Motorcycle Traction Control Using Lean-Corrected Slip Signal
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Solution Overview
Problem
Existing traction control methods for motorcycles are inaccurate due to changes in tire circumferential length ratios between front and rear wheels caused by inclining angles and speed changes, leading to ineffective slip control.
Innovation Solution
A system using driving wheel and driven wheel speed sensors to calculate a corrected slip signal by subtracting a low-frequency component from the pre-correction slip signal, which accounts for the lean component caused by banking, allowing for more precise control of the engine output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a slip ratio is calculated on the basis of rotation speeds of driving and driven wheels, then traction control can be implemented, but the slip ratio becomes inaccurate when the motorcycle is inclined due to changes in tire circumferential length ratio
Solution Approach 1:
The patent changes the parameter used for slip detection from a simple rotation speed ratio to a corrected slip signal that accounts for bank angle effects. By introducing a correction mechanism that adjusts for the geometric changes in tire circumferential length ratio during inclining, the system maintains measurement accuracy across varying operational conditions.
Solution Approach 2:
The patent introduces an intermediary correction factor or correction value that mediates between the raw rotation speed measurements and the final slip determination. This intermediary element compensates for the distorting effect of bank angle on the tire circumferential length ratio, allowing accurate slip detection despite the motorcycle's inclination.
2Reliability
If the delay angle of ignition timing is increased in accordance with bank angle to prevent slip, then traction control is improved, but the control becomes inaccurate when tire expansion ratio changes with speed
Solution Approach 1:
The patent implements a dynamic correction approach where the correction value is not fixed but adapts to changing operational conditions. By making the correction mechanism responsive to real-time parameters such as speed and bank angle, the system maintains accurate slip detection across varying tire expansion ratios and operating speeds.
Solution Approach 2:
The system employs feedback by continuously monitoring rotation speeds and applying corrections based on the detected bank angle and operational conditions. This feedback loop ensures that the correction value remains accurate even as tire expansion ratio changes with speed, maintaining reliable slip prevention.
3Ease of manufacture
If existing speed sensors are utilized for slip control, then cost is reduced, but accurate distinction between slip components and lean components becomes challenging
Solution Approach 1:
The patent segments the rotation speed signal into distinct components: slip-related high-frequency variations and lean-related low-frequency variations. By separating these components through frequency analysis or temporal filtering, the system can accurately distinguish between actual slip and the apparent slip caused by bank angle using only existing sensors.
Solution Approach 2:
The patent applies partial correction by focusing only on the relevant high-frequency slip components while filtering out the low-frequency lean components. This selective approach allows accurate slip detection using existing sensors without requiring additional expensive equipment, as the system processes only the necessary portion of the signal.
Data Source
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AI summary
A motorcycle (1) includes a driving wheel speed sensor (32) and a driven wheel speed sensor (31). An ECU (20) controls an engine (10a) on the basis of a corrected slip signal. The corrected slip signal is obtained by subtracting a low frequency component from a pre-correction slip signal. The pre-correction slip signal is obtained by subtracting a speed of a front wheel, which is detected by means of the driven wheel speed sensor (31), from a speed of a rear wheel, which is detected by means of the driving wheel speed sensor (32).