Leaning Vehicle Gear-Shift Controller Turn Radius
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Solution Overview
Problem
Existing gear-shift controllers in motorcycles cause posture changes during leaning turns, as they change gear stages based on roll angles, leading to undesirable lean angle changes and posture shifts.
Innovation Solution
A gear-shift controller that inhibits or suppresses gear stage changes in a motorcycle's multi-stage automatic transmission by using physical quantities associated with the radius of turn, such as vehicle speed, lean angle, yaw rate, or radius of curvature, to minimize posture changes while the vehicle is leaning during turns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If gear stage changes are performed based on roll angle during leaning turns, then gear-shift control is achieved, but posture changes and lean angle variations occur
Solution Approach 1:
The patent changes the control parameters from roll angle to turn-related physical quantities (yaw rate, radius of curvature, vehicle speed) to determine gear-shift timing. This parameter change allows gear-shift control to be performed while avoiding the posture changes that occur when using roll angle as the control basis, thereby resolving the contradiction between achieving automated gear-shift control and maintaining posture stability during leaning turns.
2Productivity
If gear stages are changed during lean state turns, then driving force transmission is optimized, but lean angle changes cause posture shifts
Solution Approach 1:
The patent replaces roll angle with turn-related physical quantities (yaw rate, radius of curvature, vehicle speed) as the basis for determining gear-shift timing. This parameter substitution enables the system to optimize driving force transmission through gear changes while avoiding the lean angle variations that would disrupt posture stability during turning maneuvers.
3Speed
If normal gear-shift control is performed when roll angle exceeds first roll angle, then gear-shift responsiveness is maintained, but soft gear-shift control is needed to reduce posture changes
Solution Approach 1:
The patent fundamentally changes the control parameter from roll angle to turn-related physical quantities (yaw rate, radius of curvature, vehicle speed). This parameter transformation eliminates the need for differentiated gear-shift strategies (normal vs. soft) based on roll angle thresholds, as the new parameters inherently account for turning conditions and enable responsive gear-shift control without causing posture changes.
Data Source
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AI summary
Provided is a leaning vehicle capable of reducing a posture change of the leaning vehicle by a gear-shift while the leaning vehicle turns in a lean state. A vehicle 1 as a leaning vehicle includes a gear-type multi-stage automatic transmission 12 including a plurality of gear stages and a clutch 40, and configured to change a driving force to be transferred from an engine 11 to at least one of a front wheel 3 or a rear wheel 4 by automatically changing the plurality of gear stages stepwise; and a controller 7 configured to control changing of the plurality of gear stages in the multi-stage automatic transmission 12. While the vehicle 1 turns in a lean state, changing of the plurality of gear stages is inhibited or a change of a lean angle by changing the plurality of gear stages is suppressed, based on a physical quantity associated with a radius of turn of a corner that the vehicle 1 turns in the lean state.