4 research outputs found
Design synthesis & prototype implementation of parallel orientation manipulators for optomechatronic applications
This thesis documents a research endeavor undertaken to develop high-performing
designs for parallel orientation manipulators (POM) capable of delivering the speed
and the accuracy requirements of a typical optomechatronic application. In the
course of the research, the state of the art was reviewed, and the areas in the
existing design methodologies that can be potentially improved were identified, which
included actuator design, dimensional synthesis of POMs, control system design, and
kinematic calibration. The gaps in the current art of designing each of these POM
system components were addressed individually. The outcomes of the corresponding
development activities include a novel design of a highly integrated voice coil actuator
(VCA) possessing the speed, the size, and the accuracy requirements of small-scale
parallel robotics. Furthermore, a method for synthesizing the geometric dimensions
of a POM was developed by adopting response surface methodology (RSM) as the
optimization tool. It was also experimentally shown how conveniently RSM can be
utilized to develop an empirical quantification of the actual kinematic structure of
a POM prototype. In addition, a motion controller was formulated by adopting the
active disturbance rejection control (ADRC) technology. The classic formulation of
the ADRC algorithm was modified to develop a resource-optimized implementation
on control hardware based on field programmable gate arrays (FPGA).
The practicality and the effectiveness of the synthesized designs were ultimately
demonstrated by performance benchmarking experiments conducted on POM prototypes constructed from these components. In specific terms, it was experimentally
shown that the moving platforms of the prototyped manipulators can achieve highspeed
motions that can exceed 2000 degrees/s in angular velocity, and 5×105 degrees/s2
in angular acceleration
Flow-3D CFD model of bifurcated open channel flow: setup and validation
Bifurcation is a morphological feature present in most of fluvial systems; where a river splits into two channels, each bearing a portion of the flow and sediments. Extensive theoretical studies of river bifurcations were performed to understand the nature of flow patterns at such diversions. Nevertheless, the complexity of the flow structure in the bifurcated channel has resulted in various constraints on physical experimentation, so computational modelling is required to investigate the phenomenon. The advantages of computational modelling compared with experimental research (e.g. simple variable control, reduced cost, optimize design condition etc.) are widely known. The great advancement of computer technologies and the exponential increase in power, memory storage and affordability of high-speed machines in the early 20th century led to evolution and wide application of numerical fluid flow simulations, generally referred to as Computational Fluid Dynamics {CFD). In this study, the open-channel flume with a lateral channel established by Momplot et al (2017) is modelled in Flow-3D. The original investigation on divided flow of equal widths as simulated in ANSYS Fluent and validated with velocity measurements