Design And Development Of Omni-mobile Chassis With Modular Wheel Sets

In recent decades,with the development of robot technology,omnimobile chassis has become an important branch of the field of robotics.Omnidirectional mobile chassis paly an irreplaceable role as mobile assembly unit of robot,which have many advantages,such as high stability,wide range of application and powerful carrying capacity.Wheel set is one of the most important parts of omni-mobile chassis,conventional chassis usually use omni wheel or Mecanun wheel to realize omnidirectional mobile.But these kinds of wheels have some apparent shortcomings,for example,difficult machining,short lifetime and high demands of ground.This paper overcame the above disadvantages by designing a novel omni-mobile chassis with modular wheel sets,and modular design reduces costs of changing wheel set.Meanwhile,this dissertation developed a visual control system based on QT Creator,which realized controlling and monitoring of the chassis.In addition,by assembling kinds of sensors,this paper achieved simultaneous localization and mapping(SLAM)and autonomous navigation based on Robot Operating System(ROS).The prototype of the omni-mobile chassis is composed of four pairs of two driving wheel sets,framework,control unit and sensors.Each pair of wheel set is mainly made up of steering engine,damping system and wheel hub motor.This paper offered two schemes to realize damping for different usage scenarios.Wheel hub motor is a novel integrated motor,which comprises motor,reducer and encoder.Visual control system is developed based on QT Creator.Computer controls and monitors wheel hub motors through RS-485 and Modbus protocol.Steering engines are directly controlled by Arduino microcontroller board,which communicates with computer through UART serial port.Other sensors also transmit data to computer over serial ports.This paper added laser scanning rangefinder and inertial measurement unit(IMU)to the chassis.By using these sensors and encoders of wheel hub motors,this dissertation realized SLAM based on multiple algorithm and autonomous navigation.During realizing SLAM and navigation,this paper constructed a communication network between various modules,including chassis controlling,localization,mapping and navigation,based on ROS.This dissertation displayed the performances of the omni-mobile chassis during experiments,such as controlling,SLAM and autonomous navigation.These experiment shows that the novel chassis and the control system have achieved the design targets.The chassis can stably run and be controlled and realize localization,mapping and navigation accurately.