Transportation

Brompton goes electric

by Yokogawa Test&Measurement Editorial Team September 3, 2021

Brompton bikes have come a long way from their first folding bike designed in 1975  having in 2018 introduced the first electric folding bike. Called the Brompton electric, this e-bike is powered by a 36V/8.55Ah removable battery pack and features a 250-watt brushless DC front hub motor, that boosts the rider’s pedaling input up to a top speed of 25 km/h. Offering a range of 40 to 80 km, the removable battery can be charged up to 80 percent in 3 to 3.5 hours and100 percent in 4 to 5 hours.

Achieving rider-bike harmony

Developing an electric bike involves achieving a harmony of mechatronic systems and ackowledging the far greater influence that the rider of an e-bike has on them than drivers of larger electric vehicles. This means that testing needs to better account for various rider profiles in terms of weight, way of riding  etc. all of which contribute to system responses. Partnering with key technology partners including battery manufacturers, Brompton was responsible for all the analysis, debugging and testing of electronics, software and mechanical operation during their complex development cycle.

A Bumpy Ride

“We do a certain amount of testing on the bench but in reality, most of the testing involves getting on the bike and going for a ride.” Douglas Street – Senior electronics engineer. Douglas is part of Brompton’s growing team of engineers expanded to support and continue development and enhancement for future versions. So Brompton needed both bench testing and on-road testing of controls systems such as speed loops, torque loops, current loops etc. often with the wheels and systems being subjected to harsh vibration profiles due to bumps, potholes, gravel etc.

Precision Engineering

The mission was to extract quality, efficiency and performance improvements for the rider but also to improve the development speed and time to market for Brompton. However with the complex electrical, mechanical and control systems in the bike, Engineers at Brompton , needed to get a holistic, real time, consolidated visualization of mechatronic, CAN, analog and digital data without a whole lot of post processing. This would enable them to capture, evaluate and fix bugs faster and more efficiently.

Getting there

Engineers at Brompton bikes were able to speed up development and time to market using the comprehensive real time information made available by the portable DL350 ScopeCorder .  The portability, flexibility and modularity of the unit enabled engineers at Brompton to conduct multichannel tests under varying conditions simultaneously even when the bike was moving on road.  “This allowed us to test and improve our bikes quickly and iteratively.” notes Douglas. For Brompton the bike mountable DL350 ScopeCorder was an ideal solution to evaluate mechatronic parameters at high bandwidth, sampling rates and time periods.

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