Wire Routing Research Articles

High-Performance Wave Union Time-to-Digital Converter Implementation Based on Routing Path Delays of FPGA

Time-to-digital converters (TDCs) with superior performance are in high demand in application domains like light detection and ranging (LIDAR), nuclear physics, and time interval counters. One of the interesting architectures for field-programmable gate array (FPGA)-based TDCs is the tapped delay line (TDL) approach with carry chains as delay elements. However, the resolution of TDL-TDCs is limited, and linearity is weakened by the ultra-wide bins that correspond to the FPGA’s long routing wires crossing into another clock area. This paper presents wave union TDC using FPGA internal routing wires as delay elements to subdivide ultra-wide bins. The Zynq Evaluation and Development (ZED) board is used to implement and test the wave union types: A (WU-A) and B (WU-B) TDCs. According to experimental data, the WU-A TDC based on an 8 × 128 matrix of counters has a resolution of 5.7 ps, an integral nonlinearity (INL) of 1.1170 LSB (RMS), and a differential nonlinearity of 0.329 LSB (RMS). WU-A TDC improves DNL and INL by 19% and 57%, respectively, over ordinary TDC. The WU-B TDC uses an average of sixteen different time measurements, resulting in an effective resolution of up to 0.356 ps, a DNL of 0.60 LSB (RMS), and an INL of 1.04 LSB (RMS). These characteristics make the TDC suitable for time-of-flight applications such as LIDAR and for other general-purpose scientific instruments.

Democratizing digital microfluidics by a cloud-based design and manufacturing platform.

Akin to the impact that digital microelectronics had on electronic devices for information technology, digital microfluidics (DMF) was anticipated to transform fluidic devices for lab-on-a-chip (LoC) applications. However, despite a wealth of research and publications, electrowetting-on-dielectric (EWOD) DMF has not achieved the anticipated wide adoption, and commercialization has been painfully slow. By identifying the technological and resource hurdles in developing DMF chip and control systems as the culprit, we envision democratizing DMF by building a standardized design and manufacturing platform. To achieve this vision, we introduce a proof-of-concept cloud platform that empowers any user to design, obtain, and operate DMF chips (https://edroplets.org). For chip design, we establish a web-based EWOD chip design platform with layout rules and automated wire routing. For chip manufacturing, we build a web-based EWOD chip manufacturing platform and fabricate four types of EWOD chips (i.e., glass, paper, PCB, and TFT) to demonstrate the foundry service workflow. For chip control, we introduce a compact EWOD control system along with web-based operating software. Although industrial fabrication services are beyond the scope of this work, we hope this perspective will inspire academic and commercial stakeholders to join the initiative toward a DMF ecosystem for the masses.

Mitigating the Effects of Design for Manufacturability on Design Iteration Cycles in Advanced Integrated Circuit Design

In integrated circuit (IC) design for advanced manufacturing processes, iterative improvement processes are an approach commonly used for improving design quality, particularly for low-energy, high-frequency circuits. Layout-dependent effects (LDEs) affect IC design and fabrication, resulting in differences in circuit functionality and performance in presimulation versus postsimulation. These differences can greatly increase the length of design iteration cycles. Foundries have attempted to accelerate the iterative design process by providing process design kit libraries to IC designers. However, these kits can neither fully mitigate the negative affect of LDEs on design for manufacturability (DFM) nor eliminate the difference between presimulation and postsimulation results. To address this problem, this study proposed a novel algorithm-based design process in which an IC designer can use layout parasitic extraction to extract the DFM parameters of all components in a circuit prior to the routing process; these parameters include netlists that describe the internal connectivity of components as well as their interconnectivity with other components. Accordingly, the IC designer can determine the effects of DFM parameters on the circuit and modify them in advance if necessary. When the LDEs generated by device placement have been confirmed to not affect circuit properties, physical verification of the routing of metal wires in the IC layout can be performed. In this verification, postsimulations only need to focus on problems regarding the wire loading and timing effects of metal routing. The proposed design process is useful for mitigating LDEs in IC design and considerably reduces the time required for iterative improvement processes. Specifically, this study provides a method of enhancing design iteration cycles and provides guidelines for analyzing factors that hinder IC device functionality and performance. In sum, various problems can be resolved by separately extracting the DFM parameters associated with LDEs and parasitic parameters associated with routing.

