Analysis of Power Amplifier Contribution to the Precision of Motion Systems
Marziyeh Hajiheidari, Duo Xu, Jeroen van Duivenbode, Bas J. D. Vermulst, Mircea Lazar · 2022
In a high-precision motion system, a position controller creates an appropriate current reference signal based on a position reference trajectory. Then, power amplifiers use this reference signal to drive actuators to translate the current reference into the desired force to move the subject to the desired position. Any imperfection in the power amplifier performance adversely affects the overall positioning system accuracy. Hence, to improve the motion system's performance, the effects of power amplifier imperfections on such high-precision systems are investigated through a complete mechatronics model that combines control, mechanical and electrical aspects. Additionally, to demonstrate how the system performance can be improved by changing the control strategy, a voltage-mode cascaded current controller is applied to the power amplifier and different feedforward strategies are applied to the position loop. We demonstrate that the accuracy of position control can be improved by a factor of five by taking into account the amplifier dynamics and controller design.