Chainless E-Bike Pedal-Wheel Synchronization Control
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Solution Overview
Problem
Chainless electric bicycles lack the pedaling feeling and driving torque synchronization experienced in bicycles with chains, leading to an uncomfortable riding experience.
Innovation Solution
A device for driving a chainless electric bicycle, comprising a motor, a generator, position sensors, and a controller that calculates a difference value between the rotational positions of the generator and motor, and adjusts the generator or motor currents to synchronize the rotational positions and enhance the pedaling feeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a chainless drive system is used to eliminate the chain, then the chain-related problems (long length, complicated structure, chain coming out of gear or getting caught in pants) are solved, but the pedaling feeling and synchronization between pedal and driving wheel are lost
Solution Approach 1:
The patent replaces the mechanical chain connection with an electronic control system. The controller receives signals from both the pedal position sensor and driving wheel position sensor, processes these signals electronically, and controls the motor accordingly. This substitution of mechanical connection with electronic control eliminates the physical chain while maintaining the functional relationship between pedal input and wheel output through software algorithms.
Solution Approach 2:
The patent implements a feedback mechanism where the controller continuously receives position information from both the pedal and driving wheel, compares their positions, and adjusts the motor output based on the detected difference. This closed-loop feedback system allows the electronic control to replicate the synchronization effect that the mechanical chain provided, thereby restoring the pedaling feeling without requiring a physical chain connection.
2Device complexity
If electronic control is used to transmit power from pedal to driving wheel, then the chain is eliminated, but the rotational position synchronization between pedal and driving wheel is lost
Solution Approach 1:
The patent employs feedback control by continuously monitoring the rotational positions of both the pedal (via generator position sensor) and driving wheel (via motor position sensor), calculating the difference between them, and using this difference signal to adjust motor control. This feedback mechanism ensures that the electronic system maintains rotational position synchronization equivalent to the mechanical chain connection.
Solution Approach 2:
The patent substitutes the mechanical chain's inherent position-synchronization property with an electronic control system that actively maintains synchronization through sensing and control algorithms. The controller processes position data from both components and adjusts motor operation to match pedal position, replacing passive mechanical coupling with active electronic synchronization.
3Ease of operation
If speed command or torque command is used to control the motor, then the system is simple to control, but the acceleration response and driving feeling are insufficient
Solution Approach 1:
The patent uses feedback from the position difference between pedal and driving wheel to dynamically adjust motor control parameters. Rather than using fixed speed or torque commands, the system continuously adapts the control signal based on real-time position synchronization requirements, improving acceleration response while maintaining control simplicity through automated feedback adjustment.
Solution Approach 2:
The patent transitions from static control commands to dynamic control that adapts in real-time. The control system continuously calculates the position difference and adjusts motor output dynamically based on current operating conditions, including road gradient and acceleration demands. This dynamic approach enables the motor to respond appropriately to changing conditions while maintaining synchronization, improving acceleration performance without complicating the control interface.
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 solution effectively synchronizes the rotational positions of the pedals and driving wheels, providing a pedaling feeling similar to that of a bicycle with a chain, and enhances the driving torque response to road gradients and pedal acceleration.
Implementation Method 1
a generator configured to generate power using a pedal
Implementation Method 2
a motor configured to drive a driving wheel
Data Source
AI summary
The present invention relates to a system for driving a chainless electric bicycle comprising: a driving wheel; a pedal; a motor mechanically connected to the driving wheel; a generator mechanically connected to the pedal; and a battery, wherein provided is a system comprising: a generator location sensor for measuring the value of a rotation location of the generator; a motor location sensor for measuring the value of a rotation location of the motor; and a controller configured to calculate a difference value of the value of the rotation location of the motor minus the value of the rotation location of the generator multiplied by a gear ratio, and to control at least one of the generator and the motor on the basis of the difference value.