Papers by Keyword: Precision Motion Control

Abstract: The Precision Micro-Assembly Machine was developed to manufacture the ICF targets, which have submillimeter-sized components with micrometer sized features. The machine provides simultaneous manipulation of three objects in a 3-cm3 operating arena and can stitch together multiple millimeter-scales operating arenas over distances spanning tens of centimeters with micrometer-level accuracy. In this report, we will discuss the technologies that are merged to help assist the research community with micro-component fabrication. Furthermore, we also present the design of the online monitoring system, which contains two kinds of non-contact measurement system, microscopic image and laser confocal. The online monitoring system can characterize the positions of the target components during the assembly process. The effect and mathematic model of on-line measuring was analyzed. The results of target assembly experiments show position tolerance of the assembly is not more than 10μm.

Abstract: This paper describes the design and proof of concept for an active eddy current damper which is integrated into a single-axis linear motor. Although developments on active eddy current damper are well documented, none has been implemented in a linear motor. The advantage of such a system is two-fold. Firstly, the relative motion between the magnets and the conducting sheet produces eddy currents resulting in an electromagnetic force opposing the direction of motion; which can be utilized to suppress vibrations. Secondly, it is possible to enhance the damping effect of the system; Due to environmental noise, it is normally not possible to increase the D coefficient in a PID controller as much as desirable. The damper is thus able to supplement this damping effect to improve settling time. Here, we will present the damper design as well as the preliminary experiment results for both vibration suppression and motion damping.

Abstract: In this paper, a smart structure for the micro position control is proposed using the piezo stack actuator. The smart structure is comprised with PZT based stack actuator, mechanical displacement amplifier and positioning devices. Based on the bridge-type flexural hinge mechanism, a displacement amplifier is designed and integrated with a piezo stack actuator to produce a desirable positioning stroke of the device. In order to achieve the high precision control performance in a positioning device, a stick-slip phenomenon should be suppressed in contacting surfaces of the device, which is generally indispensable in the mechanically connected systems and particularly obvious for the micro-scale system. Therefore, the stick-slip model is enhanced by theoretically calculating the static friction based on the statistical rough surface contact model. Then, a PID feedback control algorithm with the developed stick-slip model is formulated for achieving accurate positioning of the device. Using the proposed smart structure, simulations of precise position control under the representative operating condition of positioning are conducted to demonstrate the stick-slip suppressing and micro positioning performance.