bluuebunny/crossref_metadata_2025 huggingface dataset:
Noise Reduction by Means of Non-Uniform Placement of Pistons in a Fluid Power Machine
Authors: Ericson Liselott , Johansson Andreas , Palmberg Jan-Ove
Published: September 2010

In conventional machines, the pulsations are periodic and originate from the uniform placement of a given number of pistons. This paper discusses the possibilities to introduce nonuniform placement of the pistons. The pulsations’ periodicity is thus changed, which can have a major impact on the noise level and how the noise is experienced. A number of approaches are presented, evaluated and ranked and the usefulness of the modifications is assessed. This study employs a transfer function methodology to map simulated internal pump dynamics, such as piston forces and bending moments, to audible noise. Using these transfer functions, it is possible for instance to predict how changed valve plate timing affects simulated piston forces and bending moments and in turn how this will affect audible noise.
Modeling of Biodynamic Feedthrough in Backhoe Operation
Authors: Humphreys Heather C. , Book Wayne J. , Huggins James D.
Published: September 2010

An advanced backhoe user interface has been developed which uses coordinated control with haptic feedback. Results indicate that the coordinated control provides more intuitive operation that is easy to learn, and the haptic feedback also relays meaningful information back to the user in the form of force signals from digging forces and system limitations. However, results show that the current system has significant problems with biodynamic feedthrough, where the motion of the controlled device excites motion of the operator, resulting in undesirable forces applied to the input device and control performance degradation. This unwanted input is difficult to decouple from the intentional operator input in experiments. This research presents an investigation on the effects of biodynamic feedthrough on this particular backhoe control system, using system identification to empirically define models to represent each component. These models are used for a preliminary simulation study on potential methods for biodynamic feedthrough compensation.
Hybrid-Dynamic Modeling and Characterization of Mechanical Transmissions With Unidirectional Coupling
Authors: Richter Hanz , Maynard Rachel E.
Published: September 2010

This paper discusses modeling approaches for mechanical systems which may be driven from more than one source of power and which include unidirectional coupling elements. These systems arise in various settings, including heavy-lift helicopters and hybrid automobiles. In this paper, two kinds of mathematical model are examined for the free-wheeling clutch, a key element in these systems. It is shown that it is not possible to define transition rules between coupled and decoupled states using only relative speed or only torque if idealized models are used. A model involving a mixed torque-velocity transition rule is shown to capture the essential switching behavior. By using the bond graph formalism, the inclusion of realistic continuous effects such as inertia and friction becomes simple by modular cascading. A simplified two-driver hybrid dynamical model is constructed and characterized using the mixed model and the concept of clutch line is introduced to characterize the dynamic behavior. This work serves as a basis for subsequent controllability studies and selection of feedback control strategies.
Virtual Development Environment for Fluid Power Mechatronic Systems
Authors: Verkoyen Torsten , von Dombrowski Rene´ , Murrenhoff Hubertus
Published: September 2010

In this paper the results of the German state-funded research project “Fluidtronic”, that deals with a virtual development environment for fluid technical mechatronic systems, is presented. Firstly the conventional development process of a fluid technical mechatronic system is introduced. The conventional development process typically takes a long time because design failures are often only identified during the plant commissioning. Secondly the new virtual development environment, which is worked out in the “Fluidtronic” project is presented. It shows how both the system performance can be optimized and also how the commissioning time can be reduced extensively, if the interactions between mechanical, electrical and fluid power parts are tested at an early point of time in the development process. Optimizations in the development process are realized with the help of new and improved simulation models as well as soft- and hardware in the loop simulations.
Enhancing Vehicle Stability Through Model Predictive Control
Authors: Beal Craig E. , Gerdes J. Christian
Published: September 2010

Vehicle stability control systems have been widely and accurately cited as a significant influence in reducing the rate of severe injuries and fatalities in automotive crashes. However, these systems are purely reactive, providing additional control input only after undesired vehicle behavior is sensed. This paper presents a new approach to controlling the motion of a vehicle in highly dynamic situations. This approach solves a convex optimization problem over a finite time horizon to predict and prevent these hazardous situations. Thus, the controller determines input that simultaneously tracks the driver’s intended trajectory while preventing tire saturation. Simulation results are presented to demonstrate the efficacy of this control approach.
Free-Locomotion of a Fish-Like Robotic Swimmer Propelled by a Vibrating Ionic Polymer Metal Composite
Authors: Kopman Vladislav , Aureli Matteo , Porfiri Maurizio
Published: September 2010

