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Articles 1 - 30 of 313

Full-Text Articles in Operations Research, Systems Engineering and Industrial Engineering

Extended Version Of Simple Sagittal Running: Stability Of A Quadrupedal Bound, Jeff Duperret, D. E. Koditschek Dec 2019

Extended Version Of Simple Sagittal Running: Stability Of A Quadrupedal Bound, Jeff Duperret, D. E. Koditschek

Technical Reports (ESE)

This paper develops a three degree-of-freedom sagittal-plane hybrid dynamical systems model of a bounding quadruped. Simple within-stance controls yield a closed form expression for a family of hybrid limit cycles that represent bounding behavior over a range of user-selected fore-aft speeds as a function of the model's kinematic and dynamical parameters. Controls acting on the hybrid transitions are structured so as to achieve a cascade composition of in-place bounding driving the fore-aft degree of freedom thereby decoupling the linearized dynamics of an approximation to the stride map. Careful selection of the feedback channels used to implement these controls affords ...


Composition Of Templates For Transitional Pedipulation Behaviors, Thomas T. Topping, Vasileios Vasilopoulos, Avik De, Daniel E. Koditschek Sep 2019

Composition Of Templates For Transitional Pedipulation Behaviors, Thomas T. Topping, Vasileios Vasilopoulos, Avik De, Daniel E. Koditschek

Departmental Papers (ESE)

Abstract. We document the reliably repeatable dynamical mounting and dismounting of wheeled stools and carts, and of fixed ledges, by the Minitaur robot. Because these tasks span a range of length scales that preclude quasi-static execution, we use a hybrid dynamical systems framework to variously compose and thereby systematically reuse a small lexicon of templates (low degree of freedom behavioral primitives). The resulting behaviors comprise the key competences beyond mere locomotion required for robust implementation on a legged mobile manipulator of a simple version of the warehouseman’s problem.


Economic Model Predictive Control And Process Equipment: Control-Induced Thermal Stress In A Pipe, Helen Durand Jul 2019

Economic Model Predictive Control And Process Equipment: Control-Induced Thermal Stress In A Pipe, Helen Durand

Chemical Engineering and Materials Science Faculty Research Publications

Recent work on economic model predictive control (EMPC) has indicated that some processes may be operated in a more economically-optimal fashion under a time-varying operating policy than under a steady-state operating policy. However, a concern for time-varying operation is how such a change in operating policy might impact the equipment within which the processes being controlled are carried out. While under steady-state operation, the operating conditions to which equipment would regularly be exposed can be estimated, this would be more difficult to assess thoroughly a priori under time-varying operation. It could be explored whether the EMPC could be made aware ...


Systematizing Gibsonian Affordances In Robotics: An Empirical, Generative Approach Derived From Case Studies In Legged Locomotion, Sonia F. Roberts, Lisa J. Miracchi, Daniel E. Koditschek May 2019

Systematizing Gibsonian Affordances In Robotics: An Empirical, Generative Approach Derived From Case Studies In Legged Locomotion, Sonia F. Roberts, Lisa J. Miracchi, Daniel E. Koditschek

Departmental Papers (ESE)

A Gibsonian theory of affordances commits to direct perception and the mutuality of the agent-environment system. We argue that there already exists a research program in robotics which incorporates Gibsonian affordances. Controllers under this research program use information perceived directly from the environment with little or no further processing, and implicitly respect the indivisibility of the agentenvironment system. Research investigating the relationships between environmental and robot properties can be used to design reactive controllers that provably allow robots to take advantage of these affordances. We lay out key features of our empirical, generative Gibsonian approach and both show how it ...


Mechanical And Virtual Compliance For Robot Locomotion In A Compliant World, Sonia F. Roberts, Daniel E. Koditschek May 2019

Mechanical And Virtual Compliance For Robot Locomotion In A Compliant World, Sonia F. Roberts, Daniel E. Koditschek

Departmental Papers (ESE)

This abstract was accepted to the Robot Design and Customization workshop at ICRA 2019.

For more information: Kod*lab.


