bluuebunny/crossref_metadata_2025 huggingface dataset:
In Situ Thermal Measurements for Estimaton of Relative Metabolic Utilization in Skeletal Muscle
Authors: Gustafson Kenneth J. , Reichenbach Steven H.
Published: January 2022

A variety of systems to drive cardiac assist devices with power from skeletal muscle have been proposed and are under development. The power available from a fixed mass of muscle is metabolically limited and maximizing sustained power is required for the successful application of such devices. The purpose of this study is to develop an approach that can yield relative metabolic utilization measures from single contractions of whole muscle used for cardiac assistance. Similar to classical muscle energetic studies, myothermic methods were employed in which muscle temperature was measured with a fast responding thermister and an infrared radiation thremopile transducer. In a series of tests on rabbit soleus muscle, the relative temperature increases during contractions were recorded. Relative muscle temperature increase was linearly related to the contraction duration. This relationship was incorporated into an existing muscle model to predict the optimum parameters for sustained skeletal muscle power generation.
Senior Design Projects to Aid the Disabled: The University of Toledo Experience
Authors: Hefzy Mohamed Samir , Kramer Steven , Naganathan Nagi , Nemunaitis Gregory
Published: January 2022

This paper describes the experience of the Department of Mechanical, Industrial and Manufacturing Engineering (MIME) at the University of Toledo (UT) during the past five years in supporting its senior students in developing custom designed devices for physically disabled individuals within the Toledo community. The goal of these projects is to assist disabled individuals to enjoy life and to reach toward their maximum potential. These projects significantly enhance the education of student engineers through the experience of designing and building devices to meet a real need with feedback on how well the device satisfies that need.
Model for Predicting Temperature Distribution During Medullary Reaming
Authors: Hekman Edsko E. G. , Nijenbanning Gert , Grootenboer Henk J.
Published: January 2022

Prior to placement of medullary nails the marrow cavity often needs to be reamed to a larger size. Measurements of the (potentially damaging) temperatures reported in literature show substantial variation. This paper describes a mathematical model which predicts a temperature profile throughout the bone cortex.
Doing Less for More: A New Mobile Arm Support
Authors: Landsberger Samuel , Shaperman Julie , Vargas Vicente , Meadows Ernest , Mitani Margaret , McNeal Donald R.
Published: January 2022

Mobile arm supports (MAS) are wheelchair-mounted mechanical linkages designed to support the weight of the arm and facilitate shoulder and arm motions. They enable individuals with flaccid paralysis or paresis of the shoulder and elbow muscles to function independently in many daily tasks. However, problems with commercially available designs have limited their use in spite of their low cost and functional benefits. This project aims to create a new MAS design to address these deficiencies.
A Novel Numerical Formulation for Modeling Tissue Compressibility
Authors: O’Dell W. G. , McCulloch A. D.
Published: January 2022

Nearly all mathematical and computational models of biological tissue impose the constraint that the material remain incompressible during deformation. The incompressibility assumption simplifies the determination of analytic solutions by removing a degree of freedom from the motion. However, many biological tissues, including myocardium, are sufficiently compressible to have enormous effects on the predicted stress equilibrium state[1]. Being able to model the compressibility of living tissue is a major step toward realistic modeling of intact, living tissue.
Comparison of Knee Flexion Angle Using Two Measurement Techniques
Authors: Patterson Rita M. , Buford William L. , Fay James M. , Nelson Carl J. , Ivey F. Marty
Published: January 2022

The motion across human joints is in general three-dimensional. Past researchers have1–4 studied the motion of the tibia with respect to the femur and discussed the application of several 2-D graphical methods to injury diagnosis and fixed axis prosthesis design. Others have studied the six degree of freedom motion of the knee.5,6 Though there are many reports of knee kinematics, most have reported large variations between measurements and conflicting results. The large variation makes it difficult to draw conclusions about normal knee kinematics.
A New Precision 3D Motion Analysis System
Authors: Wang Mei , Zhang Yong-M. , Abell Mike , D’Angelo Gregory L. , Voor Michael J.
Published: January 2022

A new in vitro technique for measuring three-dimensional six-degree-of-freedom motion was developed. The system consists of twenty-four nylon lines activating digital rotary encoders which are mounted on six panels of a rigid frame that surround the testing space. The system is capable of tracking motion of up to four independent bodies in a space of approximately 0.5 × 0.5 × 0.5 meter. By knowing the coordinates of three non-collinear points on the frame and the straight line distances from these points to any point on the moving body, the spatial location of that point can be determined based on simple geometry. The location and orientation of a rigid body can be further calculated from the spatial coordinates of three non-collinear points on the rigid body or its extension. The system has an accuracy of 1% in the vertical direction and 0.7% in the horizontal plane. The system can be used in biomechanical analysis of multi-segment spinal motion and motion of other joints.
Effects of Joint Loading on the Passive Moment at the Ankle
Authors: Amankwah Kofi , Triolo Ronald J. , Kirsch Robert , Zhao Weifeng
Published: January 2022

