## Current Projects

### Continuum representation of granular material used to simulate mobility of VIPER rover replica

SBEL students Wei Hu and Jason Zhang collaborated on a simulation of a VIPER-replica rover operating on granular material. The highlight here is that the terrain was actually represented as a continuum material. This trick …

### Modeling Multiphase Flows with Incompressible SPH on GPU

Incompressible multiphase flows with complex interface geometries are involved in many industrial and environmental applications. In contrast to the widely-used Eulerian approaches, as a Lagrangian method, SPH handles the interface representation naturally without the need …

### Chrono::GPU, Modeling and Simulation of Granular Dynamics using GPU Computing

Modeling granular system of large degree of freedom poses high computation cost. Chrono::GPU is designed to simulate granular material via the framework of Discrete Element Method (DEM) to produce realistic results. The physics-based features include …

## Completed Projects

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### AV/Robotics

**Chrono Integration with Cognitive Systems Lab Driving Simulator – **SBEL partnered with the Cognitive Systems Lab (CSL) and Professor Sue Ahn’s lab on an NSF-sponsored project to better understand traffic flows in the context of human takeover from autonomous vehicles.

**SynChrono Moves Off-Road – **The SynChrono autonomous vehicle simulation platform has recently added support for SCM deformable terrain, allowing vehicles to operate in time coherent off-road environments.

**Chrono::Sensor – modeling and simulating virtual sensors for robots and autonomous vehicles – **Chrono::Sensor is a specialized module in Project Chrono for the modeling and simulation of sensors within a Chrono simulation. This simulation module is in development with current support for simulation of camera, lidar, GPS, and IMU.

**Synchrono: A Multi-Agent Simulation Framework for Robotics and Autonomous Vehicle Applications – **SynChrono is a framework in which dynamic multi-agent simulations can be conducted to understand agent interplay and develop control algorithms in a safe and flexible environment.

**Chrono::Vehicle – Template-Based Ground Vehicle Modeling and Simulation –** A module of the open-source multi-physics simulation package Chrono, aimed at modeling, simulation, and visualization of wheeled and tracked ground vehicle multi-body systems.

**High Performance Computing Framework for Co-simulation of Ground Vehicle – Terrain Interaction – **To alleviate the prohibitive computational costs of a coupled simulation of the overall problem (resulting in a multi-physics, multi-scale dynamical system with millions of degrees of freedom), HPC co-simulation framework was developed which enables a decoupled simulation.

**Modeling and Simulation of the RoboSimian Robot – **Developed a Chrono model of RoboSimian, an apelike robot developed and built at NASA’s Jet Propulsion Laboratory. The goal of this project is to provide a simulation-based assessment of RoboSimian’s mobility characteristics over deformable soil and compare its performance in one of its four possible locomotion modes (driving, walking, inchworming, and sculling).

**Chrono Benchmarking for Next Generation NATO Reference Mobility Model (NG-NRMM) – **As part of the development of the Next Generation NATO Reference Mobility Model (NG-NRMM), UW-Madison participated in an industry-wide multibody-dynamics simulation benchmarking activity that occurred in 2016 and 2017.

### High Performance Computing

**SPIKE GPU – Implementation of Recursive Divide-And-Conquer Parallel Strategy for Solving Large Systems of Linear Equations – **This project proposes to investigate, produce, and maintain a methodology and its software implementation that leverage emerging heterogeneous hardware architectures to solve billion-unknowns linear systems in a robust, scalable, and efficient fashion.

**Quantum-Assisted Machine Learning for Mobility Studies – **In this project we explore and provide a proof-of-concept approach to solving ground vehicle mobility-related problems on emerging quantum computing (QC) machines, in particular as embodied in the D-Wave quantum annealer systems.

**Characterization of Xeon Phi with Linear Algebra Workloads – **The efforts behind this independent study are to analyze how well suited Xeon Phi is for some frequently used linear algebra routines such as factorization and solvers. We are working with Intel MKL 11.1 on Xeon Phi based on KNC (MIC) architecture. The workloads under study include factorization and solving of dense and banded systems.

**Performance Analysis of CULA on different NVIDIA GPU Architectures – **The CULA is a next generation linear algebra package that uses the GPU as a co-processor to achieve speedups over existing linear algebra packages. CULA supports matrix inversion operation which helps in solving and factorizing the linear algebra matrices.

**Performance Comparison Study between NVIDIA Fermi and Kepler Architecture– **A comparative study between Nvidia Fermi and Kepler architectures are being undertaken. The key aspects being targeted are performance scaling for computational kernels like tiled matrix multiplication, memory transfer behavior, gains using streaming and performance difference observed when using THRUST library.

### Fluid-Solid Interaction (FSI)

**Continuum Modeling of Granular Material Flows and their Interactions with Solid Bodies – **Outlines a continuous approach for treating discrete granular flows that hold across multiple scales from experiments that focus on centimetre-sized control volumes to tests that involve landslides and tall buildings.

**Modeling Multiphase Flows with Incompressible SPH on GPU** **– **Incompressible multiphase flows with complex interface geometries are involved in many industrial and environmental applications. In contrast to the widely-used Eulerian approaches, as a Lagrangian method, SPH handles the interface representation naturally without the need for computationally expensive interface tracking techniques.

**Fluid-Solid Interaction – **Studying fluid-solid interaction (FSI) problems involves several aspects of scientific computing. Perhaps the more remarkable aspect is that in our group we use a Lagrangian-Lagrangian framework to tackle FSI problems.

**Coupled Fluid-Flexible Body Investigation Using Chrono::Fluid– **The interaction of fluid-flexible bodies was studied via a Lagrangian-Lagrangian framework. The dynamics of the two phases, fluid and solid, are coupled with the help of Lagrangian markers, referred to as Boundary Condition Enforcing (BCE) markers which are used to impose no-slip and impenetrability conditions.

### Flexible-Body Dynamics (FBD)

**Accelerating Nonlinear Finite Element Formulations for Multibody Dynamics –**Formulations have been developed for integrating nonlinear flexible bodies within multibody dynamics frameworks, of which the runtime performance is slow to the point where their usefulness is questionable. In this project, we used software optimization techniques and new numerical techniques with the goal of producing speed-ups of 1 to 2 orders of magnitude.

### Granular Materials

**Distributed-Memory Granular Simulation – **The project focuses on expanding the capabilities of granular simulation to include simulations with numbers of bodies on the order of billions. In order to do so, the simulation is broken into a number of smaller, mostly-disjoint sub-problems that can be solved each on a separate node of a computing cluster with minimal communication between nodes.

### Friction/Contact

**Representing Fluid Dynamics as a Rigid-Body Dynamics Problem with Friction and Contact – **The purpose of this project is to understand if fluid motion can be accurately represented as a large collection of rigid spheres. Fluid motion is traditionally modeled using the Navier-Stokes equations, whereas rigid body motion is governed by the Newton-Euler equations. This work attempts to achieve a high-resolution representation of a continuum problem using bodies interacting via frictional contact.