Study On Fromation Control Strategy For Quadrotors

With the rapid development of science and technology, service robots and unmanned aerial vehicles(UAVs) have attracted more and more attention in robotics. A single UAV has many advantages, however there still exist some problems. For example, the capacity of load and cruising ability are limited due to the small volume. These problems cause a limitation of the applications of the UAVs. How to solve the problem becomes one of the research focuses in the UAV field. In recent years, some experts have put forward the concept of multiple unmanned aerial vehicles formation, which was originally proposed for space vehicles.In this dissertation, we focus on the study of formation control strategy for quadrotors. The main contents include the research of velocity controller, formation constraints, formation controller designing, the system stability analysis, comparisons and simulations for the control algorithm. In order to realize the formation of multiple quadrotors, the dynamic model of quadrotors was analyzed, and then the mathematical model was applied to accomplish the control of the quadrotors, especially the velocity control. Then, we proposed the formation control strategy, and verified the stability and feasibility.There already exist many research results of ground robots formation, where the most essential task is to find out a suitable control strategy. Additionally, the control of quadrotors is much more difficult than ground robots. So w e need to design a new controller for the UAVs combined with the model of quadrotors. Thus, the synchronization controller which is based on the position errors and synchronization errors was designed. We first defined the position errors and synchronization errors by utilizing hypereliptic equation. And then the synchronization controller was designed by utilizing the Euler-Lagrange dynamic equation.To make the controller effective and feasible, the stability in theory was further analyzed. Because the quadrotors can carried out tasks in dynamic and complex environments, how to establish quadrotors formation constraints and make them change formation under different requirements should be considered carefully. To achieve this objective, we firstly employed the designed formation controller to make the quadrotors formation switch flexibly. And then the MATLAB simulator was used to perform simulations and comparisons of the formation control algorithm. According to the results, the Gazebo with ODE dynamic model is employed to perform further simulations. According to the simulation results, the stability, flexibility and fault tolerance of the proposed formation control algorithm were verified.