In this study, the aim was to measure the passive moment at the ankle under different loading conditions. During the experiment, the ankle was rotated at 20 deg/s and the load on the ankle was varied over a 60lb range. The results showed that increasing the joint load affects the amount of hysteresis seen in the moment vs. joint angle relationship. This result suggests that friction within the joint may be more significant than previously thought and therefore that joint loading may be a more important factor during dynamic activities such as gait and in disturbance rejection for static situations such as quiet standing.
Shaft/Shaft-Seal Interaction of a Multiple Disk Centrifugal Blood Pump: A Study of Thermal and Wear Characteristics
Authors: Manning Keefe B. , Miller Gerald E.
Published: January 2022

A multiple disk centrifugal pump (MDCP) is under investigation as a potential left ventricular assist device. As is the case with most shaft driven pumps, leakage problems around the shaft/shaft-seal interface are of major interest. If leakage were to occur during or after implantation, potential events such as blood loss, clotting, blood damage, and/or infections might result in adverse effects for the patient. Because these effects could be quite disastrous, potential shaft and shaft-seal materials have been investigated to determine the most appropriate course to limit these effects.

Teflon and Nylon were analyzed as potential shaft-seal candidates with both a stainless steel shaft and a Melonite® coated shaft, the latter provided by Houston Unlimited Inc. Metal Processing in Chappell Hill, Texas. The materials and shafts were evaluated under time, motor, and outer diameters. Motor speed and geometrical configurations were typical for the MDCP under normal physiologic conditions. The three parameters analyzed were the inner diameter (ID), the inner temperature, and the outer temperature. Statistical comparisons were computed for the shaft seal materials, the shafts, and the outer diameters along with the inner and outer temperatures.
The Application of Biot’s Consolidation Theory to Chromatography Column Gel Collapse
Authors: He Weiwei , Bruley Duane F.
Published: January 2022

Protein C is a vitamin K dependent glycoprotein which is synthesized by the liver [1]. It is the zymogen of a serine protease which acts as an anticoagulant by inhibiting activated factors V and VIII thus enhancing fibrinolysis. An increased risk for the development of venous thrombosis has been attributed to Protein C deficiency[2]. This work is to establish theoretical and experimental relationships for the scale up of Immobilized Metal Affinity Chromatography (IMAC) and Immuno Affinity Chromatography for the low cost production of large quantities of Protein C. Gel matrices for Protein C separation are being analyzed to determine the relationship between the materials properties of the gel and column collapse characteristics.
Design and Material Synergy for High-Performance Actuator Components
Authors: Adley J. , Jones M. , Stole S. , Perettie D. , Fox R.
Published: January 2022

The continuing magnetic disk drive storage industry goals of higher recorded data densities will require increases in tracks per inch (TPI) which will ultimately demand changes in designs/or materials. Rotary actuators represent one application whose configuration and material composition can influence disk drive performance through projected enhancements in tracking accuracy. Ceramic-metal composites allow specific component geometries to be altered to take advantage of the new material properties. This synergistic approach to design and materials allows a much greater improvement to the mechanical performance of actuator components than either material or design substitution alone would allow. This work describes both the fabrication of Aluminum-Boron Carbide reacted metal matrix materials and their practical implementation with specific design strategies developed through numerical models to achieve high performance head/suspension/actuator structure assemblies. Improvements in the overall frequency response behavior of the head support structure are contrasted with equivalent example configurations of conventional materials through simulations which have been experimentally verified.
Implementing Both a Disturbance Observer and a Repetitive Controller for Track Following in a HDD With Emphasis on the Disturbance Observer Design
Authors: Mok Chun-Ho Michael , Bickel Robert J. , Saitoh Mitsuhide , Okuya Hiroaki
Published: January 2022

It is important to provide good tracking for a hard disk drive actuator, since good tracking can allow us to minimize the track pitch and thus increase the data storage capacity of a hard disk drive. Repeatable disturbances, such as disk vibration, and non-repeatable disturbances, such as shocks, are major problems in tracking control of a hard disk drive. It has been shown that a combination of a disturbance observer and a repetitive controller can effectively solve these two problems. In this research, these two controllers are implemented on a real computer hard disk drive, and design of the disturbance observer is emphasized.
Solution of the One Dimensional Foil Bearing Problem Using Matched Asymptotic Expansions
Authors: Renshaw Anthony A.
Published: January 2022