In this paper, we study the free-locomotion of a miniature bio-mimetic underwater vehicle inspired by carangiform swimming fish. The vehicle is propelled by a vibrating Ionic Polymer Metal Composite (IPMC) attached to a compliant passive fin. The IPMC vibration is remotely controlled through the vehicle’s onboard electronics that consists of a small-sized battery pack, an H-Bridge circuit, and a wireless module. The planar motion of the vehicle body is described using rigid-body dynamics. Hydrodynamic effects, such as added mass and damping, are included in the model to enable a thorough description of the vehicle’s surge, sway, and yaw motions. The time-varying actions exerted by the vibrating IPMC on the vehicle body, including thrust, lift, and moment, are estimated by combining force and vibration measurements with reduced order modeling based on modal analysis. The model predictions are validated through experimental results on the planar motion of the fish-like robotic swimmer.
A General Framework for Control Systems Approach to Collaborative Human-Machine Systems
Authors: Lin Yingzi , Cai Hua
Published: September 2010

This paper presents a new work for the effective management of human-machine collaboration by applying a model-based control systems approach. One fundamental idea is that contemporary machines are assumed to be equipped with human assistance systems (HAS) with varying levels of intelligences. Thus, machines are collaboratively managed by both the human and HAS. This view goes beyond the full automation paradigm which is considered as a special case and is more general than the human-machine interaction paradigm. Another fundamental idea is to take a control systems view of collaborative human-machine systems, especially the so-called model-based control systems paradigm. The HAS technology is developed based on these two views. This paper in particular describes details of these two views along with a preliminary development of a HAS system for management of human cognitive engagement through regulating a multi-modal interface in a car-following case study. HAS revoked drivers’ cognition engagement for decision making first and retained the right of action interception as last. This approach demonstrated reduced driver intrusion while maintaining similar driving safety. In general, this approach minimized the deviation between the required human cognitive interference with the human state and the actual level of the interference based on the machine state.
Hybrid Control of a Pneumatic Gantry Robot for Contour Tracking: Proportional Pressure Versus Proportional Flow Control
Authors: Abu-Mallouh Mohammed , Surgenor Brian , Taghizadeh Sasan
Published: September 2010

The application of a pneumatic gantry robot to contour tracking is examined. A hybrid controller is structured to control the contact force and the tangential velocity, simultaneously. In a previous study, experimental contour tracking results for the robot were obtained with electronic proportional pressure control (PPC) valves. The results demonstrated the potential of pneumatic actuation for contour tracking applications. In another study it was found that improvement in performance was limited by system lag and Coulomb friction. A neural network (NN) compensator was developed to counter both effects. Simulation results demonstrated the effectiveness of the NN compensator. Although improvement in performance with NN compensation was significant, this was offset by the requirement for substantive design effort. This paper shows experimentally that equally significant improvement can be achieved by switching from PPC valves to proportional flow control (PFC) valves. The PFC approach requires less design effort.
Identification of the Input-Output Behavior of Hydraulic Two-Port Networks
Authors: Manhartsgruber Bernhard
Published: September 2010

Fluid power systems consist of components like pumps, valves and actuators and of the lines and hoses interconnecting these systems. Simple interconnections without branch points can be modelled as hydraulic two-port networks. This paper demonstrates the identification of linear state space models describing the input-output behaviour of hydraulic two-port networks in terms of pressure and flow-rate. The linear modelling approach restricts the applicability to the case of laminar flow with negligible influence of convective terms. Special attention is paid to a priori knowledge of certain model properties: The numerical optimization procedure used in the proposed identifcation method guarantees the passivity of the models and allows for instantaneous coupling of collocated pressure and flow variables according to the Joukowsky relation. The method takes experimental frequency response data as an input and generates a series of state-space approximations with increasing system order starting at order one. A hydraulic hose is presented as an example.
Multi-Time Scale Modeling Strategy for Bearing Life Prognosis
Authors: Sheng Shuangwen , Gao Robert X.
Published: September 2010

Prediction of a bearing service life is traditionally achieved by empirical or physical models, which have their own strengths and limitations. In an effort to combine the strengths of these modeling approaches, this research investigates the concept of Multi-Time Scale Modeling (MTSM). Specifically, a MTSM strategy for bearing life prognosis is developed by correlating experimentally acquired bearing vibration data with physics based model of microscopic growth of crack size. The strategy is composed of a fast scale empirical model (e.g., root mean square value of vibration), a slow scale physical model (e.g., change of crack length over one loading cycle), and a model coupling mechanism (e.g., bidirectional mapping functions). The fast and slow scale models are obtained by polynomial regression analysis and using the concept of the Paris Law, respectively. The coupling mechanism is established through introduction of dynamic mass into the model. The improvement in bearing service life prediction, obtained by the presented MTSM strategy is experimentally validated.
Modeling and Control of the Oxygen Saturation in Neonatal Infants
Authors: Keim Timothy , Amjad Ramak , Fales Roger
Published: September 2010

