GOALI/Collaborative Research: Precision Control of Nanopositioners

Villanova University, Villanova PA

Investigators

Abstract

The goal of this collaborative Grant Opportunities for Academic Liaison with Industry (GOALI) research project between the University of Utah (UU), Villanova University (VU), and industry partner Molecular Vista, Inc. (MVI) is to study new design and control system approaches for the development of advanced nanopositioning systems for nanoscale science and engineering applications. Specifically, the research outcomes will lead to improvement in the performance of nanotechnologies, such as video-rate scanning probe microscopy, desktop nano-rapid prototyping and nanomanufacturing systems, precision advanced additive manufacturing systems, and micro rapid inspection and repair systems. The research collaboration and the proposed education plan will expose engineering students (graduate and undergraduate), K-12 students, and the community to cutting-edge research and findings in control, nanotechnology, and high-impact industry applications. Additionally, students involved in the research will be encouraged to pursue graduate studies and industry positions in control and nano-scale science and engineering. The scope of this research is to study new design and control paradigms for dual-stage nanopositioners that consider both spatial and temporal constraints. Emerging dual-stage nanopositioners have the unique ability to achieve long-range and high-speed operation, as well as operating bandwidths two- to three-orders of magnitude higher than existing systems. However, typical control strategies rely on temporal (frequency-based) information to split the control effort between the two actuators, which results in some precision positioning trajectories being unachievable. Specifically, low-speed trajectories are assumed to be long-range and diverted to the long-range, low-speed actuator while high-speed trajectories are assumed to be short-range and diverted to the short-range, high speed actuator. Thus, short-range, low-speed inputs are diverted to the long-range, low-speed actuator, which can be problematic since the long-range actuator has a lower positioning resolution than the short-range, high-speed actuator, which is better suited to track the short-range trajectory (regardless of speed). Therefore, dual-stage nanopositioners cannot achieve high positioning resolution when range and frequency are not inversely correlated. To advance the state-of-the-art, a control-centered design approach is planned to establish the guidelines and requirements for creating high-performance dual-stage nanopositioners. To enhance the understanding and control system design process, detailed input-output models that capture the dynamics of the system (nonlinear and dynamic effects) and sensor characteristics will be obtained. An innovative control algorithm which systematically considers both spatial and temporal information will be developed to effectively allocate the control input. Finally, with support from the industry partner, the research team will evaluate the technology on a commercial atomic force microscope (AFM) system and consider future commercialization opportunities.