Wireless networks today are able to brake just one bike, but in the future, they could regulate entire trains. Computer scientists at Saarland University in Germany are designing mathematical calculations to check such systems automatically. Professor Holger Hermanns, whose group developed the wireless bicycle brake, explained that wireless networks are never a failsafe method. Train and airplane experiments are far too sophisticated, and could even endanger the lives of human beings in case of malfunction.
Therefore, the mathematical methods developed by the team should verify the correct function and interaction of the components automatically. The wireless bicycle brake provides the platform to optimize these methods for operation in much more complex systems, according to Hermanns. His group examines the brake prototype with algorithms that normally are used in control systems for aircraft or chemical factories. As a result, they found out that the brake works with more than 99.9 percent reliability. This implies that out of a trillion braking attempts, there are three failures.
To brake with the wireless brake, a cyclist needs only to clench the rubber grip on the right handle. The more tightly the grip is clenched, the harder the disk brake on the front wheel works. A combination of several electronic components enables the braking. Integrated in the rubber grip is a pressure sensor, which activates a sender if a specified pressure threshold is crossed. The sender is integrated in a plastic box the size of a cigarette pack, and is attached to the handlebar. Its radio signals are sent to a receiver attached at the end of the bicycle’s fork.
The receiver forwards the signal to an actuator, transforming the radio signal into the mechanical power by which the disk brake is activated. The electrical energy is supplied by a battery, which is also attached to the bicycle’s fork. To enhance reliability, there are additional senders attached to the bicycle. These repeatedly send the same signal.
Its current configuration enables the bike to brake within 250 milliseconds. This means that at a speed of 30 kilometers per hour, the cyclist has to react two meters before reaching the dangerous situation. But the scientists are not satisfied with just this functionality. “It is not difficult to integrate an anti-lock braking system and traction control. That takes only a few adjustments,” Hermanns explained.