Damping Controller Design for Triangular Scanning of a Third-Order Nanopositioning Stage

In this paper, a design procedure of damping controller for third-order nanopositioning stage is presented for high-speed triangular scanning. Conventionally, damping control schemes of integral resonant control (IRC) and resonance-shifted IRC (RS-IRC) are designed providing that a second-order model can be identified for a nanopositioning stage. For a third-order system, existing control schemes cannot be applied directly. For this, a pole-zero cancellation technique is presented to design IRC scheme. In addition, a state observer based pole placement technique is proposed for RS-IRC design. The effectiveness of the proposed design procedures is demonstrated through both simulations and experiments based on a piezo-actuated nanopositioning stage platform. Results show that a closed-loop bandwidth of 156 Hz and 186 Hz are obtained by designed IRC and RS-IRC for the third-order nanopositioning stage, and the root-mean-square (RMS) errors of 40 Hz triangular tracking are 49 nm and 13 nm under IRC and RS-IRC control, respectively.