bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of the Conductivity of the Oil on the Electrorheology of Zeolite/Mineral Oil Suspensions
Authors: Wu C. W. , Chen Y. , Conrad H.
Published: July 2023

The effect of the conductivity of various mineral oils on the dc current density and electrorheology (ER) of suspensions (ϕ = 0.28) of zeolite particles in these oils was determined at 25°C and a shear rate γ˙=2s-1. The measured electric field (E) dependence of the conductivity of the oils was in accord with the modified Onsager equation for nonpolar liquids, which givesσf(E)=σf(0)[(1-A)+Aexp⁡(E/Ec)1/2] where σf(0), A, and Ec are constants. The electric field dependence of the Onsager dissociation parameter b was evaluated. The current density and yield stress of the suspensions were in reasonable accord with those predicted by the conduction model for ER behavior. The effect of heating on the conductivity of the two oils which exhibited the lowest and highest current density was determined.
The Response of an Electrorheological Fluid to a Step Change in Applied Voltage in Dynamic Squeeze Flow
Authors: El Wahed Ali K. , Sproston John L. , Stanway Roger
Published: July 2023

This paper is concerned with an experimental investigation of the performance of an ER fluid in oscillatory squeeze-flow and the development of a quasi -steady theoretical model in which the rheological behaviour of the fluid is assumed to follow a bi-viscous shear stress/shear rate characteristic. The fluid is sandwiched between two parallel plane circular electrodes, the upper one fixed and the lower one oscillating normal to its plane. Of particular interest are the results of an experimental assessment of the response of the fluid to a step change in applied voltage and the effect of a change in the size of the solid phase.
Fully Conservative Forms of a System of Unified Electro-Magneto-Hydrodynamic Equations
Authors: Dulikravich George S. , Jing You-Hao
Published: July 2023

A system of partial differential equations governing unsteady multidimensional electro-magneto-hydrodynamic flows has been rewritten in its fully conservative (divergence-free) form. Linear polarization and magnetization effects were allowed while assuming an incompressible fluid and a single type of electrically charged particles in the flow. Both vector operator formulation and a scalar Cartesian coordinate system formulation have been derived in detail. The resulting fully conservative forms are suitable for further transformations to other coordinate systems or for direct discretization leading to their numerical integration.
Centrifugal Compressors for Automotive Air Conditioners: Component Design
Authors: Yun Hayong , Smith Joseph L.
Published: July 2023

The application of a novel, electric motor-driven, variable-speed centrifugal compressor for automotive air conditioners has been investigated.

For the feasibility analysis, a configuration design has been performed. It includes refrigerant selection, thermodynamic cycle analysis, compressor aerodynamic design, and mechanical layout of the integrated motor-compressor structure. Both the motor constraints (provided by the Laboratory for Electromagnetic and Electronic Systems at M.I.T.) and the compressor constraints were considered for the configuration design.

The result is an inter-cooled two-stage compression system using R123 as the refrigerant. The inter-cooling is achieved by feeding back a small fraction of the condenser liquid into the return channel between the first and the second stage through the electric motor. At the design condition, the pressure ratio is 3.2 for the first stage and 1.9 for the second stage. The design rotational speed is 75,000 rpm, and the maximum cooling capacity is 5,275 Watts.

High efficiency is expected by varying the compressor speed to match the required cooling load at each instant.
Centrifugal Compressors for Automotive Air Conditioners: System Design and Operation Strategy
Authors: Yun Hayong , Smith Joseph L.
Published: July 2023

System designs and operation strategies for a motor-driven, variable-speed compression system (described in the companion paper) have been developed.

Systems which can cover the required range of operating conditions (i.e. various cooling loads) have been designed. They require a compromise between high efficiency at high cooling loads and compressor surge prevention at low cooling loads.

Therefore, compressor operation strategies consist of a variable speed strategy for stable operating points (to match the cooling load at any instant) and a compressor stabilization strategy (to prevent compressor surge instability at low cooling load operations) for unstable operating points.

The system design and the operation strategy study results indicate that the novel compression device can improve the overall system efficiency by matching the compressor characteristics with the rest of the air conditioning system.
An Approach for the Calculation of Compression Loads in Helical Twin Screw Compressors
Authors: Qin Zhaohui , Adams Glynn P.
Published: July 2023

The main components of a twin screw compressor are two helical rotors. Its complicated geometry makes it difficult to compute the forces and moments induced on each rotor due to the compression process, the compression loads. However, the compression loads are an important consideration in the design and analysis of twin screw compressors. In this paper, a numerical method is presented for computing the compression loads by integrating the pressure over the rotor surface. Vector calculus and numerical integration schemes are implemented to calculate the compression loads in order to obtain a robust procedure that can be applied to arbitrary rotor profiles. The calculated results are given for a specific compressor configuration in terms of the compression loads as a function of the rotor angular position. It is shown that the rate of change of the profile radius as a function of the angular coordinate is an important factor affecting the accuracy of the integrations.
Entropy Generation in Multicomponent Reacting Fluid Flow With Heat and Mass Transfer
Authors: Teng Ho , Kinoshita Charles M. , Masutani Stephen M.
Published: July 2023

