bluuebunny/crossref_metadata_2025 huggingface dataset:
Lane Keeping Control Using Finite Spectrum Assignment With Modeling Errors
Authors: Vörös Illés , Várszegi Balázs , Takács Dénes
Published: November 2019

Lane keeping control of the single track vehicle model with linear tire characteristics is analyzed in the presence of time delay. In order to compensate time delay, the predictor control approach called finite spectrum assignment is applied. This controller uses an internal model of the plant to predict current system states in spite of the time delay. The predictions are based on a simplified version of the vehicle model, neglecting tire dynamics. The predictive control approach is compared with traditional feedback control using analytically derived stability maps and numerical simulations. Robustness to parameter mismatches and numerical issues related to the implementation of the control law are also analyzed.
Engine Calibration Optimization Based on its Surrogate Models
Authors: Pal Anuj , Wang Yan , Zhu Ling , Zhu Guoming G.
Published: November 2019

Diesel engines are becoming increasingly complex to control and calibrate with the desire of improving fuel economy and reducing emissions (NOx and Soot) due to global warming and energy usage. With ever increased control features, it is becoming more and more difficult to calibrate engine control parameters using the traditional engine mapping based methods due to unreasonable calibration time required. Therefore, this research focuses on the problem of performing engine calibration within a limited budget by efficiently optimizing three control parameters: namely variable geometry turbocharger (VGT) position, exhaust gas recirculation (EGR) valve position, and start of injection (SOI). Engine performance in terms of fuel consumption (BSFC) and emissions (NOX) are considered as objective function here with the constraint on boost pressure and engine load (BMEP). Since the engine calibration process requires a large number of high-fidelity evaluations, surrogate modeling methods are used to perform calibration quickly with a significantly reduced computational budget. Kriging metamodeling is used for this work with Expected Improvement (EI) as acquisition function. Results show more than 60% decrease in computational cost with results close to actual near Pareto optimal set.
Learning Flatness-Based Controller Using Neural Network
Authors: Ren Hailin , Qi Jingyuan , Ben-Tzvi Pinhas
Published: November 2019

Publisher’s Note:

This paper was selected for publication in ASME Letters in Dynamic Systems and Control.

https://www.asmedigitalcollection.asme.org/lettersdynsys/article/doi/10.1115/1.4046776/1082074/Learning-Flatness-Based-Controller-Using-Neural
Identification of Temperature Dynamics Using Subspace and Machine Learning Techniques
Authors: Haber Aleksandar , Pecora Francesco , Chowdhury Mobin Uddin , Summerville Melvin
Published: November 2019

Identification, estimation, and control of temperature dynamics are ubiquitous and challenging control engineering problems. The main challenges originate from the fact that the temperature dynamics is usually infinite dimensional, nonlinear, and coupled with other physical processes. Furthermore, the dominant system time constants are often long, and due to various time constraints that limit the measurement time, we are only able to collect a relatively small number of input-output data samples. Motivated by these challenges, in this paper we present experimental results of identifying the temperature dynamics using subspace and machine learning techniques. We have developed an experimental setup consisting of an aluminum bar whose temperature is controlled by four heat actuators and sensed by seven thermocouples. We address noise reduction, experiment design, model structure selection, and overfitting problems. Our experimental results show that the temperature dynamics of the experimental setup can be relatively accurately represented by low-order models.
Performance Study of a Bat Searching Algorithm From System Dynamics Perspective
Authors: Zhang Haopeng , Schutte Nathan
Published: November 2019

In this paper, the performance of a bat searching algorithm is studied from system dynamics point of view. Bat searching algorithm (BA) is a recently developed swarm intelligence based optimization algorithm which has shown great success when solving complicated optimization problems. Each bat in the BA has two main states: velocity and position. The position represents the solution of the optimization problems while the velocity represents the searching direction and step size during each iteration. Due to the nature of the update equations, the dynamics of the bats are formulated as a group of second-order discrete-time systems. In this paper, the performance of the algorithm is analyzed based on the nature of the responses in the second-order systems. The over-damped response, under-damped responses are studied and the parameters requirements are derived. Moreover, unstable scenarios of the bats are also considered when examining the performance of the algorithm. Numerical evaluations are conducted to test different choices of the parameters in the BA.
Dynamics of a Vibration Driven Bristlebot
Authors: Gandra Chandravamsi , Tallapragada Phanindra
Published: November 2019

