Application Spotlight: Aerial Working Platform with Two Force Sensors in One
The challenge
Aerial work platforms (AWPs) are mobile devices used to help people or equipment access inaccessible areas, such as heights. To prevent instability, the EU updated the EN280 standard, specifying a higher performance level per the EN13849 safety standard, which requires accurate monitoring of the load on AWP platforms, as well as the lift on their masts.
A leading AWP manufacturer had been using a low-cost analog pressure sensor to monitor the load on its platforms. It met the previous industry standards, but the pressure sensor wasn’t very accurate. When the EN280/EN13849 standard was updated, it imposed stricter safety requirements on AWPs.
To meet the new standard, and wanting to provide more accurate measurements, the AWP manufacturer began looking to update its products.
The main requirement was to be able to accurately measure force at the four bolt points at the junction of the platform and the mast without the need for mechanical adjustment on the machine. The company decided to adopt strain gauge technology and created a design that included a double shaft with four sensors, including CAN bus output to monitor the stability of the overload of the platform. However, with four sensors, the design was too expensive for that company’s market. Another option was to place a pressure sensor under the mast, but the cabling created problems, making that approach less than ideal.
The solution: An innovative two-in-one force sensor
The VPG R&D team took on the challenge and came up with a new, creative solution. Rather than using four sensors on a double shaft, they built one CAN bus board with two outputs—two sensors in one. The new design, based on an existing VPG double-ended shear beam load cell, maximized performance and cost savings by creating two sensors in one—one sensor body, two Wheatstone bridges, one board with two separated channels, and one cable exit.
Benefits
The two-sensors-in-one solution developed by VPG was instrumental in enabling the AWP manufacturer to meet the new PLd/EN13849 standard (the highest level of the standard) while remaining within budget.
This innovative VPG design can help other AWP producers improve force measurement accuracy and performance.
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Learn more about force sensor solutions for AWPs and other construction applications
