A Network Virtual Machine for Real-Time Coordination Services

Project Summaries

• Real-Time Design and Simulation of An Actuator Failure Compensation Algorithm for A Rocket Fairing Vibration Reduction
  
  Active vibration control for a rocket fairing system requires tight timing constraints to guarantee desired system real-time performance. Actuator failures can cause performance deterioration or dysfunction of a fairing system, which needs to be effectively compensated in a timely manner. In this paper, the actuator failure compensation problem is formulated and an adaptive actuator failure compensation scheme is evaluated for a typical actuator failure model that the actuator output is stuck at some unknown values at unknown time instants. The adaptive compensation controller is implemented as a task competing with other tasks for system resources in a real-time context. The effects of timing constraints such as sampling interval and control latency are illustrated by simulation on a real-time simulator. A timing compensation scheme is implemented to compensate for the detrimental effects caused by real-time constraints. The effectiveness of timing compensation together with failure compensation is demonstrated by simulation results.
  
  
• Adaptive Actuator Failure Compensation for Vibration Suppression Control of A Vibroacoustic Structure Model
  
  Actuator failures may lead to performance deterioration of control systems. A desirable feedback control scheme should be able to coordinate the remaining actuators to compensate for the damaging effects of the faulty actuators. This paper develops an adaptive failure compensation technique for vibration suppression control of a vibroacoustic structure model with uncertain actuator failures. A baseline vibration suppression controller is studied first and the deleterious impact of unknown actuator failures on system performance is evaluated. An adaptive actuator failure compensation scheme is then developed to modify the baseline controller design to accommodate actuator failures whose values, pattern and time instants are uncertain. Simulation results show that the adaptive design is able to ensure desired system performance in the presence of actuator failure uncertainties.
  
  
• Actuator Failure Compensation Schemes for Vibration Control of A Rocket Fairing Model
  
  In this paper, the actuator failure compensation problem is formulated for active vibration control of a launch vehicle payload fairing. Performance of a nominal optimal control scheme for active vibration control is analyzed in light of a typical actuator failure model that certain actuator outputs are stuck at unknown fixed values at unknown time instants. Three stabilizing control schemes handling uncertain actuator failures are developed to ensure closed-loop system signal boundedness in the presence of uncertain actuator failures. Simulation results are presented to demonstrate their effectiveness.