A comprehensive equation to determine the rate of local entropy generation in multicomponent, reacting, laminar fluid flow involving heat and mass transfer is formulated based on species-average velocity in a multicomponent continuum. The entropy-generation equation developed in this study suggests that species diffusion induces a diffusive-viscous effect, heretofore not reported in the literature, which could contribute significantly to entropy generation in multicomponent fluid systems, and that entropy generation in a multicomponent system exceeds that in a single-component fluid system having similar velocity and temperature distributions because a greater number of irreversible processes, such as species diffusion, chemical reaction, and the Soret and Dufour effects, are involved. Under appropriate conditions, if the diffusive-viscous effect is neglected, the entropy-generation equation of this study reduces to those reported in the literature for simpler fluid systems based on mean flow.
Development of Constrained Equilibrium Codes and Their Applications in Non-Equilibrium Thermodynamics
Authors: Bishnu Partha S. , Hamiroune Djamel , Metghalchi Mohamad , Keck James C.
Published: July 2023

Two constrained equilibrium codes, GNASA and GSTANJAN, have been developed which determine the composition of constrained equilibrium gas mixture. These codes use NASA and STANJAN equilibrium programs as the basis for generalized equilibrium routines. Gas mixture composition is determined by minimizing Gibbs free energy of the mixture subject to any specified constraints in addition to elemental constraints. Performances of these two codes have been compared to each other and it has been found that GSTANJAN converges over a wider range of constraints while the convergence of GNASA is limited. These codes have been applied in non-equilibrium evolution process of hydrogen-oxygen or H/O mixture. The non-equilibrium process has been modeled by using only two constraints in addition to elemental constraints. The results are in good agreement with detailed kinetic solution.
Local Optimization of Energy Systems
Authors: Lozano Miguel Angel , Valero Antonio , Serra Luis
Published: July 2023

Many thermal systems are very complex due to the number of components and/or its strong interdependence. This complexity makes difficult the optimization of the system design and operation. The Theory of Exergetic Cost is based on concepts such as resources, structure, efficiency and purpose (belonging to any theory of production) and on the Second Law.

This paper will show how is it possible to obtain from the theory of exergetic cost the marginal costs (Lagrange multipliers) of local resources being consumed by a component. This paper also shows the advantage of the proposed Theory of Perturbations when describing the complexity of structural interactions in a straightforward way. This theory allows to formulate simple procedures for local optimization of components in a plant.

Finally strategies for optimization of complex systems are shown. They are based in the sequential optimization from component to component. This clear and efficient method comes form the fact that we have now an operative application of the Thermoeconomic Isolation Principle.
Exergy Analysis of a Fuel Cell Power System for Transportation Applications
Authors: Cownden Ryan , Nahon Meyer , Rosen Marc
Published: July 2023

An exergy analysis of a solid polymer fuel cell power system for transportation applications is reported. The analysis was completed by implementing the derived fundamental governing second law equations for the system into a fuel cell performance model developed previously. The model analyzes all components of the system including the fuel cell stack and the air compression, hydrogen supply, and cooling subsystems. From the analysis, it was determined that the largest destruction of exergy within the system occurs inside the fuel cell stack. Other important sources of exergy destruction include irreversibilities within the hydrogen ejector and the air compressor, and the exergy emission associated with the heat rejected from the radiator. To increase the accuracy of the model and extend the results, a more comprehensive model for the fuel cell stack should be developed, and an investigation should be performed into the effects of varying the operating parameters of the system. The results may aid efforts to optimize fuel cell systems.
Performance of a Hybrid Photovoltaic Thermal Solar Collector
Authors: Sopian K. , Liu H. T. , Kakac S. , Veziroglu T. N.
Published: July 2023

Closed form solutions have been obtained for both a single-pass and a double-pass collectors and, for a passively cooled photovoltaic panel. The mean plate temperature, photovoltaic cell, thermal, and combined efficiencies have been obtained. The results show that the double-pass photovoltaic thermal collector has a more productive cooling effect compared to the single-pass photovoltaic thermal collector, and thus has better photovoltaic cells performance. The effect of the mass flow rate, duct depth, and packing factor on the photovoltaic cell performance are also discussed.
Three-Dimensional Absorption Process in Aqua-Ammonia Absorption Refrigerators Using Helium as Inert Gas
Authors: Kouremenos D. A. , Stegou-Sagia A. , Antonopoulos K. A.
Published: July 2023

In order to eliminate the danger of a possible explosion in neutral gas NH3/H2O absorption refrigerators using hydrogen as the inert gas, helium can be used as a substitute.

