Vehicle Deceleration Control Using a Control Barrier Function
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Solution Overview
Problem
Existing vehicle control systems struggle to efficiently and comfortably decelerate vehicles to stop at target locations, such as traffic lights or stop signs, without causing occupant discomfort.
Innovation Solution
Implementing a control barrier function (CBF) that models vehicle motion and applies constraints to determine optimal deceleration parameters, ensuring the vehicle stops at the target location while maintaining comfort and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional vehicle control systems are used for deceleration and stopping, then the vehicle can stop at target locations, but the deceleration control is inefficient and uncomfortable for vehicle users
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the deceleration rate parameter based on vehicle speed, distance to target location, and user preferences. The system transitions from fixed deceleration parameters to variable parameters that adapt to real-time conditions, optimizing both comfort and efficiency. The control barrier function continuously modifies acceleration commands to maintain desirable deceleration levels throughout the stopping process.
2Ease of operation
If a control barrier function is implemented to constrain deceleration input, then deceleration comfort is improved, but the system complexity increases
Solution Approach 1:
The patent replaces traditional mechanical control approaches with a mathematical control barrier function framework. Instead of complex mechanical deceleration control mechanisms, the system uses computational mathematics to constrain and optimize deceleration commands. This substitution of mechanical complexity with algorithmic control achieves comfortable deceleration while maintaining system manageability.
Solution Approach 2:
The control barrier function acts as an intermediary layer between the vehicle's propulsion/braking systems and the control objectives. It mediates the control input by transforming high-level stopping commands into constrained acceleration commands that satisfy both performance and comfort requirements, without requiring direct complex control of underlying mechanical systems.
3Reliability
If the control barrier function constrains acceleration output to maintain desirable deceleration levels, then stopping effectiveness is improved, but the computational requirements increase
Solution Approach 1:
The patent applies partial action by implementing selective constraint application within the control barrier function. Rather than constraining all control parameters equally, the system applies constraints only to the extent necessary to ensure safe and effective stopping. The control barrier function evaluates and applies minimal necessary constraints on acceleration commands, achieving reliable stopping without excessive computational burden from over-constraining the system.
Data Source
AI summary
A system includes a computer including a processor and a memory. The computer is programmed to determine a target location for a vehicle; based on a vehicle speed and a distance to the target location, determine a tunable acceleration parameter; determine a constraint, based on the tunable acceleration parameter, for a control barrier function to that outputs an acceleration to stop the vehicle at the target location; and upon solving the control barrier function to satisfy the constraint, actuate the vehicle to decelerate based on the acceleration output from the control barrier function.