Rapid In Situ Characterization Of Soil Erodibility With A Field Deployable Robot, Feifei Qian, Dylan Lee, George Nikolich, Daniel E. Koditschek, Douglas J. Jerolmack May 2019

Rapid In Situ Characterization Of Soil Erodibility With A Field Deployable Robot, Feifei Qian, Dylan Lee, George Nikolich, Daniel E. Koditschek, Douglas J. Jerolmack

Departmental Papers (ESE)

Predicting the susceptibility of soil to wind erosion is difficult because it is a multivariate function of grain size, soil moisture, compaction, and biological growth. Erosive agents like plowing and grazing also differ in mechanism from entrainment by fluid shear; it is unclear if and how erosion thresholds for each process are related. Here we demonstrate the potential to rapidly assemble empirical maps of erodibility while also examining what controls it, using a novel “plowing” test of surface-soil shear resistance (𝜏r) performed by a semi-autonomous robot. Field work at White Sands National Monument, New Mexico, United States, examined gradients ...


Mitigating Energy Loss In A Robot Hopping On A Physically Emulated Dissipative Substrate, Sonia F. Roberts, Daniel E. Koditschek May 2019

Mitigating Energy Loss In A Robot Hopping On A Physically Emulated Dissipative Substrate, Sonia F. Roberts, Daniel E. Koditschek

Departmental Papers (ESE)

We work with geoscientists studying erosion and desertification to improve the spatial and temporal resolution of their data collection over long transects in difficult realworld environments such as deserts. The Minitaur robot, which can run quickly over uneven terrain and use a single leg to measure relevant ground properties such as stiffness, is an attractive scout robot candidate for inclusion in a heterogeneous team in collaboration with a heavily geared, sensor-laden RHex. However, Minitaur is challenged by long-distance locomotion on sand dunes. Previous simulation results suggested that the energetic cost of transport can be mitigated by programming a virtual damping ...


Task-Based Control And Design Of A Bldc Actuator For Robotics, Avik De, Abriana Stewart-Height, Daniel E. Koditschek Jan 2019

Task-Based Control And Design Of A Bldc Actuator For Robotics, Avik De, Abriana Stewart-Height, Daniel E. Koditschek

Departmental Papers (ESE)

This paper proposes a new multi-input brushless DC motor current control policy aimed at robotics applications. The controller achieves empirical improvements in steady-state torque and power-production abilities relative to conventional controllers, while retaining similarly good torque-tracking and stability characteristics. Simulations show that non-conventional motor design optimizations whose feasibility is established by scaling model extrapolations from existing motor catalogues can vastly amplify the effectiveness of this new control-strategy.


A Multi-Stage Optimization Model For Flexibility In Engineering Design, Ramin Giahi, Cameron A. Mackenzie, Chao Hu Jan 2019

A Multi-Stage Optimization Model For Flexibility In Engineering Design, Ramin Giahi, Cameron A. Mackenzie, Chao Hu

Industrial and Manufacturing Systems Engineering Conference Proceedings and Posters

Engineered systems often operate in uncertain environments. Understanding different environments under which a system will operate is important in engineering design. Thus, there is a need to design systems with the capability to respond to future changes. This research explores designing a hybrid renewable energy system while taking into account long-range uncertainties of 20 years. The objective is to minimize the expected cost of the hybrid renewable energy system over the next 20 years. A design solution may be flexible, which means that the design can be adapted or modified to meet different scenarios in the future. The value of ...


Reactive Navigation In Partially Known Non-Convex Environments, Vasileios Vasilopoulos, Daniel E. Koditschek Dec 2018

Reactive Navigation In Partially Known Non-Convex Environments, Vasileios Vasilopoulos, Daniel E. Koditschek

Departmental Papers (ESE)

This paper presents a provably correct method for robot navigation in 2D environments cluttered with familiar but unexpected non-convex, star-shaped obstacles as well as completely unknown, convex obstacles. We presuppose a limited range onboard sensor, capable of recognizing, localizing and (leveraging ideas from constructive solid geometry) generating online from its catalogue of the familiar, non-convex shapes an implicit representation of each one. These representations underlie an online change of coordinates to a completely convex model planning space wherein a previously developed online construction yields a provably correct reactive controller that is pulled back to the physically sensed representation to generate ...


