E-Bike Torque Control for Friction-Aware Regenerative Braking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional electronic bicycles waste kinetic energy as heat during braking and lack control over torque application, leading to potential wheel slipping and tipping issues due to the inefficiencies of traditional braking systems.
Innovation Solution
A torque control system that uses front and rear wheel hub motors to apply positive or negative torque based on user input, detects slipping and tipping, and determines the coefficient of friction to manage torque application, switching between active and passive braking as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional friction brakes are used to slow or stop the electronic bicycle, then the braking function is achieved, but the kinetic energy is wasted as heat and there is no control over torque application
Solution Approach 1:
The patent replaces traditional mechanical friction brakes with an electric motor-based torque control system. The motor controller applies electromagnetic torque to the wheel hub to achieve braking, substituting mechanical friction with electrical control. This enables both energy recapture through regenerative braking and precise torque management without the energy waste and control limitations of traditional friction brakes.
Solution Approach 2:
The patent dynamically adjusts the torque parameter applied to the wheel based on riding conditions, friction coefficient measurements, and braking requirements. By changing the torque parameter from fixed (traditional brakes) to variable and controlled, the system achieves both energy efficiency through selective regenerative braking and precise control to prevent wheel slip and tipping.
2Loss of energy
If regenerative braking is used to recapture kinetic energy, then energy is recovered, but the maximum torque is limited based on bicycle speed
Solution Approach 1:
The patent implements a dynamic braking system that transitions between regenerative and friction braking based on real-time conditions. At higher speeds, regenerative braking provides sufficient torque for energy recovery. As speed decreases and regenerative torque becomes insufficient, the system dynamically engages friction brakes to supplement the braking force, ensuring both energy recovery and adequate braking performance across all speed ranges.
Solution Approach 2:
The patent performs preliminary measurement of the friction coefficient between tire and road surface before determining the braking strategy. This advance knowledge allows the system to pre-calculate the optimal combination of regenerative and friction braking torques needed, ensuring that energy recovery is maximized while maintaining sufficient braking force even when regenerative torque is limited by low speed.
3Productivity
If high torque is applied to the wheels for rapid acceleration or braking, then performance is improved, but the wheels may slip against the ground or the bicycle may tip over
Solution Approach 1:
The patent implements a feedback control system that continuously measures the friction coefficient between tire and road, monitors wheel angular velocity, and detects signs of wheel slip or bicycle tipping. Based on this feedback, the motor controller dynamically adjusts the applied torque to remain below the slip threshold while maximizing acceleration performance. The system reduces torque immediately when slip is detected and can apply counter-torque to prevent tipping.
4Reliability
If the friction coefficient is continuously monitored to adjust torque, then wheel slip is prevented, but the system complexity increases
Solution Approach 1:
The patent employs a friction coefficient measurement system that uses the bicycle's own operational data (motor current, wheel speed, acceleration) to infer road surface conditions. Rather than requiring external sensors or complex measurement equipment, the system self-determines the friction coefficient by analyzing how the wheel responds to applied torque during normal operation, thereby achieving reliable torque control without significantly increasing system 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 torque control system effectively recaptures kinetic energy, prevents wheel slipping and tipping, and optimizes torque application for safe and efficient braking, enhancing the overall performance of electronic bicycles.
Implementation Method 1
When passively braking, the electronic bicycle may use the generated power to power a battery of the electronic bicycle or may dissipate the generated power as heat
Implementation Method 2
The friction from the force being applied to the surface causes the kinetic energy of the electronic bicycle to be released as heat energy due to friction
Data Source
AI summary
An electronic bicycle includes a torque control system that controls what torque is applied to wheels of the electronic bicycle by electronic hub motors. The torque control system may determine a torque to apply to the wheels based on user input signals. The torque control system also may detect when the wheels of the electronic bicycle are slipping, and adjust the torque to minimize the time that the wheel is slipping. Additionally, the torque control system may determine a coefficient of friction between the wheels and the ground and determine a maximum torque to apply to the wheels based on the coefficient of friction. Furthermore, when braking, the torque control system may determine whether torque is applied to the wheels by passive braking or by active braking.