Positive Stage Jerk Feedback Combined with Positive Base Plate Jerk Feedback to Improve the Positioning Speed of a Pneumatic Stage

Abstract

In this paper, a unidirectional positioning stage which is supported by four coil-type spring isolators and actuated by four pneumatic cylinders is considered. The stage jerk feedback scheme (SJFB) with positive polarity is proposed to reduce the stage mass, resulting in the improvement of positioning speed. However, reduction of stage mass results in the overshoot that can be controlled by increasing the stage stiffness through the outer feedback loop controller. In addition, to avoid the self-oscillation of stage caused by high gain of SJFB and to improve the repeatability, the conventionally used scheme, namely, base plate jerk feedback (BPJFB) with positive polarity based on its damping role is combined with the SJFB scheme. It is concluded from the experimental results that the proposed control system obeys the related theory and provides high speed positioning with improved repeatability. The amount of the reduced mass through SJFB scheme is also experimentally estimated.

Keywords

• pneumatic
• positioning stage
• base plate
• pdd2 controller
• jerk
• positive feedback
• coil-type spring isolator
• perfect integrator