A DMOC-based Research On Trajectory Optimization And Control Algorithms

Quadrotor is a kind of typical rotor aircraft which model is strong coupling, nonlinear,multivariable and under-actuated. At present, the main research interests consist of systemstructure design, modeling, control and path planning, etc. In practice, in order to realizerisk aversion to search or tracking with the limitations of its load, it is particularly importantto preplan a minmum time trajectory and design the accurate tracking controller.Due to its features and the complexity of the mission, in this paper, we propose someappropriate improvements on the basis of the existing trajectory optimization algorithm andthe tracking control algorithm to improve the convergence speed, solvability andapplicability. Then, some simulation experiments are verified and analyzed. The mainresearch contents are as follows:In this paper, the optimal trajectory generation and tracking control of the quadrotorare mainly researched by a large amount of simulation experiments to verify the proposedmethods. The main contributions of the paper are as follows:1. The establishment of the quadrotor model. The reasonable hypothesis is introduced anda double coordinate system is set up. Via analyzing the characteristic of the quadrotor andaccording to the Newton’s law and Euler equation, we deduce the corresponding dynamicequations. At the same time, for the sake of the subsequent trajectory optimization andprogress of the controller design, the mathematical model is linearized and decoupled.2. The MDMOC algorithm and the AIGS is put forword. By the comprehensivecomparison of the traditional DMOC, GPM and the proposed MDMOC, we finally drawthat the MDMOC with AIGS in optimization efficiency and procedural aspects are betterthan that of GPM. What’s more, MDMOC is more suitable under complex requirementsand flight environment with certain accuracy. Therefore, MDMOC will serve as the methodof generating optimal reference trajectory in the following controller design.3. Adaptive tracking controller design of the quadrotor. Because of the complicateddynamic characteristics and many uncertainty makes the tracking controller design of thequadrotor becomes more difficult. This paper is based on the classic PD control algorithmand the backstepping method with sliding mode variable structure adaptive controlalgorithm under unknown quality to design tracking controller respectively. The simulationresults show that both control algorithms can achieve a stable tracking control. Specifically, as for the robustness, the rise time and the stability time of the system reach a steady state,the backstepping method with sliding mode variable structure adaptive control algorithmhas great advantage.