 |
|
 |
|
 |
|
HYGE Sled Control - PC-Based Industrial Automation
By David Hoadley, Ph.D., Project Scientist, V I Engineering, Inc.
Products Used
BridgeVIEW
Industrial Automation Server
The Challenge
Update an aging control system for an Automotive Crash Test Simulator.
The Solution
A BridgeVIEW-based human-machine interface (HMI) incorporating control and automation, operator security, and data recording.
Introduction
V I Engineering, Inc., a National Instruments Premier Alliance Member, was contracted by Ford Motor Company to update the control system for their HYGE sled. The HYGE system consists of a 12" diameter pneumatic ram that is used to accelerate a two-ton sled on a 100' track. The applied acceleration pulses are tailored to mimic the acceleration profiles observed in vehicle-barrier crash tests. In HYGE tests, a single ruggedized automobile frame can be used repeatedly to study air bag and passenger restraint system performance. Sled instrumentation includes high-speed video and cameras, accelerometers, and sensor-laden crash test dummies.
System Description
The system was previously controlled by an obsolete programmable logic controller (PLC) that provided signals to various relays which in turn would open valves, start compressors, and more. These relays incorporate logic that allows failsafe operation by requiring various permissive signals to pressurize the ram cylinder. These include closure signals from numerous doors, automatic locks, and area surveillance light curtains. All permissive signals are required before the cylinder can be filled with high pressure air and the ram can be fired, simulating up to a 35 mph head-on collision.
V I Engineering replaced the PLC and its program, updated system valves, and produced an intuitive user interface to the control system. This interface provides controls for every automatic function of the system, from the automatic filling of system pressure to the storing of successful test parameters and environmental data. The tendency for human error is removed by incorporating proper procedures into the code and providing a live system schematic on screen.
HMI Features
The HMI provides an operator with controls and indicators used to run the HYGE sled system. Several features of BridgeVIEW facilitated development of the system. One such feature, the built-in security functions, proved to be a very efficient means of implementing user authorization for the control system.
The logical progression of steps that is required to fire the ram is incorporated into the structure of the control software. The first screen a user visits after logging in is dedicated to data entry of test parameters, as well as to displaying the output of ambient temperature and humidity sensors. These sensors and several pressure transducers provide signals to the computer via communication with PLC input modules. These signals are calibrated by the BridgeVIEW engine as determined by tag scaling settings. Users, based on security privilege, are given access to the Tag Configuration Editor in the application software to enter calibration information.
Other screens are accessed as necessary to run the test. They feature controls and indicators that allow the user to run the pressure systems and receive appropriate feedback. Pressure system preparation is accomplished on the screen depicted in Figure 1.
The 'system schematic' design of this screen overcomes the potential crowding that a complex system requires for numerous controls and indicators. The user has the ability to control various doors, compressors, valves, and other system components while monitoring every pressure transducer and the state of permissive and control power signals. System procedure is a major part of the code in this and other screens. While the relays guarantee that unsafe conditions are never possible, the system often requires that a process be carried out in a particular order to have the desired effect. By incorporating these requirements, a major source of user error has been eliminated. A significant benefit of this change is seen in the retraining of personnel on the new system, which has progressed very smoothly.
Automation features in the system include filling pressures to target values, an audible ten second countdown over a PA system, logging of test parameters and environmental data after a successful test, and the firing process itself. As in the original system, the user actuates one control to start the PLC's ram-firing process. This incorporates control of various lights, film and video cameras, as well as the arming and firing of the air bag. This program also provides a 'T0' signal to the onboard data acquisition system, signifying exactly when the ram was fired. Automation is a necessity for this timing, since the acceleration pulse only lasts on the order of 100 milliseconds.
Summary
V I Engineering has implemented a modern, PC-based control system for a major automotive test facility in BridgeVIEW. The built-in user security and tag configuration components have shortened development time considerably while allowing the end user the ability to manage the system. This software is a well-designed HMI, and provides much more functionality than a mere graphical "front-end" for the embedded programmable logic controller. The ability to incorporate G code into the interface has allowed many of the problems associated with operator error to be removed from the system, easing the transition for technicians from the familiar control panel to the more intuitive PC screens.
|
|
| << Back to Automotive |
|
|
|