Pedelec Speed Sensor Cross-Check via Periodic Power Interruption
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Solution Overview
Problem
Existing methods for checking the speed of pedelecs fail to reliably detect defective speed sensors, leading to potential overheating and mechanical failure due to motor assistance at speeds above 25 km/h.
Innovation Solution
A method and device that intermittently power off the speed signal transmitter, use a speed sensor to measure a second speed, and compare it with the first speed to detect faulty sensors, with additional checks using a third speed if necessary, and implement actions like system shutdown when thresholds are exceeded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the speed is determined continuously using a speed signal transmitter, then the speed measurement is available at all times, but the reliability of the speed sensor cannot be verified and defective sensors cannot be detected
Solution Approach 1:
The patent implements periodic interruption of the power supply to the speed signal transmitter at predefined intervals. During these interruption periods, the system switches to a speed sensor to determine speed. This periodic action allows the system to verify sensor reliability while maintaining continuous speed measurement capability through alternation between the two measurement methods.
2Reliability
If the power supply is interrupted frequently to test the speed sensor, then the reliability detection is improved, but the system complexity and energy consumption increase
Solution Approach 1:
The power supply interruption is implemented periodically at predefined intervals rather than continuously or randomly. This approach balances the need for reliability verification with system simplicity, as the periodic nature allows for predictable power management and reduces the complexity of control logic compared to continuous or event-driven interruption schemes.
3Duration of action of stationary object
If the speed signal transmitter is used continuously, then accurate speed determination is maintained, but defective sensors cannot be detected and component lifespan is reduced
Solution Approach 1:
The system alternates between the speed signal transmitter and the speed sensor through periodic power supply interruptions. This periodic switching reduces continuous operation time of the speed signal transmitter, thereby extending its lifespan and allowing detection of defects, while maintaining accurate speed measurement through the alternative speed sensor during interruption periods.
Data Source
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AI summary
The invention relates to a method for checking the speed of a bicycle, in particular a pedelec, comprising the steps of: - providing a power supply (4) for a speed signal transmitter (2), - determining a first speed for the bicycle with the speed signal transmitter (2), - interrupting the power supply for the speed signal transmitter (2) for a predefinable interruption period, - during the switched-off power supply, determining a second speed with a further speed sensor (3), - determining a comparison result by comparing the determined first and second speeds, and - detecting a faulty speed signal transmitter (2) depending on the comparison result.