Straddle-Vehicle Speed Control for Wobble Suppression
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Solution Overview
Problem
Straddle-type vehicles experience wobble phenomena at medium-to-high speeds, which destabilize straight traveling, and existing solutions like caster angle variable devices increase vehicle size or weight.
Innovation Solution
A travel control device that includes a vehicle speed detector and vibration detector to decelerate the vehicle when specific speed and vibration thresholds are met, preventing wobble without adding mechanical components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a caster angle variable device with an actuator is added to prevent wobble, then straight traveling stability is improved, but vehicle size and weight increase
Solution Approach 1:
The patent replaces the mechanical caster angle variable device with an electronic control system that uses engine braking force to suppress wobble. The control unit detects wobble through vibration sensors and commands the engine control unit to adjust ignition timing or fuel injection, creating a non-contact mechanical substitution that eliminates the need for physical actuators and heavy mechanical components.
Solution Approach 2:
The patent introduces the engine braking force as an intermediary mechanism to suppress wobble. Instead of directly actuating the front wheel fork, the system uses the engine's resistance to wheel rotation to create a stabilizing effect, mediating between the detection system and the wobble suppression outcome without requiring additional mechanical components on the steering assembly.
2Reliability
If a caster angle variable device with an actuator is added to prevent wobble, then straight traveling stability is improved, but vehicle size increases
Solution Approach 1:
The patent replaces the mechanical caster angle variable device with an electronic control system that uses engine braking force to suppress wobble. The control unit detects wobble through vibration sensors and commands the engine control unit to adjust ignition timing or fuel injection, creating a non-contact mechanical substitution that eliminates the need for physical actuators and heavy mechanical components.
Solution Approach 2:
The patent makes the engine serve multiple functions: it not only provides propulsion but also acts as a braking mechanism for wobble suppression. By utilizing the engine's existing components (ignition system, fuel injection system) for dual purposes, the patent avoids adding dedicated mechanical devices, thereby maintaining compact vehicle dimensions while achieving stability control.
3Reliability
If existing wobble prevention devices are added, then vibration control is improved, but device complexity increases
Solution Approach 1:
The patent merges the wobble detection function and wobble suppression function into a single integrated control system. The control unit that monitors vibration signals also directly controls the engine parameters, combining sensing and actuation functions that would traditionally require separate mechanical devices. This integration leverages existing engine control infrastructure to avoid adding complex dedicated wobble control mechanisms.
Solution Approach 2:
The patent replaces the mechanical caster angle variable device with an electronic control system that uses engine braking force to suppress wobble. The control unit detects wobble through vibration sensors and commands the engine control unit to adjust ignition timing or fuel injection, creating a non-contact mechanical substitution that eliminates the need for physical actuators and heavy mechanical components.
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
Travel control device (1, 31) for controlling traveling of a straddle-type vehicle includes a control device (11, 32), a vehicle speed detector (4) configured to detect a traveling speed of the vehicle, and a vibration detector (7) configured to detect a detection target vibration which is a vibration in a yaw direction or roll direction of the vehicle and has a frequency within a reference frequency range. The control device (11, 32) includes a deceleration device (22) configured to perform a deceleration control to decelerate the traveling speed if the traveling speed exceeds a control start reference speed and an amplitude of the detection target vibration exceeds a control start reference amplitude, and a deceleration stop device (23, 35) configured to stop the deceleration control if the traveling speed becomes equal to or less than a target limited speed after the deceleration control is started by the deceleration device.