Improved THEI input shaper for the vibration suppression of flexible systems under variable loads

Aiming at the problem of insensitivity optimization of the input shaper under the variation of natural frequency and damping ratio caused by the load change of a flexible system in high-precision multi-axis motion stages, an improved two-hump extra-insensitive ( THEI ) input shaper design method was proposed. The improvement of the insensitivity of the THEI input shaper with the same delay time was realized, in which an inverse optimization carried out on the two-parameter insensitivity was incorporatied to the traditional forward design of the THEI input shaper. Firstly, an evaluation index for quantifying the two-parameter insensitivity of the THEI input shaper was derived by using a three-dimensional sensitivity curve. Then, a two-parameter insensitivity optimization model of the THEI input shaper under the optimal impulse constraints with the amplitude adjustment factor as a design variable was developed. The design variables were solved based on the ant colony optimization (ACO) algorithm and the impulse amplitude of the improved THEI input shaper was updated to achieve insensitivity optimality. Finally, the numerical simulation and experimental results jointly verify the effectiveness of the proposed method. © 2024 Chinese Vibration Engineering Society. All rights reserved.