bluuebunny/crossref_metadata_2025 huggingface dataset:
Fault Modelling for Hierarchical Fault Diagnosis and Prognosis
Authors: Zhang Jiyu , Rizzoni Giorgio , Ahmed Qadeer
Published: March 2014

Fault modeling, which is the determination of the effects of a fault on a system, is an effective way for conducting failure analysis and fault diagnosis for complex system. One of the major challenges of fault modeling in complex systems is the ability to model the effects of component-level faults on the system. This paper develops a simulation-based methodology for failure analysis through modeling component-level fault effect on the system level, with application to electric vehicle powertrains. To investigate how a component fault such as short circuit in a power switch or open circuit in a motor winding affects the vehicle system, this paper develops a detailed simulator which allows us to see system and subsystem failure behaviors by incorporating fault models in the system. This fault modeling process provides useful knowledge for designing a reliable and robust fault diagnosis and prognosis procedures for electrified powertrains.
Optimal Control of a Wind Turbine for Tradeoff Analysis Between Energy Harvesting and Noise Emission
Authors: Shaltout Mohamed L. , Chen Dongmei
Published: March 2014

An optimal control approach for a wind turbine drivetrain with the objective of maximizing energy harvesting and minimizing noise emission is presented. One of the major challenges facing the public acceptance for continuous growth of wind turbine installation is its noise emission. However, reducing the noise emission could lead to decreased wind energy harvesting. As a result, a tradeoff arises between power generation and noise emission, especially when a wind turbine operates under the partial-load condition.

This paper will show that through controlling the generator electromagnetic torque and/or the blade pitch angle, an optimal tradeoff between wind turbine energy harvesting and noise emission can be obtained. The dynamic model of a wind turbine drivetrain and a noise emission prediction model are also presented. Simulation results of using the proposed control design for different wind speed ranges are analyzed and compared.
Dynamic Energy Management of a Residential Energy Eco-System
Authors: Muratori Matteo , Chang Chin-Yao , Rizzoni Giorgio , Zhang Wei
Published: March 2014

In this paper, an automated dynamic energy management framework for a generic residential eco-system is presented. The proposed distributed, non-disruptive management framework is based on highly-resolved personal energy consumption models developed using a novel bottom-up approach that quantifies consumer energy use behavior. The incorporation of stochastic consumers behavior provides more accurate estimation of the actual amount of available controllable resources, hence enabling better interactions with the grid. The energy management problem is solved by use of a dynamic programming algorithm that considers household members’ behavior, as predicted by the highly-resolved stochastic personal energy consumption model, and finds the optimal schedule for all the controllable appliances and plug-in electric vehicles charging. The algorithm is flexible enough to accommodate diverse costs functions, and simulate different scenarios.
Bio-Inspired Robot Control for Human-Robot Bi-Manual Manipulation
Authors: Warren Stephen , Artemiadis Panagiotis
Published: March 2014

As robots are increasingly used in human-cluttered environments, the requirement of human-likeness in their movements becomes essential. Although robots perform a wide variety of demanding tasks around the world in factories, remote sites and dangerous environments, they are still lacking the ability to coordinate with humans in simple, every-day life bi-manual tasks, e.g. removing a jar lid. This paper focuses on the introduction of bio-inspired control schemes for robot arms that coordinate with human arms in bi-manual manipulation tasks. Using data captured from human subjects performing a variety of every-day bi-manual life tasks, we propose a bio-inspired controller for a robot arm, that is able to learn human inter- and intra-arm coordination during those tasks. We embed human arm coordination in low-dimension manifolds, and build potential fields that attract the robot to human-like configurations using the probability distributions of the recorded human data. The method is tested using a simulated robot arm that is identical in structure to the human arm. A preliminary evaluation of the approach is also carried out using an anthropomorphic robot arm in bi-manual manipulation task with a human subject.
Bridge Life Extension Using Semi-Active Vibration Control
Authors: Nelson G. , Rajamani R. , Gastineau A. , Schultz A. , Wojtkiewicz S.
Published: March 2014

The fatigue life of a bridge can be extended by fifty years just by reducing the peak strain levels it experiences by 33%. This paper utilizes a dynamic model of the Cedar Avenue tied arch steel bridge in Minnesota to investigate active control technologies for peak strain reduction. Simulations show that the use of passive structural modification devices such as stiffeners and dampers is inadequate to reduce the key resonant peaks in the frequency response of the bridge. Both active and semi-active vibration control strategies are then pursued. Active vibration control can effectively reduce all resonant peaks of interest, but is practically difficult to implement on a bridge due to power, size, and cost considerations. Semi-active control with a variable orifice damper in which the damping coefficient is changed in real-time using bridge vibration feedback can be practically implemented. Simulation results show that the proposed semi-active control system can reduce many of the resonant peaks of interest, but is unable to reduce the response at one key resonant frequency. Further analysis reveals that the location of the actuator on the bridge chosen for the semi-active controller is inappropriate for controlling the specific resonant frequency of issue. By modifying the actuator location, it would be possible to obtain control of all bridge resonant frequencies with the semi-active control system.
The Dubins Traveling Salesperson Problem With Stochastic Dynamics
Authors: Anderson Ross P. , Milutinović Dejan
Published: March 2014

