Controllers
The controllers provided for the nees@berkeley Laboratory perform near real time digital control of the hydraulic system for the pseudo-dynamic testing. The controllers support local testing with real specimens only and hybrid simulation with virtual specimens (computer models) and real specimens coupled in a complex system through geographically distributed network.
There are two separate digital control platforms provided by MTS for the nees@berkeley Laboratory. The first is the MTS 493 Real-Time Controller (supporting software called Structural Test System: STS) that performs the real time, or near real time pseudo-dynamic structural testing capabilities. The second digital control platform is the MTS FlexTest GT Controller that provides a highly flexible and user configurable control environment to support more conventional structural testing applications.
The MTS 493 Real-Time Controller is a part of the Hybrid Simulation Controller.
Flextest
Model 793.00 System Software is a bundle of applications that perform various test activities for the FlexTest GT MTS Controller. The Model 793.00 System Software bundle consists of the following standard applications:
Station Builder is a station design application. This application allows you to allocate controller resources, such as valve drivers and conditioners, to station configuration files.
Station Manager is a sophisticated controller application. This application maintains station servo control, and allows you to perform typical test operations.
Basic TestWare is a simple test design application. This application allows you to create simple monotonic and cyclic tests and to acquire data.
Station Desktop Organizer is an application management utility. This utility allows you to manage the windows and displays associated with Series 793 software applications.
Detailed description of the FlexTest GT is provided by MTS in the manual entitled Model 793.10 MultiPurpose TestWare.
Structural Test System
The Real-Time Controller is a real-time, digital controller that provides PID closed loop control with a differential pressure transducer (delta-P) feedback signal. It also provides an operator interface (the Structural Test System application) to the real-time hardware from a PC over an Ethernet link. The control hardware architecture is based on Digital Signal Processing technology, which optimizes the performance of the embedded control system, and allows for the implementation of advanced control and data filtering operations.
The controller system consists of a MTS console assembly, associated cabling and control software. The MTS console assembly has an imbedded processor and real-time hardware. The control software consists of the real-time control software and the control panel software. The real-time control software drives the processors to generate command and error signals. The control panel software runs on a PC and has a graphical user interface consisting of interactive, modeless dialogs that are used to enter system parameters and execute a test.
The Structural Test System application contains the control software, calibration data, and the default setting parameters for your system. Opening this application will load the calibration parameters and open the Structural Test System Main Panel and the default Settings file.
The Structural Test System main panel is the control center of this application. You can use the menus of this panel to access all options for calibrating, configuring, setting up tests, and displaying data. You can also use the controls and displays of this panel to set or check functions, and to run a test.
The detailed description of the Structural Test System application is posted on the MTS web site at the following link http://longitude.mts.com/nees (username: neesinfo; password: 4neesinfo). For convenience, the document can be also downloaded from this site.
Many of the camera systems available on site can be used in a conventional manner to document an experiment manually. However, the true benefit of the system is its ability to acquire dozens of images simultaneously under computer control. Digital image acquisition devices are available to acquire ultra-high resolution still images, high-resolution video, and point clouds. These images can be acquired at regular intervals, ranging from one image per day up to hundreds of images per second, or at intervals that depend on a predefined loading or displacement history (e.g., images are captured every 5 mm of actuator movement) or on real-time characteristics of measured response (e.g., images a captured whenever the measured base shear is zero, the displacement of an actuator reaches a peak, or the stiffness changes by a specified amount).
Hybrid System
A stand-alone user manual is aimed to familiarize the interested user with the hybrid simulation controller provided by nees@berkeley. It is assumed that an external user of the nees@berkeley Equipment Site will only program hybrid simulation algorithms using the Matlab/xPC environment and operating their program during the test. Thus this manual focuses on using Simulink, Scramnet, and xPC along with the MTS controller and Pacific Data Acquisition System for the implementation of hybrid simulation algorithms. It is expected that experienced on-site personnel will operate the main servo-controller or Structural Testing System (STS) controlling the actuators. Documentation on the use of the STS software package is available for interested users (Operation Manual: Reconfigurable Reaction Wall (RRW) Structural Test System for University of California, Berkeley, MTS 2003). Separate documentation on use of the Pacific Instruments data acquisition software is also available. The user should refer to the related manuals for setting up test specimen in the strong floor, calibrating instrumentation and tuning actuators.
Simulink
Simulink is a platform for multidomain simulation and Model-Based Design of dynamic systems. It provides an interactive graphical environment and a customizable set of block libraries that let you accurately design, simulate, implement, and test control, signal processing, communications, and other time-varying systems.
Add-on products extend the Simulink environment with tools for specific modeling and design tasks and for code generation, algorithm implementation, test, and verification.
Simulink is integrated with MATLAB, providing immediate access to an extensive range of tools for algorithm development, data visualization, data analysis and access, and numerical computation.
Documentation: Data sheet Mathworks web site
Scramnet
The SCRAMNet+ Network (Shared Common RAM Network) was developed to satisfy the demanding real-time requirements of high-fidelity simulations, but its capabilities extend equally well to virtually all other distributed real-time applications. Based upon a replicated shared-memory concept, the SCRAMNet+ Network is optimized for the high-speed, ultra-low-latency transfer of data among many computing platforms that are all solving portions of the same real-time problem. Its simplicity and speed are ideally suited for applications requiring a high degree of synchronization and control.
In critical real-time systems, computer-to-computer data latency is dependent on two factors: network speed and, more importantly, data throughput between the host computer and the network node. The SCRAMNet+ Network's shared-memory speed and simplicity insure that communication at every computer is optimized for minimal data latency. It virtually guarantees that all computers in the system are operating simultaneously on the same set of data.
To utilize the replicated shared-memory concept, distributed processes map their global data structures into the dual-port memory located on each SCRAMNet+ node. Any time an application process updates a data structure located in its local SCRAMNet+ memory, the address and data are immediately (and automatically) broadcast to all other nodes on the SCRAMNet+ Network. This automatic data transfer requires no software intervention or backplane loading, enabling the host computer to provide more processing resources to the application.
Documentation: Specifications Systran web site
XPC
The xPC Target provides a high-performance, host-target prototyping environment that enables you to connect Simulink and Stateflow models to physical systems and execute them in real time on PC-compatible hardware. xPC Target includes proven capabilities for rapid prototyping and hardware-in-the-loop simulation of control and audio/speech signal processing systems.
The xPC Target enables you to add I/O interface blocks to your models, automatically generate code with Real-Time Workshop and Stateflow Coder, and download the code to a second PC running the xPC Target real-time kernel. You can use any PC with Intel 386/486, Pentium, or AMD K5/K6/Athlon processor as your real-time target. The target PC can be a desktop computer, an industrial computer such as xPC TargetBox, PC/104, PC/104+, CompactPCI, all-in-one embedded PC, or any other PC-compatible form factor. With the xPC Target Embedded Option (available separately), you can deploy your real-time embedded systems on PC hardware for production, data acquisition, calibration, and testing applications.
Documentation: Specifications Mathworks web site
