Wireless Time Synchronization for Intermittently Connected Electrical Units
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Solution Overview
Problem
Existing methods for wireless time synchronization between intermittently connected electrical units, such as those in e-bikes, are inefficient and lack sufficient accuracy, particularly during gear changes, leading to increased wear and energy consumption.
Innovation Solution
A method involving data packet exchange and timestamp-based synchronization at predetermined connection intervals, with error detection and correction mechanisms, ensures accurate and energy-efficient time synchronization between intermittently connected electrical units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If continuous wireless connection is maintained between electrical units, then time synchronization accuracy is improved, but energy consumption increases
Solution Approach 1:
The patent implements periodic connection events at predetermined intervals instead of continuous connection. The first electrical unit transmits timestamp data packets only at these scheduled connection events, allowing the second electrical unit to update its time counter periodically. This maintains sufficient synchronization accuracy for gear change operations while significantly reducing energy consumption compared to continuous connection.
2Measurement precision
If frequent connection events are scheduled, then time synchronization accuracy is improved, but wear on components increases
Solution Approach 1:
The system schedules connection events periodically at optimized intervals that balance synchronization accuracy requirements with wear reduction. By concentrating synchronization updates at specific moments rather than maintaining constant communication, the patent reduces the cumulative wear on wireless communication components and mechanical parts involved in gear changes.
Solution Approach 2:
The first electrical unit pre-calculates suitable time windows for gear changes based on load minimums (crank dead center positions) and performs time synchronization in advance within these windows. This preliminary synchronization ensures accurate timing for subsequent gear change operations without requiring frequent ongoing connection events, thereby reducing wear.
3Use of energy by moving object
If intermittent connection is used, then energy consumption is reduced, but time synchronization accuracy deteriorates
Solution Approach 1:
The patent uses timestamp data packets as an intermediary mechanism to transfer time reference information between electrical units during intermittent connections. The first electrical unit includes its time counter timestamp in transmitted data packets, allowing the second electrical unit to accurately determine the first unit's time without requiring continuous connection. This intermediary data exchange maintains synchronization accuracy despite intermittent connectivity.
Solution Approach 2:
The system copies timestamp information from the first electrical unit's time counter into transmitted data packets. The second electrical unit receives these copied timestamp values and uses them to synchronize its own time counter. This copying mechanism allows accurate time transfer during brief connection events, maintaining synchronization accuracy while enabling intermittent operation.
Data Source
AI summary
A method for wireless time synchronization of a first electrical unit with a second electrical unit is disclosed, which can in particular be intermittently wirelessly connected to each other, in particular via a low-energy connection, wherein the first electrical unit includes a first time counter and the second electrical unit comprises a second time counter, and wherein a connection event occurs repeatedly at predetermined connection time intervals. The method includes (a) transmitting a first data packet, by the first electrical unit, to the second electrical unit upon a first connection event, (b) receiving the first data packet and creating a second timestamp based on the second time counter, by the second electrical unit, (c) transmitting a second data packet with the created second timestamp, by the second electrical unit, to the first electrical unit upon a next connection event, (d) receiving the second data packet by the first electrical unit, (e) determining a current time, by the first electrical unit, based on one or more time periods of the predetermined connection time interval and the second timestamp, and (f) setting the first time counter to the current time determined.