Design, build, and test of an autonomous myRIO based Segbot

This paper describes the design, programming, and construction of a battery operated autonomous Segbot. The Segbot, a two wheeled robot, has some similarities to the inverted pendulum cart system in that it is underactuated, exhibits non-minimum phase behavior, and requires a stabilizing controller to stand upright. The Segbot differs from the inverted pendulum cart system in that the dynamics are nonholonomic. The National Instruments^® myRIO microcontroller is used for control implementation. The myRIO allows WiFi communication between the Segbot and a host computer for supervisory control. The LabView^® VI used for real-time data acquisition and control consists of two main loops. The first loop collects state measurements from an accelerometer, rate gyros, and wheel position encoders. These measurements are passed to the second loop which calculates the desired control law. Included is a summary of the system identification procedure used to determine parameters that cannot be directly measured and the use of a CAD program to estimate inertial values and mass center location. An example of the Segbot tracking a figure-8 path with a novel navigation controller, derived herein, is presented. Finally, a URL link is included for CAD device drawings, a parts list, control programs, wiring diagrams, and a video demonstration of the Segbot.