The foil bearing problem describes a longitudinally translating, flexible, tensioned, magnetic tape that rides on a thin film of air as it partially wraps around a stationary recording head. Equilibrium and linear, harmonic vibration analyses of the one dimensional formulation of this problem are performed using matched asymptotic expansions including the effects of tape bending stiffness, compressibility, and molecular slip as regular perturbations. Simple analytic expressions are derived for the nominal film thickness and the vibration frequencies of the free spans. These expressions give designers sharper insight into the usefulness of potential design changes that normally would be evaluated using extensive numerical computations.
Dynamics for Micromachined Silicon Dual Negative Pressure Slider Bearings With an Integrated Microsuspension Mechanism in Proximity Magnetic Recording
Authors: Tagawa Norio , Mori Atsunobu , Kajitani Hiroshi , Hashimoto Masanobu
Published: January 2022

This paper describes head/disk interface dynamics for micromachined silicon dual negative pressure slider bearings with an integrated microsuspension mechanism which we proposed, at steady state flying in proximity magnetic recording. The authors first indicated the analitycal model for air bearing dynamics of dual structure mother ship slider mechanisms, and the advantages of this mechanisms were discussed from the dynamics points of view, compared with conventional flying head slider mechanisms. Furthermore, the effects of stiffness and damping characteristics of an integrated microsuspension mechanism on mother ship slider system dynamics were also analyzed numerically. Considering those numerical simulation results, optimum design method for microsuspension gimbals was established to suppress the coupled vibration between primary and secondary sliders, caused by secondary slider’s piggy-backed structure. It became clear that micromachined integrated microsuspension mechanisms have to be designed not only from the static and silicon micromachined process points of view, but also from the mother ship slider dynamics points of view, in order to achieve head/disk interface reliability in high density proximity magnetic recording.
Optimal Shape Design of Three Dimensional MEMS With Applications to Electrostatic Comb Drives
Authors: Ye Wenjing , Mukherjee Subrata
Published: January 2022

A methodology for solving inverse problems in Micro-electromechanical (MEM) systems is proposed in this paper. Design of variable shape electrostatic comb drives (shape motors), in order to obtain desired force profiles, is presented as an application of the general methodology. This analysis includes simulation, sensitivity analysis and optimization.

A comb drive is one of the most important microactuators in MEM systems. In a standard comb drive, the capacitance varies linearly with displacement, resulting in an electrostatic driving force which is independent of the position of the moving fingers (relative to the fixed ones) except at the ends of the range of travel. It is of interest in some applications to have force profiles such as linear, quadratic or cubic. Such shaped comb drives could be useful, for example, for electrostatic tuning or to get actuators with longer ranges of travel than those of standard comb drives.

The present paper addresses the issues of simulation, sensitivity analysis, and then design (inverse problem) of comb drives with variable height profiles. Three-dimensional simulations of the exterior electrostatic field, and the resultant forces on the comb drive, are carried out with the exterior, indirect, boundary element method. Following direct simulation, sensitivity analysis is carried out by the direct differentiation approach. The variable of interest is the driving force while the design variables are parameters that determine the shape of the moving fingers. Next, an inverse problem is posed as follows: determine the height profile of the moving fingers such that the driving force is a desired function of the displacement of the comb drive. Comb drives of appropriate shapes, that produce desired force profiles, are obtained by this approach. Numerical results are given for shape motors that produce linear or cubic force profiles as functions of travel. The optimization code “E04UCF”, from the NAG package, is used for this phase of the work.
Fatigue Crack Propagation Under Variable-Amplitude Load: Part I — A Deterministic State-Space Model
Authors: Patankar Ravindra , Ray Asok
Published: January 2022

The two-part paper addresses modeling of fatigue crack damage in metallic structures for on-line diagnostics and health monitoring of operating machinery. This paper which is the first part presents a dynamical model of fatigue crack propagation in the deterministic state-space setting based on the crack closure concept under cyclic stress excitation of variable-amplitude loading where the model state variables are crack length and crack opening stress. The second part which is a companion paper extends the deterministic model to formulate a stochastic state-space model of fatigue crack propagation under both constant-amplitude and variable-amplitude load. The state-space model is capable of capturing the effects of stress overload and underload on crack retardation and sequence effects, and the model predictions are in fair agreement with experimental data on the 7075-T6 aluminum alloy. Furthermore, the state-space model recursively computes the crack opening stress via a simple functional relationship and does not require a stacked array of peaks and valleys of stress history for its execution. Therefore, savings in both computation time and memory requirement are significant. As such, the state space model of fatigue crack propagation allows real-time execution of decision algorithms for diagnostics, risk analysis, and life prediction on inexpensive platforms such as a Pentium processor.
Controls Education on the WWW: Using MATLAB for Control Design, Simulation and Visualization
Authors: Tilbury Dawn , Messner William
Published: January 2022

