Riaz K.,Ghulam Ishaq Khan Institute of Engineering Sciences and Technology |
Bazaz S.A.,Center for Advance Studies in Engineering |
Saleem M.M.,Ghulam Ishaq Khan Institute of Engineering Sciences and Technology |
Shakoor R.I.,National Institute of Lasers and Optronics NILOP
Sensors and Actuators, A: Physical | Year: 2011
This paper reports the design implementation of three degree-of-freedom (3-DoF) non-resonant MEMS gyroscope having 2-DoF drive-mode oscillator. The proposed architecture utilizes structurally decoupled active-passive mass configuration to achieve dynamic amplification of oscillation in 2-DoF drive-mode. This results in higher sensitivity and eliminates the need of mode matching for resonance. A low cost standard Metal-Multi User MEMS Processes (MetalMUMPs) is used to fabricate 20 μm thick nickel based gyroscope with an overall reduced size of 2.2 mm × 2.6 mm. The experimental characterization demonstrated that the frequency response of the 2-DoF drive-mode oscillator has two resonant peaks at 754 Hz and 2.170 kHz with a flat operational region of 1.4 kHz between the peaks. The sense-mode resonant frequency lies at 1.868 kHz within this flat operational region where gain is less sensitive to structural parameters and environmental variations. This results in improved robustness to fabrication imperfections and environmental variations and long term stability without utilizing tuning and feedback control. Gyroscope dynamics and system level simulations using behavioral modeling are carried out to predict the performance of the device. Experimental results show close agreement with the behavioral simulation results due to incorporation of improved damping models in behavioral model developed in CoventorWare.
Liao X.,Chongqing University |
Kulsoom A.,Center for Advance Studies in Engineering |
Ullah S.,COMSTAS Institute of Information Technology
Multimedia Tools and Applications | Year: 2015
A Modified Dual Fusion (MDF) technique of image encryption is proposed in this paper to overcome the limitations that exist in the original research work of Q. Zhang et al. (Optik 124:3596–3600, 2013). A novel technique of DNA encoding is applied through chaotic maps on pixel level and SHA-256 hash of the plain image is used to generate secret keys to avoid chosen-plaintext attack. Also, in the modified scheme, two random images are generated from chaotic maps to fuse with the plain image after permutation in digital and DNA domains using XOR and addition operations respectively. The simulated experimental results and security analysis show that the proposed cryptosystem has fairly good encryption effect than the original fusion scheme but also has the capability to sustain noise which gets add during transmission over noisy channel. Besides, the paramount factor of improved scheme is suitable for the real time applications. © 2015 Springer Science+Business Media New York
Zaidi N.A.,Ghulam Ishaq Khan Institute of Engineering Sciences and Technology |
Bazaz S.A.,Center for Advance Studies in Engineering
Industrial Robot | Year: 2014
Purpose - The purpose of this paper is to present the design of a microgripper system that comprises a dual jaw actuation mechanism with contact sensing. Design/methodology/approach - Interdigitated lateral comb-drive-based electrostatic actuator is used to move the gripper arms. Simultaneous contact sensing of the gripper jaws has been achieved through transverse comb-based capacitive sensor. The fabricated microgripper produces a displacement of 16 μm at gripper jaws for an applied actuation voltage of 45 V. Findings - It is observed that the microgripper fails to operate for the maximum performance limits (70 μm jaws displacement) and produces uncontrolled force at the tip of the jaws > 45 V. Originality/value - A novel behavioral model of the microgripper system is proposed using the fabricated dimensions of the system to carry out a detailed analysis to understand the cause of this failure. The failure analysis shows that the microgripper system failed to operate in its designed limits due to the presence of side instability in the designed combs structure. Our proposed failure model helps in redesigning the actuator to ensure its operation above 45 V so that the gripper jaw can be displaced to its maximum limit of 70 μm and also result in the increase of the controlled force from 250 to 303 μN at the microgripper jaws. © Copyright - 2014 Emerald Group Publishing Limited. All rights reserved.
Farooq M.O.,Center for Advance Studies in Engineering |
Shah G.A.,Center for Advanced Research in Engineering
Ad-Hoc and Sensor Wireless Networks | Year: 2011
In this paper, we present an admission control with multi-path routing algorithm that establishes QoS enabled label switched paths. The algorithm provides rigorous QoS provisioning within the Differentiated Services (DiffServ) enabled mobile ad-hoc network. The proposed schemeworks by merging the signaling with the routing messages. It directs QoS sensitive traffic on multiple paths provided that each path satisfies the QoS requirements of a flow. Decision for granting admission to the flow depends upon total available bandwidth (considering the interference range), minimum delay required by an application, and delay offered by the network in a given DiffServ class. Extensive simulations are performed to measure the effectiveness of the presented idea. It is observed that our scheme meets stringent QoS requirements of real time flows compared to the existing QoS models. Each admitted flow gets low delay, low jitter and almost guaranteed bandwidth. © 2011 Old City Publishing, Inc.
Qureshi W.S.,Air University |
Alvi A.-B.N.,Center for Advance Studies in Engineering
World Academy of Science, Engineering and Technology | Year: 2011
Vision based tracking problem is solved through a combination of optical flow, MACH filter and log r-θ mapping. Optical flow is used for detecting regions of movement in video frames acquired under variable lighting conditions. The region of movement is segmented and then searched for the target. A template is used for target recognition on the segmented regions for detecting the region of interest. The template is trained offline on a sequence of target images that are created using the MACH filter and log r-θ mapping. The template is applied on areas of movement in successive frames and strong correlation is seen for in-class targets. Correlation peaks above a certain threshold indicate the presence of target and the target is tracked over successive frames.