E-Bike Wheel Slip Control Using Driven and Undriven Wheel Speeds
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electric bicycles and similar vehicles face issues with wheel slip due to incorrect operation or external factors like low friction surfaces, leading to unstable driving conditions, especially when starting on hills or in wintry conditions.
Innovation Solution
The vehicle is equipped with a control unit that compares the speeds of the driven and undriven wheels using speed sensors and reduces the speed of the driven wheel by adjusting the electric drive's support power, applying braking, or changing gears to prevent excessive slip, thereby maintaining traction and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the electric drive provides high support power to assist the rider, then the vehicle acceleration and climbing ability are improved, but wheel slip occurs on low-friction surfaces or during incorrect operation
Solution Approach 1:
The control unit continuously monitors the rotational speeds of both driven and undriven wheels and uses this feedback to detect slip conditions. When the speed difference exceeds a threshold, the system automatically reduces electric drive support power to prevent excessive wheel slip, thereby maintaining reliable traction while allowing high power delivery under normal conditions
Solution Approach 2:
The electric drive support power is made dynamically adjustable based on real-time wheel speed measurements. The system transitions between different power levels (high support power for normal operation, reduced power for slip prevention) according to the detected driving conditions, optimizing both acceleration performance and traction stability
2Force
If the vehicle starts on an incline or low-friction surface, then the vehicle can overcome the initial resistance, but the driven wheel exceeds its traction limit and slips
Solution Approach 1:
The control unit uses feedback from rotational speed sensors to detect when the driven wheel begins to slip during incline starts or on low-friction surfaces. Upon detecting a speed difference between driven and undriven wheels exceeding the threshold, the system reduces electric drive support power to keep the tractive force within the traction limit, maintaining vehicle handling stability
Solution Approach 2:
The system takes preliminary action by continuously monitoring wheel speeds and preparing to reduce support power before excessive slip occurs. The control unit is configured to reduce the rotational speed of the driven wheel when slip is detected, preventing the vehicle from entering an unstable state
Data Source
Figure 1
AI summary
The invention relates to a vehicle that can be driven by muscle power or electrically, in particular an electric bicycle, comprising: a drive (2) that can be operated by muscle power; an electric drive (3); an energy storage means (6) for supplying electrical energy to the electric drive (3); a control unit (10), which is designed to control the electric drive (3) on the basis of a pedal frequency and/or a vehicle speed and/or a torque applied by a rider and/or an assistance mode selected by a rider; a first device (11) for determining a rotational speed of a wheel (7) driven by the electric drive (3); and a second device (12) for determining a rotational speed of a rotating undriven wheel (8) of the vehicle (1); wherein the control unit (10) is also designed to perform a comparison of the rotational speeds of the driven wheel (7) and the undriven wheel (8) and, if a rotational-speed difference between the driven wheel (7) and the undriven wheel (8) is detected, which difference exceeds a specified threshold value, to reduce a rotational speed of the driven wheel (7).