Jeanne M. Peters

Virtual Reality Enhanced Online Learning Environments as a Substitute for Classroom Instruction

In this paper we present the main features of a virtual-reality enhanced online learning environment that can be used to deliver fully automated online courses with an ultimate goal of substituting traditional classroom instruction for many science, technology, engineering and math courses. The learning environment incorporates a high level of interactivity that will make the student an active participant in the learning experience, rather than a passive spectator. Virtual-reality is seamlessly integrated in order to simulate lab experiments, scientific instruments and/or industrial equipment. This will help bridge the gap between real world experience and online learning. The learning environment is illustrated using recently developed online courses for freshman university Physics, welding, CNC machining, and centrifugal pump maintenance.© 2011 ASME

Coupled Multibody Dynamics and Discrete Element Modeling of Vehicle Mobility on Cohesive Granular Terrains

Multibody dynamics and the discrete element method (DEM) are integrated into one solver for predicting the dynamic response of ground vehicles which run on wheels and/or tracks on cohesive soft soils (such as mud and snow). Multibody dynamics techniques are used to model the various vehicle components and connect those components using various types of joints and contact surfaces. A penalty technique is used to impose joint and normal contact constraints. An asperity-based friction model is used to model joint and contact friction. A soft cohesive soil material model (that includes normal and tangential inter-particle force models) is presented that can account for soil compressibility, plasticity, fracture, friction, viscosity, cohesive strength and flow. A Cartesian Eulerian grid contact search algorithm is used to allow fast contact detection between particles. A recursive bounding box contact search algorithm is used to allow fast contact detection between the particles and polygonal contact surfaces. The governing equations of motion are solved along with joint/constraint equations using a time-accurate explicit solution procedure. Numerical simulations of a typical vehicle going over a slopped soft soil terrain are presented to demonstrate the integrated solver. The solver can be used in vehicle design optimization.Copyright

Real-Time Explicit Flexible Multibody Dynamics Solver With Application to Virtual-Reality Based E-Learning

A flexible multibody dynamics explicit time-integration parallel solver suitable for real-time virtual-reality applications is presented. The hierarchical “scene-graph” representation of the model used for display and user-interaction with the model is also used in the solver. The multibody system includes rigid bodies, flexible bodies, joints, frictional contact constraints, actuators and prescribed motion constraints. The rigid bodies rotational equations of motion are written in a body-fixed frame with the total rigid body rotation matrix updated each time step using incremental rotations. Flexible bodies are modeled using total-Lagrangian spring, truss, beam and hexahedral finite elements. The motion of the elements is referred to a global inertial Cartesian reference frame. A penalty technique is used to impose joint/contact constraints. An asperity-based friction model is used to model joint/contact friction. A bounding box binary tree contact search algorithm is used to allow fast contact detection between finite elements and other elements as well as general triangular/quadrilateral rigid-body surfaces. The real-time solver is used to model virtual-reality based experiments (including mass-spring systems, pendulums, pulley-rope-mass systems, billiards, air-hockey and a solar system) for a freshman university physics e-learning course.Copyright

Coupled Multibody Dynamics and Discrete Element Modeling of Bulldozers Cohesive Soil Moving Operation

Multibody dynamics and the discrete element method are integrated into one solver for modeling the excavation and moving operation of cohesive soft soil (such as mud and snow) by bulldozers. A soft cohesive soil material model (that includes normal and tangential inter-particle force models) is presented that can account for soil flow, compressibility, plasticity, fracture, friction, viscosity, gain in cohesive strength due to compression, and loss in cohesive strength due to tension. Multibody dynamics techniques are used to model the various bulldozer components and connect those components using various types of joints and contact surfaces. A penalty technique is used to impose joint and normal contact constraints. An asperity-based friction model is used to model joint and contact friction. A Cartesian Eulerian grid contact search algorithm is used to allow fast contact detection between particles. A recursive bounding box contact search algorithm is used to allow fast contact detection between the particles and polygonal contact surfaces. The governing equations of motion are solved along with joint/constraint equations using a time-accurate explicit solution procedure. A numerical simulation of a bulldozer performing a shallow digging operation in a cohesive mud-type soil is presented to demonstrate the integrated solver. The solver can be used to improve the design of the various bulldozer components such as the blade geometry, tire design, and track design.Copyright

