Novel Rail Clamp Architectures and Their Systematic Design

abstract: Rail clamp circuits are widely used for electrostatic discharge (ESD) protection in semiconductor products today. A step-by-step design procedure for the traditional RC and single-inverter-based rail clamp circuit and the design, simulation, implementation, and operation of two novel rail clamp circuits are described for use in the ESD protection of complementary metal-oxide-semiconductor (CMOS) circuits. The step-by-step design procedure for the traditional circuit is technology-node independent, can be fully automated, and aims to achieve a minimal area design that meets specified leakage and ESD specifications under all valid process, voltage, and temperature (PVT) conditions. The first novel rail clamp circuit presented employs a comparator inside the traditional circuit to reduce the value of the time constant needed. The second circuit uses a dynamic time constant approach in which the value of the time constant is dynamically adjusted after the clamp is triggered. Important metrics for the two new circuits such as ESD performance, latch-on immunity, clamp recovery time, supply noise immunity, fastest power-on time supported, and area are evaluated over an industry-standard PVT space using SPICE simulations and measurements on a fabricated 40 nm test chip.Dissertation/ThesisDoctoral Dissertation Electrical Engineering 201

Investigation of Novel Displacement-Controlled Hydraulic Architectures for Railway Construction and Maintenance Machines

This dissertation aims at showing how to transform hydraulic systems of railway multi-actuator machinery characterized by inefficient state-of-the-art systems into the 21st Century. Designing machines that are highly efficient, productive, reliable, and cost affordable represents the target of this research. In this regard, migrating from valve-controlled architectures to displacement-controlled layouts is the proper answer. Displacement-controlled systems remove the losses generated by flow throttling typical of conventional circuits, allow an easy implementation of energy recovery (e.g. during regenerative braking), and create the possibility for the use of hybrid systems capable of maximizing the downsizing of the combustion engine. One portion of the dissertation focuses on efficient propulsion systems suitable for railway construction and maintenance machines. Two non-hybrid architectures are first proposed, i.e. a novel layout grounded on two independent hydrostatic transmissions (HSTs) and two secondary controlled hydraulic motors (SCHMs) connected in parallel. Three suitable control strategies are developed according to the specific requirements for railway machines and dedicated controllers are implemented. Detailed analyses are conducted via high-fidelity virtual simulations involving accurate modeling of the rail/wheel interface. The performance of the propulsion systems is proven by acceptable velocity tracking, accurate stopping position, achieving regenerative braking, and the expected behavior of the slip coefficients on both axles. Energy efficiency is the main emphasis during representative working cycles, which shows that the independent HSTs are more efficient. They consume 6.6% less energy than the SCHMs working with variable-pressure and 12.8% less energy than the SCHMs controlled with constant-pressure. Additionally, two alternative hybrid propulsion systems are proposed and investigated. These architectures enable a 35% reduction of the baseline machine’s rated engine power without modifying the working hydraulics. Concerning the working hydraulics, the focus is to extend displacement-controlled technology to specific functions on railway construction and maintenance machines. Two specific examples of complete hydraulic circuits for the next generation tamper-liners are proposed. In particular, an innovative approach used to drive displacement-controlled dual function squeeze actuators is presented, implemented, and experimentally validated. This approach combines two functions into a unique actuator, namely squeezing the ballast and vibrating the tamping tools of the work-heads. This results in many advantages, such as variable amplitude and variable frequency of the tamping tools’ vibration, improved reliability of the tamping process, and energy efficient actuation. A motion of the squeeze actuator characterized by a vibration up to 45 Hz, i.e. the frequency used in state-of-the-art systems, is experimentally confirmed. In conclusion, this dissertation demonstrates that displacement-controlled actuation represents the correct solution for next-generation railway construction and maintenance machines

