bluuebunny/crossref_metadata_2025_split huggingface dataset:
Detection of Real and Virtual Fine Surface Features With a Haptic Interface and Stylus
Authors: West Aaron M. , Cutkosky Mark R. 
Published: March 2022

Abstract
In this paper we discuss the results of displaying fine surface features using a haptic interface. A stylus was connected to a haptic interface and configured so that users could explore real and virtual surfaces using the same apparatus. The surfaces consisted of sinusoidal profiles with amplitudes of 0.01–10 mm and with frequencies of 1–20 cycles over a length of 85 mm. Subjects were asked to explore the surfaces at will and count the number of waves detected. When exploring physical profiles, tests were conducted using a stylus with friction and a “frictionless” stylus with a roller. For comparison, tests were also conducted using the subjects’ fingertips instead of a stylus for physical surface exploration. Our results show that subjects’ perceptions of sinusoidal features on virtual and physical walls are qualitatively similar. At spatial frequencies of 0.24 cycles/mm and greater, the ability of humans to accurately count virtual and physical waves was also similar, despite the limited stiffness and bandwidth of the haptic interface. The results provide insight for the display of fine features such as ridges or grooves on a virtual wall.
Sticking to the Point: A Friction and Adhesion Model for Simulated Surfaces
Authors: Chen Jun , DiMattia Christopher , Taylor Russell M. , Falvo Mike , Thiansathaporn Pichet , Superfine Richard 
Published: March 2022

Abstract
This paper describes the development and current status of our combined physics-based model to simulate friction, compliance and adhesion on surfaces using a haptic interface. We use points on the surface to which a simulated stylus sticks until enough force is exerted to break free. The model is inherently stable at all transitions (to/from kinetic/static friction and adhesion) because the force model does not change between modes of attachment. We also present our earlier, unsatisfactory attempts and the problems they had. We describe an application that uses the model and the physics behind it.
A Novel Mechanical Transmission Applied to Percutaneous Renal Access
Authors: Stoianovici Dan , Cadeddu Jeffrey A. , Demaree Roger D. , Basile Stephen A. , Taylor Russell H. , Whitcomb Louis L. , Kavoussi Louis R. 
Published: March 2022

Abstract
This paper presents a radiological guidance method and robotic system designed to facilitate renal surgical procedures. Combines the guidance procedure normally employed by practicing surgeons with a simple and cost-effective needle injection device. The needle injector exhibits an extremely low radiological profile while providing actuated needle motion. The system can be easily utilized by urologic surgeons and can be readily adaptable to any operating room.
Dynamic Control of a Four-Axis, Electrohydraulic Knee Simulator
Authors: Maletsky Lorin P. , Hillberry Ben M. 
Published: March 2022

Abstract
Joint simulators have been used frequently to generate meaningful data on prosthetic wear, bone kinematics, and ligament function. The complex and high loads associated with the knee joint have prompted the development of a wide variety of knee simulators. A four-axis knee simulator was developed at Purdue University that simulates the tibio-femoral and patello-femoral forces by four externally applied loads at the hip and ankle at the hip and ankle. The Purdue Knee Simulator has repeatedly demonstrated the ability to generate realistic prosthetic wear and kinematic motions similar to the natural knee. The operation of the Purdue Knee Simulator, the generation of input profiles, and a brief review of some of the research completed utilizing this machine is presented.
Control of a Hopping Apparatus
Authors: Larin Vladimir B. 
Published: March 2022

Abstract
A problem of control of the model of a one-legged hopping apparatus is considered. Relations determining a program mode of movement are received. The problem of synthesis of system of stabilization is reduced to periodic linear quadratic problem. Example of synthesis of control system of hopping apparatus are considered and the results of simulation of starting processes of these apparatus are presented.
Performance-Based Selection of PD Control Gains for Servo Systems With Actuator Saturation
Authors: Goldfarb Michael , Sirithanapipat Taweedej 
Published: March 2022