Vibration driven robots such as the so called bristlebot and kilobot utilize periodic forced vibration of an internal mass to achieve directed locomotion. These robots are supported on an elastic element such as bristles or cilia and contain an internal mass that is driven to oscillate at a high frequency. Besides well known applications in investigating swarming behavior, such robots have potential applications in rescue operations in rubble, inspections of pipes and other inaccessible confined areas and in medical devices where conventional means of locomotion is ineffective. Bristlebot or its commercially available variants such as hexbugs are popular toy robots. Despite the apparent simplicity of these robots, their dynamic behavior is very complex. Vibration robots have attracted surprisingly few analytical models, those models that exist can only explain some regimes of locomotion. In this paper, a wide range of motion dynamics of a bristlebot is explored using a mathematical model which accounts for slip-stick motion of the bristles with the substrate. Analytical conditions for the system to exhibit a particular type of motion are formulated and the system of equations defining the motion are solved numerically using these conditions. The numerical simulations show transitions in the kinds of locomotion of a bristlebot as a function of the forcing frequency. These different kinds of locomotion include stick-slip and pure slip motions along with the important phenomenon of the reversal of the direction of motion of the robot. In certain ranges of frequencies, the robot can lose contact with the ground and ‘jump’. These different regimes of locomotion are a result of the nonlinear vibrations of the robot and the friction between the robot’s bristles and the ground. The results of this paper can potentially lead to more versatile vibration robots with predictable and controllable dynamics.
Following Fast-Dynamic Targets With Only Slow and Delayed Visual Feedback: A Kalman Filter and Model-Based Prediction Approach
Authors: Xiao Hui , Chen Xu
Published: November 2019

Although visual feedback has enabled a wide range of robotic capabilities such as autonomous navigation and robotic surgery, low sampling rate and time delays of visual outputs continue to hinder real-time applications. When partial knowledge of the target dynamics is available, however, we show the potential of significant performance gain in vision-based target following. Specifically, we propose a new framework with Kalman filters and multirate model-based prediction (1) to reconstruct fast-sampled 3D target position and velocity data, and (2) to compensate the time delay for general robotic motion profiles. Along the path, we study the impact of modeling choices and the delay duration, build simulation tools, and experimentally verify different algorithms with a robot manipulator equipped with an eye-in-hand camera. The results show that the robot can track a moving target with fast dynamics even if the visual measurements are slow and incapable of providing timely information.
Output Feedback Control Synthesis for a Helicopter Using Explicit Nonlinear Model Predictive Control, Dynamic Inversion and Extended High Gain Observers
Authors: Seo Joohwan , Choi Jongeun
Published: November 2019

Control design for a helicopter is a challenging problem because of its non-affine inputs, complicated dynamics and it is an under-actuated system. To solve a control problem of the helicopter under model uncertainties and disturbance present environments, an Explicit Nonlinear Model Predictive Control (ENMPC), a dynamic inversion and an Extended High-Gain Observers (EHGO) are combined in a multi-time-scale fashion. The multi-time scaled structrue and the ENMPC provides the framework of the control design, the dynamic inversion deals with non-affine control inputs, and the EHGO estimates the unmeasured states and uncertainties. In addition, a discretization scheme using the saturation and adding low pass filters to the control inputs is presented. Finally, the numerical simulation of a fixed sampling period has been carried out to demonstrate the validity of the proposed multi-time-scale control design and the discretization scheme.
Optimal Lane Management in Heterogeneous Traffic Network
Authors: Karimi Shahri Pouria , Chintamani Shindgikar Shubhankar , HomChaudhuri Baisravan , Ghasemi Amir H.
Published: November 2019

This paper aims to determine an optimal allocation of autonomous vehicles in a multi-lane heterogeneous traffic network where the road is shared between autonomous and human-driven vehicles. The fundamental traffic diagram for such heterogeneous traffic networks is developed wherein the capacity of the road is determined as a function of the penetration rate and the headways of autonomous and human-driven vehicles. In this paper, we define two cost functions to maximize the throughput of the network and minimize the variation between flow rates. To solve the proposed optimization problem, an exhaustive search optimization approach is performed. Several numerical examples are presented to highlight the different influence of different design parameters on the allocation of autonomous vehicles.
The Restricted Newton Method for Fast Nonlinear Model Predictive Control
Authors: Maitland Anson , Jin Chi , McPhee John
Published: November 2019

We introduce the Restricted Newton’s Method (RNM), a basic optimization method, to accelerate model predictive control turnaround times. RNM is a hybrid of Newton’s method (NM) and gradient descent (GD) that can be used as a building block in nonlinear programming. The two parameters of RNM are the subspace on which we restrict the Newton steps and the maximal size of the GD step. We present a convergence analysis of RNM and demonstrate how these parameters can be selected for MPC applications using simple machine learning methods. This leads to two parameter selection strategies with different convergence behaviour. Lastly, we demonstrate the utility of RNM on a sample autonomous vehicle problem with promising results.
Design of a Kangaroo Inspired Hopping Robot for Unrestricted Locomotion and Controller Development
Authors: Curtis Austin , Mynderse James , Vejdani Hamid
Published: November 2019

Inspired by the agility and maneuverability of running kangaroos, a prototype robot was developed using a reduced order model to constrain the system. Both passive and active models were used to understand the relationship between system parameters and gait performance. A frequency response experiment was performed on the prototype to quantify the relationship between design parameters and system responses. Additionally, preliminary tail controllers were tested. Based on the results of the initial platform, a new robot was designed and built as a platform for the study of three dimensional hopping.
Integrated Forward and Reverse Trajectory Tracking Control for Car-Like Ground Vehicle
Authors: Chen Yuanyan , Zhu J. Jim , Lin Letian
Published: November 2019