Advanced structural and multi‐functional sandwich composites with prismatic and foam cores: A review

AbstractAdvanced sandwich structures have emerged as new multifunctional structures with low density and good mechanical performance. Sandwich composites have high strength to weight and high stiffness to weight ratio. Good thermal and sound insulation can be provided using sandwich composite materials. Sandwich composites have high energy absorbing capacity. Multifunctional sandwich composites exhibit mechanical performance and other functional properties such as energy storage, electrical conductivity, etc. Further, the core can be used for routing wires, foam filling, fluid storage, embedding bars, etc. Thus, the multifunctionality can be introduced to the resuting composite materials. This article reviews current research on innovative sandwich structures with integrally woven corrugated core, honeycomb, foam, and 3D printed core architectures, emphasizing their multifunctionality. Aspects of sandwich structure with types of face and core structure design, material design, mechanical properties, and panel performance and damage, including multifunctional benefits, are reviewed. Examples of engineering and modern uses of sandwich structures are presented, covering hypersonic vehicles, civil and marine engineering, electronics, and biological fields. A list of areas for future study initiatives is also included. This review will serve as a baseline for future studies to do more research in the same direction.Highlights A detailed review of various types of core materials and sandwich structures is presented. Sandwich structures have high energy absorbing capacity. 3D woven sandwich structures, their manufacturing and failure mechanics is discussed. Modern applications of sandwich structures are detailed.

Generation of Homotopy Classes for Unconstrained 3D Wire Routing from Characteristic Loops

Routing of wire harnesses in complex machinery is a complicated problem. In this paper, we present an approach for computing all non-homotopic paths characteristic of all the homotopy classes associated with a pair of source–destination points embedded on the surface of the product. We introduce the notion of routing graphs, which are generated from specific non-trivial loops in the first homology group associated with the surface of the product. The routing graph, which is constructed only once, encodes the homotopy of the routing environment and is, therefore, used to find all the non-homotopic paths between multiple source–destination pairs. Based on the path embedding requirements, we classify the routing process into (1) On-Surface Routing, when the paths are constrained to the surface of the product, and (2) In-Air Routing, when the paths are allowed to venture into the product ambiance space. In the former case, the routing graph is defined by both the handle and tunnel loops in the first homology group, whereas in the latter case, it is defined by only the handle loops. We propose a linking number-based strategy for computing the handle and tunnel loops for a given closed surface. The methods are extended for routing in assemblies using the so-called shell structures associated with them. The results obtained demonstrate the efficacy of the proposed approach. The results show that the computation of the routing graph is very efficient, and the homotopy classes can be generated in very little time using the proposed approach.

Wire Length-Matching Aware Placement Method for Rapid Single Flux Quantum Logic Circuits

This paper proposes a fast automatic gate placement method for gate-level-pipelined Rapid Single Flux Quantum (RSFQ) circuits that are designed to have a high throughput. In such circuits, the gates in a pipeline stage are placed in a column and wires are routed in the area between adjacent columns. In wire routing, wire length-matching is performed. The proposed method performs gate placement for a given netlist to minimize the sum of the maximum distance between connected gates in each pair of adjacent columns. It leads to short wire extensions in wire length matching for increasing the operation frequency and small circuit area. The proposed method consists of a recursive procedure including two placements, selecting a pivot column, and determining the gate placement in the pivot column. The netlist is divided into two netlists with the pivot column. The recursive procedure performs gate placements for the two divided netlist. It is repeated until the location of every gate is determined. We implemented a placement tool by the proposed method and performed the gate placement for three circuits including several hundreds of gates. The proposed placement was 14 to 40 times faster than a placement based on simulated annealing where the sum of the maximum distance between connected gates is approximately the same.

