Electric Bicycle Motor Assistance Control Algorithms
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Solution Overview
Problem
Current control methods for electric bicycle motor assistance are suboptimal, particularly in the downward regulation speed range, as they do not account for the driver's preference to ride at maximum speed with minimal effort, leading to inefficient motor assistance and driver influence on speed fluctuations.
Innovation Solution
A method involving two regulation algorithms to control motor assistance, with a first algorithm based on driver's torque and power, and a second algorithm that sets the speed to the downward regulation speed, using a transition control value for smooth switching between the two, minimizing driver influence and optimizing speed maintenance at the downward regulation speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If motor assistance is controlled based on driver's torque and power using a first regulation algorithm, then the motor assistance responds to driver input, but the speed cannot be maintained at downward regulation speed with minimal driver effort
Solution Approach 1:
The system dynamically switches between two regulation algorithms based on speed thresholds. Below the first limit speed, the first regulation algorithm (response to driver torque) is active. Above the first limit speed, the second regulation algorithm (speed maintenance at downward regulation speed) becomes active. This dynamic switching allows the system to adapt its control behavior based on operating conditions, enabling minimal driver effort while maintaining speed at downward regulation speed.
Solution Approach 2:
The system changes the control parameter from driver torque-based assistance to speed-based assistance. By monitoring speed and switching algorithms at specific threshold values, the system transitions from a torque-responsive mode to a speed-regulation mode, allowing the bicycle to maintain downward regulation speed with minimal driver effort when conditions permit.
2Reliability
If motor assistance is reduced or set by downward regulation function at downward regulation speed, then legal requirements are met, but the driver cannot ride at maximum speed with minimal effort
Solution Approach 1:
The system dynamically adapts its control strategy based on speed thresholds. When the bicycle reaches the downward regulation speed threshold, the second regulation algorithm activates to maintain speed with minimal driver effort. This dynamic adaptation allows the system to comply with legal speed limits while providing comfortable riding experience at maximum assisted speed.
Solution Approach 2:
The second regulation algorithm enables the motor assistance system to self-regulate speed at the downward regulation speed threshold without continuous driver intervention. The system automatically maintains the optimal speed and assists the driver with minimal effort, making the system serve the driver's need for comfortable riding at maximum speed while remaining legally compliant.
3Device complexity
If a single regulation algorithm is used for motor assistance control, then the control system is simple, but it cannot optimize for both driver response and speed maintenance
Solution Approach 1:
The control system is segmented into two distinct regulation algorithms, each optimized for specific operating conditions. The first regulation algorithm handles low-speed operation with driver torque response, while the second regulation algorithm handles high-speed operation with speed maintenance. This segmentation allows each algorithm to be optimized for its specific function without compromising overall system performance.
Solution Approach 2:
The system dynamically selects which regulation algorithm to execute based on the current speed threshold. This dynamic switching mechanism allows the control system to optimize performance for the current operating condition while maintaining manageable complexity through clear separation of concerns between the two algorithms.
4Ease of operation
If the downward regulation function ensures comfortable ramp-down of motor assistance, then driver comfort is maintained, but speed fluctuations occur and maximum speed is not achieved
Solution Approach 1:
The system dynamically switches from the first regulation algorithm (torque-based) to the second regulation algorithm (speed-based) when the speed threshold is reached. This dynamic transition allows the system to maintain driver comfort through smooth assistance ramp-down while simultaneously achieving speed stability and maximum speed through active speed regulation by the motor assistance system.
Data Source
AI summary
A method for controlling a motor assistance provided by a motor of an electric bicycle is disclosed. The method includes controlling a motor assistance by the motor based on a first control value when the bicycle is moved at a speed below a first limit speed, wherein the first control value is calculated by way of a first regulation algorithm. The method also includes controlling the motor assistance by the motor based on a second control value, after a transition phase has been completed, the second control value being calculated by way of a second regulation algorithm, the second regulation algorithm controlling the motor assistance in such a way that the speed of the bicycle assumes a downward regulation speed.