Conventional automatic trajectory tracking control technics for car-like ground vehicles typically decompose the controller into separate longitudinal driving control and lateral-directional steering control, owing to the nonholonomic kinematic constraint, highly nonlinear dynamics and control under-actuation of such vehicles. However, such decoupled control techniques inevitably impose operational constraints on agile maneuvers that may be critical in evading impending collisions, preventing loss-of-control of the vehicle, and special maneuvers that are needed for law enforcement missions. Thus, integrated three-Degree-of-Freedom (3DOF) tracking control of car-like ground vehicles are highly desirable but remains a challenging problem. There also appears to be a lack of research on automated reverse driving. In our previous work [ASME DSCC2017-5372, DSCC2018-9148], design and hardware validation test results of an integrated 3DOF trajectory tracking controller based on nonlinear kinematics and dynamics vehicle model using Trajectory Linearization Control (TLC) for forward driving have been reported. The present paper supplements that work with design and hardware validation test results on vehicle backward driving at fast and low speeds. The reverse driving control incurs minimal alteration to the original design with minimal tuning efforts due to the model-based TLC control approach, and it should be readily scaled-up to full-size vehicles and adapted to different types of autonomous ground vehicles with the knowledge of vehicles’ kinematics and dynamics parameters.
Diesel Engine Characterization and Performance Scaling via Brake Specific Fuel Consumption Map Dimensional Analysis
Authors: Pelletier Evan , Brennan Sean
Published: November 2019

The goal of this work is to develop easily generalized models of heavy duty truck engine maps that allow for approximate comparisons of engine performance, thus enabling fuel efficient matching of engines to a set of corresponding loads and routes. This is achieved by applying dimensional analysis to create a uniformly applicable, dimensionless Brake Specific Fuel Consumption (BSFC) map that fits the behavior of a wide range of diesel engines. A commonality between maps was found to occur when engine data is scaled by specific dimensional parameters that target data consistency among the primary operating points across engines. This common map highlights observable trends in engine performance based on the influence of these same parameters being scaled across engines. The resulting dimensionless engine map fits the minimum BSFC regions of four diesel engines to within 2.5 percent.
Instantaneous Center of Rotation-Based Master-Slave Kinematic Modeling and Control
Authors: Ramanathan Vikram , Zelenak Andy , Pryor Mitch
Published: November 2019

This article presents a novel kinematic model and controller design for a mobile robot with four Centered Orientable Conventional (COC) wheels. When compared to non-conventional wheels, COC wheels perform better over rough terrain, are not subject to vertical chatter and offer better braking capability. However, COC wheels are pseudo-omnidirectional and subject to nonholonomic constraints. Several established modeling and control techniques define and control the Instantaneous Center of Rotation (ICR); however, this method involves singular configurations that are not trivial to eliminate. The proposed method uses a novel ICR-based kinematic model to avoid these singularities, and an ICR-based nonlinear controller for one ‘master’ wheel. The other ‘slave’ wheels simply track the resulting kinematic relationships between the ‘master’ wheel and the ICR. Thus, the nonlinear control problem is reduced from 12th to 3rd-order, becoming much more tractable. Simulations with a feedback linearization controller verify the approach.
Analytical Statistical Study of Linear Parallel Feedforward Compensators for Nonminimum-Phase Systems
Authors: Noury Keyvan , Yang Bingen
Published: November 2019

In this work, a new parallel feedforward compensator for the feedback loop of a linear nonminimum-phase system is introduced. Then, analytical statistical arguments between the existing developed methods and the innovated method are brought. The compelling arguments suggest the parallel feedforward compensation with derivative (PFCD) method is a strong method even though at its first survey it seems to be optimistic and not pragmatic. While most of the existing methods offer an optimal integral of squared errors (ISE) for the closed-loop response of the nominal plant, the PFCD offers a finite ISE; in reality, typically, the nominal plant is not of main concern in the controller design and the performance in the presence of mismatch model, noise, and disturbance has priority. In this work, there are several arguments brought to bold the importance of the innovated PFCD design. Also, there is a closed-loop design example to show the PFCD effectiveness in action.
Configuration Optimization for End-Point Stabilization of Redundant Manipulators With Base Flexibility
Authors: LiBretto Michael , Cho Yong K. , Ahn Yong Han , Han Chang Soo , Ueda Jun
Published: November 2019

Publisher’s Note:

This paper was selected for publication in ASME Letters in Dynamic Systems and Control.

https://www.asmedigitalcollection.asme.org/lettersdynsys/article/doi/10.1115/1.4046684/1081845/Configuration-Optimization-for-End-Point
Adaptive Single Action Control Policies for Linearly Parameterized Systems
Authors: Ennasr Osama , Mamakoukas Giorgos , Castaño Maria , Coleman Demetris , Murphey Todd , Tan Xiaobo
Published: November 2019

