| In the development of Chinese current economy,the rapid development of intelligence and automation has played a vital role in the growth of the national economy.Automated Guided Vehicle(hereinafter referred to as AGV)is an assembly of various discipline technologies such as mechanical engineering,automation control,computer control system,and communication system.With the rapid development of modern society towards automation and intelligence,the AGV has been widely used in manufacturing,warehousing,postal delivery,medical equipment,aerospace,mountain blasting and special operations.And it has played a significant role in many fields of scientific and technological development.However,due to the current low level of manufacturing in China and strict environmental requirements,most AGVs cannot achieve free switching between outdoor and indoor,and the use efficiency is low.Outdoor AGV handling is not effective,and it is highly dependent on factors such as site and space,and the steering is not flexible,and it is not suitable for the domestic production environment.Aiming at the above problems,a mobile platform for omnidirectional handling of AGV and a full steering guidance mechanism based on the hub motor was designed,and an omnidirectional kinematics model was established.At the same time,the control strategy and path tracking research were carried out,based on the four-wheel independent drive and steering mode.The main research contents are as follows:1)The frame of the omnidirectional AGV was designed based on the principle of lightweight.The bending stiffness analysis,torsional stiffness analysis,modal analysis of AGV frame structure was carried out structured with ANSYS.The analysis shows that the performance of the frame can meet the target requirements under different working conditions.2)In view of the current complex processing of the Mecanum wheel,low motion efficiency,weak bearing capacity,easy to vibrate,slip and other weaknesses,a full steering guidance mechanism based on the hub motor was designed.Analysis of vehicle dynamics,kinematics and position were carried out.It shows that the omnidirectional AGV steering and dynamic performance can meet the target requirements.3)Fuzzy control and multi-step predictive optimal control was studied.Combining the advantages and disadvantages of the two,the strategy of using joint control technology for path tracking of omnidirectional AGV was proposed.And the two algorithms was Simulated in MATLAB.Simulation results show that the two algorithms can achieve path tracking and rectification under different conditions.4)In order to improve the control accuracy and provide sufficient corrective ability for path tracking,decoupling control between the steering motor and the hub motor were carried out.A simulation model of coupling and decoupling was established.The simulation results showed that the control performance of the two motors can be improved by decoupling control.Under the decoupling control,the step input experiment of the steering motor and the speed test of the hub motor were carried out.The experiment shows that the steering motor and the hub motor have good output response.5)The angle and speed output experiments and path tracking experiments for omnidirectional AGV mobile platforms were carried out through the experimental platform.The experimental results show that the omnidirectional AGV mobile platform has good motion performance and path tracking effect,which can meet the requirements of industrial use. |
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