A numerical procedure is presented for the calculation of the absorption process. In previous studies the problem was simplified by considering the circular absorption tube in a vertical position with the liquid NH3/H2O stream being of annular cross section, thus resulting in a two-dimensional situation. In the present study the three-dimensional heat and mass transfer process is considered, in which the absorption tube is nearly horizontal and the liquid NH3/H2O stream has a circular meniscus cross-section.

The developed procedure which is based on a finite-difference solution of the three-dimensional momentum, energy and mass transport differential equations, may be used in the design of absorbers for inert gas absorption refrigeration units. It is concluded that helium behaves similarly to hydrogen and therefore it can replace it, in order to eliminate the danger of an explosion.
A General Process-Based Methodology for Exergy Costing
Authors: Lazzaretto Andrea , Tsatsaronis George
Published: July 2023

Various exergy-based methods are suggested in the literature for calculating the average or marginal costs associated with the streams of a thermal system. This paper briefly discusses the differences between the methods and presents simple rules for developing the productive structure of a system and for formulating the auxiliary relations required in exergy-based cost accounting. These relations are written by considering every addition and removal of exergy to and from each stream. The rules are general and applicable to any component of a thermal system. They are also applicable to cases where the total exergy of a material stream is split into physical, chemical, thermal, mechanical, and/or reactive exergy.
The Productive Structure and Thermoeconomic Theories of System Optimization
Authors: Torres C. , Serra L. , Valero A. , Lozano M. A.
Published: July 2023

The aim of this paper is to achieve a better understanding of the Thermoeconomic Theory of System Optimization and the Structural Theory of Cost (Valero et al.,1992, 1993), in order to unify and to take advantage of both theories.

As the Thermoeconomic Functional Analysis (Frangopoulos, 1987, von Spakovsky, 1986), the methodology introduced in this paper, establishes that, each unit of the system has a purpose, i.e., a product to obtain, a function. For example, the function of a gas turbine is the work obtained when expanding the gases.

This methodology is a general development of the Fuel-Product representation (Torres, 1991), based on the Structural Theory of Thermoeconomics. It gives a systematic and easy way to get a functional diagram from the physical scheme. This diagram represents the units, and the relations among themselves and the environment. Each unit uses a set of functions, or resources, from the environment or other units to obtain its function or product.

Using as starting point the functional diagram, it is shown that the Structural Theory and the Thermoeconomic Functional Analysis are equivalent methods and get the same costs result values. Finally, the productive structure (causal diagram) is presented as the key structure to understand the formation of each product and then, to interrelate the whole structure. So, it could be used as a criterion to system disagregation, to obtain more accurate costs.
A Comparative Synthesis of Exergo-Economic Optimization: The «IEEB» Method
Authors: Benelmir Riad , Feidt Michel
Published: July 2023

This work intends to present a comparative exergo-economic optimization for two distinct approaches through an application to a cogeneration system. The exergy analysis is based on a «functional approach» (Franfopoulos, 1983, von Spakovsky, 1986, Benelmir, 1989). This approach uses a functional diagram in order to identify the exergy and anergy streams within the system and at its interface with the environment. Negentropy, used for cost accounting purpose, is as anergy but flowing in the inverse direction. Each exergy and negentropy stream has a unit cost associated to it. Optimization in the first approach is based on the classical Lagrange technics with the objective function being the total cost of the system (investment and operating cost). The second approach is based on a method introduced by Benelmir (1989), called sometimes the decomposition method, where an analytic expression of the optimal unit cost is developped for each component of the system through exergy and cost balance relations. In fact this method is a consequence of the application of the Lagrange Multipliers technique.
Waste Heat Boiler Optimization by Entropy Minimization Principle
Authors: Reddy B. V. , Murali J. , Satheesh V. S. , Nag P. K.
Published: July 2023

A second law anlaysis has been undertaken for a waste heat boiler having an economizer, evaporator and superheater. Following the principle of minimization of entropy generation, a general equation for entropy generation number is derived, which incorporates all the operating variables. By differentiating the entropy generation number equation with respect to the operating parameters, various optimization parameters can be obtained. Few illustrations havebeen made to see the effect of various parameters on entropy generation number.
Development and Validation of a Diagnosis Method for Diesel Engines
Authors: Kouremenos D. A. , Rakopoulos C. D. , Hountalas D. T.
Published: July 2023

