With the development of modern industry and human-machine mutual assistance technology,the defects of high labor intensity and low efficiency in fixed-point processing and fixed-point assembly methods in traditional industries have been improved.Among them,the mobile platform is an intelligent logistics switching system that integrates multiple functions.It provides an automated and intelligent transportation environment for modern equipment manufacturing,logistics and other industries,and improves the defects of traditional manufacturing.The four-wheeled Mecanum wheeled omni-directional mobile platform has the advantages of omni-directional movement in the plane,strong carrying capacity and small demand for working space,so it is widely used in application scenarios such as satellite assembly and logistics transfer.In this paper,a four-wheeled Mecanum omnidirectional mobile platform equipped with a seven-degree-of-freedom manipulator is designed in accordance with the project requirements.The main research contents are as follows:This article first analyzes the actual needs of the research group and determines the main performance indicators of the platform,and then designs the overall structure of the mobile platform according to the design principles.The geometric dimensions of the platform are determined according to the working space of the robotic arm and the load-bearing weight of the mobile platform,and the finite element static analysis of the main parts of the mobile platform is carried out.The results show that the structure of the main parts meets the requirements of rigidity and strength.In addition,the layout of Mecanum wheels was analyzed,and the optimal wheel system layout plan was finally designed,which laid the foundation for the establishment of the mathematical model of the subsequent mobile platform.According to the kinematics analysis and virtual prototype simulation of the omni-directional mobile platform,the kinematic equation of the mobile platform is established according to the motion characteristics of Mecanum,and the relationship between the motion of the mobile platform and the angular velocity of the four wheels is solved.A virtual prototype simulation of the mobile platform was carried out using Adams software,and the simulation results were graphically compared and analyzed with the kinematics theoretical results to verify the correctness of the kinematics theoretical calculations.Taking into account the stability of the mobile platform after the robot arm needs to be equipped,the motion of the mobile platform under no-load and full-load conditions is analyzed.The results show that there are similarities and differences in the motion characteristics of the mobile platform under no-load and full-load conditions.According to the functional requirements of the omni-directional mobile platform,determine the overall design plan of the control system,select the appropriate hardware,build the control system of the omni-directional mobile platform based on STM32,and design the upper computer interface and lower computer software of the control system.According to the idea of the backstepping controller,the trajectory tracking control law of the omnidirectional mobile robot is gradually designed based on the backstepping method,and the trajectory tracking simulation experiment is carried out in Matlab simulation software.The simulation results show that the backstepping-based backstepping controller makes the system It can quickly track a given reference trajectory,which proves the effectiveness of the designed trajectory tracking control algorithm.Finally,conduct a comprehensive mobile platform simulation and drive control verification experiment to analyze the motion stability of the mobile platform and verify its performance indicators.The simulation experiment mainly includes climbing simulation experiment and obstacle crossing simulation experiment.This verifies the stability of the mobile platform in the process of climbing and crossing obstacles.The driving control verification experiment of the mobile platform mainly includes the straight motion test,the lateral motion test,the oblique driving motion test and the rotation motion test around itself to verify the four-wheel angular velocity of the kinematics of the mobile platform and the theoretical mathematical relationship of the platform motion.It has been verified that the movement mode of the mobile platform can be controlled by changing the magnitude and direction of the angular velocity of the four Mecanums. |