Anti-impact Mechanism Design And Coordination Control Of Multiple Miniature Robots For Aerial Dispersing

In recent years, the frequent natural disasters, man-made terrorism and the spread of toxic or radioactive substances threaten people’s life safety seriously. After the disaster, it is necessary for the rescuers to access to the disaster scene to obtain information. However, for the personal safety assurance, it is often difficult for the rescuers to enter the site and to take effective rescue measures in time. Based on the detection requirements above and under the financial aid of the National Science-technology Support Plan Project “Multirobot System for Remote Rapid Deployment and Disaster Information Detection”, this article proposes a miniature mobile robot system, with low cost and small volume, can withstand landing impact. The proposed robots can be carried by aircraft to the specific area and be scattered in the air. The miniature robots acquire and transmit a variety of information in a multi-robot cooperative way after landing, which provides the first-hand information for rescue measures. So the topic of this paper is with theoretical significance and application value.This article mainly contributes to the following several aspects of work: anti-impact mechanism design and research of miniature robot, location technology based on low cost sensors and multi-robot cooperative obstacle avoidance methodology based on local perception. The purpose of this paper is to study the basic theory and common technology of multiple miniature robots which are suitable for the fast deployment by aircraft and to improve the superiority of the multiple miniature robots in disaster or emergency situation. In this paper, the main research contents and achievements are as follows:First of all, the domestic and overseas research status on fast deployed robot and multi-robot system control are reviewed and analyzed. According to the specific application environment and mission requirements, the main research contents and research approaches are stated. At the same time, the robot system framework is constructed and key technologies are analyzed.Secondly, focused on the robot landing impact problem caused by the rapid aerial deployment, the robot overload resistance technology is researched and the axial vibration absorber which can be separated from robot is designed. Besides, the impact resistant mechanism of the robot body is designed which makes the robot have better resistance performance to landing impact. After that, based on the finite element dynamic analysis method, the parameter optimization analysis of key buffer structure and the evaluation of overload resistance capability of the robot are both carried on.Thirdly, location problem is a basic and important issue for the control research of multiple miniature robots, which has strict limit to the size and cost. In order to overcome the shortcomings of high cost and slow speed in existing positioning method, the multirobot localization method with the combination of global positioning and relative positioning is put forward based on the limited hardware resources. This localization system not only ensures the hardware requirements of the miniature robot, but also provides the implementation basis for multi-robot formation control and motion control.Fourthly, according to the need of going to the target area for the multiple miniature robots after rapid deployment, the formation structure with fast dynamic adjustment is designed. Focus on the collaborative obstacle avoidance problem of multi-robot system in unknown environment, the obstacle avoidance strategy with dynamic formation is proposed based on local perception and environmental constraints.This paper puts forward the robot local path planning method for obstacle avoidance based on local perception and limit cycle method. The local oscillation problem in obstacle environment is solved and the obstacle avoidance movement in unknown environment is realized through the multi-robot coordinated motion planning. Based on the robot kinematics model, a dynamic surface sliding mode control method is proposed as the robot trajectory tracking algorithm, which can improve the robustness of formation control, and make up the "differential explosion" problem in the process of backstepping at the same time. The control algorithm is also simplified.At last, the control system architecture and hardware implementation suitable for the mobile robot with low cost, low power consumption and small volume is designed. Then the principle prototype of the proposed miniature robot which is suitable for aerial dispersing is designed. The experiments are completed to make the cushion performance evaluation of the miniature robot. The effectiveness of multi-robot control algorithms proposed in this paper are verified by the physical experiments of multi-robot formation maintaining, transformation and obstacle avoidance coordinated movement.