Abstract
A digital nonlinear control of a 3-link direct drive robot manipulator by means of a real time preview virtual desired signal is proposed. The digital nonlinear control is based on the principle that only the acceleration changes at the moment when the input torque changes. A linear optimal control system is designed on the basis of this principle. The real time preview virtual desired signal is the virtual one for improving tracking characteristics for the original desired signal. It is designed considering control characteristics of the already designed digital nonlinear control system and it is derived at real time by feedback of state variables. The real time preview virtual desired signal that means the real time virtual desired signal with preview feedforward compensation is also designed and its characteristics are also studied.
The digital nonlinear control system with this real time virtual desired signal is applied to the 3-link direct drive robot manipulator. And frequency characteristics, system responses for circle and square desired orbits are examind in experiment and these effectiveness is confirmed.