The rapid growth of the World Wide Web (WWW) has given educators unprecedented opportunities to provide information to students not only within their own classes, but also around the world. We are developing software which uses the WWW to distribute tutorials to students studying control systems. These tutorials provide students with information from diverse sources in a useful form when and where they need it. Animations are included so students can simulate the control systems which they design and can visualize their results on a physical system model.
Finger Touch Sensors Using Instrumented Nails and Their Application to Human-Robot Interactive Control
Authors: Mascaro Stephen , Chang Kuo-Wei , Asada H. Harry
Published: January 2022

A new type of touch sensor for detecting contact pressure at human fingertips is presented. Fingernails are instrumented with micro LEDs and photodetectors in order to measure changes in the nail color when the fingers are pressed against a surface. Unlike traditional electronic gloves, in which sensor pads are placed between the fingers and the environment surface, this new sensor allows the fingers to directly contact the environment without being impeded by any object between the finger and the environment. The finger force is detected by measuring changes in the nail color; hence the sensor is mounted on the nail side rather than the finger pad. The technique termed “photoplethysmography” is used for measuring the nail color. A prototype sensor is built and tested, and is used to create a new “free-fingered” electronic glove. The new sensor system is applied to the interface of a cooperative human-robot control system. The information acquired from the finger touch sensors is interpreted within the context of a given task description, and the robot motion is coordinated with the human motion based on the interpreted human behavior. This method is applied to a collaborative task in which a robot equipped with a powered screwdriver assists the human by observing the human hand assembling cable connectors.
Inertial Force Feedback for a Locomotion Interface
Authors: Christensen Robert R. , Hollerbach John M. , Xu Yangming , Meek Sanford G.
Published: January 2022

Inertial force feedback was implemented for a locomotion interface, the Treadport. The purpose was to make locomotion on the Treadport more like locomotion on the ground. The feedback force was applied to the user by a mechanical tether. Psychophysical experiments were performed to determine whether users preferred inertial force feedback to other types of control for the case of accelerating from rest. The results showed that all eleven subjects preferred inertial force feedback when compared to a spring force or no force.
Feeling Through a Probe
Authors: Lederman Susan J. , Klatzky Roberta L.
Published: January 2022

Subjects performed a series of haptic perceptual tasks using rigid probes or the bare finger (control). In Part I, they made roughness judgments of raised-dot textured surfaces using small or large rigid probes or the bare finger. Performance was compared using two different psychophysical tasks: magnitude-estimation (Experiment 1: “how rough?”) and roughness comparison (Experiment 2: “which is rougher?”). In Part II, performance with a small probe versus the bare linger was compared in a haptic object identification task (Experiment 3). In Part III, we discuss the applied implications of this work. Overall, our findings indicate the viability of vibratory-based coding of roughness through a rigid link and have implications for designing haptic interfaces for teleoperator and virtual-environment systems. In contrast, a substantial decline in haptic object identification highlights one limitation of using haptic interfaces that effect single-point contact.

The research reported in this paper is drawn from a comprehensive research program that focuses on feeling the world with a probe, (see also Lederman & Klatzky, 1997; in press; in preparation; Klatzky & Lederman, in press). The work addresses fundamental research on psychophysical issues concerning how human roughness perception and common object identification work when the hand contacts the external world via an intermediary link. Such questions are important to address inasmuch as tool use is such a common aspect of our manual interactions with the world. We also explore the implications of this research for the development of haptic interfaces for teleoperator and VE systems that employ point contact.
Three Degree of Freedom Haptic Interface for Precision Manipulation
Authors: Adelstein B. D. , Gayme D. F. , Ho P. , Kazerooni H.
Published: January 2022

We are developing a new portable force-reflecting haptic interface based on the three degree of freedom (dof) kinematic architecture introduced by Adelstein, Ho, and Kazerooni (1996). This new interface is intended specifically to emulate dynamic manual interaction with precision hand tools and allow single-point probing of simulated mechanical environments.
Haptic Interaction Using Magnetic Levitation
Authors: Berkelman Peter J. , Hollis Ralph L.
Published: January 2022

We have developed a system which uses magnetic levitation for high-fidelity haptic interaction with a physically-based realtime simulated environment. With this device, the user grasps a floating rigid body to interact with the system. The dynamics of the grasped handle are controlled so that the user directly feels the motion, shape, solidity, and texture of objects in the simulated environment as if manipulated using a rigid tool. This is the first magnetic levitation device designed specifically for high-performance haptic user interaction.
Cable-Suspended Haptic Interface
Authors: Williams Robert L.
Published: January 2022

A cable-suspended haptic interface (CSHI) concept is presented. The goal is to create an input/output device to provide six-degree-of-freedom (dof) wrench (force and moment) feedback to a human operator in virtual reality or remote applications. Compared to commercially-available haptic interfaces, the present concept is driving for lighter, safer, crisper, more dexterous, and more economical operation. The CSHI concept is presented, along with the required mathematical transformations for use of the device.
Compliant Micromanipulator Design for Scaled Bilateral Telemanipulation of Small-Scale Environments
Authors: Goldfarb Michael , Speich John E.
Published: January 2022

