This paper proposes a new way of designing and fabricating conformal flexible electronics on free-form surfaces, which can generate woven flexible electronics designs conforming to free-form 3D shapes with 2D printed electronic circuits. Utilizing our recently proposed foliation-based 3D weaving techniques, we can reap unprecedented advantages in conventional 2D electronic printing. The method is based on the foliation theory in differential geometry, which divides a surface into parallel leaves. Given a surface with circuit design, we first calculate a graph-value harmonic map and then create two sets of harmonic foliations perpendicular to each other. As the circuits are processed as the texture on the surface, they are separated and attached to each leaf. The warp and weft threads are then created and manually woven to reconstruct the surface and reconnect the circuits. Notably, The circuits are printed in 2D, which uniquely differentiates the proposed method from others. Compared with costly conformal 3D electronic printing methods requiring 5-axis CNC machines, our method is more reliable, more efficient, and economical. Moreover, the Harmonic foliation theory assures smoothness and orthogonality between every pair of woven yarns, which guarantees the precision of the flexible electronics woven on the surface. The proposed method provides an alternative solution to the design and physical realization of surface electronic textiles for various applications, including wearable electronics, sheet metal craft, architectural designs, and smart woven-composite parts with conformal sensors in the automotive and aerospace industry. The performance of the proposed method is depicted using two examples.

The geometric shapes of coils influence the performance of a 3D IPT system. In this paper, we proposed a 3D coil design method based on (3D) printing electronics. Given a 3D transmitter coil, the center position of the receiver coil is estimated as a random seed position in the corresponding 3D surface first. At this position, we use the heatmap method with electromagnetic constraints to iteratively extend the coil until the desired power can be transferred via the coil. For each extension of the coil, i.e. a new turn, the shape of the coil is optimized by calculating the convex hull of the new turn in the 2D projection plane. Using this method, we are able to generate a receiver coil to transmit “just enough” power at a given seed position. Then, by fixing the receiver coil, the 3D shape of the transmitter coil can be optimized as well. This zig-zag optimization process iterates until there are few changes of the position and 3D shapes in the iteration. Experiment results with Ansys Maxwell verified the effectiveness of the proposed 3D coil design method, and highlighted possible future research directions as well.

Nuclear batteries are a class of power sources that harvest energy from decaying radioactive isotopes to generate electricity for powering sensors and electronics. They are well known in the fields of space exploration and implantable medical devices, but are not widely known to micro or nano-technologists in general. Nuclear batteries are compared against chemical sources of energy applicable to small-scale systems, including energy harvesting prototypes and a mm-scale commercial lithium battery, utilizing the metrics of volumetric power and energy density. Nuclear batteries benefit from orders of magnitude more energy density than power sources derived from chemical reactions, however they also have orders smaller power density. For some sensor applications, nuclear batteries enable capabilities not possible with chemical energy sources, and examples are discussed.

Over 40 million tons of electronic devices (e.g., computers, laptops, notebooks, and cell phones) became obsolete in 2020, and this estimate is expected to grow exponentially, mainly due to the decreasing lifespan of electronics. Most of the electronics replaced end up in municipal landfills. Electronic waste (e-waste) has raised concerns because many components in these products are not biodegradable and are toxic. Some of the toxic materials and chemicals include rare earth elements (REEs), which are currently experiencing supply constraints. This study focuses on generated e-wastes from households due to the high amount of these wastes. Technologies for e-waste mining must be tailored to household needs rather than large-scale industrial processes. The use of portable e-waste recovery systems may produce win-win outcomes where industry, households, and regulatory bodies could benefit, and this will incentivize e-waste mining for all stakeholders. This study investigates the sustainability benefits of employing a portable e-waste recycling and REEs recovery, using techno-economic and life cycle assessment methods. The results indicate that the proposed approach in this study mitigates environmental impacts when maleic acid is used as one of the key ingredients in recovering and separating REEs and other metals. It is concluded that when adopted globally, this technology can significantly address the e-waste challenge while improving the availability of REEs for high-tech applications.

Cooperative or concurrent product development is gaining popularity and will become norms of the Industry of the Future. To avoid problem created by designs not amenable to manufacturing, the designer should be aware of manufacturing constraints. Electronics manufacturing is one of the fastest growing segment of manufacturing domain today. The rapid change in the manufacturing of printed wiring boards with the induction of surface mounted components makes the system design more complex. To capture the manufacturability constraints of the manufacturing of printed wiring boards (printed wiring board is another name of printed circuit boards), a knowledge-base is developed to assist the designer. Rules and guidelines pertaining to manufacturability are formulated and incorporated into the knowledge-base. The implementation of the meta-level knowledge to increase the efficiency of the system is also presented. The system is developed using an object-oriented paradigm and capable of suggesting design modification to the designer at the early stage of design to eliminate the manufacturing problems in the later phase of board production. The broad user interface makes the system very user friendly.