Cost Benefit Analysis Of Led Vs Florescent Lighting, Kurtis Clark, Phillip Humphrey Nov 2018

Cost Benefit Analysis Of Led Vs Florescent Lighting, Kurtis Clark, Phillip Humphrey

Student Research

Over the last few years, the state of Oklahoma has been looking at ways to reduce expenses to address concerns about a budget deficit. There have been efforts made to reduce expenses due to the use of energy. It has been said, when the lights are on, work is getting done. Running lights is therefore the cost of doing business. Our research examines the question, “is there a way to provide better lighting while operating at a lower cost.” This research examines the current lighting at Southwestern State University, primarily fluorescent lighting (FL), and a cost benefit analysis of switching ...


Reactive Velocity Control Reduces Energetic Cost Of Jumping With A Virtual Leg Spring On Simulated Granular Media, Sonia F. Roberts, Daniel E. Koditschek Nov 2018

Reactive Velocity Control Reduces Energetic Cost Of Jumping With A Virtual Leg Spring On Simulated Granular Media, Sonia F. Roberts, Daniel E. Koditschek

Departmental Papers (ESE)

Robots capable of dynamic locomotion behaviors and high-bandwidth sensing with their limbs have a high cost of transport, especially when locomoting over highly dissipative substrates such as sand. We formulate the problem of reducing the energetic cost of locomotion by a Minitaur robot on sand, reacting to robot state variables in the inertial world frame without modeling the ground online. Using a bulk-behavior model of high-velocity intrusions into dry granular media, we simulated single jumps by a one-legged hopper using a Raibert-style compression-extension virtual leg spring. We compose this controller with a controller that added damping to the leg spring ...


Actuator Transparency And The Energetic Cost Of Proprioception, Gavin Kenneally, Wei-Hsi Chen, Daniel Koditschek Nov 2018

Actuator Transparency And The Energetic Cost Of Proprioception, Gavin Kenneally, Wei-Hsi Chen, Daniel Koditschek

Departmental Papers (ESE)

In the field of haptics, conditions for mechanical “transparency”[1] entail such qualities as “solid virtual objects must feel stiff” and “free space must feel free”[2], suggesting that a suitable actuator is able both to do work and readily have work done on it. In this context, seeking actuator transparency has come to mean a preference for minimal dynamics [3] or no impedance [4]. While such general notions seem satisfactory for a haptic interface, actuators with good mechanical transparency are now being used in high-performance robots [5, 6] where once again they must be able to do work, but ...


Sensor-Based Reactive Execution Of Symbolic Rearrangement Plans By A Legged Mobile Manipulator, Vasileios Vasilopoulos, T. Turner Topping, William Vega-Brown, Nicholas Roy, Daniel E. Koditschek Oct 2018

Sensor-Based Reactive Execution Of Symbolic Rearrangement Plans By A Legged Mobile Manipulator, Vasileios Vasilopoulos, T. Turner Topping, William Vega-Brown, Nicholas Roy, Daniel E. Koditschek

Departmental Papers (ESE)

We demonstrate the physical rearrangement of wheeled stools in a moderately cluttered indoor environment by a quadrupedal robot that autonomously achieves a user's desired configuration. The robot's behaviors are planned and executed by a three layer hierarchical architecture consisting of: an offline symbolic task and motion planner; a reactive layer that tracks the reference output of the deliberative layer and avoids unanticipated obstacles sensed online; and a gait layer that realizes the abstract unicycle commands from the reactive module through appropriately coordinated joint level torque feedback loops. This work also extends prior formal results about the reactive layer ...


Inertial Velocity And Attitude Estimation For Quadrotors: Supplementary Material, James B. Svacha Jr, Kartik Mohta, Michael Watterson, Giuseppe Loianno, Vijay Kumar Oct 2018

Inertial Velocity And Attitude Estimation For Quadrotors: Supplementary Material, James B. Svacha Jr, Kartik Mohta, Michael Watterson, Giuseppe Loianno, Vijay Kumar

Departmental Papers (ESE)

No abstract provided.