Compliant mechanism design enables the development of revolute joint manipulators without the backlash or Coulomb friction that impede precision position and especially force control. Conventional approaches to compliant mechanism design impose several limitations, however, such as severely limited ranges of motion, poor kinematic behavior, and significant deformation under multi-axis loading. The authors have developed a new type of compliant mechanism that enables the implementation of spatially-loaded revolute joint manipulators with well-behaved kinematic characteristics and without the backlash and stick-slip behavior that would otherwise impede precision control. The design, which is based upon a unique flexure joint, has been incorporated into a small-scale three degree-of-freedom manipulator with an approximately spherical workspace two centimeters in diameter. Data from the small-scale manipulator demonstrates that positioning resolution is limited by digital quantization and sensor noise, and not by more fundamental physical limitations, such as backlash or Coulomb friction.
Stability and Performance of Haptic Displays: Theory and Experiments
Authors: Adams Richard J. , Moreyra Manuel R. , Hannaford Blake
Published: January 2022

In haptic simulation, a human operator kinesthetically explores a virtual environment. To achieve a virtual sense of touch, the human interacts with an active mechanical device, called a haptic display. This paper presents an approach to guarantee that this physical man-machine interface remains stable, while maximizing performance. The key element in ensuring stability is the virtual coupling network, an artificial link between the haptic display and the virtual environment. Considerations of structural flexibility in the haptic device are included in the derivation of design criteria for such networks. Solutions for both the impedance and admittance models of haptic interaction are included. Numerical and experimental results for a two degree-of-freedom haptic display demonstrate the effectiveness of the proposed approach in achieving performance and stability in haptic simulation.
Minimum Mass for Haptic Display Simulations
Authors: Brown J. Michael , Colgate J. Edward
Published: January 2022

This paper addresses the issue of providing stability guarantees during the implementation of multibody simulations for haptic display. Within the framework of the virtual coupling, we discuss the passivity of the haptic display. Previous work has established that, if the numerical methods used in the virtual environment are discrete time passive, it is possible to decouple the stability of the device from the virtual environment simulation. In the present work, we prove that discrete time passive operators must be implicit, making them unlikely candidates for real time implementation. Given restrictions on environment parameters, however, passivity can sometimes be preserved even when using explicit numerical methods. An important benchmark simulation is that of a point mass, and restrictions take the form of a minimum mass that can be simulated passively. This minimum mass is derived for several simple numerical integrator-virtual coupling pairs.
Effects of Shear Stress in Teletaction and Human Perception
Authors: Moy G. , Fearing R. S.
Published: January 2022

Ideally, a tactile stimulator presents information through control of surface normal stress and surface shear stresses. Psychophysical experiments measured the effect of shear stress information on the perception of static stimuli applied normal to the surface. Wax gratings in two different orientations and various spatial frequencies were used as stimuli. Elastic layers, representing the anti-aliasing filter on a tactile display, were placed over the stimuli. Using an elastic layer which reduces shear stress transmission improved perception compared to standard elastic layers. Spatial resolution differences due to different elastic layers are explained by modulation indices determined from the predicted sub-surface strain using an elastic half-plane model.
Controller Design Using Linear Programming
Authors: Keel L. H. , Bhattacharyya S. P.
Published: January 2022

This paper deals with the problem of designing a feedback controller, of a prescribed order, for a fixed plant, as well as for an uncertain family of plants containing parameter uncertainty, so that stability, robust stability and robust performance are attained. The desired closed loop specifications considered here are given in terms of a target closed loop system. In general point targets are generically unattainable with a fixed order controller. By enlarging the target from a fixed point set to an interval set the solvability conditions with a fixed order controller are relaxed and a solution is enabled. It is shown that it is possible to devise a simple linear programming problem formulation that attempts to meet the desired closed loop specifications. Both transfer function and state space approaches are described. Numerical examples will be given in the presentation.
Utilizing Loop Interaction in Multivariable Regulating Systems
Authors: de Bedout Juan M. , Franchek Matthew A.
Published: January 2022

Presented in this paper is a controller design methodology for a class of square multivariable regulating systems that utilizes loop interaction to achieve output regulation of ill-specified systems. This is accomplished by designing off-diagonal controllers to donate control effort to loops that cannot meet their performance requirements. The class of performance specifications considered are actuator saturation limits and output tolerances. The proposed controller design methodology is a frequency domain approach based on sequential loop closure that incorporates all control elements of previously closed loops into subsequent loop designs. The design of the off-diagonal controllers takes advantage of this recursive technique by isolating the effects of each off-diagonal controller on subsequent loops. The restrictions on the class of multivariable systems are that it must be invertible and the inverted plant must be stable.
Synthesis of an H∞ Controller With Preview Compensation
Authors: Choi Chintae , Tsao Tsu-Chin
Published: January 2022