This paper presents techniques used to model a two arm experimental robot developed at Iowa State University. Both arms are compliant and the robot operates in a vertical plane and is therefore influenced by gravity. The robot is being built to study different control strategies for robots containing compliant members. The system is built with extremely flexible members. This limits the required bandwidth of the control electronics, and mimics the flexible motions that are observed for stiffer faster robots. The objective of this paper is to develop a reduced order model of the robot system and to experimentally validate the model. Validation requires that the model include gravitational effects. Therefore, an assumed modes model is developed which facilitates modeling of gravitational effects. In order to select the order and mode shapes for the model, an analytical solution is derived for a linearized continuous model. This is compared to the assumed modes model to determine the number of mode shapes needed to model the system. The final model, which includes shortening effects, correlates very well with experimental results.

Smart piezoelectric structures, conventional passive materials integrated with piezoelectric sensors, actuators and control electronics, have great potentials in many engineering applications. This paper is devoted to a new theoretical development of generic piezoelectric shell distributed systems. System electromechanical dynamic equations, three translational coordinates and two rotatory coordinates, and boundary conditions, electric and mechanical, for a thick piezoelectric shell continuum with symmetrical hexagonal structure (Class C 6v = 6mm) are derived using Hamilton’s principle and linear piezoelectric theory. The thick shell system equations are simplified to thin piezoelectric shells using Kirchhoff-Love’s assumptions. Converse effect induced electric forces/moments and boundary conditions can be used to alter system dynamics via open or closed loop control systems. Applications of the theories to a thick plate and a spherical shell are demonstrated in case studies.

The main potential advantage of electro-rheological fluid when used as the interface medium between electronics and actuators in high speed machines is its ability to respond quickly to a change in the control signal. The analysis reported in this paper shows that over the operating speed range the system has a time constant of less than one millisecond and for most practical applications it can be assumed that when a suitable control strategy is employed the output torque would be proportional to the control signal. Most electro-mechanical torque transducers have time constant of over 10 milliseconds and therefore direct measurement of the torque produced by the electro-rheological clutch would be very expensive if not impractical. This paper reports a numerical method of identifying the torque response from the output of a conventional torque transducer which has a natural frequency of 110 Hz. The transfer function is first identified from a standard step input test, and the torque response of the clutch then is estimated from the measured signal. Although the noise on the signal will be always amplified with this method the use of a digital filter makes it possible to obtain an accurate estimate of the torque response.

A novel application of the PDES standard for automated group technology (GT) code generation is presented. The study focuses on microwave modules (MWM’s), which include a mechanical ground plane with machined features, as well as electrical artwork and electronic components. Several modifications and enhancements were made to the Layered Electrical Product information model of the PDES standard in order to capture the particular characteristics of MWM’s. The modified PDES model was implemented using the ORACLE relational database, and served as the primary input to the automated GT code generation system developed at the University of Maryland. The principle difficulties encountered using PDES in our work are discussed, including: (i) lack of a proper feature hierarchy, (ii) limiting supertype-subtype specifications, and (iii) complications in implementing the LEP model to a relational database schema.

Mechatronics is the synergistic combination of precision mechanical engineering, electronics, control engineering, and computer science in the design process. This paper describes a new elective course entitled Mechatronics which has been developed and was taught for the first time at Rensselaer during the fall 1991 semester to 45 senior-undergraduate and graduate students. The key areas of mechatronics which are studied in depth in this course are: control sensors and actuators, interfacing sensors and actuators to a microcomputer, discrete controller design, and real-time programming for control using the C programming language. The course is heavily laboratory-based with a two-hour laboratory weekly in addition to three hours of classroom lecture. The laboratory exercises include computer-aided control system design using MATRIXx, various analog and digital sensors, hydraulic actuators, DC and stepper motors, and computer control of a variety of physical systems. The unifying theme for the course is the integration of these key areas into a successful mechatronic design. Students are required, as a final project, to: identify a problem or need, analyze the problem, and write a problem statement; perform a state-of-the-art review; develop a list of specifications and identify the key specifications; generate an outstanding mechatronic-system conceptual design; and finally perform a detailed design of the system which may include model building and hardware development. Examples of student projects are described. This course should significantly enhance our design education program in the Mechanical Engineering Department and lay the foundation for the students to become mechatronic design engineers.

Computer Aided Engineering (CAE) Tools are being used extensively by companies in the United States to compete in an increasingly demanding global market place. Product cycle times are being reduced while quality requirements are being increased. The students enrolled in engineering and engineering technology today will be faced with competing in these competitive markets after graduation and must acquire the skills they need for that competition before graduation. In order to help make our students more competitive in that global market place, a CAE Tools course and interdisciplinary projects are being integrated into the manufacturing, plastics and electronics engineering technology programs at Western Washington University. This paper describes the new CAE Tools course at Western and decribes specific examples of interdisciplinary projects during the past academic year.