Diesel engines are used widely for power production and other applications such as sea vessels, railways, transportation etc. A serious problem for the service engineer is their maintenance and tuning in order to obtain maximum performance and reliable operation during their operational lifetime. Another serious problem is the detection of faults and their cause especially in the case when the engine does not function properly, i.e. low power output or high exhaust gas temperature. Up to now various techniques have been used for diesel engine monitoring and fault diagnosis that are mainly statistical. These techniques have serious disadvantages since they cannot be applied generally but have to be developed for the specific engine under consideration and fail to provide the actual cause in the case of a fault. To overcome these problems a new method is proposed in the present work for engine monitoring and fault diagnosis. This method allows to know the condition of the engine at each time instant and to determine if a fault exists. The method is based on a thermodynamic simulation model and on the processing of pressure diagrams taken from the engine cylinder and the high pressure fuel pipe. Using this method we can determine the actual cause for a fault and the condition of the engine and its subsystems. In this way we can save both money and time since we need only to conduct repairs that are actually required instead of making them on a time basis. Another advantage of the proposed method is that we can determine the required tuning of the engine in order to have optimum performance. This is important because the engineer tunes the engine based on data supplied by the manufacturer that correspond to a new engine condition, while for an old engine with wear the required tuning is different. In the present work the results obtained from the application of the proposed diagnosis method on two types of diesel engines, a low speed marine engine and a medium speed marine one are presented. The results obtained are promising, revealing the validity of the method.
The Design of a Control Coupled Observer for the Longitudinal Control of Autonomous Vehicles
Authors: Choi Seibum B.
Published: July 2023

This paper summarizes the evolution of “distance observers” that were developed for the longitudinal control of autonomous vehicles. A “control coupled” observer is presented that filters both the transient sensing error as well as slowly varying steady state off-set errors. The observer is implemented on a platoon of test vehicles as part of the California PATH research program. The experimental results show that the observer filters out the sensing error very effectively without any noticeable phase lag.
AHS Control Laws for Platoons Leaders
Authors: Li Perry , Alvarez Luis , Horowitz Roberto
Published: July 2023

In the AHS architecture of the California PATH program traffic is organized into platoons of closely spaced vehicles. Whenever platoons are formed or broken up, the large relative motion between platoons, increases the risk of high relative velocity collisions. In this paper we derive a safety region for the relative velocity between two platoons. By guaranteeing that the relative velocity between platoons remains in this region, impacts of high relative velocity can be avoided. For each one of the four control laws that a platoon leader can perform in normal operation, a desired velocity profile for the platoon that satisfies safety and time-optimality requirements is derived. A nonlinear velocity controller is designed to track the desired velocity profile within a given error bound. When safety is not compromised, this controller keeps the acceleration and jerk of the vehicles in the platoon within comfort limits.
Predicting Probability of Encroachment Conflicts Posed by Adaptive Cruise Control
Authors: Ervin Robert D. , Stein Jeffrey L. , Zachariou Nicolas , Bogard Scott E. , Kleinsorge Kurt
Published: July 2023

Designers of innovative control systems for vehicles such as Adaptive Cruise Control (ACC) lack tools for assessing the impact of their product on driver/vehicle performance. This paper describes a methodology for predicting the occurrence and severity of stereotypical motion conflicts identified for a ACC system design and vehicle platform. The idea is to represent the ACC system and the vehicle’s response characteristics in a mechanistic manner while the conflict variables are considered per their probability distributions as seen in empirical data. The methodology presented includes: dynamic and regression models of vehicle and ACC systems, conflict scenarios, conflict measures, condition variables embedded in empirical databases, and the processing of results to express conflict occurrence as cumulative density functions. Six conflict scenarios have been observed in field tests, with one of these that addresses the overshoot in headway that may accrue when approaching a slower moving vehicle from long range used as an example. The condition variables such as the prevailing vehicle speeds, longitudinal grade and the road curvature are varied, as appropriate, in accordance with the probability distributions seen in actual highway service. Obtaining results for a single scenario requires Monte Carlo simulations. To decrease the computational cost, a regression equation is developed for use in efficiently predicting performance over the full matrix of operating condition variables. Computed results are shown and discussed in light of the design decisions that face manufacturers concerned with introducing ACC products.
LQG-Based Fuzzy Logic Control of Active Suspension
Authors: Kashani Reza , Strelow Joseph E. , Eiler Mikell , Ariyakula Mahesh
Published: July 2023

The main terms contributing to the nonlinearities of the suspension model are kinematic constraints on motion, as well as, damping and stiffness of the tires. Considering coefficients of damping and stiffness of the tires as uncertain parameters which can assume a set of possible values, a collection of linear models can be developed that can, collectively, describe the suspension. A set of linear quadratic (LQ) controllers are designed for each linear model. All the LQ controllers, fed by their corresponding Kalman estimators, are fired, blended using fuzzy logic, and outputed to the actuator. The effectiveness of this control methodology in lowering the absorbed power and enhancing the mobility is demonstrated using computer simulation of a corner car test rig of HMMWV off-road vehicle.
Measurement of Mass Moments of Inertia Using Vibration Test Methods
Authors: Mclnerny S.
Published: July 2023

