ICT completes unique upgrade to servo-hydraulic test systems

The Illinois Center for Transportation is continuing to grow its servo-hydraulic test capabilities, this time with a major upgrade to the facility control systems as well as its hydraulic pump. 

Servo-hydraulic test systems are frequently used to conduct materials testing under various loading and environmental conditions utilizing various fixtures. Reconfigurable systems with user-defined test protocols are critical for developing new testing procedures, such as during the extensive and complex testing that took place to develop the simple Illinois Flexibility Index Test (I-FIT).

The push to create a state-of-the-art servo-hydraulic test facility took a major step forward beginning in 2016 with the addition of a new large “quiet” hydraulic power unit and the construction of an environmentally-controlled Servo-Hydraulics Lab, created specifically to house the servo-hydraulic test systems. This allowed four servo-hydraulic test systems, each built by a different manufacturer, to be consolidated into one, purpose-built space. However, the four different test systems were all still operating on different control systems. In order to ensure safe operation, bring the computers and control software up to date, and improve testing efficiency, it was determined that a holistic and uniform upgrade was needed.

MTS Systems Corporation was selected to supply the upgraded controls system due to their willingness to take on the challenge of integrating the four different test systems, only one of which was manufactured by MTS. MTS also ensured a seamless integration with the MTS HPU. Getting four different test systems to communicate with and operate on a single control platform was not easy. This upgrade was performed in a two-phased approach to best meet ICT needs and minimize downtime.

The upgrade at ICT to the servo-hydraulic test systems was a highly customized project. The challenge for MTS was that four systems made by four different manufacturers were to be integrated into a single MTS Flex Test controller. Each system had to be converted to MTS controls, one device at a time, and tested for proper control and operation. This ensured that the other systems remained operational so that only one test unit was down at any given time. In the end, all four systems were brought under the control of the MTS Flex Test controller and were aligned so that the MTS Multipurpose Elite Software could be run, giving uniformity to the lab. This will help keep the lab up to date with current electronic and software technology and allow MTS to support ICT in the future. The FlexTest processors are field-upgradable so additional capacity can be easily added, if necessary. The software is highly functional but can also be modified by the user to meet new needs as they arise. New computer workstations were also added to each of the test systems to accommodate the new software.

The upgraded control system includes safety features like e-stops and interlocks from all four stations that communicate with the HPU and shut down the system in the event of any issues. A remote system control panel was also added that reproduces the control panel on the HPU. This permits operation and system monitoring from within the Servo-Hydraulic Lab.

Efficiency has been improved at multiple levels throughout the system. One area of improved efficiency is in the training of system users. Now that all systems operate using the same software, an operator can operate all four systems once trained on one. Another improvement in efficiency is in the interchangeability between the test systems. With the unified control system, the programming to perform a given test is the same on all of the systems, instead of developing four different testing programs. Finally, the upgrade allows all instruments, such as Linear Variable Differential Transformers (LVDTs), load cells, extensometers, and all data acquisition channels to be utilized readily on any of the test frames. Not only does this allow for the instruments to be readily changed from system to system, but the full complement of instrumentation for the entire system can be utilized on any testing machine with a big number of channels.

Data integrity and security are also important. All data are saved on the University cloud following the 3-2-1 rule for data storage (2 copies onsite and 1 copy offsite). Researchers can then access data for their project from the cloud from anywhere they have internet access.

It was the vision of ICT Director Imad Al-Qadi that got the project going and ICT Senior Research Engineer Greg Renshaw was the primary guiding force that kept the upgrades on track from initial design work for the Servo-Hydraulic Lab to setting up tests on the newly completed control system. The process was supported by MTS engineers, including Matt Struve, Ryan Cacaro, and Robert Nelson. These upgrades ensure that ICT will remain at the forefront of materials research and perpetuate the center’s world-class reputation.