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RISS 인기검색어
- 검색키워드
- 저자 : Sheraz Ahmad (검색결과 6 건)
- 무료
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- 유료
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A Spiral Curve Gait Design for a Modular Snake Robot Moving on a Pipe
Sheraz Yaqub,Ahmad Ali,Muhammad Usman,Khalil Muhammad Zuhaib,Abdul Manan Khan,안보영,문현기,이지영,한창수 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.10
Modular snake robot has the ability to maneuver narrow, complex, and unstructured environments. In recent years, Snake robot with 3-D locomotion has been studied by researchers for inspection of pipes, and stairs climbing etc. One of the effective approaches to accomplishing such complex tasks is by designing gaits for modular snake robot. In this paper, A Spiral curve gait along with rolling motion is proposed to adapt to the changes in the pipe diameter while moving on the pipe, which cannot be overcome by a simple helical rolling motion. The joint angles are calculated using Bellow’s model, based on the curvature and torsion of the backbone curve. We validated the proposed gait by simulating thirty degrees of freedom modular snake robot in Open Dynamics Engine simulator.
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Ahmad, Wasim,Khan, Sheraz Ali,Islam, M M Manjurul,Kim, Jong-Myon Elsevier 2019 Reliability engineering & system safety Vol.184 No.-
<P><B>Abstract</B></P> <P>Induction motors most often fail due to faults in the rolling element bearings. Such failures can cause long and unscheduled downtime in a production facility, which can result in huge economic losses. The prediction of imminent failures and estimation of a bearing's remaining useful life (RUL) is vital for avoiding abrupt shutdowns and scheduling maintenance. In this paper, a reliable technique for the health prognosis of rolling element bearings is proposed, which infers a bearing's health through a dimensionless health indicator (HI) and estimates its RUL using dynamic regression models. The HI measures the instantaneous vibration level of the bearing with respect to a normal baseline value. The regression models are recursively updated to capture the evolving trend in the bearing's health indicator and are then used to project the future values of the health indicator and estimate the RUL of the bearing. The RUL of a bearing is estimated after determining the time to start prediction (TSP) using a new approach. The proposed algorithm is tested and validated on the PRONOSTIA dataset, and its prognostic performance is compared with two state-of-the-art techniques that are based on the extended Kalman filter and an exponential model that is improved using particle filters. The experimental results demonstrate the excellent prognostic performance of the proposed method due to its ability to determine an appropriate TSP and dynamic calibration of the regression models to adopt to the evolving trend in the bearing health indicator.</P> <P><B>Highlights</B></P> <P> <UL> <LI> This paper proposes a reliable technique for the health prognosis of rolling element bearings. </LI> <LI> The proposed algorithm is tested and validated on the PRONOSTIA dataset. </LI> <LI> The proposed method shows the excellent prognostic performance. </LI> </UL> </P>
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Motion planning for a planar mechanical system with dissipative forces
Ali, Ahmad,Yaqub, Sheraz,Usman, Muhammad,Zuhaib, Khalil M.,Khan, A. Manan,Lee, Ji-Yeong,Han, Chang-soo Elsevier 2018 Robotics and autonomous systems Vol.107 No.-
<P><B>Abstract</B></P> <P>In this paper, the geometric motion planning problem is addressed for an under-actuated mechanical system with dynamic non-holonomic constraints. Such constraints are the result of conservation of momentum that limits the mobility of the system in ambient space. However, dissipation forces due to interaction with the environment play a role enabling the system to move in constrained directions. Geometric mechanics tools are used to represent system dynamics in a structured form, which help better understand the motion planning problem. The geometric structure can be utilized to choose appropriate gaits intuitively by considering the properties of functions involved in the system dynamics. In a similar manner, dissipation forces also show the same type of geometric properties in terms of Stokes’ connection and Stokes’ Gamma functions. We can choose a gait intuitively without the need for integrating the system dynamics to generate motion in ambient space. We achieve this by exploiting the geometric properties of the friction model along with the natural dynamics of the system. By the proposed gait selection methodology, gaits are devised to move the system along a fiber direction. The simulation results are consistent with the results predicted by the proposed motion planning method. The proposed methodology is validated using experimental demonstration which also supports the simulation results. The proposed Stokes’ Height functions and Stokes’ Gamma functions can help to better understand the contribution of the dissipative forces and their anisotropy in motion of biological snakes and their robotic counterparts.</P>
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Mumtaz Ali,Muhammad Zeeshan,Muhammad Bilal Qadir,Rabia Riaz,Sheraz Ahmad,Yasir Nawab,Aima Sameen Anjum 한국섬유공학회 2018 Fibers and polymers Vol.19 No.11
Auxetic materials expand in at least one dimension, when stretched longitudinally i.e. they have negative Poisson’s ratio. Development of 2D woven auxetic fabrics (AF) is a new approach to develop mechanically stable auxetic textile structures. However, the mechanical response of such emerging structure is still not studied in detail yet, therefore different mechanical properties of 2D woven AF are compared with conventional non-auxetic fabric (NAF). AF was developed by orienting yarns in auxetic honey-comb (AHC) geometry and auxeticity is induced due to such orientation of yarns. AF was developed using conventional (non-auxetic) materials; cotton yarn and elastane cotton yarn in warp and weft dimension respectively, using air jet loom. Structure and auxeticity of AF were analyzed using a digital microscope and its different mechanical properties (tensile strength, tear strength, bursting strength, cut resistance, and puncture resistance) were studied. AF showed superior mechanical properties with a lower initial modulus, which is beneficial for different protective textiles applications like cut resistance gloves, blast resistant curtains, and puncture tolerant elastomeric composites.
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Wardah Anam,Munir Ashraf,Muhammad Bilal Qadir,Khurram Shehzad Akhtar,Sheraz Ahmad,Ali Afzal,Tehseen Ullah 한국섬유공학회 2019 Fibers and polymers Vol.20 No.12
In this research work, we have studied the dyeing behaviour of fabrics made from ring, rotor and MVS yarns. Thediscrete structure of respective yarns made by different spinning techniques have significant effect on dyeing behaviour offabrics. The fabrics were investigated for K/S values of polyester dyed, cotton dyed and polyester+cotton dyed fabrics andtheir colour fastness to crocking. The analysis of dyeing behaviour revealed that yarn manufacturing technique hassubstantial effect on the colour strength of their respective fabrics. Due to unique distribution of fibers within the crosssectionof yarn, the cotton dyed and polyester+cotton dyed fabrics made from MVS yarns exhibited better K/S values ascompared to other fabrics. The fabrics also exhibited a difference in colour fastness to crocking in dry and wet form. Thecolor fastness of fabrics to crocking in dry form were found higher than in wet form. The polyester dyed and polyester+cottondyed fabrics made from MVS yarns have shown higher color fastness to crocking.
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