Design and fabrication of a tapped densification apparatus for bulk solids

Experiments are commonly used to ascertain the flow properties of bulk solids. One such property is a measurement quantity known as the tapped density. Here, a container of granular material is subjected to a long sequence of discrete taps, after which the bulk density - the total mass divided by the volume occupied –- is determined. Current technology exists to achieve the maximum tap density by subjecting a container to a user defined number of taps at a specific, predetermined amplitude and frequency. However, the final bulk density is known to be dependent on the tap parameters. It can therefore be beneficial to alter both the frequency and the amplitude during the experimental process to determine what role these two factors contribute to the tap density of a sample. Thus, the topic of this thesis is the design, fabrication and testing of a mechanical system device that allows for finite control of the tap stroke and force, as well as quantitative measurement feedback for the motion of the sample. The first phase of the work consisted of the design and fabrication of a prototype system, which was tested for the proper functioning of the mechanical components. The results of the tests suggested modifications were required. A series of revisions were preformed on the prototype in order to satisfy the updated design requirements. Final tests and calibrations were preformed on the new apparatus and the results are discussed

The effect of autotrawl systems on the performance of a survey trawl

Three aspects of a survey bottom trawl performance—1) trawl geometry (i.e., net spread, door spread, and headrope height); 2) footrope distance off-bottom; and 3) bridle distance off-bottom—were compared among hauls by using either of two autotrawl systems (equal tension and net symmetry) and hauls conducted with towing cables of equal length and locked winches. The effects of environmental conditions, vessel heave, crabbing (i.e., the difference between vessel heading and actual vessel course over ground), and bottom current on trawl performance with three trawling modes were investigated. Means and standard deviations of trawl geometry measures were not significantly different between autotrawl and locked-winch systems. Bottom trawls performed better with either autotrawl system as compared to trawling with locked winches by reducing the variance and increasing the symmetry of the footrope contact with the bottom. The equal tension autotrawl system was most effective in counteracting effects of environmental conditions on footrope bottom contact. Footrope bottom contact was most inf luenced by environmental conditions during tows with locked winches. Both of the autotrawl systems also reduced the variance and increased the symmetry of bridle bottom contact. Autotrawl systems proved to be effective in decreasing the effects of environmental factors on some aspects of trawl performance and, as a result, have the potential to reduce among-haul variance in catchability of survey trawls. Therefore, by incorporating an autotrawl system into standard survey procedures, precision of survey estimates of relative abundanc

Adaptive Adjustable Tricycle

As a part of the Cal Poly Mechanical Engineering curriculum, all students must take part in a three quarter long senior design project. Students are presented with existing problems, select a project, and then apply the knowledge they have gained throughout their academic career to design and build a solution. The intent behind this project is to create an experience that is similar to an engineering project in industry, by applying engineering and teamwork skills to solve a problem. Team Trikeceratops’ mission was to develop an adaptive adjustable tricycle to be used in the Special Education Department of the Buena Park School District for recreational use and physical therapy. The design team was comprised of four Cal Poly mechanical engineering students and a kinesiology student-consultant who worked through three primary design phases over the course of nine months to develop a functional prototype. These phases included ideation and conception, detailed design, and manufacturing, all of which have different requirements that call for a variety of skill sets. During ideation and conception, Team Trikeceratops developed lists of requirements from sponsor input, divided the project into components, generated ideas, and refined the options to reach an overall conceptual design. This initial phase was also essential in developing a team mentality and establishing the basic rules and guidelines by which the team would operate. At the end of ideation and conception, the team had developed a full theoretical design that would meet the customer requirements. Detailed design was the second phase wherein the students took the conceptual design and applied engineering knowledge to clearly define the solution. In this phase, most of the more stereotypical engineering occurred. Students sized tubing for the frame, performed calculations and analysis on components, created manufacturing drawings, identified part numbers for acquisition, and began contacting companies for parts and services. At the end of detailed design, the team had a bill of materials, manufacturing plan, contact information for suppliers, and fully dimensioned drawings for manufacturing custom parts. The third phase of product development was manufacturing and testing. Students cut, notched, welded, and machined various custom components while simultaneously overcoming problems of improper sizing and extended lead times on ordered materials. Following this process, the students tested the tricycle to ensure that it met the customer requirements set forth in the Design Verification Plan and Report (DVPR). At the end of this phase a functioning prototype was completed and staged for delivery and the final report was compiled. This remainder of this report details Team Trikeceratops’ progress from initial concept generation to prototype realization and explores each part of the aforementioned engineering design process in depth

