Autonomous Vehicle Feedforward Control Strategy

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Solution Overview

Problem

Existing motion planning algorithms for autonomous vehicles are either computationally intensive or not designed for multiple scenarios, making them inefficient for urban and highway driving.

Innovation Solution

The implementation of a lateral controller system for determining vehicle curvature and a longitudinal controller system for determining desired acceleration, using a control loop with a velocity error and feedforward term, to generate steering and throttle/braking commands.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If existing motion planning algorithms are used for autonomous vehicles, then trajectory planning can be performed, but the processing is computationally intensive and inefficient

Engineering Contradiction:
Improveprocessing efficiencyVSAvoidcomputational load
Core Design Contradiction:
ProductivityVSPower

Solution Approach 1:

The motion planning system is divided into multiple independent modules: a trajectory generation module that creates reference trajectories, a trajectory optimization module that refines trajectories, and a feedforward control module that generates control commands. This segmentation allows each module to process specific aspects of motion planning independently, reducing overall computational load while maintaining processing efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system pre-generates feedforward control commands based on the reference trajectory before actual execution. By calculating anticipated control actions in advance and storing them for quick retrieval, the system avoids performing complex computations in real-time, thereby improving processing efficiency while reducing instantaneous computational power requirements.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If existing motion planning algorithms are used for autonomous vehicles, then trajectory planning can be performed, but the system is not designed for multiple different possible scenarios

Engineering Contradiction:
Improvescenario coverageVSAvoidalgorithm complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The trajectory generation module creates universal reference trajectories that can serve as baseline paths for multiple different driving scenarios including urban streets, highways, and curved roads. The feedforward control module applies the same control architecture across all scenarios, adapting only the trajectory parameters rather than the fundamental algorithm structure, thereby achieving scenario versatility without proportionally increasing algorithm complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system applies scenario-specific optimizations at local levels rather than redesigning the entire algorithm for each scenario. The trajectory optimization module adjusts local trajectory parameters based on scenario characteristics while maintaining the overall algorithmic framework, allowing the system to handle multiple scenarios with controlled increases in complexity.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If a control loop with velocity error and feedforward term is used, then vehicle acceleration can be determined accurately, but the control system becomes more complex

Engineering Contradiction:
Improveacceleration accuracyVSAvoidcontrol system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The control loop continuously monitors velocity error between the actual vehicle state and the reference trajectory, using this feedback to adjust the feedforward acceleration commands. This feedback mechanism enables accurate acceleration determination by compensating for deviations in real-time, achieving high measurement precision while maintaining manageable control system complexity through the use of standard control loop architecture.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS10576991B2Systems and methods for low level feed forward vehicle control strategy
Publication Date: 2020.03.03 GM GLOBAL TECHNOLOGY OPERATIONS LLC
  • US10576991B2 patent drawing
  • US10576991B2 patent drawing
  • US10576991B2 patent drawing

AI summary

Systems and methods are provided for controlling an autonomous vehicle. A method includes using a lateral controller system for determining a vehicle's curvature. A longitudinal controller system is used for determining desired vehicle acceleration. The longitudinal controller system uses a control loop with respect to a velocity error and a feedforward term. Commands are generated based on the output of the lateral controller system and the longitudinal controller system.