Adaptive Cruise Control Speed Behavior Model
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Solution Overview
Problem
Adaptive cruise control systems in vehicles often fail to maintain fuel efficiency when following a leading vehicle with different speed control behaviors or road conditions, leading to suboptimal speed adjustments and potential safety and comfort issues.
Innovation Solution
A control unit in the host vehicle monitors the time gap and speed of the leading vehicle, using external information about road conditions to determine a vehicle speed behavior model, which allows the host vehicle to predict and adapt its speed control to match the leading vehicle's behavior, optimizing fuel efficiency and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adaptive cruise control maintains a fixed time gap to the leading vehicle, then safety is improved, but fuel efficiency deteriorates when the leading vehicle changes speed behavior
Solution Approach 1:
The patent applies dynamics by making the time gap control adaptive rather than fixed. The control system dynamically adjusts the time gap based on the detected speed behavior model of the leading vehicle. When the leading vehicle maintains constant speed, a standard time gap is used. When speed changes are detected (acceleration or deceleration patterns), the system adapts the time gap accordingly, allowing the host vehicle to coast more aggressively during leading vehicle deceleration and maintain safer gaps during leading vehicle acceleration, thus improving fuel efficiency while preserving safety.
Solution Approach 2:
The patent implements feedback by continuously monitoring the leading vehicle's speed changes and using this information to adjust the host vehicle's cruise control behavior. The system detects the leading vehicle's acceleration and deceleration patterns, builds a speed behavior model, and feeds this information back to modify the time gap control strategy. This closed-loop feedback enables the system to respond to leading vehicle behavior changes and optimize fuel consumption accordingly.
2Use of energy by moving object
If cruise control allows excessive speed to save fuel, then fuel efficiency is improved, but safety deteriorates due to reduced ability to respond to leading vehicle changes
Solution Approach 1:
The patent applies dynamics by making the speed regulating range adaptive rather than fixed. The system dynamically adjusts the allowed excessive speed based on the leading vehicle's behavior model. When the leading vehicle is decelerating, the system allows a larger speed regulating range (greater excessive speed) to enable fuel-saving coasting. When the leading vehicle is accelerating or maintaining constant speed, the system reduces the speed regulating range to maintain safety. This dynamic adjustment resolves the contradiction between fuel efficiency and safety.
3Reliability
If the host vehicle brakes to maintain distance when the leading vehicle loses speed, then safety is improved, but fuel efficiency deteriorates due to loss of momentum
Solution Approach 1:
The patent applies preliminary action by detecting and predicting leading vehicle deceleration before the host vehicle would normally need to brake. The system monitors the leading vehicle's speed changes and identifies deceleration patterns in advance. By detecting this preliminary action of the leading vehicle, the host vehicle's cruise control can prepare to coast and maintain speed longer, reducing or eliminating the need for braking. This preliminary detection enables the host vehicle to preserve momentum and improve fuel efficiency while still maintaining safety through adaptive time gap control.
Data Source
AI summary
An arrangement for determining a vehicle speed behaviour model for a leading vehicle, where the leading vehicle drives along a path in front of a trailing host vehicle and where the determination is done by a control unit in the host vehicle, where the host vehicle includes an arrangement for measuring the time gap to the leading vehicle, an arrangement for measuring the speed of the host vehicle, an arrangement for obtaining external information regarding an upcoming change in a road condition, where the control unit is adapted for monitoring the change in vehicle speed of the leading vehicle, and for determining a vehicle speed behaviour model for the leading vehicle based on the monitored change in vehicle speed of the leading vehicle. The vehicle speed behaviour of a leading vehicle can be used by the host vehicle to optimize the fuel consumption, the comfort and the safety of the host vehicle.