Dynamic modeling and control of a nanotube-based linear motor

The dynamic modeling and control of a nanotube-based linear motor are investigated in this paper. The linear motor is realized using the interlayer motion of middle- supported telescoping multi-walled carbon nanotubes (MWNTs). The motion of the nanotube linear motor is dictated by the electrostatic force, van der Waals interaction, and the total intershell sliding friction force. The dynamic model is a second-order nonlinear system. Under constant voltage actuation conditions, the translational motion of the nanotube linear motor at the full range results in pull-in instability. To extend the controllable movement to a a relatively large range, closed-loop control strategy based on feedback linearization is proposed. Simulations show that the closed-loop control system has excellent step responses, and can track continuously varying references.