EFFECTS OF CIRCULAR HOLES DRILLED IN WOOD JOISTS

Holes are drilled in wood joists for routing pipes, wires or other components. This research investigated the effects of these holes on the shear and bending stresses in a wood joist. Strengths are calculated using the reduced section properties accounting for the holes. The question is whether the reduction in cross-section may account for any other stress concentration factors that may be present due to the discontinuity. It is also important to determine whether a stress concentration factor needs to be applied to wood joists with holes in them. A finite element model was created to determine the actual stresses in members with holes in their cross-sections. Holes of variable size and location were added to the members. Structural analyses were performed using standard procedures and found out that the stresses based on reduced cross-sectional properties were much less than that of the finite element model. Therefore, the calculation of stresses based on the reduced cross-sectional properties of a member does not adequately account for stress risers at the discontinuity. It was also found from the finite element model that the reduction in cross-section generates an increase in stress that is a fraction of the actual stress increase. It was suggested from this research to limit the location of a hole within a member’s cross-section to the middle third and to apply some stress concentration factors to account for the holes for both shear and bending stresses.

Consumer Electronics Product Manufacturing Time Reduction and Optimization Using AI-Based PCB and VLSI Circuit Designing

Circuit design plays an essential role in all consumer electronics products. Printed circuit board (PCB) and very-largescale integration (VLSI) circuit designing requires optimization of the electronic components placement and wire routing to connect the components. Currently, circuit routing processes have been performed manually by experts, which greatly increases the cost of human resources and time. Such heuristic circuit designs are not optimized and may have errors, which is why automated circuit routing algorithms are important. However, it is difficult to obtain an optimal solution in circuit routing as it is an NPhard problem. In addition, poor circuit routing increases the wire length of the circuit, which causes an increase in circuit cost and weight as well as performance degradation. In order to achieve routing optimization, many technologies have been proposed, in which some have applied artificial intelligence (AI) to improve the overall performance and reduce the designing time. Accordingly, in this paper, routing problems in PCB and VLSI are explained, and proposed technologies to solve these routing problems are introduced. Especially, a detailed investigation and analysis of AI technologies grafted into circuit routing algorithms are explained, and the considerations for AI-based routing algorithms are presented.

Design and Verification of Parallelogram Mechanism With Geared Unit Rolling Joints for Reliable Wiring

The structure of 1-DOF joints used in existing robots is generally a revolute or a prismatic joint. However, recently, attempts have been made to apply rolling joints to reduce the size and weight of surgical and humanoid robots. In this study, to take advantages of wire routing through robot joints, a new method for applying geared rolling units to a parallelogram mechanism is proposed. First, a kinematic analysis of the proposed gear-based mechanism is explained in comparison with the existing pivot-based mechanism. In addition, the importance of the radii of the gears is verified through force analysis to prevent damage to the applied gears, as well as through the analysis of actuation torque and singular positions, in which the parallelogram can convert into an antiparallelogram. The effect of stable wiring was verified through an experiment using a cable-driven prototype. Consequently, the proposed parallelogram mechanism composed of rolling units is expected to be applied to various robot configurations owing to its advantages.

Flexible ureteroscope capable of acute-angled and balanced omnidirectional bending based on soft and flexible porous tube and crossed control wiring.

Flexible ureteroscopes (fURSs) have performance limitations in accessing acute-angled calyxes and omnidirectional bending. We propose and develop a fURS based on a soft and flexible porous tube and crossed control wiring to overcome these limitations. The fURS prototype comprises a flexible solid polyamide-12 tube and a stretch-retractable expanded polytetrafluoroethylene distal tube with 40% porosity connected by a unique cylindrical wire-routing hook (CWH). The series tube includes four crossed but not contacting loop-formed control wires to provide balanced omnidirectional bending and optimized distal tube bending performance. Bending performance was assessed compared with a conventional fURS, and feasibility studies were performed using a renal phantom. The prototype achieved a 275° omnidirectional maximum bend angle by combining up-down and right-left directions. The bent shape was more compact than the conventional fURS. Thus, the prototype achieved approximately a 1.6-fold larger maximal active bending angle within the restricted environment and a 5.5-fold larger passive bending angle. The crossed control wiring design reduced CWH offset distance by about 75% compared with conventional straight wire routing. The prototype exhibited considerably improved steering performance, exemplified by its ability to access an acutely angled calyx. Our design could improve treatment outcomes and shorten operation times associated with calyceal stone removal.

