Lean Vehicle Roll Oscillation Control via Velocity-Dependent Wheel Angle
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Solution Overview
Problem
Vehicles that lean during turning experience increased oscillation in their width direction due to centrifugal forces, which can deteriorate driving stability.
Innovation Solution
A vehicle configuration with three or more wheels, including a pair spaced apart in the width direction, a lean mechanism, and an operation input unit that allows the vehicle body to lean, controlling the wheel angle to align with the turning direction, and adjusting the natural frequency of roll oscillation based on vehicle velocity to minimize phase delay and oscillation amplitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the vehicle leans during turning to improve turning performance, then turning capability is improved, but oscillation of the vehicle body in the width direction increases
Solution Approach 1:
The patent applies dynamics by making the wheel orientation adjustable and velocity-dependent. The turn wheels can dynamically change their orientation angle based on vehicle velocity, transitioning between following the lean angle at low velocities and maintaining a fixed orientation at high velocities. This dynamic adjustment resolves the contradiction by adapting the wheel configuration to different operating conditions, improving turning capability when needed while suppressing oscillation at higher speeds.
Solution Approach 2:
The patent changes the parameter of wheel orientation angle based on vehicle velocity. By adjusting the orientation angle of turn wheels according to velocity thresholds, the system optimizes turning performance at low speeds while preventing excessive oscillation at high speeds. This parameter change strategy allows the vehicle to achieve both good turning capability and reduced body oscillation under different velocity conditions.
2Ease of operation
If the wheel angle follows the lean angle to improve turning response, then turning responsiveness is improved, but phase delay causes increased oscillation amplitude
Solution Approach 1:
The system dynamically adjusts wheel orientation based on velocity conditions. At low velocities, the turn wheels follow the lean angle to provide responsive turning. At high velocities, the wheels maintain a fixed orientation to avoid oscillation amplification. This dynamic switching resolves the contradiction between responsiveness and oscillation control.
Solution Approach 2:
The patent applies preliminary anti-action by pre-setting a fixed wheel orientation at high velocities to counteract the potential harmful effect of phase delay. Before oscillation can be amplified by following the lean angle, the system switches to a fixed orientation that prevents the centrifugal force from increasing oscillation amplitude, thus anticipating and preventing the instability issue.
3Stability of the object's composition
If the natural frequency of roll oscillation is within a specific range to reduce oscillation, then vehicle stability is improved, but the control complexity increases
Solution Approach 1:
The control system dynamically adjusts wheel orientation based on velocity thresholds and natural frequency considerations. By switching between different control modes (following lean angle vs. fixed orientation) based on velocity and frequency conditions, the system achieves stability without requiring continuously complex control algorithms. The dynamic switching simplifies the overall control strategy while maintaining stability.
Solution Approach 2:
The system changes control parameters (wheel orientation angle) based on velocity and natural frequency conditions. By adjusting the orientation parameter according to predefined velocity thresholds and frequency ranges, the system achieves stable operation without implementing complex real-time frequency adjustment mechanisms, thus balancing stability with control simplicity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively suppresses the increase in oscillation of the vehicle body in the width direction, enhancing driving stability by aligning wheel and body movements and adjusting natural frequencies to match vehicle velocity.
Implementation Method 1
a centrifugal force caused by a turn according to the wheel orientation may increase oscillation of the vehicle body in its width direction
Implementation Method 2
a natural frequency of the roll oscillation of the vehicle body is either within a range of smaller than a reference frequency or within a range of larger than the reference frequency
Data Source
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AI summary
A vehicle is configured to travel, when a vehicle velocity is within a velocity range from not less than a first velocity of at least zero to not more than a second velocity larger than the first velocity, in a mode in which a vehicle body is leaned by a lean mechanism according to an input into an operation input unit, and a wheel angle of a turn wheel changes following a lean of the vehicle body. A natural frequency of roll oscillation of the vehicle body is either within a range of smaller than a reference frequency or within a range of larger than the reference frequency, the reference frequency being a frequency at which oscillation of the wheel angle of the turn wheel has phase delay of 90 degrees relative to the roll oscillation of the vehicle body in its width direction.