This paper presents an adaptive, needle variation-based feedback scheme for controlling affine nonlinear systems with unknown parameters that appear linearly in the dynamics. The proposed approach combines an online parameter identifier with a second-order sequential action controller that has shown great promise for nonlinear, underactuated, and high-dimensional constrained systems. Simulation results on the dynamics of an underwater glider and robotic fish show the advantages of introducing online parameter estimation to the controller when the model parameters deviate from their true values or are completely unknown.
Temperature Control to Reduce Capacity Mismatch in Parallel-Connected Lithium Ion Cells
Authors: Garg Mayank , Tanim Tanvir R. , Rahn Christopher D. , Bryngelsson Hanna , Legnedahl Niklas
Published: November 2019

The temperature and capacity of individual cells affect the current distribution in a battery pack. Non uniform current distribution among parallel-connected cells can lead to capacity imbalance and premature aging. This paper develops models that calculate the current in parallel-connected cells and predict their capacity fade. The model is validated experimentally for a nonuniform battery pack at different temperatures. The paper also proposes and validates the hypothesis that temperature control can reduce capacity mismatch in parallel-connected cells. Three Lithium Iron Phosphate cells, two cells at higher initial capacity than the third cell, are connected in parallel. The pack is cycled for 1500 Hybrid Electric Vehicles cycles with the higher capacity cells regulated at 40°C and the lower capacity cell at 20°C. As predicted by the model, the higher capacity and temperature cells age faster, reducing the capacity mismatch by 48% over the 1500 cycles. A case study shows that cooling of low capacity cells can reduce capacity mismatch and extend pack life.
Modeling and Predictive Control of an Unmanned Underwater Vehicle
Authors: Rodriguez Nunez Renato , Soudbakhsh Damoon
Published: November 2019

This paper presents a model and optimal controller for Unmanned Underwater Vehicles (UUVs). We present a nonlinear six degrees of freedom model of the UUV that includes hydrodynamic and hydrostatic terms. To design the controller, we simplify the model using the geometry of the UUV as well as its operating conditions such as the depth and expected travel speed. Instead of designing a controller for the state space system, we used feedback linearization technique to decouple the motions. Then, a set of controllers were designed for each motion. To incorporate the constraints on the input and the state variables, we designed a fast Model Predictive Controller (MPC) for the UUV and compared its performance with a conventional controller.
Torsional Oscillations of a Shape-Morphing Plate in Viscous Fluids
Authors: Ahsan Syed N. , Aureli Matteo
Published: November 2019

In this paper, we investigate finite amplitude torsional oscillations of a shape-morphing plate submerged in a quiescent, Newtonian, incompressible fluid. To address this problem, we focus on a two-dimensional cross section of the plate and para-metrically study hydrodynamic moments and power dissipation during the plate oscillation as a function of the shape-morphing deformation intensity and the oscillation amplitude. This fluid-structure interaction problem is tackled within the framework of a computational fluid dynamics model where the fluid flow is described via the Navier-Stokes equations and the deformations of the structure are prescribed. The results demonstrate a gradual reduction of hydrodynamic moment and nonmonotonic power dissipation behavior as the imposed shape-morphing becomes more aggressive. In addition, power dissipation can be minimized for an optimum value of the shape-morphing intensity. Results from this study are relevant in underwater systems subjected to torsional oscillations and demonstrate an avenue for hydrodynamic moment control and reduction of energy losses.
A Passive Jumping Mechanism
Authors: Tallapragada Phanindra , Buzhardt Jake , Seney Robert
Published: November 2019

In this paper we present a novel unactuated mechanism that utilizes gravity to jump. The passive jumper is a hoop whose center of mass does not coincide with its geometric center. When the hoop rolls down an inclined plane, the center of mass of the hoop moves along a cycloid. As the hoop gains speed moving down the inclined plane, the normal reaction between the hoop and the plane becomes insufficient to ensure contact between the hoop and the plane. This allows the hoop to ‘jump’. Experiments and analysis show that such a jump can be significant, with the jump height from the plane being as high as one body length (diameter) of the hoop. The mechanics of the passive jumping hoop powered by gravity investigated in this paper can inspire the design of actuated jumping robots that can both roll and jump.
Model-Based Analysis of a Photovoltaic Array Powering a Flywheel Energy Storage System
Authors: Mohamed Mohamed , Tafreshi Reza , Khan Zurwa
Published: November 2019

One of the current technologies widely used to extract the earth’s renewable energy is solar modules, which harness energy from the sun; however, their operating conditions and their energy storage capacities vary greatly under different weather conditions. The high-speed Flywheel Energy Storage System (FESS) presents a promising prospective solution for solar energy storage and utilization. Accurately modeling FESS can lead to its efficient design and control. In this paper, a fully integrated FESS, with comprehensive photovoltaic (PV) system, has been modeled to simulate the overall energy harvesting capabilities, power output, and efficiency. The solar module has been modeled using the one-diode solar cell model technique to predict the overall system efficiency and determine the most efficient time of day for switching between the FESS’s charging (morning time) and discharging mode (night time). To validate the developed model using experimental data, four 250 Wp Ankara Solar PV modules and a Balance of System (BOS) were installed. The solar irradiance, wind speed, cell temperature, solar module, FESS output voltage and current were logged during the system’s operation. The theoretical model predicted that the energy output for the test day was 4.80 kWh, while the experimental analysis showed that the solar modules produced 4.68 kWh, only 2.5% percentage difference. The theoretical and experimental power curves followed the same trends throughout the day, which assures that the model could accurately predict the daily energy output of the solar array. The efficiency of the solar module was determined to be 15.3%. The solar module simulation serves as a repeatable replication of the actual solar module source, which enables convenient, low-cost estimation of the solar module-FESS system under different environmental conditions. The developed solar module was integrated with a brushless DC motor and flywheel models to simulate the FESS response. Relative to the input solar energy input of 4.68 kWh, the daily energy stored in a flywheel was 3.51 kWh, giving the overall solar-module-FESS system an efficiency of 74.7%. After the experimental setup completion of FESS, the integrated solar module-FESS model will be tested for its overall power output and efficiency against the traditional solar module-battery-system.
Bidirectional LSTM Recurrent Neural Network Plus Hidden Markov Model for Wearable Sensor Based Dynamic State Estimation
Authors: Sibal Ritika , Zhang Ding , Rocho-Levine Julie , Shorter K. Alex , Barton Kira
Published: November 2019

