Remote Parameter Control™ (RPC) is a software program offered by MTS Systems Corporation (MTS) that provides fatigue analysis, advanced road simulation analysis, and signal processing capabilities in a test lab environment. When combined with servo-hydraulic test equipment, the RPC program offers a powerful test lab that is specifically designed for the evaluation of vehicle durability, noise/vibration, ergonomics, and overall system performance. The test lab environment of the RPC software program provides an efficient laboratory-based simulation of the system’s field performance.
In order to use RPC, field data needs to first be captured of the component’s or system’s actual operating environment. Field data can come from a variety of sensor outputs, but most typically using accelerometers or strain gages, attached to the vehicle while subjected to demanding loading environments on a proving ground course. The purpose of the RPC program is to reproduce the measured operating environment (proving grounds sensor output data) by playing back those parameters on an MTS laboratory servo-hydraulic simulation system. Tests can be run on a single channel test setup such as for motorcycle or tire testing or can be extended to a multiple-channel test setup, more typical of a truck frame or off-road construction equipment.
The benefit of this type of testing is that it uses measured field data to observe the user, component, or system in a typical operating environment. While working as a research engineer product evaluation analyst at Rexnord Technical Services (RTS), I used MTS RPC for a variety of laboratory simulation programs, including work for Harley Davidson, John Deere, and Caterpillar. These validation and verification testing programs were an integral part of the product development and evaluation phase for these external R&D groups. The purpose of these programs were to physically test the extreme loading events in a laboratory that were observed in the field. The accumulation of the extreme loading conditions that may take over 10 years to observe in the field, could be reproduced in the laboratory over a much short time frame, ranging from days to weeks.
Harley Davidson used to have a proving grounds test facility in Talladega, Alabama where they instrumented their motorcycles with a variety of sensors including accelerometers. The Talladega testing facility was shut down in early 2010, as all of their testing operations were consolidated to the Arizona Proving Grounds (AZPG) in Yucca, AZ.
Harley Davidson test technicians would strap a mobile data acquisition system to the bike and collect real-time data for multiple channels while riding in a variety of extreme testing conditions (see end of video below for an example). For the Harley Davidson projects that I worked on, I used acceleration data outputs collected at Talladega as input data for an RPC servo-hydraulic test setup to analyze fatigue and durability of their saddle bag supports. Harley Davidson engineers told me that the riders they used to collect the accelerometer data at Talladega could only ride for a few days before having to be rotated out of the cycle for recovery. Some of the course conditions at the proving grounds (bumpy course, pebble course, off-road) were so violent in accelerations that the riders would end up urinating blood if they rode too long.
The accelerometer output data that we used at RTS as input data for the RPC servo-hydraulic test setup contained some low acceleration profiles combined with a number of different high acceleration profiles measured as the rider was subjected to the more extreme loading conditions. The data that we used was not reflective of the subject’s entire ride. Rather, the most extreme loading conditions were extracted and combined together with some low acceleration profiles to create the most demanding loading profile to evaluate stress distribution in their supports. Having observed over 1,000 hours of this type of violent acceleration testing, I could not imagine having to ride in those conditions for any length of time.
I also performed MTS RPC testing on multi-channel test setups for Caterpillar and John Deere as well. These tests did not involve as much high acceleration data, but they did involve much more dynamic three-dimensional (3D) loading profiles representative off off-road equipment in the field. These tests typically involved either full vehicle or component testing on large test bed frames, with servo-hydraulic actuators replicating the 3D loading patterns. An example of this type of work can be found in the video below showing similar testing methodologies still used in the automotive industry.