Adaptive Bicycle Motor Control for Battery and Comfort Trade-off
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Solution Overview
Problem
Existing pedal-assisted bicycles struggle to maintain battery charge without external sources while ensuring adequate cyclist comfort, as existing algorithms either prioritize battery duration over comfort or require excessive cyclist effort.
Innovation Solution
An adaptive control system for pedal-assisted bicycles that optimizes synergy between the cyclist and the electric bicycle, calculating inversion speed and motor command signals based on battery state of charge and movement states to reduce cyclist effort and maintain battery charge, without needing a pedal torque sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If regenerative braking is used to recharge the battery, then battery duration is improved, but cyclist comfort deteriorates due to increased effort required
Solution Approach 1:
The control algorithm dynamically adjusts the inversion speed threshold based on battery state of charge. When battery charge is low, the system allows regenerative braking at lower speeds to recharge. When battery charge is sufficient, the system raises the inversion speed threshold to reduce cyclist effort during normal operation. This dynamic adaptation resolves the contradiction by making the system behavior flexible rather than fixed.
Solution Approach 2:
The system changes the critical parameter of inversion speed threshold based on battery state of charge. By modifying this parameter dynamically, the system transitions between different operational modes: at low battery charge, lower inversion speed enables more frequent regeneration; at high battery charge, higher inversion speed reduces regeneration and improves comfort. This parameter change strategy directly addresses the contradiction between battery duration and cyclist comfort.
2Duration of action of moving object
If pedal power is used to recharge batteries, then battery duration is improved, but cyclist effort increases
Solution Approach 1:
The control algorithm continuously monitors battery state of charge and uses this feedback to adjust the inversion speed threshold. When battery charge drops below a threshold, the system activates regenerative braking mode with lower inversion speed to recharge. When battery charge is sufficient, the system switches to assistance mode with higher inversion speed to minimize cyclist effort. This feedback mechanism ensures the system automatically balances energy recovery and cyclist comfort based on real-time battery conditions.
Solution Approach 2:
The system dynamically changes the inversion speed parameter based on battery state of charge feedback. At low battery charge levels, the inversion speed is reduced to enable energy recovery during deceleration. At high battery charge levels, the inversion speed is increased to minimize the cyclist's energy expenditure. This parameter adaptation directly resolves the contradiction between extending battery duration and reducing cyclist effort.
3Ease of operation
If inversion speed is increased to reduce cyclist effort, then cyclist comfort is improved, but battery charge maintenance capability deteriorates
Solution Approach 1:
The inversion speed threshold is made dynamic rather than fixed, adapting to battery state of charge conditions. The system automatically adjusts the threshold between high and low values based on whether the battery needs recharging or can tolerate reduced regeneration. This dynamic behavior allows the system to prioritize comfort when battery charge is sufficient and prioritize charge maintenance when battery charge is low, resolving the contradiction between these two objectives.
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 effectively reduces cyclist effort while maintaining battery charge, ensuring both comfort and extended battery life without external recharging, by dynamically adjusting motor assistance and regeneration based on bicycle states and battery conditions.
Implementation Method 1
the motor operates as a generator when the bicycle is decelerating, thus recharging the battery
Implementation Method 2
the electric motor operates as a motor supplied by the battery or as an electric generator when the bicycle is decelerating, thus recharging the battery
Data Source
Figure 1~2
Figure 3
Figure 4a~4f
AI summary
It is disclosed an adaptive system (1) to control a pedal- assisted bicycle (100). The system (1) comprises an electric motor (101) configured to operate as a motor and as a generator associated with a wheel (102) of the bicycle (100), a rechargeable battery (106) having a power exchange relationship with the electric motor (101), a pedal-thrust group (103) to be pedaled by a cyclist, a transmission (104) operatively interposed between the pedal-thrust group (103) and a wheel (102) of the bicycle comprising a free-wheel mechanism (105). The system comprises a sensor configured to generate a signal representative of an angular speed (ωwheel) of a wheel (102) of the bicycle, a sensor configured to generate a signal representative of an angular speed (ωfree-wheel) of the free-wheel mechanism (105), a sensor configured to generate a signal representative of the state of charge (SoC) of the battery (106), a nominal control module (2) configured to generate a motor nominal command signal (I°motor) based at least on said signals representative of the angular speed (ωwheel) of the wheel (102) and of the angular speed (ωfree-wheel) of the free-wheel mechanism (105), wherein said motor nominal command signal (I°motor) or a portion (i°cyclist) thereof is defined by a inversion speed (vlimit) of the bicycle beneath which the motor (101) supplies an assistance to the pedal- thrust and above which the motor (101) operates as a generator, and wherein said motor nominal command signal (I°motor) or a portion (i°cyclist) thereof is further defined by a maximum energy recovery value (irec,min) when the bicycle is not braking. The system further comprises an adaptive control module (3) configured to generate a motor corrected command signal ( I °motor, corr) determined from the motor nominal command signal (I°motor) corrected based on the signal representative of the state of charge (SoC) of the battery (106), which is configured to modify said inversion speed (vlimit) and said maximum energy recovery value (irec,min) of the motor nominal command signal (I°motor) or of a portion (i°cyclist) thereof based on the signal representative of the state of charge (SoC). The system is further configured to supply to the motor (101) a reference command signal (I°ref) determined based on said motor corrected command signal ( I °motor, corr) ·