Autonomous Vehicle Acceleration Control for Fuel Efficiency
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Solution Overview
Problem
Existing methods for controlling autonomously driven vehicles do not effectively optimize acceleration rates to match actual traffic situations, leading to inefficient fuel consumption and compromised drivability due to either excessive or insufficient acceleration.
Innovation Solution
A control system that dynamically switches between high and low acceleration modes based on the acceleration continuation time and traffic conditions, using a vehicle control system comprising an engine controller, driving assistance system controller, and sensors to adjust propulsion and braking forces to maintain optimal acceleration rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the acceleration rate is set high to improve drivability and reach target speed quickly, then the vehicle can catch up to preceding vehicles faster, but fuel consumption increases due to repeated sudden acceleration and stopping
Solution Approach 1:
The patent applies dynamics by making the acceleration rate adjustable rather than fixed. The control device dynamically changes the acceleration rate based on the acceleration continuation time and traffic conditions. When the acceleration continuation time is long (indicating light traffic), a higher acceleration rate is applied to improve drivability. When the acceleration continuation time is short (indicating heavy traffic with frequent stopping), a lower acceleration rate is applied to reduce fuel consumption from repeated acceleration and stopping.
2Loss of energy
If the acceleration rate is set low to reduce fuel consumption, then repeated acceleration and stopping is minimized, but drivability is compromised due to slow acceleration over long periods
Solution Approach 1:
The control device dynamically adjusts the acceleration rate based on real-time traffic conditions measured by acceleration continuation time. When traffic is light and the vehicle can accelerate for a long duration without stopping, the system applies a higher acceleration rate to maintain good drivability. When traffic is heavy and stopping is frequent, the system switches to a lower acceleration rate to minimize energy waste, thus dynamically optimizing both drivability and fuel consumption.
3Device complexity
If a fixed acceleration rate characteristic is used to simplify control, then the control system is easier to implement, but it cannot adapt to varying traffic conditions leading to suboptimal fuel consumption and drivability
Solution Approach 1:
The patent implements a dynamic control system that adjusts the acceleration rate based on the acceleration continuation time and traffic conditions. The control device monitors whether the current acceleration continues for a predetermined time or longer, and switches between first and second acceleration rate characteristics accordingly. This dynamic adaptation allows the system to optimize fuel consumption and drivability for varying traffic conditions while maintaining relatively simple control logic.
Solution Approach 2:
The control system uses feedback from the acceleration continuation time measurement to adjust the acceleration rate. By monitoring whether the acceleration continues for a predetermined time or longer, the system receives feedback about traffic conditions and accordingly switches between different acceleration rate characteristics, enabling adaptive control that optimizes both fuel consumption and drivability.
Data Source
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AI summary
An acceleration rate is controlled so that a vehicle speed during autonomous driving is caused to approach a target vehicle speed. When a host vehicle has caught up with another vehicle traveling ahead of the host vehicle, the vehicle speed of the host vehicle is limited in accordance with a headway distance to the other vehicle. An acceleration rate is changed in accordance with a frequency with which the host vehicle catches up to a preceding vehicle, which is another vehicle immediately ahead of the host vehicle, and to another vehicle ahead of the preceding vehicle.