In this work, a nonlinear model is developed to simulate the respiratory system of neonatal infants. The nonlinear model is based on a model proposed by other researchers, but with varying parameters based on the oxygen saturation output [1]. The nonlinear model response is compared to the response of a linearized model given small and large step inputs. For small step sizes, the nonlinear and linear models responses are nearly identical. For larger step sizes, the nonlinear model has a higher steady state response. The linear and nonlinear models are also compared to clinical data taken from a bedside monitor. An error model is also developed given known ranges for model parameter variations. Since the varying parameters change performance, a robust controller is designed using the error model and performance specifications using a μ-synthesis optimization. The controller is shown to have robust stability and performance.
Fast Swarm Based Lane Detection System for Mobile Robot Navigation on Urban Roads
Authors: Sarkar Saurabh , Kumar Manish
Published: September 2010

The paper presents a swarm based lane detection system which uses cooperating agents acting on different regions of the images obtained from an onboard robot camera. These agents act on the image and communicate with each other to find out the possible location of the lane in the image. The swarm agents finalize their locations based on a set of rules which includes each other’s relative position and their previous locations. The swarm agents place themselves on the lane and generate a guidance path for the robot. This proposed lane detection method is is fast and robust to noises in the image. It is faster than the regression methods commonly used and can overcome the problem of noisy image to a good extent.
Support Vector Machines Based Mobile Robot Path Planning in an Unknown Environment
Authors: Tennety Srinivas , Sarkar Saurabh , Hall Ernest L. , Kumar Manish
Published: September 2010

In this paper the use of support vector machines (SVM) for path planning has been investigated through a Player/Stage simulation for various case studies. SVMs are maximum margin classifiers that obtain a non-linear class boundary between the data sets. In order to apply SVM to the path planning problem, the entire obstacle course is divided in to two classes of data sets and a separating class boundary is obtained using SVM. This non-linear class boundary line determines the heading of the robot for a collision-free path. Complex obstacles and maps have been created in the simulation environment of Player/Stage. The effectiveness of SVM for path planning on unknown tracks has been studied and the results have been presented. For the classification of newly detected data points in the unknown environment, the k-nearest neighbors algorithm has been studied and implemented.
Identification of Phenotypic State Transition Probabilities in Living Cells
Authors: Farahat Waleed A. , Asada H. Harry
Published: September 2010

Living cells stochastically switch their phenotypic states in response to environmental cues to maintain persistence and viability. Estimating the state transition probabilities from biological observations of cell populations gives valuable insight to the underlying processes, and gives insights as to how the transition statistics are influenced by external factors. In this work, we present two Bayesian estimation approaches. The first is applicable when individual cell state trajectories are observed. The second approach is applicable when only aggregate population statistics are available. Estimation of transition probabilities when individual cell state trajectories are available is a straightforward problem, whereas estimation from only aggregate statistics can be computationally expensive. In the latter case, we present an algorithm that relies on three key ideas to cut down computational time: i) approximating high-dimensional multinomial distributions with multi-variate Gaussians, ii) employing Monte-Carlo techniques to efficiently integrate over high dimensional spaces, and iii) explicitly incorporating sampling constraints by computing lower dimensional distributions over the constrained variable. Simulation results demonstrate the viability of the algorithm.
A Novel Pressure Control Mechanism for Common Rail Fuel Injection Systems
Authors: Gupta Vivek Kumar , Zhang Zhen , Sun Zongxuan
Published: September 2010

This paper presents the modeling of a novel pressure control mechanism for a common rail (CR) fuel injection system of internal combustion engines (ICE). The pressure fluctuations in the common rail caused by multiple injections negatively affect the accuracy of both injected fuel quantities and flow rates. The objective of this work is to design a new control mechanism to suppress the pressure pulsation in the rail. First we develop a one-dimensional distributed model for the common rail by using basic fluid flow equations, which can capture the distributed dynamics of the pressure disturbances in the rail and this result is validated with a physics based simulation model in AMESIM®. The periodic nature of injection event due to stroke by stroke motion of the ICE generates disturbance in the rail which in the rotational angle domain presents a primarily periodic signal. However, the period changes in the time domain due to the variation in engine speed. We then propose the concept of an active fluid storage device like a piezoelectric actuator (PZT) to minimize this pressure fluctuations. The location of the actuator on the common rail has also been evaluated to maximize its effect. Finally a time-varying repetitive controller is designed to compensate for the periodic pressure disturbances in the rotational angle domain.
Nonlinear Identification of MIMO Smart Structures
Authors: Kim Yeesock , Hurlebaus Stefan , Sharifi Reza , Langari Reza
Published: September 2010

This paper proposes a multiple model approach for a nonlinear multi-input, multi-output (MIMO) system identification (SI) of smart structures equipped with magnetorheological (MR) dampers. The proposed model is developed through integration of MIMO autoregressive exogenous (ARX) input models, Takagi-Sugeno (TS) fuzzy model, weighted linear least squares estimators, and data clustering algorithms. Nonlinear behavior of the structure-MR damper systems is represented by a set of linear MIMO ARX input models whose operating regions are blended by TS fuzzy sets. To demonstrate the effectiveness of the proposed MIMO ARX-TS fuzzy model, a 20-story high-rise building employing MR dampers is investigated. It is demonstrated that the proposed approach is effective in modeling nonlinear behavior of the structure-MR damper system subjected to a variety of disturbances. Comparison with high fidelity data proves the viability of the proposed approach in control engineering setting.
On Fast Dynamic Programming for Power Splitting Control of Plug-In Hybrid Electric Vehicles
Authors: Bin Y. , Reama A. , Cela A. , Natowicz R. , Abderrahmane H. , Li Y.
Published: September 2010