An optimal preview controller based on the discrete-time H∞ control is presented. The preview controller is synthesized by considering the bounded unknown disturbances as well as pre-viewable commands and disturbances. The controller derivation procedure is analogous to the LQ-based scheme. The designed preview gain matrix has a similar structure as the LQ-based one. As the infinity norm γ of the transfer function matrix tends to ∞, the preview gains obtained by H∞ control method approach to the gains by the LQR. The LQ-based preview gains are verified to be subsets of the H∞-based preview gains.
Modular Control for Machine Tools: Cross-Coupling Control With Friction Compensation
Authors: Chen B.-C. , Tilbury D. M. , Ulsoy A. G.
Published: January 2022

In this paper, we consider the combination of two different types of auxiliary control modules applied to a two-axis machining system. It is known that a cross-coupling control algorithm can reduce the contour error of a two-axis system, and that friction compensation can reduce positioning errors in machining systems. Here, we address the question of how the overall performance of the system is affected when both types of control are applied at the same time. Preliminary results indicate that the performance improvement is multiplicative. That is, if the error is reduced by a factor of Pcc for cross-coupling control, by a factor of Pfc for friction compensation, and by a factor of Pcc,fc when both are applied simultaneously, then Pcc,fc ≈ Pcc · Pfc. Simulation and experimental results are presented.
High Speed Contouring Control Algorithm for CNC Machine Tools
Authors: Erkorkmaz Kaan , Altintas Yusuf
Published: January 2022

A method of estimating contouring error and its minimization using a control law are presented. The contouring error is estimated in real time by projecting the actual tool position on the desired tool path. Sudden deviations in the tool path are considered in evaluating the contouring error, which is decoupled in the axis directions. The tracking error in each axis is first minimized by cascaded zero phase error tracking and pole placement control laws. In addition to axis tracking error, the components of contouring error in each axis are also regulated with PID controllers. Smoothing the axis position commands further enhances the overall system performance, and avoids discontinuities in the velocity and acceleration values in discrete time domain. The proposed method is compared to other methods suggested in literature (ZPETC, CCC) and its effectiveness is verified in simulations and with experiments, performed on a linear d.c. motor driven high speed x-y table.
A Unified Lyapunov Setting for Continuous and Discrete Time Sliding Mode Control
Authors: DeCarlo R. A. , Drakunov S.
Published: January 2022

This paper sets forth general conditions on the existence, boundedness, and proper gains of a control for stabilizing a nonlinear plant state trajectory to an equilibrium manifold S contained in the state space using a smooth quadratic Lyapunov function, V. To state such conditions we define a time-varying (possibly discontinuous in t) state-dependent decision manifold by considering the time-derivative of the quadratic Lyapunov function. The decision manifold disconnects the control space. At each instant of time, stability is achieved by choosing a control in an appropriate half space defined by the decision manifold so that the derivative of the Lyapunov function is negative definite. If the decision manifold moves continuously, then there is no need for a discontinuous (classical VSC) controller. If the decision manifold is discontinuous, then the need for a discontinuous control is clear. The formulation unifies the various VSC control strategies found in the literature under a single umbrella and suggests new structures. The formulation also provides a simple geometric understanding of the effect of matched and norm bounded disturbances and parameter variations on the control gains. These results are extended to arbitrary normed linear spaces which allow the results to be adapted to discrete-time and discrete-event systems. Several examples are given.
Lyapunov Based Analysis and Control Design
Authors: Corless Martin
Published: January 2022

In recent years, Lyapunov theory has proven to be very useful in the analysis and control design of uncertain nonlinear systems.
Role of the Crank-Slider Structural Deformations in the Prediction of the Instantaneous Engine Friction Torque
Authors: Chalhoub Nabil G. , Nehme Hassan , Henein Naeim , Bryzik Walter
Published: January 2022

The focus of the current study is to assess the effects of structural deformations of the crankshaft/connecting-rod/piston mechanism on the computation of the instantaneous engine friction torque. This study has to be performed in a fully controlled environment in order to isolate the effects of structural deformations from those of measurement errors or noise interference. Therefore, a detailed model, accounting for the rigid and flexible motions of the crank-slider mechanism and including Rezeka and Henein’s (1984) engine component friction formulations, is considered in this study. The model is used as a test bed to generate the engine friction torque, Tfa, and to predict the rigid and flexible motions of the system in response to the cylinder gas pressure.

