Aerodynamic Feeding 4.0: A New Concept for Flexible Part Feeding

In modern production environments, the need for flexible handling systems constantly increases due to increasing uncertainties, shorter product life cycles and higher cost pressure. Part feeding systems are vital to modern handling systems, but conventional solutions are often characterized by low flexibility, high retooling times, and complex design. Therefore, in previous research, multiple approaches towards aerodynamic feeding technology were developed. Using air instead of mechanical chicanes to manipulate workpieces, aerodynamic feeding systems can achieve high feeding rates while at the same time being very flexible and reliable. Still, the complexity of the workpieces that can be oriented relies on the number of aerodynamic actuators used in the system. Previously developed systems either used one nozzle with a constant air jet or one nozzle and an air cushion, allowing a maximum of two orientation changes. This work presents a new concept for an aerodynamic feeding system with higher flexibility (with regard to the workpiece geometry) and drastically reduced retooling times compared to conventional feeding systems. In contrast to previous implementations of aerodynamic feeding systems, using only one air nozzle or an air cushion, the new concept uses multiple, individually controllable air nozzles. Using a simulation-based approach, the orientation process is divided into several basic rotations - from a random initial orientation to the desired end orientation - each performed by a distinct nozzle. An optimization algorithm is then used to determine an optimal layout of the air nozzles, enabling the feeding system to feed any desired workpiece, regardless of the initial orientation. With the proposed concept, high flexibility, low retooling times and relatively low costs are expected, setting up aerodynamic feeding as an enabler for changeable production environments

Part Feeding System for FMS

This paper describes the development of a flexible and vibratory bowl feeding system which is suitable for use in a flexible manufacturing system. The vibratory bowl feeder for automatic assembly, presents a geometric model of the feeder, and develops force analysis, leading to dynamical modeling of the vibratory feeder. Based on the leaf-spring modeling of the three legs of the symmetrically arranged bowl of the feeder, and equating the vibratory feeder to a three-legged parallel mechanism, the paper reveals the geometric property of the feeder. The effects of the leaf-spring legs are transformed to forces and moments acting on the base and bowl of the feeder. Resultant forces are obtained based upon the coordinate transformation, and the moment analysis is produced based upon the orthogonality of the orientation matrix. This reveals the characteristics of the feeder, that the resultant force is along the z-axis and the resultant moment is about the z direction and further generates the closed-form motion equation. The analysis presents a dynamic model that integrates the angular displacement of the bowl with the displacement of the leaf-spring legs

Assembly Line

An assembly line is a manufacturing process in which parts are added to a product in a sequential manner using optimally planned logistics to create a finished product in the fastest possible way. It is a flow-oriented production system where the productive units performing the operations, referred to as stations, are aligned in a serial manner. The present edited book is a collection of 12 chapters written by experts and well-known professionals of the field. The volume is organized in three parts according to the last research works in assembly line subject. The first part of the book is devoted to the assembly line balancing problem. It includes chapters dealing with different problems of ALBP. In the second part of the book some optimization problems in assembly line structure are considered. In many situations there are several contradictory goals that have to be satisfied simultaneously. The third part of the book deals with testing problems in assembly line. This section gives an overview on new trends, techniques and methodologies for testing the quality of a product at the end of the assembling line

COMPLEXITY OF PRODUCTS AND THEIR ASSEMBLY SYSTEMS

Many manufacturing and assembly challenges emerged due to the increased demand for products variety. Increased product variety caused by product evolution, customization and changes in their manufacturing systems. Variety allows manufacturers to satisfy a wide range of customer requirements, but it can also be a major contributing factor to complexity of assembly. Complexity is generally believed to be one of the main causes of the present challenges in manufacturing systems. Complex assembly systems are costly to implement, run, control and maintain. Complexity of assembly is an important characteristic worth exploring and modeling in the early design stage. Assessing complexity of a product is essential in being able to predict the cost and time needed to implement it. There is a relationship between the complexity of assembled products and the complexity of their assembly equipment and systems. The main objective of this research is to the complexity of assembly by: (1) Assessing the complexity of assembled products, (2) Assessing the complexity of their assembly systems, and (3) Derive the relationship between products and assembly systems complexities. First, a product complexity model has been developed by incorporating the information amount, content and diversity as well as the Design for Ease of Assembly (DFA) principles for assembled products. The new product complexity model assesses the total product assembly complexity using aggregated index for individual parts complexity. The new measure accounts for the different parts\u27 assembly attributes as well as their number and variety. Second, a structural classification coding (SCC) scheme has been extended to measure assembly systems complexity. It considers the inherent structural complexity of typical assembly equipment. The derived assembly system\u27s complexity accounts for the number, diversity and information content within each class of assembly system modules. Third, a dependency matrix which represents the interactions between parts assembly attributes and assembly system functions has been developed. It is used to predict the complexity of corresponding assembly equipment used for a certain product. A relationship between parts complexity and assembly equipment complexity has been developed using regression analysis. This research is applicable to the mechanical assembly of medium size products. An automobile piston, a domestic appliance drive, a car fan motor and a family of three-pin electric power plugs and their assembly systems were used as case studies to demonstrate the proposed approach and complexity assessment tools. The significance and importance of these research contributions is that: the developed complexity metrics can be used as decision support tools for products and systems designers to compare and rationalize various alternatives and select the design that meets the requirements while reducing potential assembly complexity and associated cost. Assessing complexity of assembly helps and guides designers in creating assembly-oriented product designs and following steps to reduce and manage sources of assembly complexity. On the other hand, reducing complexity of assembly helps lower assembly cost and time, improve productivity and quality, and increase profitability an

