E-Bike Drive Control Using Crank-Wheel Synchronization
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Solution Overview
Problem
Existing vehicles propelled by muscle power, such as e-bikes, require a certain amount of muscle force for the drive system to provide assistive propulsion, limiting efficiency and convenience.
Innovation Solution
A method and control device that detect synchronous operation between the rotational speed of the drive wheel and the crank mechanism, allowing the drive unit to deliver power independently of muscle force applied, using a predetermined drive power to assist propulsion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the drive system requires muscle force detection to provide assistive propulsion, then the system maintains basic operational control and reliability, but the ease of operation and productivity are reduced due to the need for continuous manual effort
Solution Approach 1:
The drive system automatically detects synchronous operation between the crank mechanism and drive wheel, and autonomously activates the drive unit without requiring the driver to manually control or monitor the assistance system. The system serves itself by self-detecting the operational condition and self-activating the motor assistance.
Solution Approach 2:
The patent replaces the traditional mechanical muscle-power-based propulsion system with an automated electromechanical system. The drive unit (electric motor) substitutes for continuous manual muscle force, converting mechanical synchronous operation detection into electrical motor activation to assist propulsion.
2Productivity
If the drive unit is activated with predetermined drive power during synchronous operation, then the productivity and ease of operation are improved, but the loss of energy increases due to continuous motor operation
Solution Approach 1:
The drive unit operates periodically rather than continuously - it is activated only during detected synchronous operation periods and deactivated during non-synchronous periods. This periodic activation pattern reduces overall energy consumption while maintaining productivity during the active assistance phases.
Solution Approach 2:
The control device continuously monitors the rotational speeds of both the crank mechanism and drive wheel, detects synchronous operation conditions, and uses this feedback information to control the activation and deactivation of the drive unit. This closed-loop feedback system ensures the motor operates only when needed, optimizing energy efficiency.
3Ease of operation
If the drive system provides continuous assistive propulsion, then the ease of operation is improved, but the reliability and safety are reduced due to potential excessive acceleration and loss of driver control
Solution Approach 1:
The drive assistance is applied periodically rather than continuously - the drive unit is activated only during detected synchronous operation and deactivated during non-synchronous operation. This periodic application prevents continuous force that could cause excessive acceleration, maintaining driver control and system safety.
Solution Approach 2:
The system replaces continuous mechanical muscle force with controlled electromechanical assistance that can be precisely regulated. The electronic control system provides more reliable and controllable force application compared to pure mechanical systems, enabling safety features like automatic deactivation during non-synchronous operation.
Data Source
Figure 1
AI summary
A method for controlling a drive device to assist a vehicle that can be propelled at least temporarily by muscle power is proposed, comprising a drive wheel that can be driven by motive power provided by the drive device and a crank device that can be rotated by a driver of the vehicle, with the following steps: (S1) querying whether a predetermined operating mode of the drive device, which can be specified by the driver of the vehicle, is present; (S2) detecting the rotational speed of the drive wheel; (S3) detecting the rotational speed of the crank device; (S4) determining synchronous operation with respect to the rotational speed of the drive wheel and the rotational speed of the crank device based on a gear ratio between the crank device and the drive wheel;(S6) Controlling the drive unit with a predetermined drive power independently of any muscle force applied to the crank unit, when the predetermined operating mode is present and it is determined that synchronous operation is present.;