Motivated by applications in which a nonholonomic robotic vehicle should sequentially hit a series of waypoints in the presence of stochastic drift, we formulate a new version of the Dubins vehicle traveling salesperson problem. In our approach, we first compute the minimum expected time feedback control to hit one waypoint based on the Hamilton-Jacobi-Bellman equation. Next, minimum expected times associated with the control are used to construct a traveling salesperson problem based on a waypoint hitting angle discretization. We provide numerical results illustrating our solution and analyze how the stochastic drift affects the solution.
A Handheld Noninvasive Sensing Method for the Measurement of Compartment Pressures
Authors: Flegel C. , Singal K. , Rajamani R.
Published: March 2014

Compartment syndrome is a major concern in cases of extremity trauma, which occur in over 70% of military combat casualty. Without treatment, compartment syndrome can lead to paralysis, loss of limb, or death. This paper focuses on the development of a handheld sensor that can be used for the non-invasive diagnosis of compartment syndrome. Analytical development of the sensing principle is first presented in which a relation is obtained between the pressure in a fluid compartment and the stiffness experienced by a handheld probe pushing on the compartment. Then a handheld sensor that can measure stiffness of an object without requiring the use of any inertial reference is presented. The handheld sensor consists of an array of three miniature force-sensing spring loaded pistons placed together on a probe. The center spring is chosen to be significantly stiffer than the side springs. The ratio of forces between the stiff and soft springs is proportional to the stiffness of the soft object against which the probe is pushed. Small mm-sized magnets on the pistons and magnetic field measurement chips are used to measure the forces in the individual pistons. Experimental results are presented using an in-vitro test rig that replicates a fluid pressure compartment. The sensor is shown to measure pressure accurately with a resolution of 0.1 psi over the range 0.75 psi to 2.5 psi.
An Experimental Study on Balancing Tasks of Human Subjects in Cooperation With Invisible Artificial Partners
Authors: Matsumoto Shigeki , Yoshida Katsutoshi
Published: March 2014

This paper studies coupled balancing tasks based on coupled inverted pendula (CIP) framework. We experimentally investigate the cooperative balancing task on a virtual CIP model, performed by a pair of an invisible artificial controller and a human subject, where experimental participants were not allowed to watch the movement of the artificial partner during experiments. The experimental result on Lyapunov exponents implies that the human subject seems to try to make the artificial controller neutrally stable as well as the visible case in our previous study. Therefore, the result implies that the visual feedback from the balancing state of the artificial partner may not be related to the dynamical property of human.
Guidance of a Robotic Off-Road Tractor-Trailer System Using Model Predictive Control
Authors: Salmon James T. , Bevly David M. , Hung John Y.
Published: March 2014

This paper presents a nonlinear Model Predictive Control approach to controlling a tractor-trailer system. Using a nonlinear tractor-trailer model, the controller determines the optimal steer angle, based on the trailer’s measured position and heading, as well as information about the path geometry in front of it. Then, the computer determines the amount of voltage to apply to the steering wheel motor to achieve the necessary steer angle. In the simulation study, the controller algorithm is capable of guiding a 2-1/2 meter long trailer around a 5-meter radius turn, towed by a four wheel drive off-road utility vehicle, with a maximum error of 8.5 centimeters.
Control of Inverted Pendulum Using Only Vertical Force via Harmonic Oscillation
Authors: Choi Changrak
Published: March 2014

Control of an inverted pendulum using horizontal force (e.g. cart-pole) is a well-established problem. However, there is no work in the literature that addresses controlling an inverted pendulum using only vertical force without horizontal movement. In this paper, control algorithm is presented that can control the inverted pendulum via only vertical force within the operating range of the given system. In the process, the dynamic stabilizing effect of vertical harmonic oscillation acting on inverted pendulum is exploited and previous works on the analysis of the stabilizing effect is utilized. The result is a nonlinear controller that combines sliding mode and energy shaping control which is capable of stabilizing the pendulum upright as well as at any titled angle within the region of attraction described. This is done for pendulum starting at any initial angle while maintaining vertical movement of the inverted pendulum within the prescribed space limit.
Haptic Glove Using Compression-Induced Friction Torque
Authors: Kuroda Yoshihiro , Shigeta Yu , Imura Masataka , Uranishi Yuki , Oshiro Osamu
Published: March 2014

The aim of this study is to develop a compact haptic glove that can present a variety of grasping sensations. This paper proposes a mechanism of compressing a finger joint to induce friction torque between the link and joint. In order to reduce weight and produce greater force, shape memory alloys were chosen as an actuator. The result of an experiment showed a linear relationship between the compressing force of a finger joint and friction torque, and suggested the effectiveness of the proposed mechanism. The prototype system suggested the proposed device is small and lightweight compared to the conventional device.
A Stackelberg Game Theoretic Driver Model for Merging
Authors: Yoo Je Hong , Langari Reza
Published: March 2014