We present a new methodology for predicting the fatigue life of solder joints for electronics applications. This approach involves the integration of experimental and computational techniques. The first stage involves correlating the manufacturing and processing parameters with the starting microstructure of the solder joint. The second stage involves a series of experiments that characterize the evolution of the microstructure during thermal cycling. The third stage consists of a computer modeling and simulation effort that utilizes the starting microstructure and experimental data to produce a reliability prediction of the solder joint. This approach is an improvement over current methodologies because it incorporates the micro-structure and properties of the solder directly into the model and allows these properties to evolve as the microstructure changes during fatigue.

Surface mounted components have become the choice of the electronics manufacturing industry to solve problems in the complex circuit boards. New components using increased lead counts on finer pitches make manufacturing difficult. The increased complexity, cost, and lead count of the Surface Mount Technology (SMT) components, and also the increasing compactness of the SMT assemblies have demanded the creation of newer rework tools as an essential part of electronics manufacturing. Therefore, it becomes essential to have a well-controlled process to assure that rework is not only possible but that it is consistent and flawless. Automation is the common answer to achieve both efficiency and quality. This paper describes a system for the automated rework of fine pitch components that is under development as part of the Center for Integrated Electronics and Electronics Manufacturing (CIEEM) at Rensselaer.

This paper describes methods to help project leaders and engineers manage the costs of providing variety to the market. As companies look for ways to stay competitive in the global marketplace, the concept of mass customization has appeared as a potential advantage. Armed with new manufacturing and information technologies, companies are trying to determine the amount of variety that they should offer to optimize profits. Our Design for Variety (DFV) research focuses on methodologies which will help companies quantify the costs of providing variety and will qualitatively guide designers in developing products that incur minimum variety costs. The proposed tools incorporate quantitative indices and qualitative design charts. Examples from electronics and automotive industries illustrate the utility of the tools.

This paper introduces the concept of a process capability matrix — an ordered set of dimensionless parameters that capture information on a manufacturing system’s response to noises. The matrix captures information on the magnitude of noise, sensitivity to noise, and tolerance to variation. Algorithms and equations are presented that use the matrix to compute the yield of a manufacturing system. The method proves to be accurate on real engineering problems for which existing techniques are inadequate due to statistical correlation among product acceptance criteria. The process capability matrix also proves useful in a new type of block diagram of production systems. The block diagrams are shown to be useful in evaluating the effectiveness of feedforward control strategies for variation reduction. An electronics assembly process serves as an example of the algorithms and their use in design decision making.

This paper temporarily sheds formal mathematical treatment and presents a more intuitive overview of inference mechanisms for quantified relations. These predicate logic expressions are a new class of design constraint among sets of variations affecting the design and performance of engineering systems. Simple examples illustrate the use of quantified relations to infer constraints on the membership of feasible sets. A small design problem from the electronics domain joins the mathematical tools with engineering concepts. A brief comparison demonstrates the advantages of this approach over conventional interval mathematics. This paper’s objective is to illustrate the application of quantified relations and their associated methods to engineering design problems.

This paper surveys end-of-life strategies currently used in the electronics and appliances industries and identifies product characteristics to guide designers to specify appropriate strategies. The survey indicates that characteristics such as wear-out life, design cycle, technology cycle, functional complexity, number of materials, number of parts and others are important in determining the end-of-life strategy. Two characteristics, product life and technology cycle, serve to demonstrate a possible categorization of products’ end-of-life path. The categorization leads to developing a methodology that guides product developers. By expanding the methodology to include all characteristics, designers will be able to specify end-of-life strategies, to seek environmentally friendly designs, and to develop new recycling technologies. This paper concludes with a proposed web-based application for identifying suitable product end-of-life strategies early in the design cycle of a broad range of products based on key product characteristics.

This paper presents a software architecture for composing complete system-level simulations of mechatronic systems. The proposed architecture will provide the designer with the infrastructure to rapidly create simulations of alternative designs. The architecture promotes modularity and composability through the use of the design entity . Moreover, the architecture supports hierarchical modeling and provides the infrastructure to seamlessly integrate mechanics models with electronics and information technology models. Finally, the architecture facilitates distributed computing to take full advantage of the power of networked computers. This paper introduces the individual concepts of our architecture, and illustrates them in the design of a missile seeker.

We demonstrate the need for treating switching converters as discontinuous systems in order to properly analyze their dynamics and stability. We also outline some concepts related to the stability analysis of these variable-structure systems. Using these concepts, we investigate the stability and dynamics of a stand alone and an integrated DC-DC buck converter, which represents a nonlinear dynamical system under closed-loop operation. We compare the results with some of the existing ones, which are based on small-signal analyses, and demonstrate the shortcomings of the latter.

Products made of compliant sheet metals are widely used in automotive, aerospace, appliance and electronics industries. One of the most important challenges for the assembly process of such compliant parts is the assembly dimensional quality, which affects product functionality and performance. This paper develops a methodology to evaluate the dimensional variation propagation in a multi-station compliant assembly system based on linear mechanics and a state space representation. Three sources of variation are analyzed, part variation, fixture variation and weld gun variation. The proposed method is illustrated through a case study on automotive body assembly.