This paper proposes a dual loop nonlinear control method based on non-linear PID(DLNPID) for the singlewheeled
robot. The control method is proposed as dual-loop non-linear control method which has roll tilt inner control loop,
pitch tilt inner control loop and ?? control loop. Every control loop consists of nonlinear PID controller. The stability of the
control system is proved by Lyapunov method. Experiment results show better rubustness of DLNPID than that of linear
methods.