Merging is one of the important issues in studying roadway traffic. Merging disturbs the mainline of traffic, which reduces the efficiency or capacity of the highway system. In this paper, we have considered the application of a Stackelberg game theory to a driver behavior model in a merging situation. In this model, the so-called payoffs that reflect the drivers’ aggressiveness affect the decision to proceed to merge and whether to accelerate or decelerate in the game theoretic framework. These merging behaviors in turn impact the mainline traffic, which may lead to a variety of influences, such as collisions or reduced roadway throughput. Consequently, this impact depends on the level of aggressiveness of the driver merging in and those in the mainline, which results in both longitudinal and lateral disturbances in the mainline due to their interaction.
Interaction Control of a Non-Backdriveable MR-Compatible Actuator Through Series Elasticity
Authors: Sergi Fabrizio , Chawda Vinay , O’Malley Marcia K.
Published: March 2014

This research aims at developing a magnetic resonance (MR)-compatible equivalent of an exoskeleton used for wrist movement rehabilitation therapy of neurological patients. As a crucial step towards the accomplishment of this goal, this paper investigates the development of a novel actuation architecture suitable for interaction control in MR environments, the MR-SEA (SEA stands for Series Elastic Actuator). MR-SEA consists of the combination of a non-backdriveable MR-compatible actuator and of a compliant force-sensing element. The preliminary design of a 1 DOF actuator is presented, in addition to non-linear dynamical model of the system featuring the most relevant actuator non linearities. A switching controller is proposed, and the asymptotic stability of the resulting discontinuous dynamical system is demonstrated for force control in blocked output conditions. Simulation results show that the proposed system is adequate for the implementation of force control for wrist movement protocols in fMRI, demonstrating a bandwidth higher than 8 Hz for force control. For stiffness control, simulation results demonstrate that the system is passive for all values of desired virtual stiffness lower than the stiffness of the physical spring, and isolated stability is obtained for the entire range of stiffness values considered.
Kinematics and Dynamics of a Biologically Inspired Index Finger Exoskeleton
Authors: Agarwal Priyanshu , Hechanova Arnold , Deshpande Ashish D.
Published: March 2014

Rehabilitation of upper extremity, especially hands, is critical for the restoration of independence in activities of daily living for individuals suffering from hand disabilities. In this work, we propose a biologically-inspired design of an index finger exoskeleton. The design has passive stiffness at each joint with antagonistic tendon driven actuation allowing for (1) improved kinematic and dynamic compatibility for effective therapy; and (2) conformation of exoskeleton and finger joints axes of rotation. We present a kinematics and dynamics model of the coupled index finger-exoskeleton system that incorporates human-like passive torques at the metacarpophalangeal (MCP), proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints. We carry out simulations using this coupled system model to study the role of passive stiffness on workspace and tendon forces, actuator force and displacement requirements, and reaction forces and moments acting at the finger joints for an index finger flexion-extension task. Results show that accurately modeling the coupled system can help in optimizing the design and control of the device, thus, exploiting its passive dynamics for effective functioning.
Dynamics Modeling and Identification of a Dual-Blade Wafer Handling Robot
Authors: Yu Xiaowen , Wang Cong , Zhao Yu , Tomizuka Masayoshi
Published: March 2014

This paper presents the dynamics modeling and dynamic identification of a dual-blade wafer handling robot. An explicit form dynamic model for this 8-link parallel robot is proposed. The dynamic model is transformed into a decoupled form to enable dynamic parameters identification with least-square regression. A well conditioned trajectory is chosen for identification experiment. Both viscous friction and Coulomb friction are considered to make the model more reliable. Model has been validated by experiments.
Pareto Optimal Setpoints for HVAC Networks via Iterative Nearest Neighbor Communication
Authors: Elliott Matthew S. , Bay Christopher J. , Rasmussen Bryan P.
Published: March 2014

HVAC systems in large buildings frequently feature a network topology wherein the outputs of each dynamic subsystem act as disturbances to other subsystems in a well-defined local neighborhood. The distributed optimization technique presented in this paper leverages this topology without requiring a centralized optimizer or widespread knowledge of the interaction dynamics between subsystems. Each subsystem’s optimizer communicates to its neighbors its calculated optimum setpoint, as well as the costs imposed by the neighbor’s calculated set-points. By judicious construction of the cost functions, all of the cost information is propagated through the network, allowing a Pareto optimal solution to be reached. The novelty of this approach is that communication between all plants is not necessary to achieve a global optimum, and that changes in one controller do not require changes to all controllers in the network. Proofs of Pareto optimality are presented, and convergence under the approach is demonstrated with a numerical and experimental example.
A Trajectory Shaping Approach for Suppressing the Fundamental Vibratory Mode in Strain Wave Gearing Mechanisms
Authors: Chan Michael , Tomizuka Masayoshi
Published: March 2014

