The Flat-Trac Dynamometer is used to determine vehicle fuel efficiency/emissions and for validating and fine tuning drivability.
The Flat-Trac Ride Comfort Roadway is designed specifically for studying phenomena that affect cabin occupant comfort.
The Flat-Trac Dynamic Ride Comfort Roadway can apply heavy loading to a test vehicle powertrain to replicate its total vibration environment.
The Flat-Trac Handling Roadway can be used to replicate a full spectrum of standard and highly dynamic handling maneuvers, and serve as a platform for advanced research and development, validation and certification.
The Evolving Flat-Trac® Roadway PortfolioThe evolution of the MTS’ roadway family tracks closely with decades of changing automotive industry priorities.
To meet demands for increased fuel efficiency in the early 1980s, MTS leveraged its patented Flat-Trac moving belt technology to build its first servo hydraulic dynamometer.
In the mid-1990s, industry recognition of the cost and efficiency advantages of lab-based testing prompted the development of full-featured, servo hydraulic handling roadways that integrated Flat-Trac moving belt technology, vertical inputs and steer capabilities. Deployed primarily for basic handling studies, these highly complex systems also saw use for durability testing.
An emphasis on ride comfort as a vehicle differentiator in the early 2000s drove the development of a high-fidelity dynamic roadway. Featuring vertical inputs and, most notably, Flat-Trac moving belts powered by high-performance permanent magnet motors, it was the first system to enable lab-based ride comfort evaluation within real-world vehicle operating ranges. This first electrified roadway led directly to the development of the Flat-Trac Ride Comfort and Dynamic Ride Comfort Roadways.
By 2015, looming fuel efficiency and emissions reduction mandates sparked demand for a more accurate, repeatable and efficient measurement tools. MTS responded with a new dynamometer, bringing the advantages of high-performance, electric Flat-Trac moving belt technology to today’s increasingly detailed studies of vehicle rolling loss.
Flat-Trac Moving Belt Technology
Critical to the evolution of these solutions is the ability to create a vehicle-to-road interface equivalent to that of a flat road. Achieving this is quite difficult. Maintaining belt integrity and position on a test system - at high speeds and under tremendous dynamic loading - poses numerous technical challenges.
MTS was the first to overcome these challenges with its Flat-Trac moving belt technology, developed originally for tire testing applications. Flat-Trac technology incorporates stainless steel belts and proprietary bearing, belt tracking and tensioning to maintain near-perfect moving belt flatness, even at speeds in excess of 320 kph. Additionally, through decades of deploying this technology effectively on a diversity of solutions – tire test systems, full-vehicle roadways, wind tunnel rolling roads for ground vehicles and aircraft – MTS can offer an unmatched variety of Flat-Trac packages.
The least complex and most recent roadway deployment of this technology is the Flat-Trac Dynamometer. Engineered for capturing highly accurate, direct longitudinal force measurements at both the full vehicle and individual tire levels, it is the ideal tool for assessing rolling loss, which is used to determine vehicle fuel efficiency/emissions. This will be critical for new electric vehicle development, where rolling resistance plays a significant role in battery and powertrain sizing. Additionally, a “soft” restraint system that allows for vehicle acceleration on the test rig make it useful for validating and fine tuning drivability.
With these capabilities, the Flat-Trac Dynamometer is far superior for meeting WLTP (Worldwide harmonized Light vehicles Test Procedures) requirements than alternative methods. Currently, coast down data are captured on the road and then used to take rolling loss measurements on a conventional chassis dyno system. This method is time and resource intensive, subject to varying weather conditions and ultimately flawed due to its reliance on chassis dynos, which employ round drums to replicate flat road surfaces. The entire procedure - capturing coast-down data and measuring rolling loss - can be performed on a single lab-based Flat-Trac Dynamometer faster, more efficiently and with far greater accuracy and repeatability.