Coupled Multibody Dynamics and Smoothed Particle Hydrodynamics for Predicting Liquid Sloshing for Tanker Trucks

Multibody dynamics and smoothed particle hydrodynamics (SPH) are integrated into one solver for predicting the dynamic response of tanker trucks. Multibody dynamics techniques are used to model the various vehicle components and connect those components using various types of joints and contact surfaces. A penalty technique is used to impose joint and normal contact constraints (between the tires and ground, and between the tank and the fluid particles). An asperity-based friction model is used to model joint and contact friction. The liquid in the tanks is modeled using an SPH particle-based approach. A contact search algorithm that uses a moving Cartesian Eulerian grid that is fixed to the tank is used to allow fast contact detection between particles. A recursive bounding box contact search algorithm is used to allow fast contact detection between polygonal contact surfaces and the fluid particles. The governing equations of motion for the solid bodies and the fluid particles are solved along with joint/constraint equations using a time-accurate explicit solution procedure. The integrated solver is used to predict the dynamic response of a typical tanker truck performing a braking test with an empty, half-full and full tank. The solver can be used in vehicle design optimization to simulate and evaluate various vehicle designs.Copyright

On-Line University Physics Course Using Intelligent Virtual-Tutors, Virtual-Reality and Advanced Multimedia

A web-based self-paced university physics course, called the Virtual Physics Lab (VPL) is described. The VPL delivers both the lecture and lab components of a physics course using interactive virtual-reality simulations, high-end multimedia lectures and 2D/3D mini-games/exercises. The VPL’s interactive simulations are delivered in a video-game-like 3D photo-realistic virtual environment using real-time models to simulate typical physics experiments performed in the lab part of the physics course such as: frictional motion of a block on an inclined plane, vibrations of a mass-spring system and impact of particles. Students can change in real-time the parameters of the experiments and observe the effect on the experiment’s response and measurements. The multimedia lectures are delivered using a multimodal combination of speech and highlighted text delivered by near-photorealistic intelligent animated lip and gesture synched virtual tutors. The multimedia lectures include synchronized interactive 2D/3D animated illustrations and movies. A search engine and a hierarchical expert system allow the virtual tutors to answer natural-language questions and execute natural-language commands given by the student. Exercises in the form of mini-games that use relevant physics principles are used to increase the students’ interest in the material being taught and to test the student’s comprehension. The VPL’s interactivity and visually stimulating instruction will result in faster assimilation, deeper understanding, and higher memory retention by the students than traditional classroom/text-book instruction.Copyright

The Automation of Education: How Computers Will Take Over Most Teaching Jobs

The cost of primary, secondary and higher education consumes large percentages of the incomes of families, states and even countries every year. In this paper, we describe how automation can not only greatly reduce the cost of education, but also create new learning paradigms that can increase the effectiveness of that education as compared to traditional classroom learning. Intelligent Tutoring Massively Open Online Courses (ITMOOCs) can seamlessly deliver entire curricula while ensuring that students achieve and maintain the required level of proficiency in every curriculum topic. This is achieved by organizing the curriculum into an ontology of interconnected topic nodes, and assessing the students’ performance after he/she covers every node. The Intelligent Tutoring System (ITS) continuously adapts the course’s delivery to the needs of each student by skipping over topics that the student demonstrates proficiency in, and reviewing topics that are determined to be the cause of assessment failures in downstream course nodes. The ITS can also ensure that students maintain the required level of proficiency in the topics they have learned throughout their educational and professional careers by assigning an expiration time to each curriculum node after which it is reassessed. The system allows each student to set unique educational goals by selecting the individual topics that he/she ultimately wants to learn.Copyright