The torsional vibrations and the angular velocity of the crankshaft, as predicted by the detailed model of the crank-slider mechanism, are used along with the cylinder gas pressure in the (P-ω) method to estimate the engine friction torque, Tfe. This method is well suited for the purpose of this study because its formulation is based on the rigid body model of the crank-slider mechanism.

The digital simulation results demonstrate that the exclusion of the structural deformations from the formulation of the (P-ω) method leads to an overestimation of the friction torque near the top-dead-center (TDC) position of the piston under firing conditions. Moreover, for the remainder of the engine cycle, the estimated friction torque exhibits large oscillations and takes on positive numerical values as if it is inducing energy into the system.
Dynamic Modeling of Multi-Unit Heavy Vehicles
Authors: Tai Meihua , Tomizuka Masayoshi
Published: January 2022

In this paper, a unique method of deriving two kinds of models: simulation model and simplified control model for an arbitrary configuration of heavy vehicle (HV) system is proposed for the Automated Highway Systems (AHS). In the simulation model, each unit of a heavy vehicle system is considered as a free body with 6 degree of freedom unless constrained by the hitching mechanisms. The roll and pitch coupling due to constraints between connected units is investigated from the geometric point of view, and the dynamics of the hitching mechanisms are incorporated. A simplifed control model is obtained independent from the simulation model. By the proper application of Newtonian and Lagrangian mechanics to the different parts of the simplified model equations, the holonomic constraint forces are eliminated from the dynamic equations of motion. The control model is given in a closed form. As a special case, an open-loop simulation of tractor-semitrailer simulation model is presented.
Design and Experimental Implementation of Control for a Platoon of Automated Vehicles
Authors: Rajamani Rajesh , Choi Seibum B. , Hedrick J. Karl , Law Boon , Prohaska Robert , Kretz Paul
Published: January 2022

This paper presents the design and experimental implementation of a longitudinal control system for the operation of automated vehicles in platoons. The control system on each vehicle is designed to have a hierarchical structure consisting of an upper level controller and a lower level controller. The upper controller determines the desired acceleration for each vehicle in the platoon so as to maintain constant accurate spacing between vehicles and ensure string stability in the platoon. The lower controller determines the throttle and/or brake commands required to track the desired acceleration. The design of the lower level controller for low speed operation is made difficult by the fact that the torque converter remains unlocked and the engine speed is not directly proportional to vehicle speed. In addition, the drive torque drops to zero for a brief time interval during each gear shift. Solutions to overcome these low speed problems are described. The design of safe intra-platoon maneuvers so as to allow any car in the platoon to exit by making a lane change are presented. Design of the co-ordination between vehicles for these maneuvers is described. The paper presents extensive experimental results from the public NAHSC demonstration of automated highways conducted in August 1997 at San Diego, California. The demonstration included an eight-car platoon operating continuously over several weeks with passenger rides being given to visitors. The maneuvers demonstrated included starting the automated vehicles from complete rest, accelerating to cruising speed, allowing any vehicle to exit from the platoon, allowing new vehicles to join the platoon and bringing the platoon to a complete stop at the end of the highway.
Emergency Vehicle Maneuvers and Control Laws for Automated Highway Systems
Authors: Toy Charmaine , Leung Kevin , Alvarez Luis , Horowitz Roberto
Published: January 2022

In this paper the operation and transit of emergency vehicles on an Automated Highway System (AHS) designed under the control architecture proposed in the California PATH program is described. The term emergency vehicles is used in a general sense to describe vehicles, such as police cars, ambulances and tow trucks, that may service faults inside or outside the AHS. The transit of emergency vehicles requires intensive participation of the Coordination layer, which directs the interactions of neighboring vehicles, and the Link layer, which regulates traffic flow along stretches of highway. In this paper, we describe various strategies for these two hierarchical layers that are needed to assign high priority transit to emergency vehicles on the AHS. These Coordination and Link layer maneuvers circulate vehicles around the emergency vehicle in both free flowing and stopped traffic.
A New Methodology for Engine Diagnostics and Control Utilizing “Synthetic” Engine Variables: Theoretical and Experimental Results
Authors: Moskwa John J. , Wang Wenbo , Bucheger Duane J.
Published: January 2022

This paper describes new engine diagnostic methodologies and algorithms that simplify and improve combustion quality monitoring and closed loop engine control in order to meet stringent emission standards. The “synthetic” variables these algorithms produce can be used to indicate the work produced by each cylinder combustion event at all engine speeds, and can be effectively used for on-board combustion quality measurements, engine diagnostics, and closed-loop control. The algorithms are very simple in form, and these methodologies can be applied to compression ignition or spark ignition, 2-stroke or 4-stroke engines.