Steerable catheter based on wire-driven seamless artificial blood vessel tube for endoscopic retrograde transpapillary interventions.

Current steerable catheters (SCs) for endoscopic retrograde cholangiopancreatography (ERCP) have performance limitations caused by an asymmetric multiple-slit tube design with a small maximum bend angle, lesser curvatures, and insufficient durability. We propose a wire-driven SC for balanced bidirectional bending using artificial blood vessel material to overcome these limitations. We assess the SC prototype's steerability using phantom and animal models. The SC prototype employed a slit-less and multiple-lumen seamless tube with a polytetrafluoroethylene (PTFE) body with stretch-retractable porous expanded PTFE at the distal end, and loop-formed control wires. We evaluated the wire routing design using a static model. The bending performance was compared with conventional SCs. Feasibility studies were performed, including major duodenal papilla insertions and ductal branch selections in desktop phantoms and a mini-pig model. The proposed design reduced the wire contact force by 48% compared to the single wire configuration. The maximum bend angle was 162°, almost twofold larger than that for conventional SCs. The lateral tip position in the bent shape was maximally 56% smaller. The tip flexibility was comparable to conventional SCs, and the insertion resistance was similar to the passive catheters. Phantom studies showed that the SC prototype could perform the large and protuberant papilla insertions and fine ductal branch selections without breaking; the animal study was completed successfully. We propose a wire-driven SC design for ERCP using a multi-lumen seamless tube and two loop-formed control wires, different from the conventional SC design with a multiple-slit tube and single control wire. The SC prototype records balanced bidirectional bending with a maximum bending angle of ± 162° without breakage risk. The phantom and animal studies show that the prototype performance potentially facilitates papilla cannulations and intrahepatic ductal branch seeking.

Design of Routing of In-Vessel Diagnostic Signals for RFXmod2

Reversed Field eXperiment modified 2 (RFXmod2) is the upgraded version of the experiment RFXmod, a toroidal fusion device that can be operated both as a Reversed Field Pinch and as a Tokamak. This experiment is hosted by Consorzio RFX, Padua, Italy, and has a major radius <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$R=2$ </tex-math></inline-formula> m and a minor radius <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$a=0.5$ </tex-math></inline-formula> m. The upgrade of the previous machine consists mainly on a larger vacuum vessel and a more efficient active and passive plasma control system. Another important improvement involves the already wide set of in-vessel diagnostics, which includes now a large variety of sensors: electrostatic (single-pin, five-pin, 12-pin, ball pen), magnetic (flux loops, pick-up coils, saddle probes, halo shunts), mechanical (strain gauges), and thermal (thermocouples), for a total of about 5000 signals. The technological relevance of RFXmod2 is related indeed to the development of advanced plasma diagnostics and control systems. This work is focused on the integration of all the in-vessel diagnostics, especially from the point of view of electromagnetic compatibility and wire routing. In fact, the presence of several different families of sensors, having considerable differences in voltage and current output, together with the limited space in which those signal have to be routed, poses a challenging problem of electromagnetic compatibility. To solve this problem, the non-compatibilities between different types of signals were identified, and a series of criteria were drawn to design the cable routing of the whole machine. A preliminary and schematic routing map was developed, then a specific cable tray was designed and tested on a mock-up. This article describes all the activities related to the design of the wiring harness for the in-vessel diagnostics for RFXmod2: the signal classification, the electromagnetic compatibility problem, and the design of wire routing and cable trays.

A Novel Plane‐Based Control Bus Design with Distributed Registers in 3D NAND Flash Memories

This work presents a novel plane-based area-saving control bus design with distributed registers in 3D NAND flash memory. 99.47% control signal routing wires are reduced compared to the conventional control circuit design. Independent multi-plane read is compatible with the existing read operations thanks to the register addresses are reasonably assigned. Furthermore, power-saving register group address-based plane gating scheme is proposed which saves about 2.9 mW bus toggling power. A four-plane control bus design with 20K-bits registers has been demonstrated in field programmable gate array tester. The results show that the plane-based control bus design is beneficial to high-performance 3D NAND flash memory design.

