Hierarchical Reinforcement Learning for Complex Autonomous Behaviors

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Solution Overview

Problem

Current reinforcement learning systems are limited in their capacity for complex decision-making due to their reliance on machine learning models other than neural nets, which restricts their ability to handle intricate scenarios effectively.

Innovation Solution

A learning system utilizing hierarchical reinforcement learning with a high-level controller and a low-level controller, where the high-level controller uses a neural net to select behaviors based on observations and the low-level controller generates output commands for scripted actions, and additional neural nets are trained to determine the duration of high-level behaviors, employing softmax learning functions for probability calculations and reinforcement learning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If traditional machine learning models (non-neural net) are used for high-level behavior selection, then the system is simpler to implement, but the capacity for complex decision-making is limited

Engineering Contradiction:
Improvesystem implementation complexityVSAvoidcomplex decision-making capacity
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The system divides behavior selection into hierarchical levels: high-level behavior selection (strategic decisions) and low-level behavior execution (tactical actions). This segmentation allows neural nets to handle only the complex high-level decisions while simpler models handle execution, resolving the contradiction between complexity and decision-making capacity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a hierarchical dimension to the decision-making process, adding a temporal and structural layer between high-level selection and low-level execution. This dimensional addition enables complex neural net processing at the high level without requiring the entire system to be complex, thus improving decision-making capacity while managing overall system complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If hierarchical reinforcement learning with neural nets is implemented, then complex autonomous behavior generation is enabled, but the device complexity increases

Engineering Contradiction:
Improveautonomous behavior generation capabilityVSAvoidcontroller architecture complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The controller architecture is segmented into distinct high-level and low-level components with clearly defined interfaces. The high-level controller handles behavior selection while the low-level controller handles execution, reducing architectural complexity through functional separation despite the advanced neural net capabilities.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary layer (the high-level behavior selection module) that mediates between the complex neural net processing and the simpler execution mechanisms. This intermediary simplifies the overall architecture by providing a clear interface and abstraction layer, reducing the complexity burden of implementing hierarchical reinforcement learning with neural nets.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If frequent high-level behavior selection is performed, then adaptability to changing environments improves, but training time and computational resources increase

Engineering Contradiction:
Improveenvironmental adaptabilityVSAvoidtraining time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The system employs periodic action by selecting high-level behaviors at discrete time intervals rather than continuously. This periodic high-level selection combined with continuous low-level execution reduces computational burden during training while maintaining environmental adaptability, as the system only needs to re-evaluate high-level decisions at specific intervals rather than at every time step.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentUS20210147079A1Autonomous behavior generation with hierarchical reinforcement learning
Publication Date: 2021.05.20 HRL LAB
  • US20210147079A1 patent drawing
  • US20210147079A1 patent drawing
  • US20210147079A1 patent drawing

AI summary

Described is a system for autonomous behavior generation. The system includes both a high-level controller and a low-level controller. The high-level controller receives observations from an environment and, using a neural net, selects a high-level behavior based on the observations from the environment. The low-level controller generates an output command for a scripted action based on the selected one high-level behavior. After generating the output command, the system can implement an action, such as causing a device to perform the scripted action.