A Fast Dynamic Programming (FDP) algorithm is proposed to optimize the fuel consumption of the Plug-in Hybrid Electronic Vehicles (PHEV) over a prescribed driving cycle. Firstly, an innovative DP mathematical model for PHEV with reduced dimension is created. It composes of a linear state transfer equation and a quadratic cost function with 1×1 dimension. Based on this model, two algorithms expressed as the simple analytic forms are derived. One is the control algorithm for the optimal power splitting ratio (PSR) between the internal combustion engine (ICE) power and demand power. Another is the recursive algorithm to calculate the optimization value of the fuel consumption. Then, the optimal output power of ICE (or electronic motor (EM)) and the optimal speed ratio of the gear position can be calculated rapidly as the consequence of using the algorithms with analytic forms. Finally, the simulation results confirm that the computational efficiency of the FDP control algorithm has been improved with a geometric ratio, while its control performance maintains in an acceptable range in contrast with conventional DP control algorithm.
Multiscale Terrain Characterization Using Fourier and Wavelet Transforms for Unmanned Ground Vehicles
Authors: Dawkins Jeremy J. , Bevly David M. , Jackson Robert L.
Published: September 2010

This paper investigates the use of the Fourier transform and Wavelet transform as methods to supplement the more common root mean squared elevation and power spectral density methods of terrain characterization. Two dimensional terrain profiles were generated using the Weierstrass-Mandelbrot fractal equation. The Fourier and Wavelet transforms were used to decompose these terrains into a parameter set. A two degree of freedom quarter car model was used to evaluate the vehicle response before and after the terrain characterization. It was determined that the Fourier transform can be used to reduce the profile into the key frequency components. The Wavelet transform can effectively detect discontinuities of the profile and changes in the roughness of the profile. These two techniques can be added to current methods to yield a more robust terrain characterization.
Imputation of Ramp Flow Data Using the Asymmetric Cell Transmission Traffic Flow Model
Authors: Muralidharan Ajith , Horowitz Roberto
Published: September 2010

The Asymmetric Cell Transmission model can be used to simulate traffic flows in freeway sections. The model is specified by fundamental diagram parameters—determined from mainline data, and on-ramp and off-ramp flows. The mainline flow/density data are efficiently archived and readily available, but the ramp flow data are generally found missing. This paper presents an imputation technique based on iterative learning control to determine these flows. The imputation technique is applied sequentially on all the segments of the freeway, and the ramp flows, which minimize the error between the model calculated densities/flows and measurements are investigated. The stability and convergence of the density and flow errors using the imputation updates is also presented. Finally an example is shown to illustrate its use in a practical scenario.
Sensing and Estimation on a Modular Testbed for Swarm Robotics
Authors: Fricke Gregory K. , Garg Devendra P. , Milutinovic´ Dejan
Published: September 2010

Collective robotics offers the promise of enhanced performance and robustness relative to that of individual robots, with decreased cost or time-to-completion for certain tasks. Having many degrees of freedom, the multi-robot control and estimation problems are challenging, specifically when the solutions require a great amount of communication among the robots. While numerical simulation is a critical tool in swarm robotics research, verification of obtained results under a physical realization of the swarm is far from routine. Therefore, we have developed and used a sensor-integrated testbed for the validation of cooperative-robotics algorithms, observation of swarm behavior, and measurement of system performance.
Derivation and Simulation Results of a Hybrid Model Predictive Control for Water Purge Scheduling in a Fuel Cell
Authors: Ripaccioli Giulio , Siegel Jason B. , Stefanopoulou Anna G. , Di Cairano Stefano
Published: September 2010

This paper illustrates the application of hybrid modeling and model predictive control techniques to the water purge management in a fuel cell with dead-end anode. The anode water flow dynamics are approximated as a two-mode discrete-time switched affine system that describes the propagation of water inside the gas diffusion layer, the spilling into the channel and consequent filling and plugging the channel. Using this dynamical approximation, a hybrid model predictive controller based on on-line mixed-integer quadratic optimization is tuned, and the effectiveness of the approach is shown through simulations with a high-fidelity model. Then, using an off-line multiparametric optimization procedure, the controller is converted into an equivalent piecewise affine form which is easily implementable even in an embedded controller through a lookup table of affine gains.
Reducing Piston Mass in a Free Piston Engine Compressor by Exploiting the Inertance of a Liquid Piston
Authors: Willhite Joel A. , Barth Eric J.
Published: September 2010

