Pedal-Assisted Bicycle Control System Using Inertial Sensors
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Solution Overview
Problem
Existing control systems for pedal-assisted bicycles that detect the presence of a cyclist are cumbersome to install and require multiple sensors, which can lead to accidental motor activation during maintenance or when the bicycle is not in use.
Innovation Solution
A control system that utilizes existing inertial sensors, such as those measuring wheel speed, acceleration, and yaw angle, to determine the presence of a cyclist, minimizing the need for additional sensors and preventing motor activation when the cyclist is not on the saddle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dedicated pressure sensors are arranged in the saddle or on the pedals to detect cyclist presence, then the presence detection accuracy is improved, but the device complexity and installation difficulty increase
Solution Approach 1:
The patent reuses existing inertial sensors (accelerometers, gyroscopes) originally designed for motor control and bicycle stabilization, making them serve a dual function by also detecting cyclist presence through analysis of mass distribution changes. This eliminates the need for dedicated presence detection sensors while leveraging already-installed components.
Solution Approach 2:
The system uses its own existing sensor infrastructure to perform the additional function of cyclist presence detection. The inertial sensors continuously collect data for motor control purposes, and this same data is analyzed to determine cyclist presence, making the system self-sufficient without requiring external dedicated sensors.
2Reliability
If multiple dedicated sensors are installed for cyclist presence detection, then the reliability of presence detection is improved, but the ease of manufacture and installation deteriorates
Solution Approach 1:
The patent makes the existing inertial sensors perform multiple functions: motor control, bicycle stabilization, and cyclist presence detection. By analyzing changes in mass distribution from the sensor data already being collected, the system achieves reliable presence detection without adding any physical sensors, thereby maintaining ease of manufacture and installation.
3Measurement precision
If pressure sensors are used to detect cyclist presence, then the accuracy of detecting cyclist position is improved, but the device complexity increases
Solution Approach 1:
The patent replaces mechanical pressure sensors with an inertial-based detection system. By using accelerometers and gyroscopes to detect changes in mass distribution and movement patterns, the system substitutes a mechanical sensing approach with an inertial measurement approach, reducing hardware complexity while maintaining detection accuracy.
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
This solution simplifies the installation process, reduces sensor complexity, and effectively prevents accidental motor activation, enhancing safety and usability by ensuring the motor only operates when the cyclist is present.
Implementation Method 1
an inertial measuring unit suitable for measuring one or more accelerations of the bicycle... and for generating signals representative of the same
Implementation Method 2
the angle sensing unit can be a G sensor, which senses a gravity change of a movement direction of the electric vehicle
Data Source
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AI summary
The present invention refers to a system (1) for controlling a pedal-assisted bicycle (100) comprising an electric motor (101) associated to a wheel (102) of the bicycle, a pedal-thrust group (103) to be pedaled by a user, a transmission (104) operatively interposed between said pedal-thrust group (103) and one of the wheels (102) of the bicycle, wherein said control system (1) comprises: - a sensor configured for detecting the speed (ωw) of said wheel (102) and for generating a signal representative of the wheel speed; - an inertial measuring unit adapted to detect at least one among the longitudinal (ax), lateral (ay) and vertical accelerations (az) and the yaw angular speed (ωz) of the bicycle and to generate signals representative of the same; - a starting device adapted to deliver an activation or deactivation (ON/OFF) signal following an activation or deactivation command by the cyclist; - a module (2) for controlling the electric motor (102), adapted to supply a motor current (Imot) to be delivered to the electric motor (102) for controlling the same; - a module (3) for determining the presence or absence of the cyclist on the bicycle, configured for delivering to the control module (2) of the electric motor (102) an activation or deactivation signal (Enable/Disable) according to whether it is detected the presence or absence of the cyclist, respectively; wherein said module (3) for determining the presence or absence of the cyclist, comprises: - one or more modules (6, 7, 8, 10, 11, 12) for preliminarily determining the presence or absence of the cyclist, each configured for generating a respective preliminary signal of absence or presence of the cyclist (1/0) based on one or more among the motor current (Imot), the signal representative of the wheel speed (ωw), the activation/deactivation (ON/OFF) signal of the starting device, the one or more signals representative of one or more magnitudes detected by the inertial measuring unit (ax, ay, az, wz); - a synthesis module (5) configured for generating said activation or deactivation signal (Enable/Disable) to be delivered to the control module (2) of the electric motor (102) based on the combination of said preliminary cyclist absence/presence signals. Further, the present invention refers to a pedal-assisted bicycle provided with such control system.