (up to 2 Mach) and the spinning rate (up to 300 rpm) of the flying munitions vehicle demand very fast computation speed from the DSP microprocessors. In other words, the system is required to be small, light, strong, fast, and smart.

Dr. Chang's recent research projects with NASA Langley Research Center have been on the design of fault detection, controller reconfiguration, and cooperative control for aircraft flight control systems. This line of research can be extended to the fault tolerant control of each individual autonomous agent or to the fault accommodation and cooperative control of a group of autonomous agents. The autonomous agent can be an aerial vehicle, ground vehicle, or a patient monitoring unit in the hospital. The fault tolerant / cooperative control system inside each individual agent is required to possess the following two capabilities. One is to reconfigure the controller inside the agent to accommodate subsystem failures so that the survivability of the agent is maximized. The other capability is to coordinate with the other agents in the group so that the workload is reconfigured optimally among all healthy agents to accomplish the mission if some agents of the group are handicapped or dysfunctional.

 

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