A dynamic model of a free liquid piston that exploits piston geometry to produce a high inertance was developed for use in a free piston engine compressor. It is shown that for the size scale targeted, advantageous piston dynamics can be achieved with a reduced piston mass compared to a rigid piston design. It is also shown that the viscous losses associated with the liquid piston are negligible for the application discussed. The slow dynamics achieved by the liquid piston also allow for reduced valve sizes for the compressor, creating a more energy-dense device on a systems level. Other advantages gained by this design compared to prior work are discussed, including the elimination of a separated combustion chamber, smaller (integrated) pump check valve, and the capability of more balanced operation for a single-piston compressor. A dynamic model of the proposed high inertance liquid piston is presented and simulation results are discussed.
Reducing Torsional Vibration in an Engine Cold-Test Cell for Improved Structural Reliability and Engine Assembly Defect Diagnostics
Authors: Gul Kamran A. , Adams Douglas E.
Published: September 2010

The driveline components of engine cold-test cells undergo large torsional vibrations during transient tests as the system resonances are excited by various engine harmonics. The excessive torsional vibrations not only compromise the structural reliability of the system but also make the fault detection process difficult by preventing accurate measurement of gear noise and by compromising the quality of diagnostic torque waveforms. This paper presents modeling of an engine cold-test cell and a methodology to quantify signal distortion levels by using the proposed distortion metrics which are based on harmonic order amplitude ratios. A rigorous validation of the simulation model using both torque amplitude and waveform distortion comparisons of experimental and simulation data is conducted. The model is used to identify the driveline inertia and stiffness parameters that can help reduce high torsional resonant amplitudes as well as waveform distortion. The design modifications are implemented in a production test cell which helped to control the torsional vibration and diagnostic signal degradation issues with a corresponding increase in the sensitivity to faults.
Hybrid Adaptive Friction Compensation of Indirect Drive Trains
Authors: Chen Wenjie , Kong Kyoungchul , Tomizuka Masayoshi
Published: September 2010

This paper investigates the friction compensation topic for indirect drive trains in the absence of precise end-effector measurements. Friction, one of the main factors that diminish control performance, is investigated and compensated by manipulating the reference trajectory as well as the torque input. The motor side torque compensation utilizes the modified LuGre model to design an adaptive friction observer, while the motor side reference is modified by injecting the estimated load side friction. A hybrid controller structure is proposed to engage or disengage the load side compensator. Both methods are combined to effectively reject the friction effects in indirect drive trains. The effectiveness of the proposed scheme is experimentally verified.
Nonlinear-Feedback Vehicle Traction Force Control With Load Transfer
Authors: Scacchioli Annalisa , Tsiotras Panagiotis , Lu Jianbo
Published: September 2010

This article deals with the nonlinear feedback regulation of the longitudinal traction forces for high-speed vehicles, possibly over a low friction surface. Hybrid models of the longitudinal vehicle dynamics incorporating load transfer effects, a crucial element in advanced driving techniques, are derived. The designed hybrid regulator allows the tracking of a given friction force profile in the presence of known disturbances and unknown model uncertainties. Simulations show good performance of the proposed hybrid regulator under all operating conditions.
A Lumped-Parameter Dynamic Model of a Thermal Regenerator for Free-Piston Stirling Engines
Authors: Hofacker Mark , Kong James , Barth Eric J.
Published: September 2010

This paper uses lumped parameter dynamic equations to model the mass flow, piston dynamics, and control volume behavior inside a free-piston Stirling engine. A new model for a Stirling engine thermal regenerator that incorporates a dynamically changing temperature gradient is presented. The use of graphite as a regenerator matrix material is justified despite its limited background by comparing the functional requirements of regenerators to heat exchangers where graphite use is commonplace. Experimental results are used to characterize a graphite regenerator and validate the dynamic model.
Development of a High-Speed Laser-Free Atomic Force Microscopy
Authors: Bashash Saeid , Saeidpourazar Reza , Jalili Nader
Published: September 2010

To reduce the cost and improve the speed of Atomic Force Microscopy (AFM) in molecular scale imaging of materials, we propose a laser-free AFM scheme augmented with an accurate control strategy for its scanning axes. It employs a piezoresistive sensing device with a high level of accuracy to avoid using the bulky and expensive laser interferometer. Change in the resistance of piezoelectric layer due to the deflection of microcantilever caused by the variation of surface topography is monitored through a Wheatstone bridge. Hence, it captures the surface topography without the use of laser and with nanometer scale accuracy. To improve the speed of imaging, however, a Lyapunov-based robust adaptive control strategy is implemented in the 2-DOF scanning stage. It has been demonstrated in an earlier publication that this control framework has superior performance over the conventional PID controllers typically used in commercial AFMs. The paper, then, demonstrates a set of experiments on a standard AFM calibration sample with 200 nm stepped topography. Results indicate accurate imaging of the sample up to the frequency of 30 Hz, for a 16μm×16μm scanning area, proving the feasibility of less costly and high speed AFM-based metrology.
Crane Operation Using Hand-Motion and Machine Vision
Authors: Peng Kelvin Chen Chih , Singhose William , Fonseca Jonathan
Published: September 2010

