Approximate Explicit Model Predictive Control And Applications On The 3-DOF Helicopter

Nowadays,helicopter has been widely used in both military and civil fields.Compared with general aircraft,helicopter system has the characteristics that normal aircraft do not have,such as vertical lift,fixed high hovering and so on.Therefore,research on helicopter is of great practical significance.In the field of Control,a lot of methods have been studied before.A Control method called Approximate Explicit Model Predictive Control is discussed in this paper,and this method is used in helicopter system.Model predictive control has become a hot research in recent years.From the past to the present,model predictive control has been widely used in the field of industrial control,but it has been limited to the situation where the system dynamic change is relatively slow.Therefore,a more advanced control algorithm named Explicit Model Predictive Control is introduced,which introduces multi-parameter quadratic programming and adapts to systems with high sampling rate and fast dynamic change,such as electric motor and helicopter systems,through off-line calculation and online calculation.However,there are problems of excessive state partition,irregular partition shape and long calculation time when off-line calculation occurs.In this paper,the approximate explicit model predictive control method is proposed to reduce the computational complexity and optimize the control method while ensuring the accuracy,also,it is applied to the 3-DOF helicopter system to compare and analyze the control effect and performance.The main work and achievements of this paper are as follows:(1)Introduce the theoretical of model predictive control based on a large number of literature.The development and research status of the model predictive control method,the approximate explicit model predictive control method and the 3-DOF helicopter control method are respectively summarized.(2)Taking the 3-DOF helicopter system developed by Quanser as the research object,thespecific structure and the composition of each component were analyzed in detail.Under ideal conditions,the mathematical model of the 3-DOF helicopter system was established according to the axial motion equation on each DOF,and the system state space model was obtained after linearization.(3)Introduce the Explicit Model Predictive Control theoretical background,main steps of control theory,and analyze its advantages and disadvantages when dealing with different situations,and lead out an approximation for solving the problem of too many state partitions and high complexity in solving complex systems.(4)In view of the explicit model predictive control to solve the problem of excessive state partition and high complexity,by studying the method of linear interpolation,adaptive hierarchical function approximation,and connecting with the center of gravity coordinate function method,the approximate explicit model predictive control method is proposed,and combined with 3-DOF helicopter system,gives the concrete application of this method in 3-DOF helicopter.(5)After modeling,controller for attitude regulation and tracking designed and numerical simulation is conducted,including adjustment and tracking experiments with disturb.To analysis the performance of approximation explicit model predictive,both the results of EMPC regulations and approximate EMPC regulations are presented for comparison.Then the algorithm of approximate explicit model predictive control is further verified in the HIL loop.(6)Finally,the paper is summarized,and the future research direction and work content are prospected.