Design and Control of a Two-Wheeled Robotic Walker

• Main Author: da Silva, Airton R., Jr.
• Format: Others
• Published: ScholarWorks@UMass Amherst 2014
• Subjects: Two-wheeled inverted pendulum; linear quadratic regulator control; hardware architecture; circuit design; software development; prototype development; Computer-Aided Engineering and Design; Electro-Mechanical Systems
• Online Access: https://scholarworks.umass.edu/masters_theses_2/79; https://scholarworks.umass.edu/cgi/viewcontent.cgi?article=1112&context=masters_theses_2

This thesis presents the design, construction, and control of a two-wheeled inverted pendulum (TWIP) robotic walker prototype for assisting mobility-impaired users with balance and fall prevention. A conceptual model of the robotic walker is developed and used to illustrate the purpose of this study. A linearized mathematical model of the two-wheeled system is derived using Newtonian mechanics. A control strategy consisting of a decoupled LQR controller and three state variable controllers is developed to stabilize the platform and regulate its behavior with robust disturbance rejection performance. Simulation results reveal that the LQR controller is capable of stabilizing the platform and rejecting external disturbances while the state variable controllers simultaneously regulate the system’s position with smooth and minimum jerk control. A prototype for the two-wheeled system is fabricated and assembled followed by the implementation and tuning of the control algorithms responsible for stabilizing the prototype and regulating its position with optimal performance. Several experiments are conducted, confirming the ability of the decoupled LQR controller to robustly balance the platform while the state variable controllers regulate the platform’s position with smooth and minimum jerk control.