Abstract
Servo-control is a common control problem that typically involves a system characterized by torque input and angular position output. A direct-drive robot, for example, is a coupled and typically nonlinear servo-control problem. One means of closed-loop control of a servo-system is proportional-derivative (PD) control. PD control is passive in character and thus stable, and since it can be easily implemented in analog form, the stability is not compromised by computational time delays. A significant issue in implementing PD control on a servo-system is the selection of the control gains. Linearizing a nonlinear servo-system and utilizing linear analysis methods suggests best performance is achieved at maximum possible gain. Maximum gain, however, drives the actuators into saturation, which renders the system nonlinear and the linear analysis invalid. This paper investigates the effect of actuator saturation on servo-system tracking performance by formulating a frequency-based equivalent to the linear system -3dB bandwidth. The proposed method utilizes a series of band-limited pseudo-random tracking inputs to characterize the “bandwidth” of a nonlinear system. Numerical analysis based on this method shows that, for a servo-system that exhibits actuator saturation, the optimal tracking performance is not achieved at maximum gain. Instead, performance improves up to a given gain, then begins to recede as the gain is increased further. The analysis also shows that avoiding actuator saturation to ensure linear behavior significantly sacrifices system performance. The performance characterization scheme is illustrated by an example of a servo system with actuator saturation. The methodology is also compared with linear analysis techniques, and the two shown to be well-correlated for a linear system.
Adaptive, Backstepping Control of a Magnetically Levitated System
Authors: Green Scott A. , Craig Kevin C. 
Published: March 2022

Abstract
This paper presents an evaluation of the adaptive, backstepping control technique applied to a single-degree-of-freedom, magnetic levitation system. Comparisons are made between a linear compensator and a backstepping compensator for step changes in the commanded position of levitation. Performance is evaluated based upon percent overshoot, settling time, steady-state error, and robustness to variations in levitated mass. The adaptive, backstepping compensator is found to achieve superior performance over the linear compensator when subjected to variations in both levitated mass and commanded position. By investigating the performance of this emerging technique known as backstepping under these inherently nonlinear conditions, it is intended to determine the feasibility and capabilities of this approach for practical applications to magnetic levitation systems.
Control of a Class of Nonlinear Systems Subject to Periodic Exogenous Signals
Authors: Alleyne Andrew G. 
Published: March 2022

Abstract
This paper examines the control of Single-Input, Single-Output Feedback Linearizable nonlinear systems that are either (i) subject to periodic disturbances or (ii) tracking periodic reference trajectories. The key concept is the straightforward combination of well known Differential Geometric techniques with the Internal Model Principle resulting in a nonlinear repetitive control strategy. A formulation is presented for the case of Input-State Linearizable and Input-Output Linearizable systems in continuous time. The potential benefits of the nonlinear repetitive controller are given. It is shown that while the standard nonlinear control techniques can be made robust to known disturbances, the nonlinear repetitive technique has desireable charateristics in that it does not require knowledge of the disturbance magnitude and does not need an increased loop gain to accomplish robustness. The procedure is applied to a numerical simulation example with the resulting benefits being clearly shown.
The Design of Quality Engineered Control Systems
Authors: Nwokah O. D. I. , Happawana Gemunu S. , Afolabi Daré 
Published: March 2022

Abstract
Every optimization based engineering design produces a quality metric which as a function of the tolerance parameters, is structurally stable but not generic. This can lead to a severe loss of performance (catastrophes) under a smooth change in the tolerance parameters. This paper gives an exposition of how norm based optimal control methods naturally lead to performance catastrophes, as well as an alternative systematic loop shaping design methodology which corrects the problem.
Modeling and Error Analysis for Assessing Spindle Radial Error Motions
Authors: Tu Jay F. , Bossmanns Bernd , Hung Spring C. C. 
Published: March 2022

