Modeling and control of MEMS with high speed synchronous micromotors and controllers/drivers-on-VLSI-chip ICs

Abstract This articles addresses and solves the modeling, analysis and control problems for microelectromechanical systems (MEMS) that integrate high speed permanent magnet synchronous micromotors (motion microdevices) and controllers/drivers-on-VLSI-chip ICs. High performance micromotors (2, 4 and 6 mm diameter) with and without Hall effect microsensors are fabricated using high aspect ratio and surface micromachining techniques, while the ICs are made using biCMOS technology. In addition to fabrication, a wide spectrum of fundamental problems in MEMS synthesis, modeling, analysis and control are solved. The MEMS synthesis is performed using basic principles with the ultimate goal to guarantee operationability, functionality, compatibility, integrity, controllability and synergy. Synchronous micromotors are designed by applying the MEMS Synthesis and Classification Solver. Signal processing, filtering, computing, interfacing and amplification are performed by the controllers/drivers-on-VLSI-chip ICs that control the micromotors by properly applying the phase voltages to the micromotor windings. Analysis, control and optimization are based on mathematical models. Mathematical modeling is done by applying basic principles and the fundamental laws of electromechanics. The derived lumped parameter mathematical model, which is given in the form of nonlinear differential equations, allows one to perform the data intensive analysis, heterogeneous simulations with outcome prediction and controller design. Based on micromotor electromagnetics–electromechanics and microelectronics capabilities, we derive control algorithms. An innovative synthesis procedure is reported to design soft switching continuous controllers with nonlinear switching surfaces. These control laws, which ensure robust tracking and disturbance rejection, are implemented. The algorithms designed are different from the existing variable structure control laws. Compared with hard switching discontinuous controllers, the advantages of the soft switching sliding mode control paradigm are that the singularity and sensitivity problems are avoided, robustness and stability are improved, chattering (high frequency switching) is eliminated, etc. These features expand the MEMS operating envelopes, enhance robustness and controllability, as well as improve efficiency and reliability. Experimental verification to assess the fundamental results is performed. Integrated MEMS and their components are fabricated and tested. We study the MEMS performance, verify mathematical models, analyze applicability and effectiveness of soft switching algorithms for micromotors controlled by ICs, etc.