E-Bike Drive Assist Control Using Rider Torque Load Matching
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Solution Overview
Problem
Conventional electrically drivable bicycles adjust drive assist based on predefined assistance factors independent of the rider's performance, leading to suboptimal riding dynamics and potential overloading of components, which can affect the service life of the bicycle.
Innovation Solution
A method and system that adapt drive assist by an electric drive motor based on instantaneous rider torque, using an evaluation unit to ascertain rider torque statistics and apply an assignment rule to match the load spectrum to a target load spectrum, ensuring optimal motor torque adjustment according to the rider's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If predefined fixed assistance factors are used for drive assist, then the control system is simple, but the riding dynamics are suboptimal and do not adapt to different rider performance levels
Solution Approach 1:
The system continuously measures actual rider torque via a torque sensor and compares it to a target load spectrum, using this feedback to dynamically adjust assistance factors. This closed-loop control enables the system to adapt to different rider performance levels while maintaining manageable complexity through automated adjustment.
Solution Approach 2:
The assistance factors transition from static predefined values to dynamic values that change in real-time based on measured rider torque and comparison with target load spectrum characteristics. This dynamic adaptation allows the system to optimize performance for each rider without requiring complex manual configuration.
2Reliability
If assistance factors are established independently of rider performance, then the control implementation is simple, but the load spectrum may be exceeded by high-performance riders causing component overloading
Solution Approach 1:
The system replaces subjective assessment of rider performance with objective mechanical measurement using a torque sensor. This substitution provides reliable, quantifiable data about actual rider torque output, enabling automated adjustment of assistance factors to prevent component overloading without requiring complex performance evaluation methodologies.
Solution Approach 2:
The system automatically adjusts assistance factors based on measured rider torque characteristics, eliminating the need for manual performance assessment or configuration. The drive system self-adapts to each rider's capabilities, ensuring reliable load management within the target load spectrum without external intervention.
3Productivity
If gears and components are designed with respect to a conservative load spectrum, then component durability is ensured, but the riding experience is compromised for high-performance riders
Solution Approach 1:
The system dynamically changes the effective load on components by adjusting motor assistance based on actual rider torque measurements and target load spectrum parameters. This allows the bicycle to operate at optimal performance levels for each rider while keeping actual component loads within durable boundaries, effectively decoupling riding performance capability from component strength requirements.
Data Source
AI summary
A method and a drive system for adapting a drive assist by an electric drive motor of an electrically drivable bicycle. The method includes: ascertaining an instantaneous rider torque exerted by a rider of the bicycle on a drive train of the bicycle, ascertaining rider torque statistics based on a plurality of rider torques ascertained over time, ascertaining an assignment rule between the rider torque statistics and a predefined target load spectrum for the bicycle, the assignment rule approximating the rider torque statistics to the target load spectrum, establishing a motor torque corresponding to the instantaneous rider torque, based on the assignment rule, and operating the electric drive by specifying the ascertained motor torque.