Impact Of Communication Latency On The Bus Voltage Of Centrally Controlled Dc Microgrid During Islanding, Mahmoud Saleh, Yusef Esa, Ahmed Mohamed Oct 2018

Impact Of Communication Latency On The Bus Voltage Of Centrally Controlled Dc Microgrid During Islanding, Mahmoud Saleh, Yusef Esa, Ahmed Mohamed

Publications and Research

Maintaining a sustainable and reliable source of energy to supply critical loads within a renewable energy based microgrid (MG) during blackouts is directly related to its bus voltage variations. For example, voltage variation might trigger protection devices and disconnect DERs within the MG. Centrally controlled MGs (CCMGs) type is dependent on communication. Therefore, it is very important to analyze the impact of communication networks performance degradation, such as latency, on the bus voltage of CCMGs. This paper investigates the effect of wireless communication technologies latency on the bus voltage and performance of centralized DC MGs. Two mathematical models were developed ...


What Is A Good Pattern Of Life Model? Guidance For Simulations, Barry G. Silverman, Gnana K. Bharathy, Nathan Weyer Aug 2018

What Is A Good Pattern Of Life Model? Guidance For Simulations, Barry G. Silverman, Gnana K. Bharathy, Nathan Weyer

Departmental Papers (ESE)

We have been modeling an ever-increasing scale of applications with agents that simulate the pattern of life (PoL) and real-world human behaviors in diverse regions of the world. The goal is to support sociocultural training and analysis. To measure progress, we propose the definition of a measure of goodness for such simulated agents, and review the issues and challenges associated with first-generation (1G) agents. Then we present a second generation (2G) agent hybrid approach that seeks to improve realism in terms of emergent daily activities, social awareness, and micro-decision making in simulations. We offer a PoL case study with a ...


Economic Model Predictive Control Design Via Nonlinear Model Identification, Laura Giuliani, Helen Durand Aug 2018

Economic Model Predictive Control Design Via Nonlinear Model Identification, Laura Giuliani, Helen Durand

Chemical Engineering and Materials Science Faculty Research Publications

Increasing pushes toward next-generation/smart manufacturing motivate the development of economic model predictive control (EMPC) designs which can be practically deployed. For EMPC, the constraints, objective function, and accuracy of the state predictions would benefit from process models that describe the process physics. However, obtaining first- principles models of chemical process systems can be time-consuming or challenging such that it is preferable to develop physics-based process models automatically from process operating data. In this work, we take initial steps in this direction by suggesting that because experiments that are used to characterize first-principles models often target specific types of data ...


Analytically-Guided Design Of A Tailed Bipedal Hopping Robot, Abdulaziz Shamsah, Avik De, Daniel E. Koditschek Jul 2018

Analytically-Guided Design Of A Tailed Bipedal Hopping Robot, Abdulaziz Shamsah, Avik De, Daniel E. Koditschek

Departmental Papers (ESE)

We present the first fully spatial hopping gait of a 12 DoF tailed biped driven by only 4 actuators. The control of this physical machine is built up from parallel compositions of controllers for progressively higher DoF extensions of a simple 2 DoF, 1 actuator template. These template dynamics are still not themselves integrable, but a new hybrid averaging analysis yields a conjectured closed form representation of the approximate hopping limit cycle as a function of its physical and control parameters. The resulting insight into the role of the machine's kinematic and dynamical design choices affords a redesign leading ...


Data-Based Nonlinear Model Identification In Economic Model Predictive Control, Laura Giuliani, Helen Durand Jul 2018

Data-Based Nonlinear Model Identification In Economic Model Predictive Control, Laura Giuliani, Helen Durand

Chemical Engineering and Materials Science Faculty Research Publications

Many chemical/petrochemical processes in industry are not completely modeled from a first-principles perspective because of the complexity of the underlying physico-chemical phenomena and the cost of obtaining more accurate, physically relevant models. System identification methods have been utilized successfully for developing empirical, though not necessarily physical, models for advanced model-based control designs such as model predictive control (MPC) for decades. However, a fairly recent development in MPC is economic model predictive control (EMPC), which is an MPC formulated with an economics-based objective function that may operate a process in a dynamic (i.e., off steady-state) fashion, in which case ...


