MPC Trajectory Planning for Dynamic Automated Vehicle Control

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Solution Overview

Problem

Current trajectory planning methods for automated vehicles, especially at mid/high speeds, fail to generate dynamically feasible, comfortable, and customizable trajectories, and often neglect the dynamic behavior of other vehicles, leading to instability and inefficiency.

Innovation Solution

A trajectory planning algorithm based on constrained optimizations that decouples longitudinal and lateral dynamics planning using Model Predictive Control (MPC), incorporating vehicle and obstacle state observation, and behavioral planning to generate feasible and comfortable trajectories, compatible with current vehicle actuations like Electric Power Steering (EPS) and Braking System Module (BSM).

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If geometric-based methods are used for trajectory planning, then the trajectory can be generated based on simple parametric curves, but the dynamic behavior of the vehicle and other vehicles cannot be considered at mid/high speeds

Engineering Contradiction:
Improveease of trajectory generationVSAvoiddynamic feasibility
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent segments the trajectory planning into two independent parts: path planning (geometric) and trajectory planning (dynamic). The path is generated using geometric methods, then a speed profile is computed separately to ensure dynamic feasibility. This segmentation allows each part to be optimized independently while ensuring overall system reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces dynamic considerations by computing a speed profile that accounts for vehicle dynamics, including acceleration limits, curvature constraints, and safety margins. This transforms the static geometric path into a dynamically feasible trajectory suitable for mid/high speed operation.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If heuristic-based methods with AI techniques are used, then complex patterns can be recognized and paths can be found in discrete lattices, but the trajectories lack dynamic feasibility and comfort for automated driving

Engineering Contradiction:
Improvepattern recognition capabilityVSAvoidtrajectory comfort
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent separates path generation (handled by heuristic methods) from trajectory generation (handled by dynamic constraints). The speed profile computation ensures that the final trajectory meets comfort and safety requirements, compensating for the limitations of purely heuristic approaches.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transforms the discrete path points into a continuous trajectory by introducing a speed profile with specific parameters (acceleration, jerk limits, safety margins). This parameter-based approach ensures dynamic feasibility and comfort while maintaining the adaptability of the underlying heuristic method.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If optimal control techniques are used to generate trajectories directly, then dynamic feasibility can be achieved, but the computational cost increases and customization becomes more difficult

Engineering Contradiction:
Improvedynamic feasibilityVSAvoidcomputational complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the optimization problem into two simpler sub-problems: path optimization (geometric constraints) and speed profile optimization (dynamic constraints). This segmentation reduces the dimensionality of each optimization problem, lowering computational complexity while maintaining dynamic feasibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts the dynamic constraints from the full trajectory optimization problem and handles them separately through speed profile computation. This extraction allows the use of simpler geometric methods for path planning while adding dynamic feasibility through a dedicated speed profile module.

Inventive Principle:
Principle #2Taking out (Extraction)

4Device complexity

If other vehicle dynamics are not considered in trajectory planning, then the planning process is simpler, but the generated trajectories may be unstable and inefficient in dynamic environments

Engineering Contradiction:
Improveplanning process complexityVSAvoidtrajectory stability
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The patent performs preliminary detection and prediction of other vehicles' states before generating the trajectory. By anticipating potential conflicts and dynamic obstacles in advance, the system can plan more stable trajectories without requiring complex real-time interaction modeling.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent incorporates other vehicle dynamics through parameter adjustments in the speed profile computation, such as adding safety margins and adjusting acceleration profiles based on detected traffic conditions. This approach maintains stability without requiring full dynamic simulation of surrounding vehicles.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4031428B1Model-based design of trajectory planning and control for automated motor-vehicles in a dynamic environment
Publication Date: 2024.11.13 CENTRO RICERCHE FIAT SCPA
  • EP4031428B1 patent drawingFigure 1
  • EP4031428B1 patent drawingFigure 2
  • EP4031428B1 patent drawingFigure 3

AI summary

An automotive electronic dynamics control system for an automated motor-vehicle. The electronic dynamics control system is designed to implement two distinct Model Predictive Control (MPC)-based Trajectory Planners comprising a Longitudinal Trajectory Planner designed to compute a planned longitudinal trajectory for the automated motor-vehicle; and a Lateral Trajectory Planner designed to compute a planned lateral trajectory for the automated motor-vehicle. The electronic dynamics control system is further designed to cause the planned longitudinal trajectory to be computed before the planned lateral trajectory.