Publisher’s Note:

This paper was selected for publication in ASME Letters in Dynamic Systems and Control.

https://www.asmedigitalcollection.asme.org/lettersdynsys/article/doi/10.1115/1.4046685/1081846/Bidirectional-LSTM-Recurrent-Neural-Network-Plus
Multi-Mobile Sensing With Temporal-Spatial Coupling via Compressed Sensing
Authors: Li Tianwei , Zou Qingze
Published: November 2019

In this paper, the problem of using a limited number of mobile sensors to sense/measure a time-varying distribution of a field over a multi dimensional space is considered. As the number of sensors, in general, is not adequate for capturing the dynamic distribution with the needed spatial resolution, the sensors are required to be transited between the sampled locations, resulting in intermittent measurement at each sampled location. Therefore, it becomes challenging to use the measured data to recover/restore not only the dynamic process at each sampled/measured location, but also the dynamic distribution over the entire measured space, with high temporal and spatial resolutions. Such a multi-mobile sensing problem, however, cannot be addressed by using existing methods directly. In this work, we propose to tackle this problem through the compressed sensing framework. The randomness requirement of the compressed sensing, however, results in the temporal-spatial coupling, and the constraints in selecting the sampled locations due to the limit of the sensor speed. We propose a spatial-temporal pairing method to avoid the temporal-spatial coupling, and a checking-and-removal process to remove the sensor speed constraint. Simulation results of a video recovery example is presented and discussed to illustrate the proposed method.
Modeling Peripheral Artery Behavior Beneath a Non-Invasive Wearable Sensor Subject to Varying Outside Pressure
Authors: Wang Lu , Ansari Sardar , Cai Yingjie , Ward Kevin R. , Najarian Kayvan , Oldham Kenn R.
Published: November 2019

The state of the peripheral arteries is known to be a key physiological indicator of the body’s response to both acute and chronic medical conditions. In this paper, changes in peripheral artery behavior are tracked by combining a photo plethysmograph (PPG) sensor and a piezoelectric (PVDF) sensor with an outside pressure-varying cuff. In a swine subject, a simple mechanical model for the local artery and tissue captures broad features present in the PPG and PVDF signals, with respect to varying cuff pressure. These behaviors may provide insight into robustness of cardiovascular property identification by non-invasive wearable sensing.
Modeling of Thermal Dynamics of a Connected Hybrid Electric Vehicle for Integrated HVAC and Powertrain Optimal Operation
Authors: Doshi Nehal , Hanover Drew , Hemmati Sadra , Morgan Christopher , Shahbakhti Mahdi
Published: November 2019

Integrated energy management across system level components in electric vehicles (EVs) is currently an under-explored space. Opportunity exists to mitigate energy consumption and extend usable range of EVs through optimal control strategies which exploit system dynamics via controls integration of vehicle subsystems. Additionally, information available in connected vehicles like driver schedules, trip duration and ambient conditions can be leveraged to predict the operating conditions for a vehicle when a validated model of the vehicle is known. In this study, data-driven and physics-based models for heating, ventilation and air-conditioning (HVAC) are developed and utilized along with the vehicle dynamics and powertrain (VD&PT) models for a hybrid electric vehicle (HEV). The integrated HVAC and VD&PT models are then validated against real world data. Next, an integrated relationship between the internal combustion (IC) engine coolant and the cabin electric heater is established and used to promote potential energy savings in cabin heating when the operating schedule is known. Finally, an optimization study is conducted to establish a control strategy which maximizes the HVAC energy efficiency whilst maintaining occupant comfort levels according to ASHRAE standards and improving usable range of the vehicle relative to its baseline calibration.
Cooperative Collision Avoidance Control of Robotic Fish Propelled by a Servo/IPMC Driven Hybrid Tail
Authors: Yi Xiongfeng , Chen Zheng , Chakravarthy Animesh
Published: November 2019

