Time Optimal Trajectory Generation For 5 Axis On The Fly Laser Drilling
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Time Optimal Trajectory Generation For 5 Axis On The Fly Laser Drilling
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Author : Ammar Alzaydi
language : en
Publisher:
Release Date : 2011
Time Optimal Trajectory Generation For 5 Axis On The Fly Laser Drilling written by Ammar Alzaydi and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with categories.
On-the-fly laser drilling provides a highly productive method for producing hole clusters (pre-defined groups of holes to be laser drilled) on freeform surfaced parts, such as gas turbine combustion chambers. Although the process is capable of achieving high throughputs, current machine tool controllers are not equipped with appropriate trajectory functions that can take full advantage of the achievable laser drilling speeds. While the problem of contour following has received previous attention in time-optimal trajectory generation literature, on-the-fly laser drilling presents different technological requirements, needing a different kind of trajectory optimization solution, which has not been studied prior to this thesis. The duration between consecutive hole locations, which corresponds to the laser pulsing period, has to be kept constant, ideally throughout the part program. However, the toolpath between the holes is not fixed and can be optimized to enable the shortest possible segment duration. To preserve the dynamic beam positioning accuracy and avoid inducing excessive vibrations on the laser optics, the axis velocity, acceleration, and jerk profiles need to be limited. Furthermore, to ensure that hole elongation does not violate the given part tolerances, the orthogonal component of part velocity relative to the laser beam needs to be capped. All of these requirements have been fulfilled in the trajectory optimization algorithm developed in this thesis. The hole locations are provided as pre-programmed sequences by the Computer Aided Design/Manufacturing software (CAD/CAM). A time-optimized trajectory for each sequence is planned through a series of time-scaling and unconstrained optimization operations, which guarantees a feasible solution. The initial guess for this algorithm is obtained by minimizing the integral square of the fourth time derivative (i.e. 'snap'). The optimized trajectories for each cluster are then joined together or looped onto themselves (for repeated laser shots) using a time-optimized looping/stitching (optimized/smooth toolpath to repeat/loop a cluster or connect/stitch between consecutive clusters) algorithm. This algorithm also minimizes the integral square of jerk in the faster axes. The effectiveness of the overall solution has been demonstrated in simulations and preliminary experimental results for on-the-fly laser drilling of a hole pattern for a gas turbine combustion chamber panel. It is shown that the developed algorithm improves the cycle time for a single pass by at least 6% (from kinematic analysis of the motion duration), and more importantly reduces the integral square of jerk by 56%, which would enable the process speed to be pushed up further.
Laser Drilling Trajectory Generation And Way Point Sequencing
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Author : Ammar A. Alzaydi
language : en
Publisher:
Release Date : 2017-01-17
Laser Drilling Trajectory Generation And Way Point Sequencing written by Ammar A. Alzaydi and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017-01-17 with categories.
Time Optimal Trajectory Generation And Way Point Sequencing For 5 Axis Laser Drilling
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Author : Ammar Alzaydi
language : en
Publisher:
Release Date : 2016
Time Optimal Trajectory Generation And Way Point Sequencing For 5 Axis Laser Drilling written by Ammar Alzaydi and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with Laser drilling categories.
Laser drilling provides a highly productive method for producing arrays of holes on planar and freeform shaped components. Industrial applications include fuel injection nozzles, printed circuit boards (PCB's), inkjet printer heads, pinholes and slits for scientific instrumentation, high-resolution circuitry, sensors, fiber-optic interconnects, medical devices, and gas turbine combustion chamber panels. This thesis deals with time-optimal trajectory planning for two mainstream laser drilling methods: on-the-fly drilling and percussion drilling, which are used in the aerospace industry. The research has been conducted in collaboration with the Canadian aero-engine producer, Pratt & Whitney Canada (P&WC). The algorithms developed have been tested in a target application involving the laser drilling of cooling hole arrays on gas turbine engine combustion chamber panels. On-the-fly drilling is an operation in which each hole receives one low powered shot at a time while the workpiece is in motion, and the beam focal point is continuously proceeding to the next hole location. The positioning sequence repeats itself until all holes are gradually opened up in small increments. Each hole location has ample time to cool down before the next shot is received. Thus, this process can yield favorable material properties in terms of preserving the desired crystal structure, and also hole quality in terms of dimensional (size) and form (shape) accuracy, due to the reduction of local thermal loading. However, there is no existing trajectory planner, in industry, or in literature, capable of generating time-optimized positioning trajectories for on-the-fly laser drilling. This thesis studies this problem and presents a new algorithm, capable of handling 5 degree-of-freedom (axis) positioning capability. The ability to generate spline-based smooth trajectories is integrated within a Traveling Salesman Problem (TSP) type sequencing algorithm. The sequencing algorithm optimizes both the order of the waypoints (i.e., hole locations) and also the timing levels in between, which affect the temporal (time-dependent) nature of the motions commanded to the laser drilling machine's actuators. Furthermore, the duration between consecutive holes has to be an integer multiple of the laser pulsing period, considering a machine configuration in which the laser is firing at a constant frequency, and unused pulses are diverted away using a quick shutter. It is shown that the proposed algorithm is capable of generating 17-25% reduction in the beam positioning time spent during a manufacturing cycle, compared to some of the contemporary practices in industry. 