Juan P. Benitez-Rangel

Directional morphological approaches from image processing applied to automatic tool selection in computer numerical control milling machine

Automatic tool selection in milling operation has become a very important step in the manufacturing and planning processes for 2.5D piece machining. The main contribution of this article is the development of a new method based on directional morphological approaches, applied to automatic tool selection in computer numerical control milling machines for machining a 2.5D of a geometry piece provided of three-dimensional model of computer-aided design or from an image taken with other devices. First, the image is preprocessed by applying several image processing techniques. Later, mathematical morphology as erosion or dilation to create structural element with the shape of the cutting tool is used. The method displaces a structural element throughout the entire image with the values of the lengths of the piece boundary and the cutting tool to select the correct cutting tool and tool path. Besides, with the same structural element, the zig and zig-zag contour trajectories are obtained in standard computer numerical control code. Results from these experiments show that the method makes it possible to obtain good performance in automatic tool selection when several types of pieces are processed.

A hardware–software system for coordinated multi-axis control based on a non uniform rational B-splines interpolator applied to industrial computer numerically controlled machines

Motion controllers are widely used in many mechatronic applications such as computer numerically controlled machine tools and robots. These applications demand the use of high performance controllers. Some desirable characteristics in motion controllers are coordinated multi-axis control, smooth movements, and advanced interpolation methods. An important manufacturing aspect involves the production of a workpiece in a free form or using the parametric surfaces in modern computer aided design/computer aided manufacturing systems. The use of parametric curves and surfaces has become standard due to their ability to represent objects having complex surfaces with less data. Another mandatory characteristic of motion controllers is the real-time operation. The contribution of the present work is the design and implementation of a hardware–software system for multi-axis motion control featuring non uniform rational B-splines interpolation. Advantages over other reported works are the hardware implementation which allows the application to real computer numerically controlled machines; also the parallel processing permits the incorporation of additional modules to form an integral system without dependence on external devices. Two experiments were carried out in a retrofitted-to-computer numeric control milling machine in order to show the efficiency of the developed system.

New approach for automatic tool selection in computer numerically controlled lathe by applying image processing

Tool selection is a very important step in manufacturing processes so as to improve productivity with high quality. The contribution of this work is the development of a new method for automatic tool selection in computer numerical control lathe machines, based on image processing techniques and information of the boundary of the piece, provided by either a .DXF file (drawing exchange format) or from an image taken with other devices. The proposed method detects the preferential direction in the boundary of the piece and creates a directional field through a directional gradient aiming at selecting the correct tool. Results from experiments show that the method makes it possible to work with a resolution of 1.1 micrometers, and to obtain good performance in automatic tool selection when several types of two-dimensional parts in the image are processed.

FPGA-Based Multiprocessor System for Injection Molding Control

The plastic industry is a very important manufacturing sector and injection molding is a widely used forming method in that industry. The contribution of this work is the development of a strategy to retrofit control of an injection molding machine based on an embedded system microprocessors sensor network on a field programmable gate array (FPGA) device. Six types of embedded processors are included in the system: a smart-sensor processor, a micro fuzzy logic controller, a programmable logic controller, a system manager, an IO processor and a communication processor. Temperature, pressure and position are controlled by the proposed system and experimentation results show its feasibility and robustness. As validation of the present work, a particular sample was successfully injected.

Time-frequency analysis of power quality signals using compact kernel distribution technique

Detection of power quality disturbances (PQD) has become an important concern due to the increasing number of disturbing loads connected to the power line and to the susceptibility of some loads to the presence of these disturbances. Nowadays, this detection becomes more complicated since several disturbances can appear simultaneously. In this paper, a new time-frequency analysis technique called compact kernel distribution (CKD) is presented to detect different PQD. To test the proposal, synthetic and real signals provided by real electrical loads are analyzed. The viability of CKD technique is studied by analyzing their power spectrum. For comparison purposes, the Hilbert Huang transform, another recent time-frequency technique, is also used. The results indicate that CKD technique is a powerful tool for disturbances detection even when they appear simultaneously.

A new approach to obtain a colour palette in thermographic images

ABSTRACT This work presents a methodology for automatic colour allocation in thermographic images which is based on two thermograms, one with an Iron colour palette for segmentation and the other in grayscale for thermal analysis through the thermal matrix. With the fusion of both procedures, a palette of colours image is obtained. The colour palette allows characterising the thermography in a controlled manner and gain a better interpretation of the colours. Likewise, the colour palette permits to work in temperature level. With this proposed methodology, it is possible to assign any colour desired. An experiment to induce human emotions (joy, disgust, anger, fear, and sadness) was carried out to prove the application of this proposed method. In a quantitative way, a thermal index of emotions that shows the emotion concerning the baseline was obtained, which correlates with the colours assigned to the new image. Each emotion was associated with one colour. The results attained from both the thermal index of emotions and the hue allocation show the applicability and validation of the proposed palette; thus, it could be employed in any application of thermographic analysis.

Segmentation in thermography images for bearing defect analysis in induction motors

This paper proposes a methodology to be used in the segmentation of infrared thermography images for the detection of bearing faults in induction motors. The proposed methodology can be a helpful tool for preventive and predictive maintenance of the induction motor. This methodology is based on manual threshold image processing to obtain a segmentation of an infrared thermal image, which is used for the detection of critical points known as hot spots on the system under test. From these hot spots, the parameters of interest that describe the thermal behavior of the induction motor were obtained. With the segmented image, it is possible to compare and analyze the thermal conditions of the system.

Triangulation intersection approach from Poisson’s equation applied to automatic tool selection in computer numerical control mill-lathe

This article presents a new method for automatic tool selection using discrete techniques based on Poisson’s equations for computer numerical control lathe-mill machine operations and rapid tooling. This method proposes to generate linear triangulation in the boundary of the piece and tool, after creating moves of tool around the piece to detect intersection; thus, this creates directional field through mesh allowing selecting the type of tool in agreement with the size, magnitude and direction of tool. The proposed methodology has been implemented in computer-aided manufacturing software, in different types for two-dimensional, two and a half–dimensional and three-dimensional pieces computer-aided design, showing the correct selection of the cutting tools. The novelty of this article is the use of discrete technique applying Poisson’s equation; the piece thus checks the intersection between the piece and tool when the tool is moving.