Payload oscillation inherent to all cranes makes it challenging for human operators to manipulate payloads quickly, accurately, and safely. A new type of crane control interface that allows an operator to drive a crane by moving his or her hand freely in space has been implemented on an industrial bridge crane. An image processing system tracks the movement of a glove worn on the operator’s hand and its position is then used to drive the crane. Matlab simulations of the crane dynamics and hand-motion control were compared with actual experimental data. The results show that a combination of aggressive PD gains and an input shaper is able to generate the desired characteristics of fast payload response and low residual oscillations.
Nonlinear Dynamic Battery Model With Boundary and Scanning Hysteresis
Authors: Bin Yang , Li Yaoyu , Feng Nenglian
Published: September 2010

Battery has drawn much more attention due to the accelerating development of Electric Vehicle (EV) and Plugin Hybrid Electric Vehicles (PHEV) for sustainable mobility. It is worthwhile to study the dynamic model of battery in order to achieve better performance in power management. This paper proposes a nonlinear dynamic battery model for PHEV power management. First, an existing RC equivalent circuit is used to simulate the dynamics of the battery states with respect to the input current. Then, a concept of nonlinear hysteresis degree is introduced, and is adopted to implement the mathematical description of the battery nonlinear boundary and scanning hysteresis. Finally, the dynamics and the nonlinear boundary (scanning) hysteresis are integrated into a comprehensive battery model with an affine nonlinear state-space equation. The effectiveness of the proposed model is verified using some simulation tests.
Optimal Efficiency-Power Relationship for an Air Motor-Compressor in an Energy Storage and Regeneration System
Authors: Sancken Caleb J. , Li Perry Y.
Published: September 2010

Compressing air from atmospheric pressure into high pressure storage and expanding the compressed air in reverse is a means of energy storage and regeneration for fluid power systems that can potentially improve energy density by an order of magnitude over existing accumulators. This approach, known as the “open accumulator” energy storage concept, as well as other applications such as compressed air powered cars, rely on the availability of efficient and power-dense air motor/compressors. Increasing power is typically accompanied by reducing efficiency with the trade-off being determined by the heat transfer capability. In this paper, the authors present the Pareto optimal trade-off between the efficiency and power for a given heat transfer capability and ambient temperature in an air motor/compressor to achieve a given pressure ratio. It is shown that the optimal frontier is generated by an air motor/compressor that compresses and expands the air via a sequence of adiabatic, isothermal, and adiabatic processes. For the same efficiency of 80%, such an optimal volume trajectory achieves 3–5 times increased power over ad-hoc volume trajectories. It is also shown that approximating the infinitely fast adiabatic portions by finite time processes do not significantly reduce the effectiveness of the optimal operating strategy.
Passive Bilateral Tele-Operation and Human Power Amplification With Pneumatic Actuators
Authors: Durbha Venkat , Li Perry Y.
Published: September 2010

In this paper a passive bilateral tele-operation between two pneumatic actuators is presented. The co-ordinated system is controlled to behave as a rigid mechanical tool that interacts with the human and other environment inputs. The input human forces when applied via a force sensor, can be amplified through the tele-operator to provide assistance for the human operator to perform the task either remotely or on-site. By ensuring that the system is energetically passive, robust stability is gauranteed during interaction with humans and various environments. Heat transfer during actuation affects the force output of a pneumatic actuator. The significance of this effect is studied by modeling the actuator dynamics for isothermal and adiabatic process. Control schemes for these two extreme cases of heat transfer are developed separately. Experimental evaluation of the controllers is done on two single d.o.f. pneumatic actuators. Results show good co-ordination between master and slave actuators, both in free motion and during hard contact. The root mean square position co-ordination error for isothermal model is 1mm in free motion and 3.5mm during hard contact. The corresponding errors for adiabatic model are 0.8mm and 2.5mm respectively. Human force amplification, and force reflection during hard contact are also experimentally demonstrated for both isothermal and adiabatic model. From these results it is apparent that the difference between isothermal and adiabatic assumptions is not very significant.
Timing Error Compensator Design for Self-Servowriting System in Hard Disk Drives
Authors: Dong Feng Dan , Tomizuka Masayoshi
Published: September 2010

