1. Introduction
The field of multiple input/multiple output (MIMO) vibration testing has grown substantially in the past few years. MIMO vibration testing provides the capability to match a field environment more accurately and at more locations on the test article than traditional single-axis vibration testing. Unfortunately, many existing vibration control systems are proprietary, which makes it difficult to implement new MIMO techniques.
Currently, MIMO vibration practitioners must either develop a control system from scratch to implement their ideas, or alternatively convince an MIMO vibration software vendor to implement their ideas into existing devices, and neither of these approaches are conducive to the rapid and iterative nature of research.
The Rattlesnake framework was developed to overcome these limitations and facilitate MIMO vibration research. Rattlesnake is a MIMO control system that provides the user the ability to overcome testing challenges by providing a flexible framework that can be extended and modified to meet testing demands. Rattlesnake can run multiple environments simultaneously, providing a combined-environments capability that does not yet exist in commercial software packages. It can target multiple hardware devices, or even perform control virtually using a state space model, finite element model (FEM) results, or a SDynPy System.
1.1. Document Overview
This document provides information about the functionality in the Rattlesnake software, as well as instructions for how to use that functionality. The document is divided into Parts targeting different aspects of the software.
- Part I provides an overview of the software as well as instructions for how to acquire and run the software. Chapter 2 includes instructions for setting up the Python ecosystem required to run the software, if necessary. Chapter 3 describes the Rattlesnake userinterface (UI). Each main portion of the Rattlesnake interface is described along with the parameters that should be defined within that interface.
- Part II describes the hardware devices available to the Rattlesnake software, as well as the hardware-specific considerations in the controller. Each Chapter in this Part is dedicated to a specific hardware device. Synthetic or virtual control is also discussed in this part, as well as instructions to extend Rattlesnake to additional hardware devices.
- Part III describes the various control environments contained within the Rattlesnake software. The environments defined within Rattlesnake are where the next output data that will be sent to the exciters are computed based off the previously acquired data. Each chapter in this Part is dedicated to a environment type within Rattlesnake. This chapter also provides instructions to combine environments as well as extend Rattlesnake to additional environments.
- The Appendices contain several example problems. Users with a reasonable understanding of the Rattlesnake workflow can use these chapters as a kind of "Quick Start" guide to the software. Appendix B demonstrates a series of tests on a simple beam using a NI cDAQ hardware device. Appendix C and Appendix D demonstrate virtual control problems using SDynPy System and State Space models, respectively, which only require a computer to run.