Procedures for the determination of solid body mass moments of inertia from low frequency, multiple-input, multiple-output vibration test data are presented. These procedures are considered possible replacements for the trifilar pendulum method. The first approach uses only measured resonance frequencies and mode shapes, but requires that mounting stiffnesses be known. The second requires that the forces on the test specimen at each of the spring mount attach points be directly measured using dynamic force gages. Using the third and fourth parameter estimation procedures, estimates of the mass, stiffness and damping matrices, or of just the unique elements of the inertia and stiffness matrices, would be simultaneously generated. These procedures have the potential to reduce the time required to measure motor-gearbox mass moments of inertia by a factor of 5.
Steering Damper Effect on Brake Roughness and Bump Steer Feedback
Authors: Tseng Hongtei E.
Published: July 2023

This paper presents the effect of a steering damper on brake roughness and bump steer feedback. Brake roughness (brake judder) refers to the tactile vibrations that occur during braking, and bump steer feedback is the steering wheel feedback perceived by the driver during vehicle bump steer.

The paper attempts to capture the significant characteristics of the transfer path of brake roughness and bump steer feedback in the steering system. An analytical model was derived and an experimental study was performed. Both quantitative road test data and qualitative analysis were presented to show the influence of the application of a steering damper.

The experimental study verifies the source of brake roughness and shows the improvement in the steering system with the application of a steering damper. The paper further discusses how the steering system can be tuned to be more robust against brake roughness and bump steer feedback. Conclusions are made for steering damper effect and recommendations are made for brake roughness problem.
Electro-Mechanical Transducer for Rail Car Onboard Power
Authors: Nagurka Mark , Tabacchi John , Kaufman William , Simizu Satoru
Published: July 2023

This paper describes a key component of an onboard power generation system that converts mechanical vibrations into electrical power to support a train’s electronically controlled pneumatic brake system. The translational generator acquires its energy from naturally occurring rail car displacements during normal train operation. The generator uses high field strength Nd-Fe-B magnets embedded in an iron-core cup assembly. When the generator is exposed to rail car vibrations, the magnet cup assembly reciprocates with respect to a copper coil. By special design of the magnet assembly, the magnetic flux lines are concentrated and made perpendicular to the coil maximizing the electrical output for a given relative displacement. In this paper the unit’s design, development, and construction are reviewed. In addition, the results of laboratory testing to characterize the unit’s performance as well as design considerations in meeting the vibrational energy available in a rail car environment are presented.
Inverse Filtering of Unwanted System Dynamics in Cutting Force Measurement
Authors: Jensen Steven A. , Shin Yung C. , Davies Patricia
Published: July 2023

The need for accurate measurement of cutting force frequently arises in manufacturing processes. Dynamics of the measurement system, however, becomes a major hindrance in obtaining accurate data. Use of a direct inverse filter to compensate for these dynamics is often times not realizable due to the occurrence of non-minimum phase zeros in the transfer function to be inverted. The main objective of this paper is to develop an algorithm which would successfully invert a stable transfer function with non-minimum phase zeros. The design procedure is described and illustrated with some examples. Finally, the algorithm is applied to a face milling case and the successful extraction of the true cutting force signature is demonstrated.
Investigation of Stick-Slip Friction in Slideways
Authors: Bailey George E. , McFarland D. Michael
Published: July 2023

This work is an experimental investigation of the stick-slip friction characteristics of a plain bearing slideway, representative of those found in precision machine tools. A test slideway driven by a brushless DC servomotor and ballscrew was designed to isolate the friction effects to one plane. The friction surfaces were steel on cast iron, both with a ground finish, using mineral oil as the lubricant. The applied force was sensed by measuring the displacement across a compliant spring with a capacitance gauge, and the resulting motion was measured using an LVDT.

Limitations of available friction models were identified, including the dependence of the static coefficient of friction on both the time of stick and loading rate, and changes in the coefficient of friction during sliding. Knowledge of these factors is expected to be valuable in future work aimed at controlling slideway motion.
Flexible Automation of Can-Filling Operation in Fish-Processing Industry
Authors: Singh G. , de Silva C. W. , Croft E. A.
Published: July 2023

This paper studies flexible automation of a salmon canning line. The performance of the existing special purpose machines is examined to identify problem areas and possible causes. An alternative design is presented which uses advanced technology to improve the performance of canning operations. Two design concepts, elliptical and rotary, are discussed for can-filling. The results of some preliminary experiments and analysis are presented. An economic study is made to establish the cost advantages of proposed technology.
Discrete-Time Well-Conditioned State Observer Design and Evaluation
Authors: Huh Kunsoo , Kwak Byunggil , Stein Jeffrey L.
Published: July 2023