Additionally, MTS can configure the Flat-Trac Dynamometer to accommodate virtually any vehicle on the road by varying track width, wheelbase, type of positioning (manual or automated), power density (29 - 300 kilowatt per wheel) and bearing type (air or water).
Flat-Trac Ride Comfort Roadways
MTS developed its Flat-Trac Ride Comfort Roadways specifically for studying phenomena that affect cabin occupant comfort. Engineered to apply highly precise and repeatable longitudinal acceleration and vertical excitation to a vehicle at the tire patches, and subsequently the wheel spindles, these systems enable developers to study vibration transmissibility through a vehicle’s suspension and body, affecting cabin acoustics, steering wheel feel, seat feel, floor pan noise, etc.
MTS offers two versions of this system: the Dynamic Ride Comfort Roadway and the Ride Comfort Roadway. The Dynamic Ride Comfort Roadway can apply realistic loading to a test vehicle powertrain to replicate its total vibration environment in longitudinal and vertical directions. It can reproduce the majority of ride comfort events likely to be encountered in real world driving with very high fidelity and correlation, making it an effective tool for acquiring both objective sensor data and subjective driver assessments of vehicle comfort.
An economical alternative to the dynamic version, the Ride Comfort Roadway is capable of lightly loading test vehicle powertrains, providing more basic insight into a vehicle’s vibration environment in the vertical direction with spinning tires, which exhibit significantly different dynamic response than non-spinning tires.
Ride Comfort Roadways can be employed to great advantage in the early stages of vehicle development, as well. For example, the characteristics of a virtual suspension concept could be integrated into a roadway’s inputs and then played out on an existing vehicle, enabling subjective evaluation of the conceptual suspension’s feel and behavior well before it ever reaches physical production. This capability allows engineers to evaluate and disqualify designs while still in the concept stage, eliminating costly iterations and rework and enabling faster convergence on an optimal design.
Flat-Trac Handling Roadway
The most complex roadway system, the Flat-Trac Handling Roadway, incorporates longitudinal acceleration, vertical excitation and an additional steer input for assessing vehicle handling characteristics under a broad spectrum of real-world conditions. These can range from standard maneuvers like single lane change, double lane change, turning a corner or braking in a straight line to extreme, highly dynamic scenarios like testing rollover propensity. The most recent iteration of this roadway system employs MTS-developed inverted electric motors to drive the flat belts, making its Flat-Trac wheel drive units more compact and power dense than ever before.
A key component of the Handling Roadway is its active Center of Gravity Restraint (CGR), which makes high-fidelity replication of dynamic scenarios possible. The active CGR holds the test vehicle in position over the wheel drive units, confining it in longitudinal, lateral, and yaw directions but allowing unrestricted movement in the vertical pitch and roll degrees of freedom. This allows the test vehicle suspension and body to respond freely to highly dynamic maneuvers, as they would on an actual road.
A significant advantage of the Handling Roadway is its broad range of potential applications. With its original, standard programming environment, the roadway system can be used for wide range of standard and customer-defined testing, and playing out road load data collected on the test track. A next-generation programming environment can be employed to integrate the roadway system into hybrid simulation scenarios, combining a physical vehicle on the roadway with programmable digital roads and drivers. Additionally, add-on hardware systems, like MTS’ new Axle Carrier Fixture (ACF), enable the system to be employed for focused axle and suspension studies.
Looking forward, the Handling Roadway is poised to continue tracking closely with evolving industry priorities. For example, in support of electric vehicle development, it could be used to study thrust vectoring – varying the thrust among the electric powered vehicle corners to maximize vehicle stability during cornering and dynamic maneuvers. It could also be used to validate Advanced Driver Assisted Systems (ADAS). Currently, there is no standard methodology for ADAS validation, so many OEMs conduct experiments at the test track. These could all be programmed into simulation and played out on a handling roadway with greater efficiency and far more repeatability.
Contact MTS today and explore how Flat-Trac Roadways can be deployed to enhance your fuel efficiency/emissions testing, ride comfort evaluation or standard and advanced handling studies.
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