Research And Implementation Of Trailer-type Autonomous Medical Distribution Robot

In recent years,with the development of robot technology,various fields begin to combine robot technology to create intelligent industries.With the increasing demand for hospital services in China,the gap of medical staff is also increasing year by year.Medical delivery robot is an application of mobile robot technology in the field of hospital service.It aims to relieve the working intensity and pressure of medical staffs in hospital.In order to solve the problem that the current medical delivery robot mostly adopt the single-body structure,which leads to much less memory and the actual environment in the hospital.This thesis designed and developed a trailer-type autonomous medical delivery robot,including the key structure,the control system of hardware and software of the trailer-type medical delivery robot.The robot's SLAM algorithm and path planning algorithm are analyzed and improved,and the mapping,positioning and autonomous navigation functions of the trailer-type medical delivery robot are realized.The main research contents of this thesis are as follows:First of all,the key mechanical structure of a trailer-type autonomous medical delivery robot was designed.The chassis structure of the robot was analyzed and designed.According to the characteristics of the off-axis trailer,two types of trailer connection devices were designed.Three-dimensional modeling was also carried out.Built the experimental platform of trailer-type medical delivery robot.Secondly,the trailer-type autonomous medical distribution robot control system was designed..In terms of hardware,each module of the robot control system was analyzed and selected according to the actual situation.And the layout of the hardware system was designed.As for software,the overall schemes is proposed for the upper and lower computers respectively.And the functions of the node in the upper computer were analyzed.The lower computer applied the incremental PID algorithm to realize the closed-loop control of the driving motor.And utilized serial communication to implement the communication function of the upper and lower computer.Thirdly,the applied research of SLAM algorithm was carried out.Analyzed the factors that effecting SLAM results.And the sensor error was analyzed and corrected.The positioning and mapping principles of Gmapping algorithm based on filtering and Cartographer algorithm based on optimization are analyzed and compared,and the mapping ideas of this paper are put forward.Aiming at the situation where Cartographer algorithm maps are misplaced,a loop detection method based on odometer information matching was proposed,which improves the mapping effect and quality.Fourth,the path planning algorithm of the trailer-type robot was studied.The A*algorithm was analyzed and selected as the global path planning algorithm of the trailer-type robot.And the process of path planning was analyzed and derived.In contrast,the dynamic window algorithm was selected as the local path planning algorithm of the trailer robot.The working principle of the algorithm was analyzed.And a dynamic window algorithm suitable for the multi-vehicle structure of the trailer robot was proposed based on the motion characteristics of the trailer structure.Simulations were performed for the verification of the proposed algorithm by MATLAB.Finally,the algorithm verification experiments were presented.In order to verify the feasibility of the above algorithms,experiments on mapping and positioning,autonomous navigation,and obstacle avoidance were carried out on an experimental platform of a trailer-type medical distribution robot built independently.The corridor environment and simulated ward environment were selected as the experimental environment,and the mapping effect,accuracy and robustness of Gmapping algorithm,Cartographer algorithm before optimization and Cartographer algorithm after optimization were compared and analyzed.The best map established was used to conduct the turn navigation experiment and the promenade obstacle avoidance experiment on the trailer platform,and the experimental results were analyzed.The results verified that the trailer-type autonomous medical distribution robot can achieve mapping,positioning,and navigation functions.According to the characteristics of the hospital environment,the mechanical structure of the trailer-type medical distribution robot is designed in this thesis.Based on this mechanical structure,the robot's software and hardware control systems are designed,and the prototype of the trailer-type autonomous medical distribution robot is developed.In view of the fact that the hospital is mostly a corridor environment,a loop-closure method matching odometer information is proposed,which improves the influence of Cartographer algorithm for misalignment in map construction.Aiming at the structural characteristics of off-axis trailers,a dynamic window algorithm based on path tracking for multi-car body structure is proposed.Finally,the effectiveness and practicability of the trailer medical delivery robot system are verified through simulation and physical experiments.