Motorcycle ACC Braking Control for Pitch-Stable Deceleration
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Solution Overview
Problem
Straddle-type vehicles, such as motorcycles, exhibit unstable posture and unintended behavior during adaptive cruise control due to automatic braking, which compromises driver comfort.
Innovation Solution
A controller that initially distributes braking force more heavily on the rear wheel and gradually increases the front wheel's share, minimizing pitching and reducing the burden on the rear-wheel brake mechanism during adaptive cruise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If adaptive cruise control is implemented with automatic braking on straddle-type vehicles, then the vehicle can maintain distance from preceding vehicles and follow motion patterns, but the vehicle exhibits unstable posture and unintended pitching behavior that compromises driver comfort
Solution Approach 1:
The braking force distribution is made dynamic by continuously adjusting the ratio between front and rear wheel braking forces based on vehicle motion state. The control section calculates a dynamic front-wheel braking force ratio and adjusts the braking force distribution in real-time, allowing the system to adapt to changing vehicle conditions while maintaining stable posture during adaptive cruise control operation
Solution Approach 2:
The system changes the parameter of braking force distribution ratio as a function of vehicle speed. By defining the front-wheel braking force ratio as a decreasing function of vehicle speed with upper and lower limits, the system optimizes braking distribution across different operating conditions, preventing pitching while ensuring effective deceleration
2Speed
If braking force is applied to stop the straddle-type vehicle during adaptive cruise control, then the vehicle can decelerate and maintain safety distance, but the rear wheel bearing excessive braking burden causes instability and driver discomfort
Solution Approach 1:
The system implements speed-dependent parameter changes by setting the front-wheel braking force ratio as a function of vehicle speed. The ratio has an upper limit at high speeds and a lower limit at low speeds, with monotonic increase in between. This parameter optimization ensures that braking burden is appropriately distributed at each speed level, preventing rear-wheel overload and maintaining vehicle stability throughout the deceleration process
Solution Approach 2:
The braking force distribution is dynamically adjusted during deceleration based on real-time vehicle speed feedback. The control section continuously calculates the optimal front-wheel braking force ratio and adjusts the braking forces on front and rear wheels accordingly, ensuring smooth deceleration while maintaining stable vehicle posture and preventing driver discomfort
Data Source
AI summary
The present invention obtains a controller and a control method capable of appropriately executing adaptive cruise control for a straddle-type vehicle while securing a driver's comfort.In the controller and the control method according to the present invention, when braking forces are generated on wheels of the straddle-type vehicle during adaptive cruise control, in which the straddle-type vehicle is made to travel according to a distance from the straddle-type vehicle to a preceding vehicle, motion of the straddle-type vehicle, and the driver's instruction, at a braking start time point at which the braking force starts being generated on each of the wheels, braking force distribution between the front and rear wheels is brought into an initial state where the braking force generated on the rear wheel is larger than the braking force generated on the front wheel. Then, a distribution ratio for the front wheel in the braking force distribution between the front and rear wheels is increased with a lapse of time.