Analytical Approach to Describe Properties in Transition Zones Between Ballasted and Non-Ballasted Track

Norway has for a long time used railways as a means of transport. This method of transportation been used to haul raw materials such as wood and ore. Trains have today become competitors to cars and other means of transportation as a way to commute. However, the tracks used when hauling heavy loads are still being used regardless if the train's goods are commuters or raw materials. Heavy freight trains have a relatively low velocity compared with high-speed trains and because of this, ballasted tracks often used in Norway. The increase in commercial use of train transport has lead to a train-velocity increase and as a result of that, development of non-ballasted tracks have therefore become more favorable. The non-ballasted tracks have a higher stiffness than the ballasted, consequently problems arises when the softer ballasted track transitions over to the stiffer non-ballasted track. Because of the difference in stiffness, will there be a point in the track where the stiffness abruptly changes from one stiffness to another. This will cause damages to the rail, track and train if not dealt with carefully. The railway company Bane NOR have therefore published an interest in the topic of equalizing the stiffness in transition zones. Gaining a deeper understanding of what happens during a transition zone is important so that unnecessary track degradation can be prevented. However, because of the scarcity of information about this particular topic, this thesis could be beneficial to the community. Transition zones are usually designed based upon prior experiences, and the construction of the zones are commonly done by subcontractors. Bane NOR is therefore aspiring to acquire theoretical models that can describe the rail behaviour in transition zones. This master's thesis covers the development of an analytical mathematical model that describes the rail's deflection in both ballasted and non-ballasted tracks. The model takes root in an older theory called "beams on elastic foundation" and the "moving force on a beam" problem. Beams on elastic foundation theory is often used in the railway industry to describe the deflection of rails. Furthermore, the numerical analysis software ANSYS, was utilized to generate an animation of the deflection of the rail beam

Product Insertion Test Fixture

The sponsor has a manufacturing process that requires the insertion of a product into a housing slot. This stage of the assembly has been a source of scrap; however, the primary cause is undetermined. This project outlines the design of a testing fixture to simulate the product insertion process and analyze the effects of misalignment on the success of assembly attempts. A linear servo is used to simulate the tooling approach path. A micrometer-driven XY stage is used to induce an adjustable offset between the housing and tooling in the plane perpendicular to the tooling approach. Sensors are used to align the product and housing slot and to measure the geometric characteristics of the product. The nest and tooling are mounted on modular plates to allow various product lines to be tested

Dyno-Mite Redesign

The Cal Poly Mechanical Control Systems Laboratory currently employs an outdated device, known as the Motomatic, to teach students about various motor characteristics and control methods. These include open-loop vs. closed-loop control, speed vs. position control, and DC motor response curves. The current device does not function properly and produces unreliable data due to overwhelming non-linear effects such as stiction and shaft misalignment. Our team was tasked with designing a replacement device that retains many of the same educational goals as the original lab procedure, while also adding new educational goals pertaining to the device system dynamics. The new apparatus, dubbed the Dyno-Mite is a one tenth scale tire testing machine, incorporating two DC brushed motors, adjustable mechanisms, and load cell measuring devices. The design will also pay special attention to modularity so that future adjustments and modifications can be made to the lab apparatus, allowing for instructors to tailor the machine to meet their specific educational goals

Calibration of the Urbana lidar system

A method for calibrating data obtained by the Urban sodium lidar system is presented. First, an expression relating the number of photocounts originating from a specific altitude range to the soodium concentration is developed. This relation is then simplified by normalizing the sodium photocounts with photocounts originating from the Rayleigh region of the atmosphere. To evaluate the calibration expression, the laser linewidth must be known. Therefore, a method for measuring the laser linewidth using a Fabry-Perot interferometer is given. The laser linewidth was found to be 6 + or - 2.5 pm. Problems due to photomultiplier tube overloading are discussed. Finally, calibrated data is presented. The sodium column abundance exhibits something close to a sinusoidal variation throughout the year with the winter months showing an enhancement of a factor of 5 to 7 over the summer months