Adaptive Cruise Control for Lead Vehicle Acceleration Lag
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Solution Overview
Problem
Existing semi-autonomous and autonomous vehicle systems react to perceived acceleration changes in lead vehicles, leading to potential gaps between vehicles becoming too large or small, causing uncomfortable ride conditions due to sudden accelerations or braking, as they do not account for acceleration lag in lead vehicles.
Innovation Solution
A method and system that process information about a lead vehicle's velocity and gap using sensors like radar or lidar to compute a desired acceleration for the host vehicle, considering the lag in the lead vehicle's acceleration by using a look-up table for lag time and delay constants, and adjusting the acceleration to maintain a specified gap range, incorporating model-based factors for smoother operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the host vehicle reacts to perceived acceleration changes in the lead vehicle, then the response time is reduced, but the gap between vehicles becomes unstable causing uncomfortable ride conditions
Solution Approach 1:
The system performs preliminary action by predicting the lead vehicle's intended acceleration before it fully manifests as perceived acceleration. By detecting early signals (steer angle, brake pressure, throttle position) and computing predicted acceleration, the host vehicle prepares for the upcoming maneuver in advance, maintaining stable gap control while responding promptly to the lead vehicle's intentions.
2Device complexity
If the host vehicle uses perceived acceleration to compute desired acceleration, then the control system is simple, but the acceleration lag causes gap maintenance errors
Solution Approach 1:
The system introduces an intermediary element - a prediction model that computes intended acceleration from detected lead vehicle parameters (steer angle, brake pressure, throttle position). This intermediary translates indirect indicators of the lead vehicle's intent into accurate acceleration predictions, bridging the gap between simple sensor input and precise control output without requiring complex direct acceleration sensing.
3Reliability
If the host vehicle reacts to actual acceleration changes, then the control response is accurate, but the acceleration lag in the lead vehicle causes delayed and incorrect responses
Solution Approach 1:
The system applies preliminary anti-action by counteracting the expected acceleration lag. It detects early indicators of the lead vehicle's intended acceleration (steer angle changes, brake pressure buildup, throttle position) and computes the predicted acceleration before the lead vehicle actually accelerates. This allows the host vehicle to preemptively adjust its gap maintenance control, compensating for the time delay inherent in reacting to actual acceleration changes.
Data Source
AI summary
A method includes obtaining information about a lead vehicle. The lead vehicle is traveling directly ahead of the host vehicle and the information includes velocity of the lead vehicle and a gap g between the host vehicle and the lead vehicle. Based on detecting a change in the velocity of the lead vehicle in the information, a corresponding desired acceleration is computed for the host vehicle using perceived acceleration of the lead vehicle to maintain the gap g within a specified range of gap values. The perceived acceleration of the lead vehicle is based on the change in the velocity indicated by the information. Based on a check of parameters involved in the computing the corresponding desired acceleration, a modified desired acceleration is computed for the host vehicle using a lag for the lead vehicle that results in an intended acceleration of the lead vehicle differing from the perceived acceleration.