While strain wave gearing mechanisms, such as harmonic drives, have many practical benefits when properly utilized, they also create challenging problems for control engineers. Namely, these flexible gear reduction mechanisms can create output vibrations which cannot be directly measured or controlled by the actuator. In this paper, an input shaping approach will be proposed to pre-compensate the desired output trajectory to account for the transmission dynamics such that the system’s actual output will follow the original desired trajectory. Several system parameters need to be empirically identified prior to using the proposed procedure. This identification process will also be outlined. Both simulation and experimental results on a 6 degree of freedom industrial robot will be provided to demonstrate the effectiveness of the proposed approach.
Nonlinear Passive Elements Using Cam-Based Springs for Powered Robotic Ankles
Authors: Realmuto Jonathan , Klute Glenn , Devasia Santosh
Published: March 2014

There is increasing interest in powered prosthesis. To reduce energy, power, and torque requirements on the active input, current systems, such as powered ankle prosthetics, utilize a combination of passive and active components. By storing and releasing energy during gait, the passive component reduces the energy/power/torque requirements of the active component. Therefore, it is advantageous to maximize the use of the passive component for achieving the desired motion. Typically, the passive component utilizes elastic elements such as springs, which cannot be easily adjusted to achieve a desired optimal nonlinear response. In this work, we report the use of a cam profile to achieve a general desired nonlinear response. The results show that the added design flexibility (to achieve nonlinear response of the passive element) can substantially reduce the energy/power/torque requirement of the active component.
A Gradient-Based Method for Team Evasion
Authors: Liu Shih-Yuan , Zhou Zhengyuan , Tomlin Claire , Hedrick Karl
Published: March 2014

We formulate the problem of an autonomous agent team facing the attack of an adversarial agent as a single-pursuer-multiple-evader pursuit-evasion game, with the assumption that the pursuer is faster than all evaders. In this game, the pursuer aims to minimize the capture time of the last surviving evader, while the evaders as a team cooperate to maximize this time. We present a gradient-based approach that quickly computes the controls for the evaders as a team under an open-loop formulation that is conservative towards the evader team by deriving analytical formulas. We demonstrate the advantage of the gradient-based approach by comparing performance both in computation time and in optimality with the iterative open-loop method studied in our previous work. Multiple heuristics have been designed to deal with the inherent intractability of evaluating all possible capture sequences. Extensive simulations have been performed, with results discussed.
An Interactive Multimedia Framework for Education on Vehicle Electrification
Authors: Rothenberger Michael J. , Fathy Hosam K.
Published: March 2014

This paper presents an interactive multimedia framework for introducing students to vehicle electrification/hybridization. The framework familiarizes its target audience with: (i) the societal factors driving the development of hybrid and plug-in hybrid electric vehicles (HEVs/PHEVs); (ii) the differences between conventional vehicles, HEVs, and PHEVs; and (iii) the high-level performance constraints and tradeoffs inherent in hybrid vehicle design. The framework consists of two coupled components: (i) a set of educational videos on vehicle electrification; and (ii) a 3D videogame built around physics-based models of conventional and series hybrid ambulances. The paper presents both the above education framework and the specific principles from the pedagogy literature guiding its design.
Optimal Subcooling in Vapor Compression Systems via Extremum Seeking Control
Authors: Koeln Justin P. , Alleyne Andrew G.
Published: March 2014

Building systems constitute a significant portion of the overall energy consumed each year in the U.S., and a large portion of this energy is used by air-conditioning systems. Therefore, the efficiency of these systems is important. This paper presents a method to increase system efficiency using an alternative system architecture for vapor compression systems. This architecture creates an additional degree of freedom which allows for independent control of condenser subcooling. It is found that there exists a non-zero subcooling that maximizes system efficiency; however, this optimal subcooling can change with different operating conditions. Thus, extremum seeking control is applied to find and track the optimal subcooling using only limited information of the system. In a simulation case study, a 10% reduction in energy consumption is reported when using the alternative system architecture and extremum seeking control when compared to a conventional system configuration.
Active Control of Wind Turbine Rotor Torsional Vibration
Authors: White Warren N. , Yu Zhichao , Miller Ruth Douglas , Ochs David
Published: March 2014

Transient and harmonic stresses in wind turbine rotor shafts contribute to gearbox failure. This paper investigates the reduction of rotor shaft torsional vibrations through active control of the generator torque. A 5 MW turbine model is used to test the procedure. A model of a permanent magnet synchronous generator is included as part of the wind turbine simulation. The simulations are carried out using the software FAST from the National Renewable Energy Laboratory (NREL). The PI and feedback linearized controller for the generator is derived together with the means for vibration isolation. Examples of steady, time varying, and turbulent wind are presented which all show significant reduction in the torsional oscillations.
Fault Diagnosis on a Digital-Displacement Pump/Motor
Authors: Wang Chunjian , Ayalew Beshah , Filipi Zoran
Published: March 2014