Design, Performance Prediction and Validation of a Seed Orienting Corn Planter

Investigations into active control of corn canopy architecture through manipulation of seed orientation at planting have shown that specific seed orientations produce highly aligned leaf azimuths. Data obtained from hand planted field trials with across-row oriented leaves show that such canopies intercept more light and ultimately produce higher yields. This study was conducted to investigate the feasibility of mechanized seed orientation through the concept of part orientation by pushing. 3D-scans of 15 "medium flat" kernels of the hybrids DKC-6342, DKC-6346, P0902HR and P1162HR have been computationally analyzed to determine stable seed orientations when subjected to pushing. These predicted results were compared to data obtained in bench tests. The concept was then refined and integrated into a prototype planter based on a standard off-the-shelf row unit. The prototype was first tested in a soil bin at laboratory conditions and then in the field. Because field tests do not allow measurement of seed orientations directly greenhouse studies of the relationship between seed orientation and seed leaf azimuth distributions were conducted to assess the feasibility of an indirect post-emergence performance measure. The computational model was able to predict seed orientation by pushing very accurately. The analysis and subsequent bench unit and prototype tests revealed that orientation performance is dependent on seed shape with the kernels of DKC-6342 being the most and those of P1162HR the least suitable. Soil bin and field data confirmed that at least parity between seed and ground velocity must be achieved in order to maintain orientation during transition from the orientation mechanism to the ground. The greenhouse studies led to the conclusion that seed-to-leaf azimuth distributions can be described by von Mises models. Due to the specific design of the orienter, the shape of the kernels, and the observed seed-to-leaf azimuth properties the measureable seed leaf azimuth distribution in the field is expected to be a von Mises mixture containing four modes. The complexity of such a mixture inhibits the accurate, indirect determination of seed orientation performance in the field.Biosystems & Agricultural Engineerin

Model Identification and Control Design for a Humanoid Robot

In this paper, model identification and adaptive control design are performed on Devanit-Hartenberg model of a humanoid robot. We focus on the modeling of the 6 degree-of-freedom upper limb of the robot using recursive Newton-Euler (RNE) formula for the coordinate frame of each joint. To obtain sufficient excitation for modeling of the robot, the particle swarm optimization method has been employed to optimize the trajectory of each joint, such that satisfied parameter estimation can be obtained. In addition, the estimated inertia parameters are taken as the initial values for the RNE-based adaptive control design to achieve improved tracking performance. Simulation studies have been carried out to verify the result of the identification algorithm and to illustrate the effectiveness of the control design

Flexible Object Manipulation

Flexible objects are a challenge to manipulate. Their motions are hard to predict, and the high number of degrees of freedom makes sensing, control, and planning difficult. Additionally, they have more complex friction and contact issues than rigid bodies, and they may stretch and compress. In this thesis, I explore two major types of flexible materials: cloth and string. For rigid bodies, one of the most basic problems in manipulation is the development of immobilizing grasps. The same problem exists for flexible objects. I have shown that a simple polygonal piece of cloth can be fully immobilized by grasping all convex vertices and no more than one third of the concave vertices. I also explored simple manipulation methods that make use of gravity to reduce the number of fingers necessary for grasping. I have built a system for folding a T-shirt using a 4 DOF arm and a fixed-length iron bar which simulates two fingers. The main goal with string manipulation has been to tie knots without the use of any sensing. I have developed single-piece fixtures capable of tying knots in fishing line, solder, and wire, along with a more complex track-based system for autonomously tying a knot in steel wire. I have also developed a series of different fixtures that use compressed air to tie knots in string. Additionally, I have designed four-piece fixtures, which demonstrate a way to fully enclose a knot during the insertion process, while guaranteeing that extraction will always succeed