Robot Control Policy Training With Bellman Uncertainty Variance

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Solution Overview

Problem

Reinforcement learning methods face inefficiencies in exploration and sample-efficiency due to over-approximation of value function variance, leading to suboptimal control policy training, especially in scenarios with high epistemic uncertainty.

Innovation Solution

Solving the Bellman uncertainty equation with a revised reward function that sets the difference between total uncertainty about the mean of the subsequent state and average aleatoric uncertainty, allowing for tighter variance estimates and biasing the control policy towards regions with higher variance, thereby enhancing exploration and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If reinforcement learning uses standard exploration methods, then the control policy can be trained, but the training requires many episodes and has low sample-efficiency due to over-approximation of value function variance

Engineering Contradiction:
Improvetraining efficiencyVSAvoidnumber of episodes required
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent changes the parameter definition by redefining the reward function in the Bellman uncertainty equation to compute the difference between total uncertainty about the mean and average aleatoric uncertainty. This parameter change enables tighter variance estimation, which directly improves training efficiency by reducing the number of episodes needed for convergence while maintaining accurate exploration guidance.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If reinforcement learning uses over-approximated variance estimates, then exploration can be performed, but the control policy training becomes suboptimal and less stable

Engineering Contradiction:
Improvecontrol policy qualityVSAvoidvariance estimation accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent extracts and separates the aleatoric uncertainty component from the total uncertainty in the Bellman uncertainty equation. By taking out the average aleatoric uncertainty term and computing its difference from total uncertainty, the method obtains a precise epistemic uncertainty estimate that accurately guides exploration without the noise and bias introduced by over-approximation, thereby improving both policy quality and training stability.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If standard Bellman uncertainty equation is used, then variance estimation can be obtained, but it provides only upper bounds rather than tight estimates

Engineering Contradiction:
Improvevariance estimation accuracyVSAvoidreward function complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by making the reward function in the Bellman uncertainty equation state-specific rather than uniform. By setting the reward to the difference between total uncertainty and average aleatoric uncertainty for each state, the method achieves tight variance estimates locally for each state region, enabling precise exploration guidance without requiring overly complex global modifications to the uncertainty estimation framework.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS20240198518A1Device and method for controlling a robot
Publication Date: 2024.06.20 ROBERT BOSCH GMBH
  • US20240198518A1 patent drawing
  • US20240198518A1 patent drawing

AI summary

A method for training a control policy. The method includes estimating the variance of a value function which associates a state with a value of the state or a pair of state and action with a value of the pair by solving a Bellman uncertainty equation, wherein, for each of multiple states, the reward function of the Bellman uncertainty equation is set to the difference of the total uncertainty about the mean of the value of the subsequent state following the state and the average aleatoric uncertainty of the value of the subsequent state and biasing the control policy in training towards regions for which the estimation gives a higher variance of the value function than for other regions.