Abstract
The rotating accuracy of a machine tool spindle directly affects the roundness of machined parts. Commonly, a precision arbor and one or two probes are used to inspect the spindle axis error motion. When a reference precision arbor is not available or when the spindle error motion is in the same order of magnitude as the accuracy of the reference arbor, it is imperative to separate the roundness error of the reference arbor from the spindle error. One of the most widely used method is the three-probe method. This paper presents an exact model and in-depth error analysis for the conventional three-probe method. The results show that contrary to conventional wisdom that a precise arbor is not needed with the three-probe method, the arbor accuracy should be at least ten times better than that of the axis motion. To reduce inaccuracy in the converted axis motion and arbor contour, it is also suggested that the mounting error of the probes should be less than one-fiftieth of the size of the axis motion and the arbor size. The exact geometric model developed in this paper can also be extended to analyze the precision aspect of other methods.
Adaptive Controller for a Centerless Grinding Process
Authors: Kurfess Thomas R. , Yim Sungshik 
Published: March 2022

Abstract
This work proposes an approach using a Kalman filter and an adaptive controller to control the product size in centerless grinding. Plant parameters are estimated in real time by a weighted recursive least squares technique. The Kalman filter receives these parameters, along with the current input and output signals of the plant, to estimate the main trend of the plant output signal. An adaptive controller uses this information and the estimated main trend signal to generate a control signal. However, this linear control signal cannot be directly used to control the product size in a grinding process because of plant nonlinearities. Thus, the linear control signal is converted to the appropriate compensation signal used by the machine tool.
The Role of Electric-Current Induced Heating in Damage Evolution at the Crack Tip in Thin Film Conductors
Authors: Bastawros Ashraf -F. , Kim Kyung -S. 
Published: March 2022

Abstract
The time-dependent temperature distribution induced by electric-current heating in a double edge-cracked, unpassivated thin aluminum or gold film interconnect lines is monitored using a high-resolution infrared imaging system. A pure aluminum or gold film of 0.2 micron thickness is deposited by high-vacuum evaporation coating and patterned into test structures of varying widths. The operative mechanisms of mass transport are assessed in view of the monitored temperature profile. The pre-cracked aluminum film showed fine crack growth toward the positive electrode, which originated from the initial crack tips. The crack-tip temperature was close to melting, during propagation. A hot spot was formed afterward between the two elongated cracks and led to failure. The crack growth generated a backward mass flow toward the negative electrode. The gold film showed a different pattern where the original cracks propagated toward each other with a slight tilt toward the negative electrode. The tip temperature was lower than the melting temperature.
Penetration Performance of the Train of Solid and Hollow Disks
Authors: Lee M. 
Published: March 2022

Abstract
The penetration performance of homogeneous disk (μ = 0) and thick walled disk (μ &lt; 0.5) projectiles are investigated numerically for length-to-diameter ratio (L/D) of 1/8 and 1/4, where μ is the ratio of inner to outer diameter of a disk. Penetrations of tungsten alloy projectiles up to 4 successive solid disks (SD) and hollow disks (HD) with spacing of 1.5, 2 and 3 diameters into rolled homogeneous armor (RHA) at 2.6 km/s were simulated with a finite difference nonlinear wave propagation program. The most obvious results from the calculations are that even at 2.6 km/s the total penetration of a 4-segmented projectile can not be obtained simply be multiplying the depth of a single disk by four, especially for L/D = 1/8. Although HD may be more efficient, in terms of mass, than SD of equal outer diameter, it is observed that precursor or jet interacts with a train of spaced HD. This interaction significantly reduces the penetration performance, which was also measured in the long tubular projectiles. The degradation in total penetration becomes worse as μ increases. For HD of L/D = 1/4 case, the degradation in penetration becomes less since the effect of the interaction of jet with successive disks is relatively small.
The Influence of Material Damping on Flexural Vibration of Thick Cylinders
Authors: Hamidzadeh Hamid R. , Afolabi Dare 
Published: March 2022

