Autonomous Vehicle Distance Control Using Polynomial Velocity Profiles
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Solution Overview
Problem
Conventional technologies for maintaining vehicle distance in autonomous driving are complex and unstable, requiring precise tuning of control gains, which limits their ability to handle various driving environments and ensure collision avoidance.
Innovation Solution
An apparatus and method that use a third-order polynomial-based longitudinal acceleration and deceleration velocity profile, incorporating a convergence time to calculate desired acceleration, allowing flexible handling of diverse driving situations while ensuring collision avoidance with a preceding vehicle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional PID control with predetermined control gains is used to maintain vehicle distance, then the control system is simple to implement, but the control becomes unstable and cannot ensure collision avoidance in various driving environments
Solution Approach 1:
The patent changes the control parameters from fixed PID gains to dynamic parameters including a third-order polynomial velocity profile with coefficients a0, a1, a2, a3, convergence time tc, and safety distance ds. These parameters are continuously adjusted based on real-time driving conditions, relative velocity, and relative distance to the preceding vehicle, enabling adaptive control that maintains reliability across various driving environments.
Solution Approach 2:
The control system transitions from static predetermined gains to dynamic time-varying control. The velocity profile v(t) and acceleration profile are dynamically generated based on current driving state, making the control system adaptable to changing conditions while maintaining collision avoidance reliability.
2Adaptability or versatility
If predetermined arbitrary control gains are used for future situations, then the control system is easy to implement, but it has limited ability to flexibly handle various driving environments
Solution Approach 1:
The system uses parameter changes to achieve adaptability. The polynomial coefficients, convergence time, and safety distance are adjusted based on driving environment, vehicle speed, and distance to preceding vehicle. This allows the same control framework to handle diverse scenarios from highway cruising to urban stop-and-go traffic.
Solution Approach 2:
The control algorithm incorporates feedback from real-time measurements of relative distance and relative velocity to continuously adjust the velocity profile and acceleration commands. This feedback mechanism enables flexible adaptation to various driving environments while maintaining a relatively simple control structure.
3Ease of operation
If PID control with tuned gains is used, then the control response is straightforward, but it is complicated and requires different gain settings for different driving environments
Solution Approach 1:
The third-order polynomial-based control framework serves as a universal solution for all driving environments. Instead of requiring different PID gain sets for different conditions, the same polynomial framework with dynamically adjusted coefficients handles all scenarios, simplifying operation while maintaining versatility.
Solution Approach 2:
The system maintains ease of operation through a unified parameter adjustment mechanism. Rather than manually tuning multiple PID gains for different environments, the controller automatically adjusts the polynomial coefficients and convergence time based on real-time conditions, making the system both easy to operate and highly adaptable.
Data Source
AI summary
A method of controlling autonomous driving of a vehicle includes: selecting a target object ahead of the vehicle based on driving information, generating a velocity profile for maintaining a desired distance to the target object, calculating a desired acceleration based on the velocity profile and a delay time of the vehicle, and controlling an actuator of the vehicle based on the desired acceleration.