In Self-Servowriting (SSW) process, an accurate timing system is required for propagating the servo patterns. The timing jitters in this process induce significant timing error propagation in both radial direction and circumferential direction. In this paper, a control scheme based on Adaptive Feedforward Compensation (AFC) is proposed for SSW timing control loop. An adaptive filter is designed to minimize the closure error along circumferential direction and contain the timing error propagation along radial direction. The Filtered-X Least Mean Square (FXLMS) technique is used to design the adaptive filter. Simulation results prove that the proposed control method has achieved its objectives.
Wet Shape Memory Alloy Actuated Robotic Heart
Authors: Ertel Joel , Mascaro Stephen
Published: September 2010

This paper presents a conceptual design and preliminary analysis for a biomimetic robotic heart. The purpose of the robotic heart is to distribute hot and cold fluid to robotic muscles composed of wet shape-memory alloy (SMA) actuators. The robotic heart is itself powered by wet SMA actuators. A heart design concept is proposed and the feasibility of self-sustaining motion is investigated through simulation and experiment. The chosen design employs symmetric pumping chambers for hot and cold fluid. Analysis of this design concept shows that there exists a range of design parameters that will allow the heart to output more fluid than it uses. Additionally, it is shown that the heartbeat rate decreases as the system increases in size, and that the number of actuators and their length limit the power output of the pump. Experimental results from a prototype heart agree with the predicted trends from theoretical analysis and simulation.
Design and Implementation of Dual-Stage Track-Following Control for Hard Disk Drives
Authors: Nie Jianbin , Horowitz Roberto
Published: September 2010

This paper discusses the design and implementation of two track-following controllers for dual-stage hard disk drive servo systems. The first controller is designed by combining an outer loop sensitivity-decoupling (SD) controller with an inner loop disturbance observer (DOB). The second is designed by combining mixed H2/H∞ synthesis techniques with an add-on integral action. The designed controllers were implemented and evaluated on a disk drive with a PZT-actuated suspension-based dual-stage servo system. Position error signal (PES) for the servo system was obtained by measuring the slider displacement with an LDV and injecting a simulated track runout.
Mechatronics and Control of a Precision Motion Stage for Nano-Manufacturing
Authors: Ruben Shalom D. , Tsao Tsu-Chin , Hocken Robert J. , Fesperman Ronnie , Ozturk Ozkan , Brien John , Caskey Greg
Published: September 2010

High precision motion is critical in the semiconductor industry and as feature size continues to decrease, the need for higher precision increases. This paper presents the control system design and integration of a novel multi-degree of freedom precision stage for nano-manufacturing. It is composed of a 6 DOF wafer holder and a 3 DOF module holder. The modules can be chosen for a desired task, such as a nano-imprint lithography module. Capacitance gauges, interferometers, and photo detectors provide position feedback of the stage. Piezo-electric actuators and linear motors, that produce two orthogonal forces each, produce the desired output. Modeling of the coordinate transformation among the spaces of sensors, stage position, and actuators along with dynamic modeling of the stage is presented. Controller design, hardware, and software is described and results comparing simulation and implementation show a closed-loop positioning of less than 1 nm error in x and y and 0.01 arc seconds in θz with a sensor noise level of less than 0.2 nm.
Adaptive Disturbance Cancellation for Indirect Drive Robots Using Joint Sensing Information
Authors: Han Cheng-Huei , Tomizuka Masayoshi
Published: September 2010

Harmonic drives are widely used in robotics and precision positioning systems because of their unique properties such as near-zero backlash, and high speed reduction ratio. However, they possess a periodic positioning error known as the transmission error and it causes vibrations on the output shaft of the gear. In this paper, an adaptive compensation scheme for the transmission error in indirect drive robots is proposed. To enhance the performance and to avoid deteriorating the transient response, two modifications are introduced to the basic compensation structure. The load side acceleration information is adopted in real-time control to measure and to reject the load side oscillations. Also, it is used in the adaptation laws to generate the compensation signal that cancels the vibrations on the load side. Experimental results show the effectiveness of the proposed schemes and the improvement in load side performance.
Wheel Torque Controller Development Using a Simplified Tire Model for Vehicle Handling Enhancement
Authors: Adireddy Ganesh , Shim Taehyun , Rhode Douglas
Published: September 2010

A tire model is an essential element in the vehicle controller development and various complexities of tire models have been developed and used. It is highly desirable for the control systems to use a tire model that is computationally efficient and easy to implement in control algorithms while providing desired performance. In this paper, a wheel torque controller was developed using a non-linear predictive control theory, 8 degree of freedom vehicle model, and a simplified nonlinear tire model in order to control the vehicle yaw rate and side slip angle. The performance of this controller was compared to that based on well known Magic Formula tire model. The effectiveness and limitations of the proposed controller were discussed through simulation.
Real Time Energy Management: Cutting the Carbon Footprint and Energy Costs via Hedging, Local Sources and Active Control
Authors: Luo Qi , Ariyur Kartik B. , Mathur Anoop
Published: September 2010

