Robot Policy Optimization With Gaussian Mixture Kernels

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Solution Overview

Problem

Bayesian optimization struggles to scale effectively for high-dimensional problems, such as optimizing the parameters of a Gaussian mixture model policy for robots, leading to limited optimization of mixture components and suboptimal policy performance.

Innovation Solution

A specialized kernel function based on the probability product kernel is introduced to reduce the dimensionality of the search space, utilizing symmetries and enabling efficient optimization of high-dimensional Gaussian mixture model policies through Bayesian optimization, combined with dynamic domain adaptation and retraining of Gaussian processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Bayesian optimization is applied to optimize parameters of a Gaussian mixture model policy for robots, then the policy performance can be improved, but the computational complexity and dimensionality of the search space increase significantly, making the optimization intractable for high-dimensional problems

Engineering Contradiction:
Improvepolicy performanceVSAvoidsearch space dimensionality
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The policy is segmented into multiple mixture components, each representing a distinct motion primitive or behavior mode. Instead of optimizing all parameters of a monolithic policy, the segmentation allows independent optimization of each component's parameters, reducing the overall computational complexity while maintaining policy performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transforms the high-dimensional parameter optimization problem into a lower-dimensional problem by introducing a new dimension of abstraction through the mixture model structure. The optimization operates in the space of mixture component weights and selected parameters rather than all raw policy parameters, effectively reducing dimensionality.

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

2Measurement precision

If the number of mixture components in the Gaussian mixture model is increased to improve policy accuracy, then the policy can better capture complex robot behaviors, but the optimization becomes even more difficult due to the curse of dimensionality

Engineering Contradiction:
Improvepolicy accuracyVSAvoidoptimization difficulty
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Each mixture component is segmented as an independent unit with its own parameter set. This segmentation allows the system to use multiple components for high accuracy while optimizing each component separately, avoiding the combinatorial explosion that would occur with joint optimization of all parameters across all components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The optimization process focuses on partial optimization of selected parameters for each mixture component rather than exhaustive optimization of all parameters. This partial action approach achieves sufficient policy accuracy without the computational burden of complete optimization, mitigating the curse of dimensionality.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS11992943B2Method for optimizing a policy for a robot
Publication Date: 2024.05.28 ROBERT BOSCH GMBH
  • US11992943B2 patent drawing
  • US11992943B2 patent drawing
  • US11992943B2 patent drawing

AI summary

A method for optimizing a predefined policy for a robot, the policy being a Gaussian mixture model. The method begins with an initialization of a Gaussian process, the Gaussian process including at least one kernel k which, as an input parameter, obtains a distance that is ascertained between probability distributions, which are characterized in each case by the Gaussian mixture model and the Gaussian process, according to the probability product kernel. This is followed by an optimization of the Gaussian process in such a way that it predicts the costs as a function of the parameters of the Gaussian mixture model. This is followed by an ascertainment of optimal parameters of the Gaussian mixture model as a function of the Gaussian process, the parameters being selected, as a function of the Gaussian process, in such a way that the Gaussian process outputs the optimal cost function.