A Digital-Displacement Pump/Motor (DDPM) has recently been proposed as an attractive candidate for hydraulic powertrain applications. A DDPM uses solenoid-controlled valves for each cylinder. This provision offers flexibility of control that can be exploited to boost system efficiency by matching individual cylinder operations with load conditions. However, the added complexity from individual cylinder control necessitates mechanisms for fault diagnosis and control reconfiguration to ensure reliable operation of the DDPM. Furthermore, available measurements are often limited to supply and return line pressures, shaft angle and speed. In this paper, it is shown that, with only these measurements, individual cylinder faults are structurally unobservable and un-isolable by the use of a system model relating the cylinder faults to the shaft dynamics. To overcome this difficulty, the phase angles at which possible individual cylinder faults can begin to affect the shaft dynamics are tabulated for each cylinder, and a fault indicator that is akin to a shaft acceleration fault is modeled and estimated via a fast sliding mode observer. Simultaneous detection and isolation of individual cylinder faults can be achieved using this fault indicator and a table of fault begin angles. Illustrative examples are included from simulations of a 5 cylinder DDPM to demonstrate this diagnosis process.
Decentralized Feedback Control of Smart Lighting Systems
Authors: Afshari Sina , Mishra Sandipan
Published: March 2014

This paper presents a framework for designing controllers for self-commissioning smart lighting systems with plug-and-play capability. A class of decentralized feedback control methods is proposed for this purpose. Theoretical results for stability and convergence of the proposed algorithms are presented. Further, an automated self-commissioning algorithm is designed to minimize re-identification efforts necessary for the decentralized controller in case of a change in the lighting configuration (e.g. the addition of a new fixture to an existing space). The implementation of this algorithm demonstrates significant reduction in the commissioning effort. Finally, centralized, decentralized and consensus-based control algorithms are implemented on an experimental adaptive lighting testbed. The performance of the decentralized methods is shown to be comparable to that of the centralized controller.
Model-Predictive Control and Closed-Loop Stability Considerations for Nonlinear Plants Described by Local ARX-Type Models
Authors: Cholette Michael E. , Djurdjanovic Dragan
Published: March 2014

In this paper, a model-predictive control (MPC) method is detailed for the control of nonlinear systems with stability considerations. It will be assumed that the plant is described by a local input/output ARX-type model, with the control potentially included in the premise variables, which enables the control of systems that are nonlinear in both the state and control input. Additionally, for the case of set point regulation, a suboptimal controller is derived which has the dual purpose of ensuring stability and enabling finite-iteration termination of the iterative procedure used to solve the nonlinear optimization problem that is used to determine the control signal.
Semi-Active Control Methodology for Control of Air Spring-Valve-Accumulator System
Authors: Robinson William D. , Kelkar Atul G. , Vogel Jerald M.
Published: March 2014

This paper presents a semi-active control methodology for controlling the vibration of a pneumatic air spring-valve-accumulator system. Three controllers are presented and compared, along with experimental results. Due to the semi-active nature of this system, each controller uses a skyhook switching algorithm, along with a set-point plus PI tracking algorithm to track a desired reference signal. Some combination of pressure and displacement (or relative displacement) sensor feedback is used in each case. The desired reference control signal is generated by three different methods. The first method uses an optimal LQI (Linear Quadratic Impulse) controller generated from Covariance Control Theory. The second method uses a modified skyhook algorithm, and the third method uses a command directly proportional to the relative displacement. The second two methods use the first method (LQI) to tune the required controller gains off-line.
Evaluation of Friction Models for Haptic Devices
Authors: Ahmad Aftab , Andersson Kjell , Sellgren Ulf , Boegli Max
Published: March 2014

In this work different friction models are evaluated to determine how well these models are suited for performance simulation and control of a 6-DOF haptic device. The studied models include, Dahl model, LuGre model, Generalized Maxwell slip model (GMS), smooth Generalized Maxwell slip model (S-GMS) and Differential Algebraic Multistate (DAM) friction model. These models are evaluated both numerically and experimentally with an existing 6-DOF haptic device that is based on a Stewart platform. In order to evaluate how well these models compensate friction, a model-based feedback friction compensation strategy along with a PID controller were used for position tracking accuracy. The accuracies of the friction compensation models are examined separately for both low-velocity and high-velocity motions of the system. To evaluate these models, we use criteria based on fidelity to predict realistic friction phenomena, easiness to implement, computational efficiency and easiness to estimate the model parameters. Experimental results show that friction compensated with GMS, S-GMS and DAM models give better accuracy in terms of standard deviation, Root Mean Squared Error, and maximum error between a reference and measured trajectory. Based on the criteria of fidelity, ease of implementation and ease to estimate model parameters, the S-GMS model, which represents a smooth transition between sliding and pre-sliding regime through an analytical set of differential equations, is suggested.
Dynamic Modeling and Simulation of a Remote-Controlled Helicopter With a Suspended Load
Authors: Potter James , Simpson Ryan , Singhose William
Published: March 2014