This paper develops and demonstrates cooperative collision avoidance control on two robotic fish propelled by a servo motor and an ionic polymer-metal composite (IPMC)-driven fish tail. First, experiments conducted on a servo motor/IPMC-driven fish demonstrate an impulsive turning behavior in the fish’s trajectory under the application of a specific frequency, amplitude of the servo motor, and a constant voltage on the IPMC joint. These experiments validate the ‘back relaxation’ of the IPMC joint by observing the angular velocity and the centripetal acceleration of the fish. This impulsive turning speed due to the ‘back relaxation’ of IPMC joint is subsequently modeled by a transfer function and this transfer function is then integrated into the development of the collision avoidance laws for the fish. The collision avoidance control law utilizes the impulsive turning capability of the robotic fish. An experimental validation of the collision avoidance law is performed.
A Torque Balance Method for Multi-Cylinder Gasoline Engines With Non-Uniform Cylinder-to-Cylinder Combustion Strategies
Authors: Lin Qinghua , Chen Pingen
Published: November 2019

Lean burn gasoline engines have attracted more and more attentions over the past two decades. One of the main challenges in commercializing lean burn gasoline engines in the United States is lean NOx control to meet the stringent NOx emission regulation. Several types of lean aftertreatment systems including passive selective catalytic reduction (SCR) systems and lean NOx traps (LNTs), have been intensively investigated to meet the NOx emission requirements without triggering significant penalties on fuel efficiency. One of the most promising technologies to achieve this goal is non-uniform cylinder-to-cylinder combustion (NUCCC) control strategies. However, successful implementation of NUCCC strategies are challenging tasks since it may cause cylinder-to-cylinder torque imbalance and thus deterioration of drivability. The purpose of this study is to propose and evaluate a systematic method for generating the references of fuel quantity and air quantity for different cylinders to simultaneously achieve cylinder-to-cylinder torque balance and non-uniform cylinder-to-cylinder air/fuel ratio (AFR) for multi-cylinder engines in various scenarios. To validate the effectiveness of the proposed method, simulation studies were carried out using a multi-zone engine model. The simulation results show that, the proposed references, if successfully tracked, can lead to torque balance across the cylinders as well as non-uniform cylinder-to-cylinder AFR.
Class of Stabilizing Parallel Feedforward Compensators for Nonminimum-Phase Systems
Authors: Noury Keyvan , Yang Bingen
Published: November 2019

In this work, the properties of the class of parallel feedforward compensators to stabilize linear closed-loop systems are studied. The characteristic equation and its root locus behavior, including its asymptotes, are investigated to leave out the compensators that will not result in a stable closed-loop system. Even though there have been numerous studies relevant to parallel feedforward compensation that result in the optimal integration of squared errors (ISE), the broader view of all possible compensators has not been of much interest in the literature. Nevertheless, this study is important because, in the presence of noise and disturbance, an optimal ISE control design for the nominal plant may perform poorly while a finite ISE design may have a robust and efficient performance. One of such class compensators is parallel feedforward compensator with derivative effort (PFCD) that for a vast number of processes can have impressive properties such as no branch comebacks to the right half plane (RHP) of the root locus plot (LHP black hole effect). The example in this paper shows how effectively PFCD can contract the root locus branches into the LHP.
Simulation of the Gravitational Lensing Effect of Galactic Dark Matter Halos Using 3D Printing Technology
Authors: Su Jun , Wang Weiguo , Wang Xu , Song Feng
Published: November 2019

Gravitational lensing is an interesting phenomenon in astronomy and is most typically given rise to by galaxies. The majority of the matter in a galaxy is thought to be dark matter, and the galactic gravitational lensing effect is mainly caused by dark matter halos. In gravitational lensing-related demonstrations in physics education, the feet of goblets are usually employed to simulate gravitational lensing, an approach that can seem unrealistic. This paper describes how the galactic dark matter halo model can be used to calculate an equivalent lens shape, and a stereolithography (SLA) 3D printer can then be utilized to create a “galactic gravitational lens” to simulate the gravitational lensing effect produced by real galactic dark matter halos. This method not only helps students gain a preliminary knowledge of gravitational lensing, galaxies, dark matter, and other astronomical concepts, but also increases their understanding of the application of 3D printing technology in the fields of mathematics and physical visualization.
Quick-and-Dirty Item Response Theory
Authors: Kortemeyer Gerd
Published: November 2019

Item Response Theory (IRT) has proven useful in physics education research to examine the validity of concept tests (e.g., Refs. 1-3) and online homework (e.g. Refs. 4-6), yet as a tool for the improvement of physics instruction (particularly exams), it is oftentimes perceived as a) mysterious, b) unjustified, and c) impractical. This article aims to debunk some of those prejudices and provide a quick-and-dirty guide; it does not do any justice to the associated psychometric theories (see for example the classic Ref. 7).
Surface Tension Measured with Arduino
Authors: Goncalves Alem-Mar B. , Freitas Welica P. S. , Reis Diogo D. , Cena Cicero R. , Alves Diego C. B. , Bozano Doroteia F.
Published: November 2019