Abstract
Harmonic vibrations of thick visco-elastic, infinitely long, circular cylinders subjected to boundary stresses are investigated. The cylinder is assumed to be homogeneous, isotropic, and linearly visco-elastic. The inelastic behavior of some metallic materials leads to dissipation of energy in the medium. The governing equation of motion is developed using modified theory of elastodynamics. The material damping is allowed using complex elastic moduli for the medium. Frequency responses for radial, tangential and axial displacements, as well as stresses at any location, are formulated using potential functions. The responses are computed for different circumferential and axial wave numbers for a given ratio of thickness to radius of the cylinder. The frequency range is extended to include five normalized resonant frequencies. The resonant frequency and loss factor for each mode are extracted using a circle-fit procedure in conjunction with finite difference analysis. The resonant frequency is deduced by estimating a maximum rate of sweep on the circle-fit and the loss factor is determined using selected data points on both sides of the resonance. Computation is performed to determine the effect of material loss factor on the overall damping effectiveness for the structure. Analysis was conducted by estimating resonant frequencies and modal loss factors for several circumferential and thickness to wavelength numbers.
An Investigation of the Effects of Multiple Parameters on the Fatigue Crack Growth Behavior of Ti-6Al-4V
Authors: Foster Michael , Soboyejo Alfred , Katsube Noriko , Dubey Sharmistha , Soboyejo Wolé 
Published: March 2022

Abstract
The effects of specimen thickness and positive stress ratio on the fatigue crack growth behavior of Ti-6Al-4V are discussed in this paper. Fatigue crack growth rates are shown to increase with increasing stress ratio. Stress ratio is shown to have a strong effect on fatigue crack growth behavior. However, for the range of specimen thicknesses examined in this study, the fatigue crack growth rates are shown to not be strongly affected by specimen thickness. A single intrinsic fatigue crack growth rate curve is obtained when the fatigue crack growth rates are plotted against the effective (closure-corrected) stress intensity factor range. Multiparameter extensions to the Paris law are also presented for the combined assessment of the effects of specimen thickness, stress ratio, and crack closure on the fatigue crack growth behavior of Ti-6Al-4V.
On the Performance vs. Energy Consumption Tradeoff With Semi-Active Vibration Control Using an MR-Fluid Damper
Authors: Lee Jin Kyoo , Clark William W. , Kim Sung Hwan 
Published: March 2022

Abstract
This paper discusses the issue of seeking reduced energy requirements of a magnetorheological (MR) fluid damper for vibration control through semi-active methods, without suffering unacceptable losses in performance. An experimental study is presented in which an MR fluid damper is used to suppress vibrations in a simply-supported beam under harmonic excitation. Two semi-active control approaches are compared to the “fully-on” control situation. The results show that the MR damper can be activated only for part of the vibration cycle and still provide significant vibration suppression.
Actuator Bearing Greases: Their Effect on Aerosol Contamination in Disk Drives
Authors: Prater Walter , Stone Garvin 
Published: March 2022

Abstract
Head stiction problems have driven the search for new actuator bearing greases. It is well known in the industry that heads gradually accumulate e organic products which lead to stiction seizures after the heads have landed on the disks.
Actuator pivot bearings were lubricated by the test greases. Three grease types were tested: 1) mineral oil with a polyurea thickener, 2) polyolester oil with a polyurea thickener, and 3) perfluorinated polyether oil with a polytetrafluorethelyne thickener.
Airborne particle count tests were performed on five files each to assess the grease effect on disk drive contamination levels. Particle counts for sizes 0.2, 0.5 and 1.0 micron were taken from accessing files. Differences in the generation rate of aerosolized grease were measured when the files were new and also after having been exercised 10, 20 and 60 million seeks. Cascade impaction of disk drive’s air stream was analyzed by time of flight secondary ion mass spectroscopy to confirm that the aerosol particles captured were from the grease.
Files built with the perfluorinated polyether oil based grease had the lowest particle count. Files built with bearings lubricated by the mineral oil based grease had a moderate particle count. Files containing the polyol ester oil based grease had the highest particle count.
Pivot Friction Compensation Using an Accelerometer and a Disturbance Observer for Hard Disk Drives
Authors: Ishikawa Jun , Tomizuka Masayoshi 
Published: March 2022