Vertical Hopper Compositions For Preflexive And Feedback-Stabilized Quadrupedal Bounding, Pacing, Pronking, And Trotting, Avik De, Daniel E. Koditschek Jul 2018

Vertical Hopper Compositions For Preflexive And Feedback-Stabilized Quadrupedal Bounding, Pacing, Pronking, And Trotting, Avik De, Daniel E. Koditschek

Departmental Papers (ESE)

This paper applies an extension of classical averaging methods to hybrid dynamical systems, thereby achieving formally specified, physically effective and robust instances of all virtual bipedal gaits on a quadrupedal robot. Gait specification takes the form of a three parameter family of coupling rules mathematically shown to stabilize limit cycles in a low degree of freedom template: an abstracted pair of vertical hoppers whose relative phase locking encodes the desired physical leg patterns. These coupling rules produce the desired gaits when appropriately applied to the physical robot. The formal analysis reveals a distinct set of morphological regimes determined by the ...


Sensor-Based Reactive Navigation In Unknown Convex Sphere Worlds, Omur Arslan, Daniel E. Koditschek May 2018

Sensor-Based Reactive Navigation In Unknown Convex Sphere Worlds, Omur Arslan, Daniel E. Koditschek

Departmental Papers (ESE)

We construct a sensor-based feedback law that provably solves the real-time collision-free robot navigation problem in a compact convex Euclidean subset cluttered with unknown but sufficiently separated and strongly convex obstacles. Our algorithm introduces a novel use of separating hyperplanes for identifying the robot’s local obstacle-free convex neighborhood, affording a reactive (online-computed) continuous and piecewise smooth closed-loop vector field whose smooth flow brings almost all configurations in the robot’s free space to a designated goal location, with the guarantee of no collisions along the way. Specialized attention to planar navigable environments yields a necessary and sufficient condition on ...


Applications Of Complex Network Analysis In Electric Power Systems, Mahmoud Saleh, Yusef Esa, Ahmed Mohamed May 2018

Applications Of Complex Network Analysis In Electric Power Systems, Mahmoud Saleh, Yusef Esa, Ahmed Mohamed

Publications and Research

This paper provides a review of the research conducted on complex network analysis (CNA) in electric power systems. Moreover, a new approach is presented to find optimal locations for microgrids (MGs) in electric distribution systems (EDS) utilizing complex network analysis. The optimal placement in this paper points to the location that will result in enhanced grid resilience, reduced power losses and line loading, better voltage stability, and a supply to critical loads during a blackout. The criteria used to point out the optimal placement of the MGs were predicated on the centrality analysis selected from the complex network theory, the ...


Design Of A Distributed Real-Time E-Health Cyber Ecosystem With Collective Actions: Diagnosis, Dynamic Queueing, And Decision Making, Yanlin Zhou May 2018

Design Of A Distributed Real-Time E-Health Cyber Ecosystem With Collective Actions: Diagnosis, Dynamic Queueing, And Decision Making, Yanlin Zhou

Theses, Dissertations, and Student Research from Electrical & Computer Engineering

In this thesis, we develop a framework for E-health Cyber Ecosystems, and look into different involved actors. The three interested parties in the ecosystem including patients, doctors, and healthcare providers are discussed in 3 different phases. In Phase 1, machine-learning based modeling and simulation analysis is performed to remotely predict a patient's risk level of having heart diseases in real time. In Phase 2, an online dynamic queueing model is devised to pair doctors with patients having high risk levels (diagnosed in Phase 1) to confirm the risk, and provide help. In Phase 3, a decision making paradigm is ...


Sensor-Based Reactive Symbolic Planning In Partially Known Environments, Vasileios Vasilopoulos, William Vega-Brown, Omur Arslan, Nicholas Roy, Daniel E. Koditschek May 2018

Sensor-Based Reactive Symbolic Planning In Partially Known Environments, Vasileios Vasilopoulos, William Vega-Brown, Omur Arslan, Nicholas Roy, Daniel E. Koditschek

Departmental Papers (ESE)

This paper considers the problem of completing assemblies of passive objects in nonconvex environments, cluttered with convex obstacles of unknown position, shape and size that satisfy a specific separation assumption. A differential drive robot equipped with a gripper and a LIDAR sensor, capable of perceiving its environment only locally, is used to position the passive objects in a desired configuration. The method combines the virtues of a deliberative planner generating high-level, symbolic commands, with the formal guarantees of convergence and obstacle avoidance of a reactive planner that requires little onboard computation and is used online. The validity of the proposed ...