Model-based monitoring systems based on state observer theory often have poor performance with respect to accuracy, bandwidth, reliability (false alarms), and robustness. Previous work has investigated quantitatively the above limitations of the continuous-time observers from the machine monitoring viewpoint. The authors have shown that the limitations can be represented by a single performance index, kP2(P) (condition number of the eigensystem P in terms of L2 norm). Based on the performance index, the authors developed a design methodology for the well-conditioned observer and illustrated the estimation performance compared to a pole-placement methodology. This paper extends the work to discrete-time systems. A performance index is determined to represent the limitations of discrete-time state observers and a design procedure is described for the well-conditioned observers. The estimation performance of the well-conditioned observers is demonstrated on a DC spindle system designed and built for this purpose. The results show that the robustness of the estimate is similar to that obtained with a well-known Kalman filter technique. Additional simulation-based examples show that the transient as well as steady-state error robustness to perturbations is better than or equal to Kalman filter performance depending on the nature of the modeling error. Because of this robustness, the well-conditioned observer for discrete-time systems is an important technique for the development of improved machine monitoring systems.
Petri Net Framework for Simulation and Control of Manufacturing Systems
Authors: Murgatroy Richard J. , Masory Oren
Published: July 2023

This paper describes a programming framework to execute a petri net simulation and real-time control for an automated system. This framework allows for the creation of a simulation for a proposed flexible automated system, and for the simultaneous development of the control software using the same code for both the simulation and the real-time control. The framework uses timed petri nets with inhibitor arcs to both model and control the system. The transitions represent actions to be performed, and the places either the necessary conditions to implement an action, or the conditions that exist when the action is completed. Each transition is represented by a unique function which is used within the framework to execute the petri net. When completed the program will scan the first petri net and execute each transition in order if all of the input places are marked. The framework is designed to allow a hierarchical structure to the petri net model, and a modular approach to the construction of the model is used. A set of prototype functions in C are used to create the petri net model, with the user providing the necessary programming within the function itself. A time-based diagnostic feature is incorporated into the framework to detect problems during the operation of the actual system. This diagnostic feature only requires the input of maximum times for any given action, and can be activated for only selected actions or for all actions (or functions) that the petri net performs. A sample application is provided to demonstrate the implementation of the framework for both the simulation and control of a simple robotic cell.
Timing and Performance of Open Architecture Controllers
Authors: Koren Yoram , Pasek Zbigniew J. , Ulsoy A. Galip , Wright Paul K.
Published: July 2023

This paper analyzes the effect of control architectures and communication networks on a manufacturing system’s performance in terms of part precision and productivity. The network bandwidth requirement for a distributed control system is also included in the analysis. The objective is to design the system such that the control and communications (both hardware and software) would not be the limiting factors in system performance. For simplicity we analyze the performance of a machining center control system. The base-line for comparison is a conventional computerized numerical controlled (CNC) with a discrete event management/adaptive system.
Dynamics of Machine Tool Spindle/Bearing Systems Under Thermal Growth
Authors: Jorgensen Bert R. , Shin Yung C.
Published: July 2023

Increased use of high-speed machining creates the need to predict spindle/bearing performance at high speeds. Spindle dynamic response is a function of the nonlinear bearing stiffness. At high speeds, it is apparent that thermal expansion plays a critical role in bearing stiffness. A complete model of spindle/bearing dynamic response including thermal expansion is derived. Steady-state temperature distribution is found from heat generation at the contact point and from a quasi three-dimensional heat transfer model. Solutions show an accurate prediction of thermal growth and heat generation in the bearing. Predicted highspeed spindle frequencies show an excellent agreement with experimentation. The effects of loading condition and bearing material type on bearing stiffness are also shown.
Thermal Sensor Placement Strategy for Machine Error Compensation
Authors: Lo Chih-Hao , Ni Jun , Yuan Jingxia
Published: July 2023

A method was developed to determine the suitable temperature variables for thermal error modeling on a machine structure. An optimality analysis of the best temperature variables is discussed using the analytical solutions of a one-dimensional spindle model. Finite element analyses for transient heat transfer and thermoelastic deformation are also performed on the column structure of a machining center. Different combinations of heat sources are applied to simulate diverse machining operations. From the results of FEA runs, 155 sets of 411 nodal temperatures and the 7 transformed error components are used as the database for multivariate temperature variable selection. Through an optimization method of searching unknown-order variables, 19 optimal sensor locations for the 7 error components are obtained and categorized into 6 clusters. Experiments and comparisons are presented to validate the applicability of the optimal sensor placement strategy. Superior to empirical method with trial-and-error sensor placement, this method is capable to select thermal variables globally and increases the robustness of thermal error models.
Optimization of Real-Time Multivariable Estimation in Grinding
Authors: Jenkins Hodge E. , Kurfess Thomas R.
Published: July 2023

To achieve cost-effective, high quality precision parts, it is important to determine the grinding process dynamics and subsequently control the process. Grinding is a time-varying process by nature, so real-time models are needed to develop adaptive controllers. In previous work by the authors real-time estimation of grinding model parameters was introduced. Multi-sensor input and windowing techniques for estimation of the process model parameters were presented. The paper is an extension of that work. Implementation and optimization issues as well as additional experiments are discussed in this paper.

