The task
E-bikes are an important part of the shift in mobility for short-distance travel, and sales of electric bicycles have indeed been booming for several years. Manufacturers of e-bikes and accessories do, however, face additional safety requirements that simply do not apply to conventional bicycles. Drive control is one such area.
SIGMA Sport was planning a new e-bike computer with a user interface for the drive, allowing the pushing aid to be switched on or off via a safety switch on the handlebar whenever needed. This function called for a safety monitor to track the switch position and make sure the drive only engages when the rider genuinely intends it to, rather than because of a fault during braking.
The brief called for a market-compliant safety design and the integration of the safety monitor into the already fully developed human-machine interface (HMI). As production of the new e-bike computer was planned in Asia, certification was also to be carried out through TÜV SÜD Hong Kong.
The solution
NewTec began by developing a comprehensive safety concept. On that basis, NewTec safety experts produced the complete hardware design for the pushing aid safety monitor and developed the corresponding firmware to monitor the safety switch. The interface between the safety monitor and the HMI was defined as well.
With the NewTec solution, the activation command for the pushing aid is now only sent when the safety switch is triggered at the same time. To achieve this, the state of the safety switch is compared with the messages transmitted over CAN. In the event of a fault, for instance when the transmitted message does not match the switch position, the activation command is suppressed.
The entire development was carried out in close coordination with the customer’s development department in Asia. Finally, NewTec also supported certification through TÜV SÜD Hong Kong.
