Design And Trajectory Tracking Of Swing-Arm Omnidirectional Mobile Robot

As a crucial branch of the robotics domain,mobile robots hold immense potential for widespread application.Compared to other types of mobile robots,such as tracked,legged,and wheeled-tracked hybrid robots,wheeled mobile robots have gained extensive use on flat terrain due to their reliable,durable structure,and agile maneuverability.With the increasing demand for wheeled mobile robots in diverse usage scenarios,more complex working environments have placed higher demands on their obstacle-surmounting and omnidirectional maneuvering abilities.To enhance the obstacle-surmounting and omnidirectional maneuverability of outdoor wheeled mobile robots,a pendulum-arm omnidirectional mobile robot has been developed.This robot employs ordinary wheels as driving wheels,while also considering both omnidirectional movement and obstacle-surmounting capabilities.The dual-power differential system can allocate the power of the main and auxiliary motors to the left and right half-axles.This system can achieve different driving modes by starting and stopping the main and auxiliary motors and toggling the electromagnetic clutch.Different steering modes for the mobile robot are implemented by a combination of steering swing legs and the dual-power differential system.The balance arm system links the motion of the two swing arms.After kinematic simulation experiments,it has been demonstrated that the mobile robot equipped with a balance arm system is more stable when surmounting obstacles and has better terrain adaptation ability compared to traditional integral mobile robots.For different power distribution and swing leg angles,proposes the Spot turn modes,oblique motion modes,and four-wheel steering(4WS)modes.Among them,the Spot turn modes designs a PID heading angle tracking controller,the oblique motion modes designs a multi-point preview fuzzy compensation trajectory tracking controller,and the 4WS mode designs an Incremental linear time varying-model predictive controller.The effectiveness of the controllers is verified using the Simulink/Car Sim joint simulation platform.Joint simulation results show that compared to the 4WS mode,the oblique motion modes has the advantage of low-range lateral sway angle variation,enabling the mobile robot chassis to achieve low-curvature trajectory tracking while improving its lateral stability.Regarding the designed mobile robot chassis electric control system,the hardware selection and software design have been conducted.For hardware selection,factors such as the weight,speed,and carrying capacity of the chassis were taken into consideration to select appropriate motors,drivers,encoders,and other components to form the chassis’ power execution system.Additionally,an appropriate inertial navigation system was selected for localization and navigation.In code writing,the communication principles between the upper computer and the chassis’ main control board were introduced,and serial communication tests were conducted to verify the communication’s reliability and stability.To meet the motion control requirements of the chassis,partial driver programs were written to achieve the basic motion functions of the chassis.Additionally,the manual control operation logic of the chassis was analyzed.Finally,statics analysis was conducted on the key components of the designed mobile robot chassis to demonstrate that their strength and stability meet the design requirements.By determining the constraints of the mobile robot chassis,experimental data was obtained and applied to the control system of the chassis.The accuracy of the steering was verified by experiments,which confirmed the controllability of the prototype in actual environments and the rationality of its design.The one-sided obstacle-crossing experiment demonstrated the correctness and feasibility of the balanced rocker arm system design.This system can adjust the adaptability of each driving wheel to the terrain and improve the obstacle-crossing performance of the mobile robot,thus meeting the expected design requirements.