Event-triggered Model Predictive Controller For Terminal Constraint

Event-trigger control is first applied in systems with limited resource.By designing state related trigger condition and transforming signals or commuting control actions according to the trigger condition,the system resources can be utilized effectively,which can resolve the contradiction between system resources(optimization times)and stability.In constrained system,there is a fundamental contradiction among feasibility,optimality and computational complexity,which can be solved by redesigning the terminal constraint set rationally.This paper designed a novel trigger condition based on the terminal constraint to reduce the optimization times while keeping the system stable.Additionally,the event-trigger scheme is firstly applied in controller to solve the contradiction among feasibility,optimality and computational complexity,in which,the trigger condition is based on the terminal constraint set.The solution is redesign the terminal set whenever the event is triggered.The main contributions can be summarized into following four parts:1.Event-triggered model predictive control for set trajectory: For control system with constraints,a contractive set trajectory is constructed,which is related to but not depends on a feasible closed-loop state trajectory.Its convergence property is used to design a novel trigger condition for event-trigger model predictive control.It is able to reduce the calculation times of the optimization while guarantee the stability of system.Compared to existed trigger conditions,it is easier to be obtained.2.Event-triggered model predictive control for terminal constraint with set trajectory: Since the set trajectory is able to characterize whether current system is feasible before the optimization problem is solved.A trigger condition based on set trajectory is newly applied inside the controller to arise the redesign of some controller parameter(terminal set).This scheme is able to make the domain of attraction not depend on the optimization horizon,i.e.it always has the largest domain of attraction with any optimization horizon.3.Event-triggered model predictive control for terminal constraint: The calculation of the set trajectory is complicated and the optimality of former controller is restricted to smallest set in the trajectory.Then Minkowski functional is introduced to parameterize the terminal constraint,which enables the redesign of terminal set is totally on-line.Additionally,a novel conception,feasibility margin,is proposed to characterize the feasibility of current system.It is more flexible than the one used set trajectory and has better control performance.4.Event-triggered Distributed Model Predictive Control for terminal constraint:The event-triggered model predictive control for terminal constraint is extended to distributed system.It enables to design stability guaranteed parameters more easily.Feasibility depends on event-triggered terminal set and global stability is guaranteed by Lyapunov functions defined in neighborhood,which is able to reduce the conservatism of stability constraint in traditional distributed model predictive control.