Dual-Motor Pedal-Assisted Bicycle Control for Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing pedal-assisted bicycles with electric hub motors face inefficiencies at low speeds and for transmission ratios greater than 1, which affects battery life and overall performance in various usage conditions.
Innovation Solution
A pedal-assisted bicycle system that includes a central electric motor directly connected to the pedal assembly, an electric hub motor at the wheel hub, and a control unit that manages the motors and battery charge. The control unit identifies the bicycle's operating condition and adjusts the motor operation to follow a maximum efficiency curve based on linear speed and transmission ratio, optimizing energy use and battery maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an electric hub motor is used for pedal-assisted bicycles, then the system is adaptable to traditional frames and provides servo contribution, but the efficiency is poor at low speeds and for transmission ratios greater than 1
Solution Approach 1:
The patent combines two motor systems: a central electric motor connected to the pedal assembly and an electric hub motor at the wheel hub. This merging allows the system to leverage the advantages of both configurations - the central motor's efficiency at various transmission ratios and the hub motor's adaptability to traditional frames - thereby resolving the contradiction between adaptability and energy efficiency.
Solution Approach 2:
The control unit dynamically selects which motor to operate based on real-time operating conditions such as speed and transmission ratio. At low speeds and high transmission ratios, the central motor is activated; at higher speeds, the hub motor takes over. This dynamic switching optimizes energy efficiency across different operating regimes while maintaining frame adaptability.
2Duration of action of moving object
If the battery state of charge is maintained around a predetermined value using an electric hub motor operating as both actuator and generator, then battery life is increased, but the system is not optimal for all usage conditions particularly at low speeds and high transmission ratios
Solution Approach 1:
The patent implements a universal motor system where the central electric motor and electric hub motor can perform multiple functions depending on operating conditions. The central motor provides efficient assistance at low speeds and high transmission ratios, while the hub motor handles high-speed operations and can function as a generator for regenerative braking. This multi-functionality ensures optimality across all usage conditions while extending battery life through intelligent energy management.
Solution Approach 2:
The control unit continuously monitors operating parameters such as speed, transmission ratio, and battery state of charge, and dynamically adjusts which motor operates based on these parameter changes. This parameter-driven control strategy ensures the system operates optimally under all conditions - using the central motor when efficiency is critical and the hub motor when speed is the priority - thereby resolving the contradiction between battery life extension and universal optimality.
3Use of energy by moving object
If a central electric motor is used to provide torque to the pedal assembly, then efficiency is improved at low speeds and high transmission ratios, but the system complexity increases
Solution Approach 1:
The control unit automatically determines the optimal motor configuration based on real-time operating conditions without requiring manual intervention. The system self-adjusts by activating the central motor when efficiency is needed and the hub motor when speed is prioritized, thereby managing the increased system complexity through autonomous decision-making rather than user burden.
Solution Approach 2:
The control unit receives continuous feedback from sensors monitoring speed, transmission ratio, and battery state of charge. Based on this feedback, the control unit dynamically selects which motor to operate, optimizing energy efficiency while managing system complexity through intelligent control algorithms that automatically balance the benefits of dual-motor configuration against the added complexity.
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 system optimizes the efficiency of the pedal-assisted bicycle under all conditions, improving battery life and performance by dynamically adjusting motor operation to match the bicycle's speed and usage demands.
Implementation Method 1
an electrical device (4) arranged at the hub of a wheel and operatively connected to the battery pack (2) to transfer current to the battery pack itself
Implementation Method 2
a central electric motor (3) directly connected to the pedal assembly (103) to provide a torque to the pedal assembly itself
Data Source
AI summary
A pedal-assisted bicycle comprises a traction system provided with a battery pack, a central electric motor, an electrical device operating as an electric generator and a control unit. The control unit is configured to receive a plurality of first input signals representative of an operating condition of the bicycle and to receive a second input signal representative of the state of charge of the battery pack. The control unit is configured to identify the operating condition of the bicycle as a function of the first input signals and to emit, as a function of the second input signal and the identified operating condition, a driving signal structured so as to drive the electrical device and the central electric motor so that the state of charge follows a defined reference state of charge.