The popularization of microcontrollers like Arduino bring new possibilities of experiments for physics laboratories. For instance, load cell sensors have been used in experiments on impulse and buoyancy. Here we propose an experimental apparatus using Arduino connected to a load cell to measure surface tension by the du Noüy method (or ring method). The load cell gives the instantaneous and the maximum force value achieved during the experiment. This apparatus is presented as a simple and low-cost option for physics laboratories.
Underwater radiated noise from hydrofoils in coastal water
Authors: Li Jianghui , White Paul R. , Roche Ben , Davis John W. , Leighton Timothy G.
Published: November 2019

Underwater noise from commercial shipping throughout the oceans has been increasing over the past decades and the environmental impact of this noise remains an area of great uncertainty. This has led to the measurement of noise from commercial vessels in order to understand the impacts that these vessels may engender. Hydrofoils are used by ferries in various locations around the world and locally may be a significant contributing factor of the soundscape. However, the investigation on underwater radiated noise from the activity of hydrofoils in the field has not been widely conducted. This article is an attempt to characterize the noise from hydrofoils in the field. Detailed measurements in the coastal water close to the Panarea port, Italy are reported. The investigation describes the broadband frequency spectrum with the main energy approximately centered on 30–130 Hz but covering frequencies up to tens of kHz. A key result was that the spectrum of the noise varied between the three stages (displacement, transition, and foiling) of the hydrofoils heading into or out of the port.
Learning to Lead? Race and Perceived Effects of College on Life Skill Development Among Sportswomen
Authors: Allison Rachel
Published: November 2019

Integrating the Student-Athlete Climate Study conceptual framework with critical race and intersectionality theories, I examine racial differences in the perceived effects of college on life skill development among college sportswomen. I use nationally representative data from the NCAA’s 2006 Growth, Opportunity, Aspirations, and Learning of Students in College (GOALS) survey to examine whether team and/or campus climate mediate racial differences. I find small, but statistically significant differences whereby sportswomen of color report less positive effects of college on leadership, teamwork, time management, and work ethic compared to white sportswomen, but more positive effects of college on their understanding of people of other races. Campus climate, but not team climate, partially mediates racial differences in the perceived effects of college on leadership, teamwork, time management, and work ethic.
After 20 years, Golden Rice nears approval
Authors: Stokstad Erik
Published: November 2019

Bangladesh may become the first country to adopt transgenic rice enriched in vitamin A.
The landslide laboratory
Authors: Kornei Katherine
Published: November 2019

Landslides aren't just hazards. An experiment in Taiwan could reveal their outsize effect on the climate.
Double dip
Authors: Piller Charles
Published: November 2019

An NIH program pays school debt to keep scientists in academia. Many break the rules by also taking industry money.
Artificial intelligence for global health
Authors: Hosny Ahmed , Aerts Hugo J. W. L.
Published: November 2019

Socially responsible technologies promise to help address health care inequalities
A catalytic one-two punch
Authors: Ovian John M. , Jacobsen Eric N.
Published: November 2019

Cooperative catalysis enables the controlled synthesis of unnatural amino acids
Of crows and tools
Authors: Klump Barbara C.
Published: November 2019

Tool-using crows, culture, and what it means to be human
Creating the protein version of DNA base pairing
Authors: Chen Zibo
Published: November 2019

Programmable and modular protein-protein interactions designed from scratch
Excavating Uruk
Uruk: First City of the Ancient World
Timothy Potts
, editor J. Paul Getty Museum, 2019. 404 pp.
Authors: Robinson Andrew
Published: November 2019

A richly illustrated volume reveals what life was like in the world's first city
Designer sense-response systems
Authors: Chica Roberto A.
Published: November 2019

Artificial chemically induced protein dimerization yields biological sensor-actuator devices
Complete Genome Sequence of Escherichia coli Antibiotic-Resistant Isolate AR Bank #0349
Authors: Stuart Keira L. , Shore Sarah M. , Nicholson Tracy L.
Published: November 2019

The emergence of plasmid-mediated polymyxin resistance encoded by
mcr-1
has heightened public health concerns due to the potential for rapid horizontal transfer. Here, we report the complete genome sequence of
Escherichia coli
AR Bank #0349, which exhibits resistance to colistin encoded by a plasmid-borne
mcr-1
gene.
Complete Genome Sequence of Mycobacterium avium subsp.
hominissuis
Strain JP-H-1, Isolated from an Equine Abortion Case in Japan
Authors: Kinoshita Yuta , Niwa Hidekazu , Uchida-Fujii Eri , Nukada Toshio
Published: November 2019

Here, we describe the complete genome assembly of
Mycobacterium avium
subsp.
hominissuis
strain JP-H-1, collected from an equine abortion case in Japan. JP-H-1 has a 5,491,452-bp circular chromosome and 3 plasmids.
Draft Genome Sequence of the Birch Tree Fungal Pathogen Taphrina betulina UCD315
Authors: Heneghan Padraic , Ryan Adam P. , Nimmo Darragh , Duggan Claudine , Kumar Paurush , O’Gaora Peadar , Ó.'Cinnéide Eoin , Byrne Kevin P. , Wolfe Kenneth H. , O’Brien Caoimhe E. , Butler Geraldine
Published: November 2019

