Single Radar Anti-lock Braking for Electric Bicycles
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Solution Overview
Problem
Existing anti-lock braking systems for electric bicycles face challenges in reliably preventing wheel locking during heavy braking, which can lead to steering difficulties or impossibility, especially due to the small wheel width and the deviation between vehicle and wheel speeds.
Innovation Solution
An anti-lock braking system for electric bicycles that utilizes a single radar sensor to detect the deviation between vehicle and wheel speeds by analyzing the radar frequency spectrum reflected from the ground and wheel, activating the brakes accordingly, and optionally includes a speed sensor, acceleration sensors for rear wheel lifting detection, and an adjustable spring element to maintain stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single radar sensor is used to detect wheel speed and vehicle speed, then device complexity is reduced, but measurement precision deteriorates due to the small wheel width making it difficult to distinguish between ground reflection and wheel reflection
Solution Approach 1:
The system dynamically adjusts the radar signal frequency based on the detected wheel state. When wheel locking is detected through frequency spectrum analysis, the radar operating frequency is changed to improve the distinction between ground and wheel reflections, thereby maintaining measurement precision while using a single sensor
Solution Approach 2:
The patent changes the operating parameters of the radar sensor, specifically the frequency, depending on the detected condition. By analyzing the frequency spectrum and detecting changes in reflection patterns, the system adapts the radar frequency to optimize speed measurement precision without adding more sensors
2Reliability
If the brake is activated to prevent wheel locking, then wheel locking is prevented, but steering control is lost when the wheel is locked
Solution Approach 1:
The system continuously monitors the radar frequency spectrum to detect wheel locking conditions and provides feedback to the brake control. When locking is detected, the brake activation is modulated to prevent complete locking, maintaining enough wheel rotation for steering control while still preventing unsafe locking conditions
Solution Approach 2:
The brake activation is applied in a periodic or pulsating manner rather than continuous activation. This allows the wheel to maintain periodic contact with the ground for steering control while preventing sustained locking that would eliminate steering capability
3Stability of the object's composition
If acceleration sensors are added to detect rear wheel lifting, then vehicle stability is improved, but device complexity increases
Solution Approach 1:
The acceleration sensors serve multiple functions: detecting rear wheel lifting, determining vehicle pitch state, and providing data for brake force distribution. This multi-functionality justifies the added complexity by providing comprehensive stability control with a single sensor type
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively prevents wheel locking, enhances steering control, and increases driving safety by precisely activating brakes based on real-time speed and wheel conditions, while reducing the risk of rollover and improving braking control.
Implementation Method 1
According to the Doppler effect, a speed of the vehicle can be determined from a frequency shift of the detected radar frequency spectrum in relation to the transmitted radar signal
Data Source
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AI summary
The control method according to the invention comprises at least one emission of a radar signal into a region (110) which comprises a surface (150) of the section of road and a wheel (101, 102) of the vehicle (100). Subsequently, the radar frequency spectrum reflected at the surface (150) and at the wheel (101, 102) is detected by means of the radar sensor (105). In a subsequent step, at least one brake (103, 104) is actuated as a function of a detected deviation between the vehicle speed and the wheel speed as a function of the detected radar frequency spectrum by means of the control unit. The brake is preferably a front wheel brake of an electric bicycle.