Browsing by Author "Khan, Md Raisuddin"

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Combining Fused Deposition Modelling with Abrasive Milling to Attain Higher Dimensional Accuracy and Better Surface Finish on The Finished Product
    (ResearchGate, 2018-12-01) Tomal, A.N.M. Amanullah; MIMechE, Tanveer Saleh CEng; Khan, Md Raisuddin
    Currently, two manufacturing methods, namely CNC (Computer Numerical Control) machining and rapid prototyping (RP), are widely used to produce final products and prototypes. Both the processes have their own advantages. CNC machining such as milling and grinding (subtractive method) can fabricate parts with higher precision and accuracy. On the other hand, RP (additive method), can manufacture parts with complicated 3-D (three dimensional) features, which ensures effective material usage. However, RP produced parts lack accuracy and smooth surface finish. In this research, we are aiming to achieve on-machine mechanical post-processing of 3-D printed (using Fused Deposition Modelling, a kind of RP process) parts to achieve higher dimensional accuracy and better surface roughness. To achieve the goal, we developed a new hybrid system to assimilate both of these processes. There are, however, two vital considerations needed to be taken into account for integrating the two processes. The first concern is the integration of dissimilar control systems for two processes and the second aspect is maintaining the tools’ (milling spindle and the heat extruder) setup accuracy during the changeover step. The developed hybrid machine has been tested with experimentations and the result showed that the dimensional accuracy was improved by 71% to 99% when the FDM part was compared with the final part after abrasive milling operation. At the same time, average surface roughness (Ra) was improved up to 91.3%. Further, we found that low layer thickness improves the product quality. The proposed system could push the conventional FDM system to the next level to attain better quality of final products.
  • Thumbnail Image
    Item
    Modeling and Control Simulation of a Robotic Chair-Arm: Protection against COVID-19 in Rehabilitation Exercise
    (R&D Wing, MIST, 2020-12-16) Akhtaruzzaman, M.; Shafie, Amir A.; Khan, Md Raisuddin; Rahman, Md Mozasser
    In the field of rehabilitation, lower-limbs therapeutic exercise has become a challenging job for medical professionals in COVID-19 pandemic. Providing manual therapy to lower limbs is not an easy task and, in most cases, it involves multiple persons. Moreover, it is a monotonous job, and the service providers need to be in close contact with the patient thereby creating the risk of infection. In this circumstance, robot-assisted rehabilitation exercise for lower limbs offers a risk-free solution. This paper presents dynamic modeling and control simulation of One Degree of Freedom robotic chair-arm (robotic arm attached with a special chair). The control structure is designed with two compensators for position and velocity control. The simulation results show that the proposed system has a good potential in providing automatic rehabilitation therapy for lower limbs, especially for knee joint range of motion exercise. The results also indicate faster responses with settling time less than 0.04 second and steady-state error below 0.05. The findings show that a robotic chair arm can be used for providing automatic therapy to patients in situations like COVID-19 pandemic.