Research On Trajectory Tracking Of ULD Sorting Mobile Robot Based On Model Predictive Control

ULD(Unit Load Device)is a container equipment used to load cargo in air transportation.Its function is to better handle large volume and multi-standard air cargo transportation.Airport ULD sorting has problems such as low efficiency,poor timeliness,labor cost,and high construction capital.These problems can be solved by mobile robots.Unlike traditional mobile robots,airport ULD sorting mobile robots need to have the characteristics of flexibility,heavy load,low center of gravity,high operating accuracy and high reliability.This article relies on the project entrusted by the enterprise unit,and cooperates with SF,a well-known domestic logistics company,to study a four-difference omnidirectional mobile robot used in airport ULD sorting,and design a trajectory tracking controller based on integral model predictive control.The main research contents of this article are as follows:(1)A four-differential omnidirectional mobile robot model based on differential drive is proposed.The model inherits the characteristics of low-center of gravity and high control accuracy of differential drive.The load capacity is improved through four pairs of differential units and omnidirectional Operation,meeting the requirements of mobile robots for airport ULD sorting.(2)A mathematical model of a four-differential omnidirectional mobile robot is established.Based on the analysis of the kinematic characteristics of the four-differential omnidirectional mobile robot,the kinematics analysis of the differential drive unit was carried out to establish a complete kinematic model of the four-differential omnidirectional mobile robot;the four-differential omnidirectional mobile robot was powered Analyze and build a dynamic model.(3)An integral model prediction trajectory tracking controller is constructed.Based on the mathematical model of the mobile robot,a predictive model is established,and the objective function and constraints are designed to make the controller satisfy quadratic linear programming.Integrating the integral function with the model predictive control to form an integral model predictive controller,the effectiveness and feasibility of the integral model predictive controller algorithm are verified through simulation.(4)A four-differential omnidirectional mobile robot software and hardware system was constructed.Based on the theoretical analysis,experimental verification was carried out,and a four-differential omnidirectional mobile robot experimental vehicle was built.At the same time,the vehicle stand-alone program of the mobile robot was developed using the MFC software framework of Vsiual Studio.The feasibility of the four-differential omnidirectional mobile robot model and the advancement and effectiveness of the integral model predictive control.(5)The operation scenario of the four-differential omnidirectional mobile robot is simulated,and the four-differential mobile robot is verified to have the characteristics of heavy load,low center of gravity,flexibility and high reliability,which can solve the problems of low ULD sorting efficiency,poor timeliness,and labor consumption of the airport.