Intelligent Simulation Modeling of a Flexible Manufacturing System with Automated Guided Vehicles

Although simulation is a very flexible and cost effective problem solving technique, it has been traditionally limited to building models which are merely descriptive of the system under study. Relatively new approaches combine improvement heuristics and artificial intelligence with simulation to provide prescriptive power in simulation modeling. This study demonstrates the synergy obtained by bringing together the "learning automata theory" and simulation analysis. Intelligent objects are embedded in the simulation model of a Flexible Manufacturing System (FMS), in which Automated Guided Vehicles (AGVs) serve as the material handling system between four unique workcenters. The objective of the study is to find satisfactory AGV routing patterns along available paths to minimize the mean time spent by different kinds of parts in the system. System parameters such as different part routing and processing time requirements, arrivals distribution, number of palettes, available paths between workcenters, number and speed of AGVs can be defined by the user. The network of learning automata acts as the decision maker driving the simulation, and the FMS model acts as the training environment for the automata network; providing realistic, yet cost-effective and risk-free feedback. Object oriented design and implementation of the simulation model with a process oriented world view, graphical animation and visually interactive simulation (using GUI objects such as windows, menus, dialog boxes; mouse sensitive dynamic automaton trace charts and dynamic graphical statistical monitoring) are other issues dealt with in the study

Automation and robotics for the Space Exploration Initiative: Results from Project Outreach

A total of 52 submissions were received in the Automation and Robotics (A&R) area during Project Outreach. About half of the submissions (24) contained concepts that were judged to have high utility for the Space Exploration Initiative (SEI) and were analyzed further by the robotics panel. These 24 submissions are analyzed here. Three types of robots were proposed in the high scoring submissions: structured task robots (STRs), teleoperated robots (TORs), and surface exploration robots. Several advanced TOR control interface technologies were proposed in the submissions. Many A&R concepts or potential standards were presented or alluded to by the submitters, but few specific technologies or systems were suggested

Three-dimensional flaw reconstruction using a real-time X-ray imaging system

A system has been developed for making three-dimensional flaw measurements in materials using a real-time X-ray imaging laboratory. This environment affords precise control over all positional variables, offers multiple degrees of freedom for sample movement, and the continuous nature of the real-time image eliminates ambiguity in determining correspondence points among multiple views of the sample. This system is based on film stereography in which two stereo projections are obtained of a sample either by translating the X-ray source or by translating the sample. The three-dimensional coordinates of features of interest such as crack endpoints and centroids of void-like flaws are determined by measuring the disparity between corresponding points in the stereo pair and triangulating to find the depth of the point within the sample. This new system generalizes the sample motion for arbitrary shifts and rotations, and easily accommodates more than two views to yield a least-squares estimate of the three-dimensional point locations. The system is implemented by a set of software modules which augments an existing real-time laboratory. All sub-systems to manipulate the sample position, process the image, select feature points from the display screen, and compute three-dimensional feature coordinates were seamlessly integrated. Calibration routines were implemented to accurately determine the X-ray source, sample, and detector geometry. The spatial distortion and blurring effects of the X-ray detector were characterized and modelled. An image warp was applied to correct spatial nonlinearities, and image restoration was used to increase the resolution of the detector. A high-speed digital signal processing board was used to implement on-line image processing routines for detector corrections and contrast enhancement. The performance of the complete system was determined by measuring fabricated samples and industrial samples containing crack-like defects. The three-dimensional measurements were accurate to ±0.02 cm. This system delivers much of the information found in a computed tomography image at much lower cost, and is faster and more accurate than film-based stereography

Research and development of an intelligent AGV-based material handling system for industrial applications

The use of autonomous robots in industrial applications is growing in popularity and possesses the following advantages: cost effectiveness, job efficiency and safety aspects. Despite the advantages, the major drawback to using autonomous robots is the cost involved to acquire such robots. It is the aim of GMSA to develop a low cost AGV capable of performing material handling in an industrial environment. Collective autonomous robots are often used to perform tasks, that is, more than one working together to achieve a common goal. The intelligent controller, responsible for establishing coordination between the individual robots, plays a key role in managing the tasks of each robot to achieve the common goal. This dissertation addresses the development of an AGV capable of such functionality. Key research areas include: the development of an autonomous coupling system, integration of key safety devices and the development of an intelligent control strategy that can be used to govern the operation of multiple AGVs in an area

NON-CONTACT SPATIALLY CONSTRAINED OPTICAL SCANNING METHODS APPLIED FOR DEPTH, WIDTH AND GAP MEASUREMENTS

The thesis presents the non-contact laser projection based systems utilized for quantifying the feature dimensions like width, depth and air gaps. Laser diode, Charge coupled device (CCD) and post-processing software using image processing tools are the major components of the non-contact measurement systems. The study involves two methods where the first method comprises of active laser-based triangulation and morphological edge detection for depth and width measurement applications. The second method uses edge detection technique and Dynamic Field of View (DFOV) for gap detection and tracking. Using the developed techniques, the case studies are conducted with smooth plastic fenders with induced artificial deviations, MIG welding seam and different air gap deco finishes. Experimental validations are carried out by comparing the results with commercial systems like 3D scanner and commercial sensor. Also, the Gauge Repeatability and Reproducibility (GR&R) studies are produced to identify the gap measurement tool capabilities interms of accuracy and repeatability