Marwan Nafea

Selective wireless control of a passive thermopneumatic micromixer

This paper reports a novel wireless control of a thermopneumatic zig-zag micromixer by selectively activating two passive wireless heaters enabled by an external radiofrequency magnetic field. Each heater generates heat when the external field frequency is tuned to the corresponding resonant frequency (fr) of the heater. The two heaters that are designed to have different f of 100 MHz and 130 MHz are selectively activated with a constant input power of 0.2 W by modulating the field frequency to their corresponding fr. Each heater is responsible for heating an air-heating chamber that is connected to a loading reservoir through a microdiffuser element, while the solutions pumped from each reservoir are mixed in a zig-zag micromixing element that ends with an outlet hole. The micromixer provides a mixing-ratio controllability with a flow rate of ~0.28 μL/min and biocompatibility, making it promising for biomedical applications, such as local drug delivery and cells culturing.

A Hybrid Control Approach for Precise Positioning of a Piezo-Actuated Stage

Piezo-actuated stages are composed of a piezoelectric actuator (PEA) and a positioning mechanism. Hysteresis behavior of PEAs limits the position accuracy of the piezo-actuated stages. This paper presents a hybrid control approach for precise positioning of a piezo-actuated stage, where Bouc-Wen hysteresis model is used to represent the hysteresis behavior of the PEA. A Luenberger observer-based feedforward controller is designed, and then integrated with a Particle Swarm Optimization (PSO)-based Proportional-Integral-Derivative (PID) controller to form a hybrid controller. Optimal PID gains are obtained based on a fitness function proposed to reduce the displacement error and achieve fast response time. The results show that using the proposed hybrid controller reduces the hysteresis effect significantly, and thus the maximum error is minimized to 0.127 μm, which is 0.17 % of the maximum displacement of 72.1 μm.

Modeling and simulation of a wireless passive thermopneumatic micromixer

This paper presents modeling and simulation of a wirelessly-controlled thermopneumatic zigzag micromixer. The micromixer is operated by selectively activating two passive wireless heaters with different resonant frequencies using an external magnetic field. Each heater is responsible for heating an air-heating chamber that is connected to a loading reservoir through a microdiffuser element, while the solutions pumped from each reservoir are mixed in a zigzag micromixing element that ends with an outlet hole. The performance of the micromixer is analyzed using finite element method, and mixing is investigated over a low range of Reynold’s number (Re) ⩽ 10 that is suitable various biomedical applications. The optimal activation switching time of the heaters is 10 s, at which the micromixer achieves a maximum mixing efficiency of ~96.1%, after ~65 s. The micromixer provides mixing-ratio controllability with a maximum flow rate and pressure drop of ~3.4 µL/min and ~385.22 Pa, respectively.

Racer: A Simulated Environment Driving Simulator to Investigate Human Driving Skill

The identification and the quantification of human skill is one of the major characteristics to be considered in designing an algorithm for Human Adaptive Mechatronics (HAM) application. This paper focuses on studying the Racer software, as well as the relationship of data gained and the simulated environment. The fact that Racer is chosen as the tool is described. This paper discusses the details about the software used; Racer as the driving simulator environment during the experiment. The experimental setup, data extraction process and data conversion are explained further in this paper. The experimental results meet the purpose of data collection which provides variety set of data, including many options for cars and tracks. As a conclusion, Racer is a suitable software to be used. The utmost important, the further study of this research will help during the development of car assistance system.