A planar helicopter testbed has been constructed to study the dynamic effects of loads suspended below the helicopter by cables. A dynamic model of the helicopter-load system is presented, as well as a procedure to estimate the unknown model parameters. The simulated helicopter is controlled by a virtual pilot with attributes that are scaled to match the model helicopter’s fast dynamics. Initial simulations show that the presence of a heavy load makes it difficult to maintain a steady hover position after a horizontal movement.
Inertially Actuated Baton Locomotor
Authors: Zoghzoghy Joe , Alshorman Ahmad , Hurmuzlu Yilrdirim
Published: March 2014

In this paper, we present a robotic locomotor with inertia-based actuation. The goal of this system is to generate various gait modes of a baton, consisting of two masses connected with a massless rod. First, a model for a baton prototype called Pony I is presented. This model incorporates the inertial forces generated by a rotating single pendulum. The model also accounts for the friction forces that arise in the contact points of the baton with the ground surface. We also developed an experimental prototype for a baton with a single-pendulum actuator. Consequently, we compared the nonlinear dynamics of the analytical and experimental systems. An improved double-pendulum actuation system was proposed for better regulation of the locomotion of the system and the orientation of the centrifugal force. Finally, demonstrated that this system generated steady forward locomotion.
Modal Analysis of a Motorcycle Motion During Braking for its Stabilization Control System Design
Authors: Murakami Shintaroh , Nishimura Hidekazu
Published: March 2014

In this paper, modal motion of a motorcycle during braking is analyzed to clarify influence of a stabilization control system designed to the modes. A thirteen degree-of-freedom nonlinear state-space model including rider’s motion is linearized around an equilibrium point of quasi-steady state straight running with constant deceleration, and the modal analysis is carried out using the linearized state-space models. Conducting mode separation and performing simulations utilizing the linearized state-space models, the behavior of the modes including capsize, weave, and wobble modes are analyzed. The characteristic of each mode is clarified from relationships among the impulsive responses of simulations and the eigenvectors obtained from eigenanalysis. Furthermore, the influence of a motorcycle stabilization control system to each mode is analyzed from simulation results.
Closed Loop Fusion Technique for the Shaking Table Motion Control
Authors: Shimono Keisuke , Tagawa Yasutaka
Published: March 2014

Shaking tables are frequently used for dynamical testing. To produce correct results, a shaking table must be able to move according to the desired acceleration signal in a wide range of frequencies. Accelerometers and displacement sensors are used for controlling input, and, in some cases, they have been used for preventing drift. However, at low frequencies, accelerometers do not always provide accurate values. We developed a shaking-table control system that uses a sensor-fusion control function. In this paper, we present the design scheme for our control system and the results of a simulation that validate it.
Static and Dynamic Modeling of a Multi-Axis Thin-Film Piezoelectric Micro-Actuator
Authors: Choi Jongsoo , Rhee Choong-Ho , Qiu Zhen , Wang Thomas , Oldham Kenn
Published: March 2014

Multi-axis (z, θx, θy) micro-actuators based on thin-film lead-zirconate-titanate (PZT) for use in dual axes confocal microscopy are presented with their static and dynamic models. Prototype actuators have achieved as much as 430 μm of vertical displacement and ±10° of mechanical tilting angles in both θx and θy directions in a footprint of 3.2×3.2 mm. The experimental static displacements and transient response of the actuator were used to identify residual stresses in the thin films, dimensional variance due to fabrication limitation, and damping coefficients in the model. With the identified parameters, the model predicts the static displacements of the four corners of the stage with an average absolute error of 17.4 μm over five different voltage levels and shows a reasonable agreement with the experimentally measured transient dynamic data. These results will be used to develop closed-loop controller for the system.
On the Design and Control of Exoskeleton Knee
Authors: Tung Wayne , Kazerooni H. , Hyun Dong Jin , McKinley Stephan
Published: March 2014

This paper describes a lightweight (2.7 pounds) exoskeleton orthotics knee which provides controllable resisting torque. In particular, exoskeleton knee uses friction forces between two surfaces to provide resistive torque and impede knee flexion. Creating an impeding torque at the exoskeleton knee will decrease the torque that needs to be provided by the wearer at his/her knee during flexion. The required external power (from batteries) to provide the controllable resistive torque is minimal in comparison to the dissipated locomotion power since the resistive torque generation is “self-energizing” and is using the energy of the knee itself for braking. The exoskeleton knee uses the absolute angle of the thigh for basic functionality; no other measurements such as ground reaction force or the knee joint angle are necessary for basic performance. This allows the exoskeleton knee to be worn not only independently on the wearer’s knee but also in conjunction with hip, ankle or foot exoskeletons. This gives a great deal of flexibility for use of exoskeleton knees in variety of medical, civilian and military applications.
Hybrid Particle Swarm: Tabu Search Optimization Algorithm for Parameter Estimation
Authors: Sebastian Anish , Schoen Marco P.
Published: March 2014

