Toward Co-Design of Autonomous Aerospace Cyber-Physical Systems.
详细信息
文摘
Modern vehicles are equipped with a complex suite of computing cyber) and electromechanical physical) systems. Holistic design,modeling,and optimization of such Cyber-Physical Systems CPS) requires new techniques capable of integrated analysis across the full CPS. This dissertations introduces two methods for balancing cyber and physical resources in a step toward holistic co-design of CPS. First,an ordinary differential equation model abstraction of controller sampling rate is developed and added to the equations of motion of a physical system to form a holistic discrete-time-varying linear system representing the CPS controller. Using feedback control,this cyber effector,sampling rate,is then co-regulated alongside physical effectors in response to physical system tracking error. This technique is applied to a spring-mass-damper,inverted pendulum,and finally to attitude control of a small satellite CubeSat). Additionally,two new controllers for discrete-time-varying systems are introduced； a gain-scheduled discrete-time linear regulator DLQR) in which DLQR gains are scheduled over time-varying sampling rates,and a forward-propagation Riccati-based FPRB) controller. The FPRB CPS controller shows promise in balancing cyber and physical resources. Second,we propose a cost function of cyber and physical parameters to optimize an Unmanned Aircraft System UAS) trajectory for a pipeline surveillance mission. Optimization parameters are UAV velocity and mission-critical surveillance task execution rate. Metrics for pipeline image information,energy,cyber utilization,and time comprise the cost function and Pareto fronts are analyzed to gain insight into cyber and physical tradeoffs for mission success. Finally,the cost function is optimized using numerical methods,and results from several cost weightings and Pareto front analyses are tabulated. We show that increased mission success can be achieved by considering both cyber and physical parameters together.