Leaning Vehicle Tilt Control for Low-Speed Stability
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Solution Overview
Problem
Existing leaning vehicles lack the ability to accurately control the tilt angle of the body frame in response to a rider's intentions, especially during low-speed travel and stopping, leading to potential instability on uneven road surfaces.
Innovation Solution
A control system that updates the target tilt angle based on rider input, using a left-right tilt angle control mechanism to adjust the body frame's tilt, even when stopped, and incorporates a buffer control mechanism to suppress motion and enhance control responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the vehicle uses automatic tilt control to maintain upright position at low speed, then the frame stability is improved, but the rider's ability to manually control tilt for balance on uneven surfaces is reduced
Solution Approach 1:
The control system dynamically adjusts its behavior based on vehicle speed. At low speeds where manual balance control is needed, the automatic tilt control is deactivated or reduced, allowing the rider to manually control the tilt for balance on uneven surfaces. At higher speeds or when stability is prioritized, the automatic control becomes more active, creating a dynamic balance between automated stability and manual controllability
2Speed
If the vehicle responds quickly to rider input for tilt adjustments, then the responsiveness is improved, but the stability control may become overly sensitive at low speeds
Solution Approach 1:
The control system changes key parameters based on vehicle speed and operating conditions. The response threshold and gain factors are adjusted dynamically - at low speeds, higher thresholds and lower gains prevent over-sensitivity to minor rider inputs or road vibrations, while maintaining the ability to respond to deliberate balance corrections. At higher speeds, the system becomes more responsive to rapid tilt adjustments
3Stability of the object's composition
If the actuator continuously adjusts the shock tower rotation to maintain upright position, then the frame upright maintenance is improved, but the energy consumption increases
Solution Approach 1:
Instead of continuous actuator operation, the system uses periodic or event-driven control. The actuator operates intermittently to make corrective adjustments when the frame deviates from the upright position, rather than continuously fighting gravity. This periodic action maintains upright position effectiveness while significantly reducing energy consumption compared to continuous operation
Solution Approach 2:
The vehicle's momentum and rider input serve the primary function of maintaining upright position during low-speed travel, reducing the need for actuator intervention. The actuator only provides assistance when naturally occurring stability mechanisms are insufficient, allowing the system to self-maintain upright position through passive means whenever possible
Data Source
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AI summary
A leaning vehicle (1) includes: a body frame (21); a right wheel (31) and a left wheel (32); a linkage mechanism (5) including arms (51, 52) rotatably supported on the body frame (21); a left-right tilt angle control mechanism (74) configured to control a tilt angle of the body frame (21) in a left direction or in a right direction by adjusting a rotation of the arms (51, 52) with respect to the body frame (21); and a control section (71). The control section (71) controls the left-right tilt angle control mechanism to cause the tilt angle of the body frame in the left direction or in the right direction to approach a target value based on information on at least a vehicle speed. The control section (71) updates the target value in accordance with an input to the leaning vehicle from a rider concerning a tilt of the body frame (21) and controls a left-right tilt angle control mechanism (74) to cause the tilt angle of the body frame (21) to approach the updated target value in a period in which the vehicle speed is in at least a part of a low-speed traveling range.