17% reduction in the vibrations induced onto the laser optics is also observed, which helps prevent downtime due to the optics hardware gradually losing alignment. The second type of laser drilling operation for which optimized 5-axis trajectory planning has been developed is percussion drilling. In this process, a series of pulses are sent to each hole while the part is stationary. Once the hole is completely opened up, then positioning to the next hole proceeds. While percussion drilling is less advantageous in terms of local thermal loading and achievable part quality, it is used extensively in industry; due to its simplicity of automation compared to on-the-fly drilling. Thus, a TSP-style trajectory planning algorithm has also been developed for percussion laser drilling. The novelty, in this case, is concurrent planning of 5-axis time-optimal point-to-point movements within the sequencing algorithm, and direct minimization of the total travel time, rather than just distance (in two Cartesian axes); as is the method for which significant portion of TSP solvers and trajectory planners in literature have been developed. Compared to currently applied methods at P&WC, 32-36% reduction in the beam positioning time has been achieved. Also, 39-45% reduction in the peak magnitude of vibration has been realized. Limited benchmarking with state-of-the-art TSP solvers from combinatorial mathematics, considering only 2-axis Euclidean distance as the objective function, indicate that the proposed sequencing algorithm for percussion drilling is sub-optimal by 9-12%. Thus, it can still use further improvement in future research. Nevertheless, the two trajectory planners that have been developed in this thesis for on-the-fly drilling and percussion drilling have experimentally demonstrated very promising improvements in terms of motion time and smoothness. As more advanced Computer Numerical Control (CNC) systems and laser control electronics with deterministic execution and rapid synchronization capability become available, such algorithms are expected to facilitate significant production gains in laser drilling processes used in different industries.
Cycle Time Reduction Of 5 Axis Laser Drilling Via Time Optimal Trajectory Generation And Sequence Optimization
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Author : Kyongjae Woo
language : en
Publisher:
Release Date : 2019
Cycle Time Reduction Of 5 Axis Laser Drilling Via Time Optimal Trajectory Generation And Sequence Optimization written by Kyongjae Woo and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019 with Combinatorial optimization categories.
Cycle time reduction is one of the crucial tasks in manufacturing that needs to be achieved to maximize productivity and profits. Laser drilling processes, depending on the size and complexity of the parts, require few hundreds to few thousands of holes to be drilled. Therefore, cycle time is directly related to in what order and manner the holes are visited. In this thesis, a method of cycle time reduction for 5-axis percussion laser drilling process is presented via generation of time-optimal trajectory and optimization of hole visiting sequence. In percussion laser drilling, a series of laser pulses are fired to each hole while the workpiece is stationary. Once a hole is completely opened up, then drilling of the next hole continues by repositioning the workpiece with respect to the beam. This stop-and-go nature of the drilling process enables one to describe the sequence optimization problem as a well-known Traveling Salesman Problem (TSP) in combinatorial optimization. The objective of TSP is to find a minimum cost sequence of points when the point-to-point cost information for every possible pair is known. In the case of the minimum cycle time problem, the point-to-point cost is the travel time, and the objective of TSP is to find a sequence with the minimum overall travel time. In planning of time-optimal trajectory for point-to-point motion under a specified path, industry uses CNC controller's G00 (rapid traverse) + TRAORI (5-axis transformation and tool orientation retaining tactic) commands. To be practically beneficial, time-optimal trajectory generation strategies discussed in this thesis is focused on closely estimating these CNC controller's behaviors. A total of four strategies are studied, and the most accurate strategy is chosen by comparing the results with the experimentally measured CNC trajectories. The most accurate one specifies the tool paths in Workpiece Coordinates followed by iterative velocity profiling of the tool path parameter to achieve minimum time trajectory under the machine's velocity, acceleration, and jerk limits. With every hole-to-hole travel time calculated from the above strategy, sequence optimization can be conducted. In this thesis, two methods from the industry partner, the proposed method, and the optimal solver method are discussed. Due to licensing limitations, the proposed method is developed in-house instead of using existing non-commercial TSP algorithms. The proposed method uses local search heuristics approach inspired by famous Lin-Kernighan heuristics. The iv results are compared to the optimal solutions generated from the non-commercial state-of-the-art TSP solver called Concorde for benchmarking purposes. To understand the impact of the research in a real environment, one sample part and its original drilling process information have been made available by the industry partner. Although the full experimental results are not yet acquired at the moment of writing this thesis, the simulation results show that the proposed sequencing optimization in conjunction with the proposed hole-to-hole trajectory generation strategy for correct estimation of travel time improves the overall cycle time by 26.0 %.
