Engineering

Optimal second order sliding mode control for linear uncertain systems
In this paper an optimal second order sliding mode controller (OSOSMC) is proposed to track a linear uncertain system. The optimal controller based on the linear quadratic regulator method is designed for the nominal system. An integral sliding mode controller is combined with the optimal controller to ensure robustness of the linear system which is affected by parametric uncertainties and exte...


Sensorless control of ship propulsion interior permanent magnet synchronous motor based on a new sliding mode observer
This paper proposes a sensorless speed control strategy for ship propulsion interior permanent magnet synchronous motor (IPMSM) based on a new sliding-mode observer (SMO). In the SMO the low-pass filter and the method of arc-tangent calculation of extended electromotive force (EMF) or phase-locked loop (PLL) technique are not used. The calculation of the rotor speed is deduced from the Lyapunov...
Hybrid intelligent control of substrate feeding for industrial fed-batch chlortetracycline fermentation process
The lack of accurate process models and reliable online sensors for substrate measurements poses significant challenges for controlling substrate feeding accurately, automatically and optimally in fed-batch fermentation industries. It is still a common practice to regulate the feeding rate based upon manual operations. To address this issue, a hybrid intelligent control method is proposed to en...


Unified dead-time compensation structure for SISO processes with multiple dead times
This paper proposes a dead-time compensation structure for processes with multiple dead times. The controller is based on the filtered Smith predictor (FSP) dead-time compensator structure and it is able to control stable, integrating, and unstable processes with multiple input/output dead times. An equivalent model of the process is first computed in order to define the predictor structure. Us...
Unity power factor Converter based on a Fuzzy controller and Predictive Input Current
This paper proposes analysis and control of a single-phase power factor corrector (PFC). The proposed control is capable of achieving a unity power factor for each DC link voltage or load fluctuation. The method under study is composed of two intelligent approaches, a fuzzy logic controller to ensure an output voltage at a suitable value and predictive current control. The fuzzy controller is u...


Design and fabrication of in-plane AFM probes with sharp silicon nitride tips based on refilling of anisotropically etched silicon moulds
In this paper a micromachining method for batch fabrication of in-plane atomic force microscope (AFM) probes that consist of a sharp silicon nitride tip on a monocrystalline silicon cantilever is presented. The tips are realized by conformal deposition of silicon nitride inside an anisotropically etched cavity inside a silicon wafer. The best measured radius of the sharp tips was 8 nm. Our fab...
Piezoelectric peristaltic micropump with a single actuator
A high performance piezoelectric PDMS peristaltic micropump with a single actuator is presented that enables driving with less expensive and simpler single-phase controllers while maintaining all the superior properties of conventional peristaltic micropumps, such as robustness, simplicity and purity due to the absence of valves. A simple structural design is based on a centrally placed inlet p...

A preliminary investigation of the potential mechanical sensitivity of vertical comb drives
This article describes a preliminary step taken in investigating the potential of vertical comb drives to be used as force-compensation mechanisms in interfacial force microscopes, by exploring the lower limit of the stiffness of the springs the comb drives can be fabricated with. The stiffness of their springs will affect the sensitivity of the microscope. Six vertical comb drives were fabrica...
Single-use MEMS sealing valve with integrated actuation for ultra low-leak vacuum applications
The design, modeling, fabrication and successful demonstration of a bulk-micromachined MEMS valve that enables high gas flow rates of hundreds of sccm in its initial open state and ultra low-leak, permanent sealing against gas flow once closed are demonstrated. When the valve is open, a high aspect ratio ring of solder surrounds its flow orifice without blocking the flow path. When the valve is...

Singulation for imaging ring arrays of capacitive micromachined ultrasonic transducers
Singulation of MEMS is a critical step in the transition from wafer-level to die-level devices. As is the case for capacitive micromachined ultrasound transducer (CMUT) ring arrays, an ideal singulation must protect the fragile membranes from the processing environment while maintaining a ring array geometry. The singulation process presented in this paper involves bonding a trench-patterned CM...
An investigation of the mechanical strengthening effect of hydrogen anneal for silicon torsion bar
This paper reports on the use of hydrogen anneal to enhance the torsional fracture strength of dry-etched single crystal silicon (SCS) microstructures. Moving-magnet-type scanning mirrors with torsion bars were employed as fracture test specimens. Two types of device were fabricated using SCS and silicon-on-insulator (SOI) wafers by deep reactive ion etching (DRIE). For the SCS-wafer-based devi...

A long-term stable power supply µ DMFC stack for wireless sensor node applications
In this paper, a passive, air-breathing four-cell micro direct methanol fuel cell ( µ DMFC) stack featuring a fuel delivery structure for long-term and stable power supply is designed, fabricated and tested. The fuel is reserved in a T-shaped tank and diffuses through the porous diffusion layer to the catalyst at the anode. A peak power density of 25.7 mW cm −2 and a maximum power output...
Design, fabrication and thrust measurement of a micro liquid monopropellant thruster
A liquid monopropellant MEMS thruster was designed, fabricated and tested. For application on a nanosatellite for orbit control, a liquid propellant MEMS thruster delivers better performance than a solid thruster. Two issues must be addressed for a liquid monopropellant MEMS thruster: high energy content of the monopropellant to overcome the excessive heat loss associated with the small scale o...
Real-scale fire tests of one bedroom apartments with regard to tenability assessment
Statistics reveal that people mostly die in bedrooms or lounges, from smoking-related fires. However, at present, little is known of this phenomenon, especially in terms of identifying which fire effects first injure people. Through several real-scale fire tests, two different sets of fire scenarios are explored in a single bedroom apartment. As in everyday life, the test room is equipped with ...
Performance-based analysis of cylindrical steel containment Vessels exposed to fire
This paper reports the results of a numerical investigation on the structural safety assessment of a nuclear cylindrical steel containment vessel exposed to an accidental external fire condition. A coupling procedure is proposed, linking the modeling of a nearly compressible flow with input energy given by a combustion model (CFD model) and a structural thermo-mechanical analysis (FEM model), a...