Both simulation and experimental results will be given for a two-stroke, two cylinder in-line engine. The rotational dynamics and firing sequence of this configuration of engine is very similar to a four-stroke, four cylinder in-line engine, and nearly identical results will be seen with these two designs. Even more dramatic improvements can be seen with engines of fewer cylinders because of greater variations in their inertial forces. The algorithms can be successfully applied to many other engine configurations as well. Therefore, benefits can be derived from the application of these algorithms and their “synthetic” variables to control strategies for almost all modern small and medium size automotive and marine engines, as well as utility engines used for lawn care, snow removal, and other similar applications.
A Control Design for a Flexible Two-Link System
Authors: Mutti James , Du Hongliu , Nair Satish S.
Published: January 2022

This paper investigates a particular control strategy for a flexible two-link system. The objective is to control the tip position of the flexible link to track a desired trajectory in the presence of system uncertainties. A nominal ARX model is developed for an experimental two-link setup. A neural network is used to model some of the uncertainties, and the network is then used in a particular control configuration. Preliminary results from the study are presented.
Fast Control of Linear Systems Subject to Input Constraints
Authors: Larsson P. Tomas , Ulsoy A. Galip
Published: January 2022

Efficient design of high performance automatic control systems is extremely important for complex high technology systems and their cost-effective development. To get the best cost-to-performance ratio one would like to be able to design a controller that takes full advantage of actuator capabilities, but this can lead to non-linear behavior due to actuator saturation. The saturation nonlinearities in the system may have severe effects on the system performance due, for example, to integrator-windup.

In this paper we present a new design method, based on Lyapunov stability theory, that incorporates the actuator constraints directly in the design of a state feedback controller with integral action. By incorporating the actuator constraints directly in the design method we can ensure better utilization of the available control effort in achieving the desired system behavior.
Model Identification of the JPL Microgyroscope
Authors: M’Closkey Robert T. , Gibson Steve , Hui Jason K.
Published: January 2022

This paper reports the experimental model identification of the Jet Propulsion Laboratory micromachined vibratory rate gyroscope. An adaptive lattice filter is used to identify a two-input/two-output transfer function of high order in a series of experiments at different gyro temperatures (the gyro dynamics are temperature dependent). The experiments indicate that the lattice filter algorithm is suitable for real-time adaptive sensor calibration by using test inputs of short duration (one second) to excite the sensor dynamics.
Environment, Safety and Health Considerations for Disposition of Department of Energy Facilites
Authors: Pyatt D. W. , Niyogi P. K. , Eng C. C.
Published: January 2022

Following the end of the Cold War, the Department of Energy’s (DOE) mission has been in transition from designing, testing, and building nuclear weapons to a cleanup mode of environmental restoration and surplus facility disposition. The Office of Environment Safety and Health (EH) has led the development of a standard that addresses health and safety concerns for this new mission. This standard utilizes the numerous regulatory documents developed over many years addressing design, construction and operation of these several thousand facilities. It utilizes the framework of an “integrated safety management” approach.
Foot Control Activation: Reciprocating vs. Pivoting
Authors: Barnett Ralph L. , Barroso Peter
Published: January 2022

Discriminating between the two most widely used foot control concepts, open-sided and side-shielded, requires, among other things, an understanding of reciprocating and pivoting foot motions. In single cycle machine operations, it was found that the hands are steadier when foot controls are activated by pivoting about the heel as opposed to reciprocating. Furthermore, the study reveals the counterintuitive result that the reciprocating motion delivers slightly more activations per unit time than the pivoting action. If safety is not a consideration, stroke rate, operator comfort and hand steadiness are maximized when foot controls are actuated by “riding the pedal” or “hold down/release.”
Product Enhancement Through Ceramic Shell Casting
Authors: Duncan Scott R. , Kramer Michelle A.
Published: January 2022

For the past thirty years, foundries have been experimenting with the use of polystyrene patterns to produce high quality castings. It is only in recent years that the ceramic shell (CS) casting process has been successfully implemented for the commercial production of steel castings. This paper describes the ceramic shell (CS) casting process and highlights how its unique characteristics facilitated the optimization of railroad center plate designs.
Improving Lateral Ride Quality of Freight Cars Using Hydraulic Yaw Dampers
Authors: Jeambey Jon R.
Published: January 2022

Lateral deck accelerations are an important measure of ride quality, particularly for rail shipment of finished automobiles and for intermodal rail cars. Automobiles are sensitive to cyclic lateral inputs, which may lead to resonance and vehicle damage. Intermodal loads are generally less sensitive to lateral accelerations. However, this equipment operates at high speed for long periods and has the greatest exposure to truck instability. Improving the stability of rail cars not only benefits ride quality but also reduces wear of the car and truck components.

This report details the reduction in lateral deck accelerations of autoracks and all-purpose spine cars when equipped with hydraulic yaw dampers. High speed stability measurements were recorded at the AAR Transportation Technology Center, Inc. (TTCI) near Pueblo, Colorado.