Parameter estimation algorithms using the experimental grinding data are able to identify the process variation and calculate the grinding model parameters in real-time. These real-time models are superior to fixed-parameter grinding models in terms of calculating the achieved ground surface position. Several estimation algorithms are compared to the actual experimental data. Effects of several materials on modeling, estimation, and numerical optimizations of the parameter estimation algorithms are investigated. Various process sensors are examined for their influence on the grinding model parameter estimation error covariance. An implementation strategy for multivariable estimation and adaptive force control using parallel processors is also presented.
Haptic and Visual Feedback for Manipulation Aid in a Virtual Environment
Authors: Noma Haruo , Kitamura Yoshifumi , Miyasato Tsutomu , Kishino Fumio
Published: July 2023

This paper proposes a new method of object manipulation in a Virtual Environment that uses a visual and haptic feedback based manipulation aid. If the displayed position of the object is constrained on a face of another object in the virtual environment, a user can place the virtual object at a precise position as easily as in a real environment. The visual feedback based manipulation aid constrains the motion of the virtual object as if it were moved in a real environment. Furthermore, in simultaneous correspondence with the visual constraints, the haptic feedback based manipulation aid constrains the motion of the user’s hand in the real environment. The proposed method introduces a magnetic metaphor: the user has the sensation of manipulating a virtual object on a rigid surface without using a large and powerful robot arm and the time consuming simulation of detailed physical phenomena. The properties of this manipulation aid based on two kinds of feedback are discussed. Experimental results show the effectiveness of our proposed method.
PC-Based Virtual Reality System With Dextrous Force Feedback
Authors: Pere Emmanuel , Gomez Daniel , Burdea Grigore , Langrana Noshir
Published: July 2023

This paper describes a PC-based virtual reality system that provides dextrous force feedback through the Rutgers Master II (RM II) device. The RMII “smart” interface incorporates a 386 microprocessor that handles low-level communication and control of the haptic device. This reduces communication bandwidth with the host computer and increases control bandwidth and haptic feedback quality. In a dual-user configuration two such systems are interconnected over the ethemet allowing remote users to participate hapticly in a single VR simulation. The PC hosts display 3-D real-time graphics rendered by dissimilar graphics cards (Spea Fire board and Integraph board). A machine shop assembly task and a virtual dice game were developed using WorldToolKit VR-library to illustrate the concept.
Evaluation of a Force Feedback (Haptic) Computer Pointing Device in Zero Gravity
Authors: Payette Julie , Hayward Vincent , Ramstein Christophe , Bergeron Dominique
Published: July 2023

Haptic devices and specialized force-feedback hand controllers have been proposed as alternative Input/Output devices for use in challenging operational environments such as space. In the case described here, it is proposed that a pointing device with force-feedback (a haptic mouse) be used as a generic cursor device for operating computers in weightlessness. It is believed that such devices will decrease the effective workload of operators while increasing their efficiency in space. This paper describes an experiment that was designed to measure the effectiveness of a haptic device (hereby called Pantograph) in zero gravity conditions. The Pantograph was compared to a standard trackball pointing device. Both devices were tested on the ground and aboard a NASA reduced-gravity aircraft using a common graphical test interface (GUI). Results have shown that in zero gravity, the haptic device has proven more time efficient and has provided more pointing accuracy than the trackball in performing standard GUI operations such as clicking, dragging, and selecting.
The Impact of Visual Information on the Haptic Perception of Stiffness in Virtual Environments
Authors: Srinivasan M. A. , Beauregard G. L. , Brock D. L.
Published: July 2023

To study the impact of visually presented spatial cues on the human perception of mechanical stiffness in virtual environments, a three degree of freedom, force-reflecting haptic interface, the Planar Grasper, was utilized. In a series of psychophysical experiments on the discrimination of stiffness of two virtual springs, subjects pressed the springs and felt the corresponding displacements and forces through their hands, in addition to seeing the deformation of the springs displayed graphically on a computer monitor. Unknown to the subjects, the relationship between the visually presented deformation of each spring and actual deformation was systematically varied between experimental trials. This relationship ranged from fully registered (visual deformation was equal to the actual deformation of each spring) to completely interchanged (visual deformation of the softer spring was equal to the deformation of the harder spring for that force and vice versa).