Abstract
This paper considers a pivot friction compensator using the combination of an accelerometer and a disturbance observer. Noting that the pivot friction torque is approximately the difference between the scaled voice coil motor (VCM) current and the scaled carriage angular acceleration, a disturbance observer to estimate the pivot friction torque can be constructed using the above two signals. By feeding back the friction estimate into a VCM amplifier, the dynamics between the VCM current and the carriage angular acceleration are linearized to be a constant gain within an observer bandwidth. This allows the design to assume that the plant dynamics are fixed in the subsequent stage of the controller design, for example, the design of model-based controllers. The disturbance observer is designed using stochastic estimation theory. Furthermore, because the two signals are both measured continuously, the disturbance observer can be implemented experimentally as an analog system. This enlarges the observer bandwidth and the effect of the friction compensation, and reduces the reliance on the lower sampling rate of the positioning loop. To show the validity of the proposed method, experiments were conducted using a 3-1/2 inch disk drive. It has been shown that the mechanical nonlinearity, i.e., the gain reduction and the variation in the dynamics resulting from the pivot friction can be eliminated. The loop gain reduction resulting from the variation in the VCM current-to-torque constant can be recovered to be a nominal value up to 500Hz.
Effect of Suspension Nonlinearities on Rail Vehicle Bifurcation and Stability
Authors: Ahmadian Mehdi , Yang Shaopu 
Published: March 2022

Abstract
The effect of yaw damping nonlinearities on the hunting behavior of rail vehicles is studied, using a model for a two-axle truck (bogie) that includes the dynamics of the wheelsets and the truck frame. This study is intended to complement earlier studies by True et al. where they investigated the effect of nonlinearities stemming from creep-creep force saturation and wheel/rail contact forces. The simulation results show that yaw damping can have a mixed effect on the hunting critical speed. In some ranges, increasing damping can actually lower the critical speed, unlike the results commonly obtained from a linear model.
Heat Transfer in Laminar Channel Flow With a Non-Uniform Porous Media
Authors: Huang X. Y. , Qin W. , Liu C. Y. , Toh K. C. 
Published: March 2022

Abstract
This paper presents a numerical study on heat transfer by laminar flows in a two-dimensional channel. The channel is filled with a porous material which is assumed to be non-uniform across the channel, especially near the channel walls where the permeability of the porous material increases drastically to simulate the complexity at the interface between the porous media and the solid walls. Degrees of the non-uniformity of the porous material are described in this study by a parameter β. Heat sources, either constant temperature or constant heat flux, are located on the channel walls, so that heat transfer from the sources into the channel flow is greatly affected by the condition at the wall-porous media interfaces. The temperature distribution near the heat source region and the Nusselt numbers are calculated for different β values. The sensitivity of the non-uniformity of the porous media near the channel walls on the overall heat transfer is assessed. It is found that a higher non-uniformity of the porous material near the channel wall can actually enhance the heat transfer from the sources to the channel flow, as the flow velocity near the wall has been significantly increased due to the higher permeability of the porous material in the near-wall region.
An Implementation of Concurrent Engineering Concept to Injection Molding
Authors: Wang K. K. 
Published: March 2022

Abstract
Injection molding is known to be the most effective process for producing discrete plastic parts of complex shape to the highest precision at low cost. The concept of Concurrent Engineering (CE) is also recognized to be the way to accomplish the highest performance in a manufacturing enterprise. This paper presents a proposed plan to implement the CE concept to injection molding. IMS (Integrated Molding System) is a new initiative launched at CIMP (Cornell Injection Molding Program) to achieve this goal. The paper reviews the state-of-the-art in all three major functional components in injection molding, i.e. part design, mold design and manufacturing, and process control. Some preliminary results in optimization are presented and discussed in the paper.