Measuring the effect of track count and wire segment length on the layout area of switch blocks for tile-based FPGAs

Switch block flexibility is an important design metric in FPGA architectural research. A switch block with high flexibility can provide better routability for implementing digital applications, which can lead to better performance and logic density. Flexibility, however, does come at the cost of an increase in the layout area of switch blocks, which can lower performance and logic density. Consequently, it is important to accurately estimate the layout area of increasing switch block flexibility in order to better design FPGA architectures. This work focuses on the popular disjoint switch block design and evaluates the accuracy of the traditional active-based area estimation models based on realistic layouts. We found that the current active-based area models are inaccurate in estimating the true area cost of increasing switch block flexibility. This inaccuracy is due to the inability of the current models to consider the full effect of routing track count and wire segment length, two important flexibility parameters, on the layout area of switch blocks. We found that by including wiring area into the estimation of FPGA switch block layout area, one can significantly improve the accuracy of predicting the true area cost of these flexibility parameters. These results allow FPGA architects to better optimize future FPGA designs for routability and consequently for performance and logic density.

Selective Patterning of Conductive Elastomers Embedded With Silver Powders and Carbon Nanotubes for Stretchable Electronics

Stretchable electronics are becoming popular due to their high adaptability to various environments and durability against external forces. We propose a method of designing and fabricating stretchable electronics using a multi-material conductive elastomer structure embedded with silver (Ag) powders and carbon nanotubes (CNTs). While the Ag-based polymer is used for highly conductive electrical connections, such as electrodes and signal wires, the CNTs-based polymer can be formed to be electrical components, such as resistors and sensors, due to the relatively high resistivity. Stretchable electronics composed of different types of conductive polymers have several advantages, such as noise reduction by separating signal wires from sensing components, target-specific sensing with free wire routing, and construction of fully stretchable electronics with various passive elements. In this paper, we describe the design and the fabrication of the proposed stretchable electronics with experimental characterization on the performance. We also demonstrate applications that take advantage of the proposed method, including a wearable strain sensor, an array of soft strain gauges with a rosette configuration, and a fully stretchable circuit composed of soft components, such as resistors, capacitors, and inductors. All the application devices are fabricated only by simple laser cutting.

Routing Density Analysis of Area-Efficient Ring Oscillator Physically Unclonable Functions

The research into ring oscillator physically unclonable functions (RO-PUF) continues to expand due to its simple structure, ease of generating responses, and its promises of primitive security. However, a substantial study has yet to be carried out in developing designs of the FPGA-based RO-PUF, which effectively balances performance and area efficiency. This work proposes a modified RO-PUF where the ring oscillators are connected directly to the counters. The proposed RO-PUF requires fewer RO than the conventional structure since this work utilizes the direct pulse count method. This work aims to seek the ideal routing density of ROs to improve uniqueness. For this purpose, five logic arrangements of a wide range of routing densities of ROs were tested. Upon implementation onto the FPGA chip, the routing density of ROs are varied significantly in terms of wire utilization (higher than 25%) and routing hotspots (higher than 80%). The best uniqueness attained was 52.71%, while the highest reliability was 99.51%. This study improves the uniqueness by 2% subsequent to the application of scenarios to consider ROs with a narrow range of routing density. The best range of wire utilization and routing hotspots of individual RO in this work is 3–5% and 20–50%, respectively. The performance metrics (uniqueness and reliability) of the proposed RO-PUF are much better than existing works using a similar FPGA platform (Altera), and it is as good as the recent RO-PUFs realized on Xilinx. Additionally, this work estimates the minimum runtimes to reduce error and response bit-flip of RO-PUF.

Double Proton Transfer during a Novel Tertiary α-Ketol Rearrangement in Ketol-Acid Reductoisomerase: A Water-Mediated, Metal-Catalyzed, Base-Induced Mechanism.

