Path Planning And Trajectory Optimization Algorithm Of Mobile Robot Node

Coalmine safety monitoring system is an important method to ensure the safety of modern coal mine production.Wireless sensing network technology provides effective approaches and technical means to solve the problem of coal mine safety monitoring.In contrast to traditional wireless sensor network,mobile wireless sensor network which is based on movable robot nodes can satisfy the demand of information acquisition.The information that needs to be acquired includes normal production and urgent rescue in mine.In this thesis,in order to adapt the complex environment and satisfy the requirement of producing safety in mine,the mobile robot is considered as node in sensor network.Behavior planning and control method of node directional migration and node deployment are the major research content.At first,the background and significance of the subject,development status at home and abroad,the main research content and chapter arrangement are introduced in the first part of this thesis.Secondly,the research focuses on the path planning of single mobile robot in local dynamic environment.In previous artificial potential field method,the robot avoids movable obstacles with low efficiency and there are local minima in planned path.In the proposed method,a potential field model based on potential flow theory is established.In this model,the corresponding relationship between potential flow theory and path planning is introduced.To guarantee the reliability of which the robot avoids dynamic obstacles,Zhukovsky transformation is used to optimize the configuration and function of potential model.In further investigation,the concept of the vortex and the virtual source is applied so as to prevent local minima and optimize trajectory.The last section in this research part,the issue of multi-obstacle potential superposition is discussed.To verify the algorithm,comparisons between improved method and traditional one by various circumstances in simulation are conducted.The simulation results indicate that in the improved method,potential field is able to lead robot to avoid mobile obstacles according to velocity vectors of obstacles.Besides,the method is more efficient when preventing local minima.Thirdly,in this part,the research mainly aims at optimized trajectory planning for autonomous robot based on logistic curve.After describing the basic trajectory planning and consummating the fundamental properties of logistic curve,the half S-shaped curve is presented.The dividing value of curvature,conceptualized obstacle and discontinuous passage are considered as constraints so that they can accord with demanded trajectory constraint conditions in real environment.To verify the effectiveness of the proposed method,comparisons in theory and simulation experiment are made among logistic curve and other types of curves and so as the simulation in complicated environment.The simulation results indicate that the presented method is able to control the design parameters reactively so that various kinds of contrast conditions can be satisfied.Compared with traditional curves and the corresponding means,the proposed design algorithm is simple and intuitive.Besides,its amount of calculation is relatively less than old method and it possesses the feature of interchangeability with other algorithms.Finally,the potential field path planning of multi-robot is studied.In this section,that three conditions need to be satisfied in practical operation is discussed.The social potent ial field defines the interaction force between robots,which ensures the avoidance foundation in multiple robots.The behavior potential field is aimed to strike a balance between the human safety and the move productivity of robots when there are both robots and human in working environment.The anti-congestion potential field is to distinguish and prevent global congestion.In simulation test,the validity of the raised method is verified by using the resultant potential of three kinds of potential field.Moreover,the real robot experiment result is displayed by projection and it further indicates that the efficiency of the improved method is higher than traditional ones.