The results demonstrated a clear visual dominance over the kinesthetic sense of hand position. The subjects essentially ignored all kinesthetic hand position information regarding spring deformation, and based their judgment on the relationship between the visual position information and the indentation force sensed factually. This caused an increasing misperception of stiffness with increasing mismatch between the visual and haptic position information, culminating in totally erroneous judgments when the two were interchanged. These results indicate such haptic illusions can be exploited to overcome some of the limitations of haptic interfaces and to enhance the range of haptic experience.
Nodicity and Nonlinear Interacting Dynamic Systems
Authors: Won Justin , Hogan Neville
Published: July 2023

Before solving the impedance selection problem, constraints on the impedance should be defined to guarantee the stability of the design. Often it is sufficient to constrain the selection to passive impedances, especially when interacting with passive environments but when interacting with active environments whose energy production may cause dynamic instabilities, more specific constraints must be identified. Unfortunately the tools available to perform this type of stability analysis are limited. Input/Output theory is a common method of analyzing the BIBO stability of nonlinear systems but in this paper we show that standard I/O theory cannot be applied to general interacting physical systems because it is based on a non-general assumption of nodic behavior. The non-nodic behavior of general physical systems is described and the applicability of an extension of I/O theory is considered.
The Concept and Implementation of a Passive Trajectory Enhancing Robot
Authors: Book Wayne , Charles Robert , Davis Hurley , Gomes Mario
Published: July 2023

A novel controlled passive device is described which allows its end effector to be pushed only along a specified but arbitrary path. The force to move the end effector must be provided by an external source such as a human, gravity, or fluid flow. Possible applications include computer assisted surgery, haptic displays, exercise machines, and teleoperator masters. Advantages of the passive approach taken include safety from run away motors and freedom from supplying substantial amounts of energy to the device. This paper describes the concept and how it has been implemented and shows feasibility through initial experiments with simple control of a prototype system.
Trajectory Tracking of Multibody Spacecraft
Authors: Kelkar A. G. , Joshi S. M.
Published: July 2023

This paper addresses the problem of trajectory tracking of multibody spacecraft. The class of systems considered consists of a central body to which a number of articulated appendages are attached. Each appendage itself could be a serial chain of bodies. For the case of rigid multibody systems, nonlinear equations of motion are obtained for the tracking error dynamics. The quaternion representation is used for the central body attitude. A trajectory tracking control law is given, and is shown to provide global asymptotic stability of the tracking error. For the case of multibody flexible spacecraft in the attitude-hold configuration, it is shown that the closed-loop system remains ℒ2-stable under the proposed tracking control law.
Automated Modeling to Support Robust Controller Design
Authors: Wilson Bruce H. , Eryilmaz Bora
Published: July 2023

Researchers in automated modeling and developers of automated modeling software have hitherto considered only the case in which a system’s parameters and model’s coefficients are known precisely. Researchers are well aware that real-world engineering does not provide such precision, but have perhaps operated under the common assumption that the true values are sufficiently close to the nominal values. For closed-loop system design, parametric uncertainty can easily result in a lack of robust stability: an undesirable situation. We have developed a convex-hull algorithm to analyze transfer functions with uncertain coefficients and have applied this procedure to robust controller analysis and design. This exercise, while useful, involved considerable effort and bookkeeping in synthesizing the rational functions for each model coefficient, and provided impetus for considering how automated-modeling software could support robust controller design. We discuss such support, both for the techniques illustrated in the paper, and for other techniques.
The Bond Graph Use for the Design and the Improvement of Instrumentation Architecture for System Monitoring
Authors: Tagina M. , Cassar J. P. , Dauphin-Tanguy G. , Staroswiecki M.
Published: July 2023

This paper presents two methods for direct generation of analytical redundancy relations from a bond graph model. These relations are then used to detect and isolate faults affecting the studied system, consisting of a horizontal plane robot with two arms. We also show how the bond graph model helps to conceive an instrumentation architecture, giving a satisfactory isolation ability for the monitoring system.
Verification of Hybrid Physical System Models
Authors: Mosterman Pieter J. , Biswas Gautam
Published: July 2023

Physical systems are by nature continuous, but often nonlinear. This increases model complexity and causes numerical stiffness in simulation. By modeling these nonlinearities as discontinuities, the models can be linearized and operate in multiple modes. This paper discusses a hybrid modeling methodology that combines continuous energy flow modeling using bond graphs and discrete signal flow modeling using controlled junctions with associated finite state automata to generate complex, multi-mode behavior. When threshold values are crossed, multiple discontinuous changes may occur before a new continuous mode of operation is reached. An analysis method is presented to establish physically inconsistent areas based on the energy distribution in the system at the time of switching. Time complexity of the method is constrained by a model partitioning approach based on identifying areas of instantaneous change.