On Balancing Event And Area Coverage In Mobile Sensor Networks, Hancheng Min May 2018

On Balancing Event And Area Coverage In Mobile Sensor Networks, Hancheng Min

Departmental Papers (ESE)

In practice, the mobile sensor networks have two important tasks: firstly, sensors should be able to locate themselves close to where major events are happening so that event tracking becomes possible; secondly, the sensor networks should also maintain a good area coverage over the environment in order to detect new events. Because these two tasks are usually conflicting with each other, a coverage control policy should be able to balance the event and area coverage of the environment. However, most existing work is to achieve either optimal event coverage or optimal area coverage over the environment. In this thesis, a ...


Nomadic Monument For Women In Robotics, Diedra Krieger, Gaby Alfaro, Joey Hartmann-Dow, Sonia F. Roberts Apr 2018

Nomadic Monument For Women In Robotics, Diedra Krieger, Gaby Alfaro, Joey Hartmann-Dow, Sonia F. Roberts

Departmental Papers (ESE)

We describe the Nomadic Monument for Women in Robotis (NMWR), a project celebrating women pioneers in robotics. NMWR is a 13’ semi-transparent geodesic dome with illustrations and descriptions of the women and their research on the inside faces of the triangles. Visitors can see rough outlines of the illustrations from the outside, but must enter the dome to learn about the women. As an immersive environment, the dome provides visitors not only a place to learn about inspiring women but also a space to feel that they are a member of this inspiring community.

The geodesic dome was introduced by ...


Implementing A Total Productive Maintenance Approach Into An Improvement At S Company, Xiaomeng Sun Apr 2018

Implementing A Total Productive Maintenance Approach Into An Improvement At S Company, Xiaomeng Sun

Masters Theses & Specialist Projects

The study improved the overall equipment effectiveness (OEE) of machines and processes through the implementation of a total productive maintenance (TPM) approach at Company S over a three-month period. By comparing the OEE of equipment before and after the implementation of autonomous maintenance, this study concluded that autonomous maintenance improves OEE. The target of this study was one general product line at a polytetrafluoroethylene (PTFE) plant. Due to time limitations, the study only applied autonomous maintenance to operational activities. This research involved machine and processes selection, condition assessment, baseline OEE assessment, operator training, execution of autonomous maintenance, and OEE measurement ...


A Hybrid Dynamical Extension Of Averaging And Its Application To The Analysis Of Legged Gait Stability, Avik De, Samuel A. Burden, Daniel E. Koditschek Mar 2018

A Hybrid Dynamical Extension Of Averaging And Its Application To The Analysis Of Legged Gait Stability, Avik De, Samuel A. Burden, Daniel E. Koditschek

Departmental Papers (ESE)

We extend a smooth dynamical systems averaging technique to a class of hybrid systems with a limit cycle that is particularly relevant to the synthesis of stable legged gaits. After introducing a definition of hybrid averageability sufficient to recover the classical result, we illustrate its applicability by analysis of first a one-legged and then a two-legged hopping model. These abstract systems prepare the ground for the analysis of a significantly more complicated two legged model—a new template for quadrupedal running to be analyzed and implemented on a physical robot in a companion paper. We conclude with some rather more ...


Integration Of Local Geometry And Metric Information In Sampling-Based Motion Planning, Vincent Pacelli, Omur Arslan, Daniel E. Koditschek Feb 2018

Integration Of Local Geometry And Metric Information In Sampling-Based Motion Planning, Vincent Pacelli, Omur Arslan, Daniel E. Koditschek

Departmental Papers (ESE)

The efficiency of sampling-based motion planning algorithms is dependent on how well a steering procedure is capable of capturing both system dynamics and configuration space geometry to connect sample configurations. This paper considers how metrics describing local system dynamics may be combined with convex subsets of the free space to describe the local behavior of a steering function for sampling-based planners. Subsequently, a framework for using these subsets to extend the steering procedure to incorporate this information is introduced. To demonstrate our framework, three specific metrics are considered: the LQR cost-to-go function, a Gram matrix derived from system linearization, and ...