Taphrina betulina
is the ascomycete yeast that causes the formation of witches’ brooms in birch trees. Here, we report the first draft genome sequence of
T. betulina
, from strain UCD315, isolated from soil in Ireland. The genome is haploid and 12.5 Mb long.
Chromosome-Scale Genome Assembly of Two Australian Nannochloropsis oceanica Isolates Exhibiting Superior Lipid Characteristics
Authors: Brown Reuben B. , Wass Taylor J. , Thomas-Hall Skye R. , Schenk Peer M.
Published: November 2019

Nannochloropsis oceanica
strains BR2 and KB1 are microalgal isolates from brackish water in the Brisbane River and a coastal rock pool at the Sunshine Coast in Australia which display superior productivity at high temperatures. We used long-read sequencing to sequence their genomes and to facilitate elucidation of loci associated with these traits.
Management of penetrating injury with retained intraocular lead foreign body from a writing instrument: surgical video with implications for paediatric public health and safety
Authors: Qureshi Amreen , Kelly Simon P , Carley Fiona , Jalil Assad
Published: November 2019

Penetrating ocular injuries from writing instruments that are thrown, especially by children, in the community can result in significant ocular morbidity. Often these cases present to the accident and emergency department. Accurate and prompt assessment is key in saving sight. We present a case of one such injury and how it was surgically managed.
Rationale and design of the theRapeutic effects of peroneal nerve functionAl electrical stimuLation for Lower extremitY in patients with convalescent poststroke hemiplegia (RALLY) study: study protocol for a randomised controlled study
Authors: Matsumoto Shuji , Shimodozono Megumi , Noma Tomokazu
Published: November 2019

Introduction

Increasing evidence supports the utilisation of functional electrical stimulation (FES) to improve gait following stroke; however, few studies have focused exclusively on its use in the convalescent phase. In addition, its efficacy in patients with a non-Western life style has not been evaluated.

Methods and analysis

This is a randomised, controlled, open-label multicentre study, comparing rehabilitation with and without FES. The purpose of our study is to test the hypothesis that the FES system improves walking ability in Japanese patients with hemiplegia during the convalescent phase. Two hundred patients aged 20–85 years who had an initial stroke ≤6 months prior to the enrolment, are in a convalescent phase (after the end of acute phase treatment, within 6 months after the onset of stroke) with functional ambulation classification 3 or 4 and have a hemiplegic gait disorder (drop foot) due to stroke have been recruited from 21 institutions in Japan. The patients are randomised in 1:1 fashion to usual gait rehabilitation or rehabilitation using FES (Walkaide). The trial duration is 8 weeks, and the primary outcome measured will be the change in maximum distance from baseline to the end of the trial, as measured with the 6 min walk test (6-MWT). The 6-MWT is performed barefoot, and the two treatment groups are compared using the analysis of covariance.

Ethics and dissemination

This study is conducted in accordance with the principles of the Declaration of Helsinki and the Ethical Guidelines for Medical and Health Research Involving Human Subjects and is approved by the ethics committee of all participating institutions. The published results will be disseminated to all the participants by the study physicians.

Trial registration number

The University Hospital Medical Information Network-Clinical Studies Registry (UMIN000020604).
To what degree are review outcomes aligned for new active substances (NASs) between the European Medicines Agency and the US Food and Drug Administration? A comparison based on publicly available information for NASs initially approved in the time period 2014 to 2016
Authors: Kühler Thomas Christian , Bujar Magda , McAuslane Neil , Liberti Lawrence
Published: November 2019

Objective

To compare review outcome alignment between European Medicines Agency (EMA) and US Food and Drug Administration (FDA) for medicines approved by both agencies in the time period 2014–2016.

Design

Using publicly available information from FDA and EMA websites, new active substances (NASs) approved by each agency from 2014 to 2016 were identified and their characteristics assessed. Divergences in regulatory outcomes for simultaneous (within 91 days) submissions to both agencies were identified and then examined for use of facilitated regulatory pathways and orphan designations; submitted versus approved indications; and approval times.

Results

In 2014–2016, 115 NASs were approved by EMA or FDA or both; 74/115 were new chemical entities and 41 new biological/biotechnology entities; 82/115 were approved by both agencies, 24 only by FDA and nine only by EMA. Simultaneous submission occurred for 52/115; 13/52 received expedited review by both agencies and 18 only by FDA; 8/52 received conditional approval from both agencies, 2/52 only from FDA and 1/52 only from EMA; 17/52 were designated as orphans by both agencies and 10/52 by FDA only; 31/52 indications were approved as submitted and 21 changed by EMA and 29/46 were approved as submitted (six not assessed) and 17/46 changed by FDA. Median FDA review timelines were 319 days compared with 409 days for EMA.

Conclusions

There was general agreement in EMA / FDA conditional approvals. FDA used expedited pathways and orphan designation more often than EMA, suggesting stricter EMA criteria or definitions for these designations or less flexible processes. Despite consistency in submitted indications, there was lack of concordance in approved indications, which should be further investigated. FDA review times are faster because of a wider range of expedited pathways and the two-step EMA process; this may change with recent revisions to EMA accelerated assessment guidelines and the launch of Priority Medicines.