Electric Bicycle Motor Control for Stationary Rider Torque
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Solution Overview
Problem
Existing electric bicycle systems prematurely disable motor support when the bicycle is not moving, despite the rider continuing to pedal, leading to undesired situations such as rolling backward on inclines or at traffic lights.
Innovation Solution
A control electronics system that detects when the motor is not rotating despite rider torque and maintains motor support in a blocking mode, reducing torque over time based on various sensors and conditions to prevent sudden shutdowns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motor support is disabled when the motor rotational speed falls below a threshold, then safety is ensured, but motor support is taken away even when the driver does not desire this
Solution Approach 1:
The control system dynamically adjusts the motor support behavior based on the operating state. When the motor is rotating, the threshold-based safety control is applied. When the motor is stationary and driver torque is detected, the system transitions to blocking operation mode, dynamically adapting the control strategy to maintain motor support continuity while ensuring safety.
Solution Approach 2:
The system changes the control parameters based on the motor state. In normal rotation, the motor support is controlled based on driver torque with rotational speed thresholds. In blocking operation, the system detects stationary state combined with driver torque and maintains motor torque support, effectively changing the control parameters from speed-threshold-based to state-and-torque-based control.
2Reliability
If the motor support is disabled when no rotation occurs, then motor safety is protected, but the driver loses support on inclines or at traffic lights
Solution Approach 1:
The control system dynamically adapts to different operating conditions. When the motor is stationary with driver torque applied (blocking operation), the system provides continuous motor support. When the motor rotates normally, the system uses rotational speed thresholds for safety. This dynamic adaptation ensures both motor safety and continuous power availability when needed.
Solution Approach 2:
The control electronics continuously monitor motor rotational speed, driver torque, and operating state to determine whether to enable or maintain motor support. This feedback mechanism allows the system to distinguish between unsafe stationary conditions and legitimate blocking operation scenarios, providing power when needed while ensuring safety.
3Measurement precision
If the startup threshold is strictly enforced, then false motor support activation is prevented, but the motor support shuts off during legitimate blocking situations
Solution Approach 1:
The system changes the control parameters based on the detected operating state. In normal operation, the startup threshold is strictly enforced for accurate detection. In blocking operation mode, when the motor is stationary with driver torque, the system maintains motor support despite the threshold being exceeded, effectively changing the control parameter from strict threshold enforcement to state-aware threshold application.
Solution Approach 2:
The control strategy dynamically adjusts based on the combination of motor state and driver torque. The system transitions from a static threshold-based control to a dynamic control that considers both rotational state and torque application, allowing the startup threshold behavior to adapt to the current operating context.
Data Source
AI summary
A device for controlling a motor of an electric bicycle. The device includes a control electronics system that is set up to control a torque of the motor in a normal operating mode based on an acquired driver torque; to detect during normal operation whether, at the current motor torque, no rotation of the motor is taking place even though a driver torque is being exerted, and to control the motor to continue to provide the motor torque in a blocking operating mode if it has been detected that at the present motor torque no rotation of the motor is taking place even though a driver torque is being exerted.