Object Motion Prediction Training With Lane-Rule Priors

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Solution Overview

Problem

Current autonomous vehicle motion prediction systems fail to effectively incorporate non-differentiable prior knowledge such as lane geometry and traffic rules, leading to inaccurate and unsafe motion forecasts, as they rely on symmetric loss functions that treat compliant and non-compliant trajectories equally, resulting in false positives and uncomfortable rides.

Innovation Solution

The proposed method uses a REINFORCE gradient estimation technique to incorporate non-differentiable prior knowledge into probabilistic object motion prediction models, allowing the system to learn from structured priors like lane geometry and traffic rules, and evaluate sample trajectories using reward functions that penalize non-compliant behavior, thereby improving the precision and safety of motion forecasts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If symmetric loss functions are used to train motion prediction models, then the training process is simple and computationally efficient, but the model cannot effectively incorporate non-differentiable prior knowledge about lane geometry and traffic rules, leading to inaccurate and unsafe motion forecasts

Engineering Contradiction:
Improvemotion forecast precisionVSAvoidtraining process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary reward function that bridges the gap between non-differentiable prior knowledge and gradient-based optimization. The reward function encodes lane geometry and traffic rules as differentiable constraints, allowing the model to learn from prior knowledge without requiring direct differentiation of the constraints themselves. This intermediary layer enables precise motion forecasts while maintaining training simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent transforms the training objective by changing the parameter representation from direct loss minimization to reward maximization. By formulating the training as a reinforcement learning problem where the model learns to maximize a reward function that incorporates prior knowledge, the system achieves both precision and safety without increasing computational complexity.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If prior knowledge about lane geometry and traffic rules is incorporated into the motion prediction model, then the safety and accuracy of motion forecasts improve, but the model becomes more complex and difficult to train

Engineering Contradiction:
Improvemotion forecast safetyVSAvoidmodel complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The reward function serves as an intermediary that encapsulates complex prior knowledge about lane geometry and traffic rules in a unified, differentiable form. Instead of directly embedding these constraints into the model architecture, the reward function provides a soft guidance mechanism that improves safety and reliability while keeping the model structure relatively simple and tractable.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If non-differentiable prior knowledge is directly used in the loss function, then the model can enforce strict compliance with traffic rules, but the gradient-based optimization process fails and training becomes infeasible

Engineering Contradiction:
Improvetrajectory compliance precisionVSAvoidtraining feasibility
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent changes the parameterization of the training objective from direct loss minimization with non-differentiable constraints to reward maximization with differentiable constraints. This parameter transformation allows gradient-based optimization to proceed smoothly while still achieving precise compliance with traffic rules and lane geometry through the carefully designed reward function.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11836585B2Systems and methods for training probabilistic object motion prediction models using non-differentiable prior knowledge
Publication Date: 2023.12.05 AURORA OPERATIONS INC
  • US11836585B2 patent drawing
  • US11836585B2 patent drawing
  • US11836585B2 patent drawing

AI summary

The present disclosure provides systems and methods for training probabilistic object motion prediction models using non-differentiable representations of prior knowledge. As one example, object motion prediction models can be used by autonomous vehicles to probabilistically predict the future location(s) of observed objects (e.g., other vehicles, bicyclists, pedestrians, etc.). For example, such models can output a probability distribution that provides a distribution of probabilities for the future location(s) of each object at one or more future times. Aspects of the present disclosure enable these models to be trained using non-differentiable prior knowledge about motion of objects within the autonomous vehicle's environment such as, for example, prior knowledge about lane or road geometry or topology and/or traffic information such as current traffic control states (e.g., traffic light status).