Contrastive Behavioral Similarity Embeddings for RL Generalization

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Solution Overview

Problem

Existing machine learning models, particularly policy neural networks, struggle with generalizing control policies across different environments, often resulting in overly restrictive or permissive policies that fail to adapt effectively to varying conditions.

Innovation Solution

The implementation of a contrastive loss function based on a policy similarity metric that considers both local and long-term behaviors, allowing the representation and policy neural networks to generate generalizable policy outputs across diverse environments through reinforcement or imitation learning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional techniques are used to train the policy neural network, then the policy can be learned for a specific environment, but the policy fails to generalization to different environments

Engineering Contradiction:
Improvegeneralization capabilityVSAvoidpolicy effectiveness
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes the training parameters and objective function by introducing a contrastive loss function that incorporates a policy similarity metric. This metric compares policies across different environments by considering both local behaviors (immediate actions) and long-term behaviors (future trajectories), thereby enabling the policy neural network to learn environment-invariant representations that generalize effectively to new environments while maintaining reliable policy effectiveness.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If existing methods for learning representations are used, then the policy can be trained, but the policy becomes overly restrictive or permissive resulting in poor generalization

Engineering Contradiction:
Improvegeneralization capabilityVSAvoidpolicy flexibility
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent implements a feedback mechanism through the contrastive loss function that continuously adjusts the representation learning process. The policy similarity metric provides feedback about how well the learned representations capture both local and long-term behavioral patterns, allowing the system to refine the policy flexibility to achieve optimal generalization without becoming overly restrictive or permissive.

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If the policy neural network is trained to be generalizable, then it can adapt to different environments, but the training complexity increases

Engineering Contradiction:
Improveenvironmental adaptabilityVSAvoidtraining complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent achieves universality by designing a single contrastive loss function that simultaneously handles multiple objectives: learning environment-invariant representations, capturing local behaviors, and capturing long-term behaviors. This unified approach trains the policy neural network to be adaptable across different environments while managing training complexity through a cohesive loss formulation rather than multiple separate training procedures.

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

Data Source

PatentUS20230102544A1Contrastive behavioral similarity embeddings for generalization in reinforcement learning
Publication Date: 2023.03.30 GOOGLE LLC
  • US20230102544A1 patent drawing
  • US20230102544A1 patent drawing
  • US20230102544A1 patent drawing

AI summary

Approaches are described for training an action selection neural network system for use in controlling an agent interacting with an environment to perform a task, using a contrastive loss function based on a policy similarity metric. In one aspect, a method includes: obtaining a first observation of a first training environment; obtaining a plurality of second observations of a second training environment; for each second observation, determining a respective policy similarity metric between the second observation and the first observation; processing the first observation and the second observations using the representation neural network to generate a first representation of the first training observation and a respective second representation of each second training observation; and training the representation neural network on a contrastive loss function computed using the policy similarity metrics and the first and second representations.