A hybrid intelligent algorithm is proposed. The algorithm utilizes a particle swarm and a Tabu search algorithm. Swarm based algorithms and single agent based algorithms each, have distinct advantages and disadvantages. The goal of the presented work is to combine the strengths of the two different algorithms in order to achieve a more effective optimization routine. The developed hybrid algorithm is tailored such that it has the capability to adapt to the given cost function during the optimization process. The proposed algorithm is tested on a set of different benchmark problems. In addition, the hybrid algorithm is utilized for solving the estimation problem encountered for estimating the finger force output given a surface electromyogram (sEMG) signal at the input. This estimation problem is commonly encountered while developing a control system for a prosthetic hand.
Kinematic Analysis of Virtual Reality Task Intensity Induced by a Rehabilitation Robotic System in Stroke Patients
Authors: Simkins Matt , Roldan Jay Ryan , Kim Hyunchul , Abrams Gary , Byl Nancy , Rosen Jacob
Published: March 2014

Robotic systems provide a paradigm shift in maximizing neural plasticity as part of human motor control recovery following stroke. Such a system shifts the treatment from therapist dependent to patient dependent by its potential to increase the treatment dose and intensity, as long as the patient can tolerate it. The experimental protocol included 10 post stroke hemiparetic subjects in a chronic stage. Subjects were treated with an upper limb exoskeleton system (EXO-UL7) using a unilateral mode, and a bilateral mode. Seven virtual reality tasks were utilized in the protocol. A kinematic-based methodology was used to study the intensity of the virtual reality tasks in each one of the operational modes. The proposed method is well suited for early evaluation of a given virtual reality task, or movement assistance modality during the development process. Pilot study data were analyzed using the proposed methodology. This allowed for the identification of kinetic differences between the assistance modalities by assessing the intensity of the virtual reality tasks.
Modeling and Simulation of Human Walking With Wearable Powered Assisting Device
Authors: Slavnić Siniša , Leu Adrian , Ristić-Durrant Danijela , Gräser Axel
Published: March 2014

For the purpose of developing robot-assisted human walking systems, human and robot walking dynamics are modeled using models of different complexity depending on simulation scenarios in different phases of robotic system development and selected walking parameters to be analyzed. This paper addresses the early modeling and simulation phase of the development of a novel mobile robot-assisted gait rehabilitation system to be used as a demonstrator for a cognitive robot control architecture currently under development. For simulation purposes dynamical models of walking human and powered orthosis are developed in multi-body simulation software (MSC Adams) using the LifeMod plug-in while the control algorithms are developed in Matlab. The paper introduces a novel ROS (Robot Operating System) based communication established between the real system software modules and the simulation environment. The performance evaluation was performed by running the simulation with motion data which were obtained using marker-based motion capture system and which were implemented as ROS node.
Design of Input Shaping Control for Planar Parallel Manipulators
Authors: Narayanan Madusudanan Sathia , Krovi Venkat
Published: March 2014

Parallel manipulators are well known for their superior stiffness, higher accuracy, lower inertia and faster response compared to the serial counterparts and hence is widely used for high-speed machining and heavy load applications. However, controller limitations as well as design constraints can result in un-optimized designs causing unsettling residual vibrations at the end effector and limit their applications. Though many have discussed improving the structural design, augmenting with redundant sensors/ dampers and advanced feedback control methods for serial and mobile manipulators for vibration attenuations, very few investigated such techniques for parallel manipulators (PM). In this manuscript, we evaluate a specific type of feed-forward technique for planar PM. Lagrangian based dynamic models of platform manipulators and a simple trajectory level proportional-derivative control will be used with the gains tuned to force oscillations at the end effector to ensure stability. We will then demonstrate the applicability of basic input shapers for PM based on computation of natural frequencies and damping ratio for each mode, and resulting improvements in terms of appropriate performance measures.
Diagnostics of a Nonlinear Pendulum Using Computational Intelligence
Authors: Samadani M. , Kitio Kwuimy C. A. , Nataraj C.
Published: March 2014

A novel method has been presented in this paper for the diagnostics of nonlinear systems using the features of the nonlinear response and capabilities of computational intelligence. Four features of the phase plane portrait have been extracted and used to characterize the nonlinear response of a nonlinear pendulum. An artificial neural network has been created and trained using the numerical data for the estimation of parameters of a defective nonlinear pendulum setup. The results show that, with appropriately selected features of the nonlinear response, the parameters of the nonlinear system can be estimated with an acceptable accuracy.
Detection of Contact-Type Damages by Utilizing Nonlinear Piezoelectric Impedance Modulation of Self-Excited Structures
Authors: Masuda Arata , Ogawa Yuya , Sone Akira
Published: March 2014

