Motorcycle Stability Control via Bank Angle Tire Radius Correction
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Solution Overview
Problem
Existing stability control systems for vehicles, such as motorcycles, face challenges in accurately determining tire radius and slip rates due to deviations from design values caused by factors like tire wear and vehicle inclination, leading to misdetected spins and inappropriate ABS intervention.
Innovation Solution
A stability control system that includes a wheel rotation speed sensor, vehicle speed sensor, and attitude detector to calculate a tire radius correction value based on wheel rotation speed and vehicle speed, adjusting the wheel speed to accurately determine slip rates and improve traction control and ABS performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If tire radius correction is performed using only wheel rotation speed data during constant speed travel, then tire radius learning can be achieved, but learning occurs incorrectly when the vehicle is inclined (on loops, arched bridges, or rotaries)
Solution Approach 1:
The patent introduces vehicle inclination angle detection as an intermediary parameter to identify and exclude learning conditions. By detecting the inclination angle and comparing it against threshold values, the system determines whether the vehicle is on an inclined road section, thereby preventing incorrect tire radius learning under such conditions
Solution Approach 2:
The patent replaces pure mechanical/wheel-speed-based learning determination with a sensor-based inclination detection system. By substituting the learning condition judgment from solely wheel speed analysis to inclination angle measurement, the system achieves more reliable condition assessment
2Ease of manufacture
If tire radius correction uses static tire lateral radius values, then correction can be applied, but misdetection occurs because the dynamic tire profile during travel differs from the static profile
Solution Approach 1:
The patent transitions from using static tire lateral radius values to dynamically calculated effective tire radii based on actual wheel rotation speeds and vehicle speed. This dynamic approach accounts for the changing tire profile during travel, improving the accuracy of slip rate calculations
Solution Approach 2:
The system continuously monitors wheel rotation speeds and vehicle speed to calculate and update the effective tire radius in real-time. This feedback mechanism ensures that the tire radius correction adapts to actual traveling conditions rather than relying on predetermined static values
3Reliability
If wheel speed difference is continuously reduced to prevent ABS misintervention, then inappropriate ABS operations are suppressed, but tire radius learning cannot be performed under all driving conditions
Solution Approach 1:
The patent changes the determination parameter for learning conditions from wheel speed difference to vehicle inclination angle. This parameter change allows learning to occur during various driving conditions including acceleration and deceleration, as long as the inclination angle is within acceptable ranges, thereby increasing adaptability while maintaining ABS reliability
Data Source
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AI summary
The stability control system includes: a wheel rotation speed sensor configured to acquire a wheel rotation speed, the wheel rotation speed being a rotation speed of the first wheel; a vehicle speed sensor configured to acquire a vehicle speed of the vehicle; an attitude detection unit configured to acquire a bank angle of a vehicle body; and an arithmetic unit configured to, based on the wheel rotation speed and the vehicle speed under a predetermined travel condition, calculate a value representing a relationship between the wheel speed of the first wheel and the wheel speed of the second wheel as a tire radius correction value for each different bank angle, and calculate a control-purpose wheel speed by correcting the wheel rotation speed based on a tire radius correction value corresponding to a current bank angle. The braking force or driving force of the vehicle is changed by using the control-purpose wheel speed.