Time Optimal Trajectory Generation For Laser Drilling
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Author : Ammar A. Alzaydi
language : en
Publisher: LAP Lambert Academic Publishing
Release Date : 2011-08
Time Optimal Trajectory Generation For Laser Drilling written by Ammar A. Alzaydi and has been published by LAP Lambert Academic Publishing this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011-08 with categories.
On-the-fly laser drilling provides a highly productive method for producing hole clusters (pre-defined groups of holes to be laser drilled) on free-form surfaced parts, such as gas turbine combustion chambers. Although the process is capable of achieving high throughputs, current machine tool controllers are not equipped with appropriate trajectory functions that can take full advantage of the achievable laser drilling speeds. While the problem of contour following has received previous attention in time-optimal trajectory generation literature, on-the-fly laser drilling presents different technological requirements, needing a different kind of trajectory optimization solution, which has not been studied prior to this book. Trajectories for individual hole clusters are optimized by minimizing the integral square of the 4th time derivative, and by adjusting the velocity and acceleration conditions at the hole locations to enable the maximum time compression (i.e., highest laser pulsing frequency). Axis constraints are also considered. Individually optimized clusters are stitched together using time-optimal segments with nonzero velocity boundary conditions.
Inverse Dynamics Problems
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Author : Hamed Kalhori
language : en
Publisher: MDPI
Release Date : 2021-06-15
Inverse Dynamics Problems written by Hamed Kalhori and has been published by MDPI this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-06-15 with Technology & Engineering categories.
The inverse dynamics problem was developed in order to provide researchers with the state of the art in inverse problems for dynamic and vibrational systems. Contrasted with a forward problem, which solves for the system output in a straightforward manner, an inverse problem searches for the system input through a procedure contaminated with errors and uncertainties. An inverse problem, with a focus on structural dynamics, determines the changes made to the system and estimates the inputs, including forces and moments, to the system, utilizing measurements of structural vibration responses only. With its complex mathematical structure and need for more reliable input estimations, the inverse problem is still a fundamental subject of research among mathematicians and engineering scientists. This book contains 11 articles that touch upon various aspects of inverse dynamic problems.
Planning Algorithms
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Author : Steven M. LaValle
language : en
Publisher: Cambridge University Press
Release Date : 2006-05-29
Planning Algorithms written by Steven M. LaValle and has been published by Cambridge University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006-05-29 with Computers categories.
Planning algorithms are impacting technical disciplines and industries around the world, including robotics, computer-aided design, manufacturing, computer graphics, aerospace applications, drug design, and protein folding. Written for computer scientists and engineers with interests in artificial intelligence, robotics, or control theory, this is the only book on this topic that tightly integrates a vast body of literature from several fields into a coherent source for teaching and reference in a wide variety of applications. Difficult mathematical material is explained through hundreds of examples and illustrations.
Analysis Of Machining And Machine Tools
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Author : Steven Liang
language : en
Publisher: Springer
Release Date : 2015-12-29
Analysis Of Machining And Machine Tools written by Steven Liang and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015-12-29 with Technology & Engineering categories.
This book provides readers with the fundamental, analytical, and quantitative knowledge of machining process planning and optimization based on advanced and practical understanding of machinery, mechanics, accuracy, dynamics, monitoring techniques, and control strategies that they need to understanding machining and machine tools. It is written for first-year graduate students in mechanical engineering, and is also appropriate for use as a reference book by practicing engineers. It covers topics such as single and multiple point cutting processes; grinding processes; machine tool components, accuracy, and metrology; shear stress in cutting, cutting temperature and thermal analysis, and machine tool chatter. The second section of the book is devoted to “Non-Traditional Machining,” where readers can find chapters on electrical discharge machining, electrochemical machining, laser and electron beam machining, and biomedical machining. Examples of realistic problems that engineers are likely to face in the field are included, along with solutions and explanations that foster a didactic learning experience.
Machine Tools For High Performance Machining
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Author : Norberto Lopez de Lacalle
language : en
Publisher: Springer Science & Business Media
Release Date : 2008-10-01
Machine Tools For High Performance Machining written by Norberto Lopez de Lacalle and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2008-10-01 with Technology & Engineering categories.
Machine tools are the main production factor for many industrial applications in many important sectors. Recent developments in new motion devices and numerical control have lead to considerable technological improvements in machine tools. The use of five-axis machining centers has also spread, resulting in reductions in set-up and lead times. As a consequence, feed rates, cutting speed and chip section increased, whilst accuracy and precision have improved as well. Additionally, new cutting tools have been developed, combining tough substrates, optimal geometries and wear resistant coatings. “Machine Tools for High Performance Machining” describes in depth several aspects of machine structures, machine elements and control, and application. The basics, models and functions of each aspect are explained by experts from both academia and industry. Postgraduates, researchers and end users will all find this book an essential reference.
Foundations Of Robotics
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Author : Tsuneo Yoshikawa
language : en
Publisher: MIT Press
Release Date : 1990
Foundations Of Robotics written by Tsuneo Yoshikawa and has been published by MIT Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 1990 with Computers categories.
Foundations of Robotics presents the fundamental concepts and methodologies for the analysis, design, and control of robot manipulators.