(KARI) catalyzes the conversion of (S)-2-acetolactate or (S)-2-aceto-2-hydroxybutyrate to 2,3-dihydroxy-3-alkylbutyrate, the second step in the biosynthesis of branched chain amino acids (BCAAs). Because the BCAA biosynthetic pathway is present in bacteria, plants, and fungi, but absent in animals, it is an excellent target for the development of new-generation antibiotics and herbicides. Nevertheless, the mechanism of the KARI-catalyzed reaction has not yet been fully solved. In this study, we used iterative molecular dynamics (MD) flexible fitting-Rosetta techniques to optimize the three-dimensional solution structure of archaea KARI from Sulfolobus solfataricus (Sso-KARI) determined from cryo-electron microscopy. On the basis of the structure of the Sso-KARI/2Mg2+/NADH/(S)-2-acetolactate complex, we deciphered the catalytic mechanism of the KARI-mediated reaction through hybrid quantum mechanics/molecular mechanics MD simulations in conjunction with umbrella sampling. With an activation energy of only 6.06 kcal/mol, a water-mediated, metal-catalyzed, base-induced (WMMCBI) mechanism was preferred for deprotonation of the tertiary OH group of (S)-2-acetolactate in Sso-KARI. The WMMCBI mechanism for double proton transfer occurred within a proton wire route with two steps involving the formation of hydroxide: (i) Glu233 served as a general base to deprotonate the Mg2+-bound water, forming a hydroxide-coordinated Mg2+ ion; (ii) this hydroxide ion acted as a strong base that rapidly deprotonated the ternary OH group of the substrate. In contrast, the direct deprotonation of the substrate by Glu233 was kinetically unfavorable. This mechanism suggests a novel approach for designing catalysts for deprotonation and provides clues for the development of new-generation antibiotics and herbicides.

10.3: A Fast Method for Equalizing Resistance in Touch Panel Design

In the field of special‐shaped panel design, TP (touch panel) design engineers need to manually complete the wiring routing work between the driven IC port and the TP pad port. Due to the routing channel is not regular, the equal line width method is usually adopted. Complete the routing in the channel in advance, and then adjust the routing line width to reduce the resistance discrepancy manually. As the resistance difference between the shortest and longest wire is relatively large, it is very extremely complicated for engineers to manually modify the line width to reach equal resistance for all the routing wires. At the same time, because the routing channel is often limited to a certain area, when adjusting one wire, the other wires will be affected. In order to achieve the purpose of automatic routing, we designed a routing method that distributes the line width in a limited area automatically, plus a method of superimposing serpentine wiring in the specified area to achieve the overall wiring resistance balance. In the paper, we referred to the idea of channel routing, first split the routing channel, and then routed in the split channel, and then connected the same net wiring in the channel, and adjusted the split channel according to the requirements of resistance. In the process of adjusting the resistance, the strategy of the simulated annealing algorithm is deployed to search the optimum routing result.

DNA-Helix Inspired Wire Routing in Cylindrical Structures and Its Application to Flexible Surgical Devices.

In general wire-driven continuum robot mechanisms, the wires are used to control the motion of the devices attached at the distal end. The slack and taut wire is one of the challenging issues to solve in flexible mechanism. This phenomenon becomes worse when the continuum robot is inserted into the natural orifices of the human body, which inherently have uncertain curvilinear geometries consisting of multiple curvatures. Inspired by the unique characteristic of DNA-helix structure that the length of the helix remains almost constant regardless of the deflection of the DNA structure, this article proposes a new idea to design useful flexible mechanism to resolve slack of wires. Using modern Lie-group screw theory, the analytic model for length of helix wire wrapped around a single flexible backbone is proposed and then extended to a general model with multiple flexible backbones and different curvatures. Taking advantage of this helix type wire mechanism, we designed and implemented a flexible surgical device suitable for laryngopharyngeal surgery. The effectiveness of the proposed flexible mechanism is demonstrated through both simulation and phantom experiment.

Simulation installation space of the vehicle to solve the problems of component layout, electrical wiring and wire routing

The presented work is devoted to modeling the mounting space of a vehicle onboard electrical equipment complexes for solving the problems of assembling elements, wiring of electrical circuits and routing of wires. A model of the mounting space of the onboard electrical equipment complex has been developed. Various modifications of on-board electrical equipment of modern vehicles under various restrictions are considered and investigated.