This article provides an analysis of the effect on the overall energy bill of a commercial facility of active energy management. We first show the benefits of pure hedging, hedging when the facility has its own power source—we consider the use of co-generation in winter and the use of solar power in summer. We next show how active control of facility temperature set points augments the benefits of the hedging and use of local power. Our studies are based on real consumption data of a large commercial facility, the corresponding real time prices of grid power, prices of natural gas, intensity of solar radiation, and temperature history of the period under consideration. We show that the combination of hedging, local power generation and active control can reduce facility energy bills by up to 30%, and bill variance by up to 80%. Thus, we have a scenario where consumers save significantly while using power sources with a smaller carbon footprint.
A Method of Characteristics Based Coupled Pump/Line Model to Predict Noise Sources of Hydrostatic Transmissions
Authors: Klop Richard , Vacca Andrea , Ivantysynova Monika
Published: September 2010

This study is a part of a larger research project to predict noise sources of hydrostatic transmissions and investigating new methods for designing quieter systems. The aim of this study is to validate the developed model describing pump dynamics coupled with effects of a connecting line, thus validating a coupled pump-motor-line model for hydrostatic transmissions. This paper illustrates a numerical approach for evaluating pressure and flow oscillations generated by a hydraulic pump coupled with a connecting line. The presented model describes pump dynamics using a lumped parameter approach as well as one-dimensional unsteady compressible fluid flow by means of method of characteristics (MOC). Several lumped parameter models have been developed for hydraulic pumps and motors and the method of characteristics has been applied for many applications; however, the presented model uniquely utilizes both approaches and considers influence of pump dynamics and propagating pressure and flow pulsations throughout the line. Measurements of pressure ripple in the line at two different points were carried out at various loading conditions to validate the developed model. Comparisons between measurements, the developed model, and another more simplified model were conducted. Results indicate a reasonable match between the developed model and measurements as well as the importance of considering a line model based on method of characteristics.
Connectability-Based Controllability of Large Scale Nonlinear Dynamic Thermal Systems
Authors: Shoureshi Rahmat , Permana Virdi
Published: September 2010

A new approach using graph-theory to determine the controllability and observability of large scale nonlinear dynamic thermal systems is presented. The novelty of this method is in adapting graph theory for a nonlinear class and establishing graphic conditions that describe the necessary and sufficient conditions for a class of nonlinear systems to be controllable and observable which is equivalent to the analytical method of Lie algebra rank condition. Graph theory of directed graph (digraph) is utilized to model the system and its adaptation to nonlinear problems is defined. The necessary and sufficient conditions for controllability are investigated through the structural property of a digraph called connectability. In comparison to the Lie Algebra, this approach has proven to be easier, from a computational point of view, thus it is found to be useful when dealing with large scale systems. This paper presents the problem statement, properties of structured system, and analytical method of Lie algebra rank condition for controllability and observability of bilinear systems. The main results of graphical approach which describe the necessary and sufficient conditions for controllability of nonlinear systems are presented and applied to the problem of a coupled two heat exchangers, connected in an arbitrary fashion.
MIMO Self-Sensing Control of a Piezoelectric Tube Scanner
Authors: Kuiper Stefan , Schitter Georg
Published: September 2010

Piezoelectric tube scanners are commonly used in Scanning Probe Microscopy (SPM) to provide the scanning motion of the tip or sample. Oscillations due to the weakly damped resonances of the scanner are a major source of image distortion in SPM-imaging. In this contribution, multiple input-multiple output (MIMO) self-sensing actuation of a piezoelectric tube scanner is presented, allowing to actively dampen the scanner oscillations. By connecting the tube scanner in a capacitive bridge-circuit, the piezoelectric tube is simultaneously used as a sensor and actuator. In order to enable the use of low-order decentralized controllers, the cross-talk between both axes is reduced by compensating for the capacitive coupling. The MIMO self-sensing actuation allows to actively dampen the scanner’s fundamental resonance by 18dB, while simultaneously reducing the resonance induced coupling by 30dB. Experimental results verify a significant reduction of the scanner oscillations in both positioning axes during fast scanning.
Bond Graph Model of a Multi-Layer Piezoelectric (PZT) Beam and Its Application in Semi-Active Hydraulic Mounts
Authors: Vahdati Nader , Heidari Somayeh
Published: September 2010

Passive fluid mounts have been in use for the purpose of cabin noise and vibration reduction in the automotive and the aerospace industry. Cabin noise and vibration isolation is provided at a frequency coined “notch frequency”. To obtain the greatest cabin noise and vibration reduction at any desired frequency, the notch frequency needs to be close to that desired frequency. But, due to tolerances on all the fluid mount dimensions, and elastomer material properties, the notch frequency never ends up at the right location on the first manufacturing pass. To resolve notch frequency tuning cycle time, a new fluid mount design is proposed which consists of a conventional single-pumper fluid mount and a 3-layer piezoelectric cantilever beam resulting in a tunable notch frequency mount. Since this new design involves multi energy domains, bond graph modeling technique is used. This new design concept, its mathematical model and simulation results are presented.