Research And Design Of Omnidirectional AGV Positioning System Based On Inertial Navigation

As a flexible automatic handling equipment,Automated Guided Vehicle(AGV)has been paid more and more attention by many industries in recent years.In solving the shortage of labor supply to improve production efficiency and reduce production costs,AGV has been playing an increasingly prominent role.The basic and prerequi-site for AGV to complete the specified tasks is the function of autonomous positioning and navigation.Currently,the methods applied to AGV positioning generally have problems such as strict requirements on the operating environment and complex control methods.Based on the principle of inertial navigation,this thesis proposes a positioning method for omnidirectional AGV.The AGV can be located using only inertial measurement units and encoders,and its not subject to the interference of external signals or attached to external equipment to provide support and help.Based on the study of the traditional inertial navigation process,the thesis aims at the problem that the system error caused by inertial navigation accumulation over time affects the system stability,the causes of the error are discussed,and the structure and control method are optimized to improve the positioning accuracy of the system.The main research contents are as follows:1.The design scheme of positioning system and omnidirectional mobile platform was determined,and the overall control architecture was built.The kinematics model of four-wheel omnidirectional mobile mechanism was established through the structural analysis and research of Mecanum wheel.And the working principle of inertial measurement unit and encoder was analyzed from the structural level.The acquisition and processing methods of attitude and displacement data were deduced.2.Attitude algorithm and omnidirectional AGV location method are studied.The principle of solving attitude Angle by quaternion was analyzed in depth.The quaternion updating equation of gyroscope and acceleration was constructed and then the data was fused by EKF,so that the drift error of gyroscope can be corrected and stable attitude information can be obtained.In the process of positioning,a method of using orthogonal encoders on distance measurement was designed.By obtaining the displacement information in the orthogonal direction directly,an improved method of dead reckoning positioning was proposed,which reduces the positioning error of the system and improves the positioning accuracy.3.The realization of omnidirectional mobile platform and positioning system.A four-wheel omnidirectional moving platform with damping mechanism and an orthogonal encoders positioning system with suspension structure were built.The distributed modular design was adopted in the system circuit,including the main controller module,motor drive module,orthogonal encoders positioning module and remote control module,and the algorithm design and debugging of the corresponding control software were completed.4.Experimental verification and analysis of omnidirectional mobile platform and positioning system.The dynamic tracking effect of heading angle was verified by the turntable experiment.The stable orientation experiment results during the robot's running process were ensured by the course tracking experiment.It was shown that the proposed positioning algorithm and positioning method could obtain the pose information of the experimental platform in real time and obtain the high-precision positioning results.