This paper presents an improvement of a nonlinear piezoelectric impedance modulation (NPIM)-based damage detection method, a damage-sensitive, baseline-free structural health monitoring technique proposed by the authors, by introducing self-excited oscillation. The NPIM-based damage detection utilizes the modulation of high-frequency wave field of structures caused by the contact acoustic nonlinearity at the damaged part. In this study, the high-frequency wave field is induced as a self-excited oscillation of the structure by positively feed-backing the strain signal measured by a surface-bonded piezoelectric sensor, followed by a phase-shift in 90 degrees and a nonlinear element consisting of a saturation element and a negative linear gain. The induced self-excitation can have multiple stable limit cycles at certain eigenmode frequencies, and one can switch among them by inputting an auxiliary excitation signal into the feedback loop. The current flowing through the piezoelectric sensor is measured to detect its modulation due to the stiffness fluctuation due to the existence of the contact-type damage. Experiments using a specimen with a simulated damage are conducted to examine the performance of the self-excitation circuit and its applicability to the NPIM-based damage detection method.
Transient Control in Multivariable Systems: A Study Motivated by Fuel Cells
Authors: Madani Omid , Das Tuhin
Published: March 2014

Controlling the transient response of variables for which sensing or accurate estimation is not feasible, and a detailed plant model is also largely unavailable, poses significant challenges. It is a situation that is true in solid oxide fuel cells. In SOFCs, transient control is essential for fuel utilization, especially if the fuel cell is to be operated in a dynamic load-following mode at high fuel utilization. The objective is to design the control input(s) such that it isolates the output (fuel utilization in this case) from measurable disturbances, while the plant itself maybe largely unknown. The features assumed known are the output’s functional dependence on states which is essentially the output definition, and the steady-state equation relating the multiple inputs and the output of interest. Simulations have shown good disturbance rejection in fuel utilization through input shaping. This idea is abstracted to linear multi-variable systems to provide conditions when this approach is applicable. The analysis is carried out in time-domain as well as in frequency domain (through singular value analysis). The type of output variables that are amenable to transient control using this approach is derived through analysis. It is shown that the fuel utilization, although inherently nonlinear within the nonlinear dynamics of the fuel cell, has some similarities with the linear abstraction that leads to the observed transient control.
Designing Network Motifs in Connected Vehicle Systems: Delay Effects and Stability
Authors: Zhang Linjun , Orosz Gábor
Published: March 2014

Arising technologies in vehicle-to-vehicle (V2V) communication allow vehicles to obtain information about the motion of distant vehicles. Such information can be presented to the driver or incorporated in advanced autonomous cruise control (ACC) systems. In this paper, we investigate the effects of multi-vehicle communication on the dynamics of connected vehicle platoons and propose a motif-based approach that allows systematical analysis and design of such systems. We investigate the dynamics of simple motifs in the presence of communication delays, and show that long-distance communication can stabilize the uniform flow when the flow cannot be stabilized by nearest neighbor interactions. The results can be used for designing driver assist systems and communication-based cruise control systems.
Effects of Non-Collocated Sensors and Actuators on the Controller of a Flexible Beam
Authors: Mastory Constantine G. , Chalhoub Nabil G.
Published: March 2014

The current work examines the adverse effects of non-collocated sensors and actuators on the phase characteristics of flexible structures. The sensor location is allowed to sweep the entire length of a pinned-free flexible beam while the actuator is fixed at the pinned-end. The phase angle contour of the system has been generated as a function of the normalized sensor location and the excitation frequency. It clearly reveals the minimum and non-minimum phase regions of the system and illustrates the changes in the system’s zeros induced by varying the sensor location.

A basic sliding mode controller has been used to attenuate the unwanted vibrations of the beam. Based on the phase angle contours of the system, the structural controller has been modified to ensure a desirable controller performance irrespective of the sensor location with respect to the actuator. The simulation results demonstrate the efficacy of the modified controller in attenuating the overall transverse deformation of the beam irrespective of its phase characteristic.
A Nonlinear Observer Design for a Rigid Body in the Proximity of a Spherical Asteroid
Authors: Izadi Maziar , Bohn Jan , Lee Daero , Sanyal Amit K. , Butcher Eric , Scheeres Daniel J.
Published: March 2014

We consider an observer design for a spacecraft modeled as a rigid body in the proximity of an asteroid. The nonlinear observer is constructed on the nonlinear state space of motion of a rigid body, which is the tangent bundle of the Lie group of rigid body motions in three-dimensional Euclidean space. The framework of geometric mechanics is used for the observer design. States of motion of the spacecraft are estimated based on state measurements. In addition, the observer designed can also estimate the gravity parameter of the asteroid, assuming the asteroid to have a spherically symmetric mass distribution. Almost global convergence of state estimates and gravity parameter estimate to their corresponding true values is demonstrated analytically, and verified numerically.