Innovative Online Course Using an Integrated Virtual Reality Based E-Learning Tool with Course Management Tool

An innovative online course in advanced manufacturing is developed based on a unique integration of a state-of-the-art learning tool (AVML, or Advanced Virtual Manufacturing Laboratory) with a course management tool (OnCourse). The AVML is a collaborative web-based virtual learning environment for integrated lecture and lab delivery that allows for the first time the delivery of effective, realistic and complete advanced manufacturing curriculum which includes hands-on practice. The system seamlessly and synergistically integrates multimedia lecture, interactive 3D simulation, and realistic experimentation in a virtual reality environment. The learning experience is further enhanced by the use of intelligent virtual tutors and lab instructors. The AVML is built around two engines. IVRESSTM, which allows for the creation of virtual lab with near-realistic, fully functional, and interactive CNC machine tools. The development involves three main elements, namely, a simulator for CNC milling and lathe machines, a virtual-environment display engine, and an intelligent-agent engine. LEATM (Learning Environment Agent), provides a platform for lecture delivery. The lecture is presented by the speaking virtual instructor and involves high end multimedia using flash and movies for real-life illustrations, 2D/3D interactive simulation, and different types of practice questions. The lecture material is delivered in different formats to address the needs of different types of learners (visual, auditory, and kinesthetic). On the other hand, OnCourseTM course management tool is seamlessly interfaced with the learning environment and acts as a gateway to the lectures and labs that are delivered in the AVML environment. It provides a platform for accessing/taking projects, homework, quizzes and exams, for online monitoring and assessment of student work and performance, and for supporting interaction and collaboration. In this paper, the implementation the course is presented. In addition, the results of the assessment of the usability of the interface of the learning environment is described and discussed.

Effect of Flat Belt Thickness on Steady-State Belt Stresses and Slip

A necessary condition for high-fidelity dynamic simulation of belt-drives is to accurately predict the belt stresses, pulley angular velocities, belt slip, and belt-drive energy efficiency. In previous papers, those quantities were predicted using thin shell, beam, or truss elements along with a Coulomb friction model. However, flat rubber belts have a finite thickness and the reinforcements are typically located near the top surface of the belt. In this paper, the effect of the belt thickness on the aforementioned response quantities is studied using a two-pulley belt-drive. The belt rubber matrix is modeled using three-dimensional brick elements. Belt reinforcements are modeled using one-dimensional truss elements at the top surface of the belt. Friction between the belt and the pulleys is modeled using an asperity-based Coulomb friction model. The pulleys are modeled as cylindrical rigid bodies. The equations of motion are integrated using a time-accurate explicit solution procedure.

High-Fidelity Multibody Dynamics Vehicle Model Coupled With a Cohesive Soil Discrete Element Model for Predicting Vehicle Mobility

Multibody dynamics and the discrete element method (DEM) are integrated into one solver for predicting the mobility characteristics (including the no-go condition, maximum speed, and required engine torque/power) of ground vehicles on rough off-road soft soil (such as mud and snow) terrains. High fidelity multibody dynamics models are used for the various vehicle systems including: suspension system, wheels, steering system, axle, differential, and engine. A penalty technique is used to impose joint and normal contact constraints. An asperity-based friction model is used to model joint and contact friction. A DEM model of the soil with a cohesive soft soil material model is used. The material model can account for the soil compressibility, plasticity, fracture, friction, viscosity, gain in cohesive strength due to compression, and loss in cohesive strength due to tension. The governing equations of motion are solved along with joint/constraint equations using a time-accurate explicit solution procedure. The model can be used to predict the mobility of ground vehicles as a function of soil type, terrain long slope, and terrain side slope. Typical simulations of a Humvee-type vehicle are provided to demonstrate the model.Copyright