*As Featured on NI.com
Original Authors: Chris Yu, Specialized Bicycle Components
Edited by Cyth Systems
In a sport where seconds often separate winning from losing, it’s critical to understand and optimize each factor affecting a cyclist’s body and bike while riding. One of the biggest challenges cyclists face is drag caused by wind. To minimize drag by creating better cycling products and understanding how riders can better position themselves on their bikes, Specialized needed an accurate way to measure and test the effects of drag on cyclists as they ride in a real-world environment.
Instead of relying on data collected in third-party wind tunnels designed for the aerospace and automotive industries, not for cyclists, Specialized became the world’s first bike and equipment manufacturer to build a sport-specific wind tunnel located at its Morgan Hill, California facility.
Left: Cyclists in the Specialized Bicycle Components wind tunnel.
Right: Engineers performing remote monitoring and analysis using multiple camera views.
In a sport in which seconds often separate winning from losing, it is critical to understand and optimize each factor that affects a cyclist’s body and bike while riding. Drag caused by wind presents one of the biggest challenges for cyclists. As they pick up speed while riding, their bodies, bikes, and equipment force a separation of air, resulting in a resistance called pressure drag. Since drag increases with speed, riders feel more resistance at higher speeds and must use more power to overcome the forces working against them. Cyclists use between 70 and 90 percent of the power they generate to overcome aerodynamic drag. Thus, minimizing drag through effective body positioning and aerodynamically refined equipment helps cyclists achieve maximum efficiency and speed. To minimize drag by creating better cycling products and understanding how riders can better position themselves on their bikes, Specialized Bicycle Components (Specialized) needed an accurate way to measure and test the effects of drag on cyclists riding in a real-world environment.
Specialized built a wind tunnel to bring all aspects of the aerodynamics testing process to its Morgan Hill, California, facility. Specialized now conducts a continuous loop of development and testing for all of its bikes and equipment and supports its team of professional cyclists by evaluating and optimizing their riding positions. The bike and rider are almost never steady in real-world conditions and constantly interact with each other. Testing bikes in this realistic, dynamic way, as opposed to the traditional tests with the bike rigidly bolted to the tunnel, will uncover new information that would not have surfaced otherwise.
Left: View of Specialized Wind Tunnel Data Acquisition.
Right: NI PXIe Hardware is used as a flexible test platform for Specialized's Wind Tunnel.
Specialized used LabVIEW system design software, PXI hardware, NI Vision Development Module software, and commercial off-the-shelf (COTS) components to develop a custom measurement and control system. With LabVIEW, Specialized can interface with the sensors placed on a bike and cyclist in the wind tunnel while engineers perform remote monitoring using the Data Dashboard for LabVIEW. Additionally, the COTS cameras capture real-time visual data, which easily integrates into the system using the Vision Development Module.
The flexibility of the NI PXI chassis helps Specialized create additional tests using new sensors and controllers with relatively quick turnaround times. This is especially important since test needs are changed and updated regularly—for example, performing R&D testing on equipment versus performance testing with professional athletes. With the NI PXI chassis, users can swap in the right hardware effortlessly.
Specialized developed the entire measurement and control system in just a few months while seamlessly integrating each element of the system, which optimized time to market and is the biggest advantage of the system design approach. LabVIEW provided a single software framework to meet the unique requirements of performing control, measurement, and vision acquisition. The consolidation to a single software solution, tightly integrated with reconfigurable hardware, also simplifies the maintenance and supportability of the system.
Chris Yu, Specialized Bicycle Components
Edited by Cyth Systems