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RISS 인기검색어
- 검색키워드
- 저자 : Mohammad Keshmiri (검색결과 3 건)
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Visual Servoing Using an Optimized Trajectory Planning Technique for a 4 DOFs Robotic Manipulator
Mohammad Keshmiri,Wen-Fang Xie,Ahmad Ghasemi 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.3
Although visual servoing has been considered as a solution to increase dexterity and intelligence ofthe robotic systems specially in unstructured environments, some prominent deficiencies are preventing it frompractical employment. Trajectory planning is a solution to overcome the shortcomings of visual servoing andmakes it practical for industrial applications. In this paper, a new trajectory planning technique is developed toperform image-based visual servoing (IBVS) tasks for a 4 DOFs robotic manipulator system. In this method, thecamera’s velocity screw is parameterized using time-based profiles. The parameters of the velocity profile are thendetermined such that the velocity profile takes the robot to its desired position. This is done by minimizing theerrors between the initial and desired features. A depth estimation technique is proposed to provide the trajectoryplanning algorithm with an accurate initial depth. This algorithm is tested and validated via the experiment on a4 DOFs Denso robot in an eye-in-hand configuration. Experimental results demonstrate that the proposed methodprovides with a reliable visual servoing algorithm by overcoming the IBVS drawbacks such as surpassing the systemlimits and causing instability of the system in fulfilling the tasks which require a 180o rotation of the camera aboutits center.
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Navid Keshmiri,Parisa Najmi,Mohammad Ramezanzadeh,Bahram Ramezanzadeh 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.117 No.-
The control over the in-situ growth of metal-organic framework (MOF) thin films on a metal surface isstill challenging. As an interesting subdivision of MOFs, the zeolite imidazole framework (ZIF) has beenthe research hotspot in various research areas, from separation to sensing in the form of nanocrystals,thin films, and membranes. Continuous thin films of ZIF crystals need binding sites for desirable heterogeneousnucleation. This study proposed a novel and facile surface treatment at room temperature basedon zinc-phosphate conversion coating to provide nucleation sites for the intergrown ZIF-8 crystals onmild steel as a corrosion protective layer. The successful growth of ZIF-8 crystals on the modified carbonsteel was characterized using FT-IR, Raman, GIXRD, XPS, and FE-SEM tests. This thin layer led to a superprotective barrier film for up to 10 days in a harsh corrosive environment of salt spray. On the other hand,EIS reported almost 100 kO.cm2 total resistance after 72 h immersion in 3.5% wt. NaCl solution which is agreat achievement compared to conventional primer coatings. The total resistance of an epoxy coatingwith the proposed primer was improved by 135% when there was a deep mechanical scratch in the coating. The ZIF-8 thin film could significantly improve the epoxy coating’s anti-corrosion ability. The goodnews is that this concept is transferable to other ZIF-based MOFs.
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Active structural acoustic control of a smart cylindrical shell using a virtual microphone
Loghmani, Ali,Danesh, Mohammad,Kwak, Moon K,Keshmiri, Mehdi Institute of Physics Publishing 2016 Smart materials & structures Vol.25 No.4
<P>This paper investigates the active structural acoustic control of sound radiated from a smart cylindrical shell. The cylinder is equipped with piezoelectric sensors and actuators to estimate and control the sound pressure that radiates from the smart shell. This estimated pressure is referred to as a virtual microphone, and it can be used in control systems instead of actual microphones to attenuate noise due to structural vibrations. To this end, the dynamic model for the smart cylinder is derived using the extended Hamilton’s principle, the Sanders shell theory and the assumed mode method. The simplified Kirchhoff–Helmholtz integral estimates the far-field sound pressure radiating from the baffled cylindrical shell. A modified higher harmonic controller that can cope with a harmonic disturbance is designed and experimentally evaluated. The experimental tests were carried out on a baffled cylindrical aluminum shell in an anechoic chamber. The frequency response for the theoretical virtual microphone and the experimental actual microphone are in good agreement with each other, and the results show the effectiveness of the designed virtual microphone and controller in attenuating the radiated sound.</P>
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