Actuator Control Strategy Using Bellman Value Function Approximation
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Solution Overview
Problem
Existing actuator control systems face challenges in achieving optimal control, particularly when state variables and actions can take on continuous values, as they struggle to efficiently determine the optimal control strategy that maximizes the value function over time, considering system dynamics and statistical uncertainties.
Innovation Solution
The method employs an iterative approach to determine the value function using the Bellman equation, projecting it onto a linear function space spanned by basis functions, allowing for efficient numerical solution and error control, and utilizes a Gaussian process model to adapt the control strategy based on actual behavior, ensuring reliable and efficient actuator control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an iterative approach using the Bellman equation is employed to determine the value function, then optimal control can be achieved with continuous state and action variables, but the computational complexity and numerical error increase
Solution Approach 1:
The patent transforms the continuous value function determination problem into a discrete iterative process using the Bellman equation. By projecting the value function onto a linear function space spanned by basis functions, the continuous optimization problem is converted into a sequence of discrete linear algebra operations that can be efficiently computed while maintaining optimality guarantees.
Solution Approach 2:
The patent replaces direct numerical optimization of continuous value functions with an iterative projection method based on the Bellman equation. This substitution transforms a computationally intensive continuous optimization problem into a structured iterative process that alternates between projection onto basis functions and application of the Bellman operator, reducing numerical complexity while preserving accuracy.
2Device complexity
If the value function is projected onto a linear function space spanned by basis functions, then numerical errors are reduced and computation is simplified, but the precision of the value function approximation decreases
Solution Approach 1:
The patent employs dynamic basis function selection where the set of basis functions is adaptively expanded during the iterative process. As iterations proceed, additional basis functions are incorporated into the linear span to capture finer details of the value function, allowing the approximation precision to dynamically improve while maintaining computational tractability through controlled expansion.
Solution Approach 2:
The patent performs preliminary projection of the value function onto a chosen basis function space before applying the Bellman operator. This preliminary action establishes a computationally manageable representation that serves as the foundation for subsequent iterations, enabling efficient computation while systematically improving precision through iterative refinement of the projection.
3Adaptability or versatility
If Gaussian process models are used to adapt the control strategy, then the system can handle statistical uncertainties and continuous variables effectively, but the model complexity and data requirements increase
Solution Approach 1:
The patent employs Gaussian process models as a universal framework that simultaneously handles continuous state and action variables, quantifies statistical uncertainties, and adapts the control strategy. The same Gaussian process infrastructure serves multiple functions: modeling the value function, characterizing uncertainties, and guiding policy optimization, eliminating the need for separate mechanisms for each function.
Solution Approach 2:
The patent implements feedback through the iterative Bellman equation process where the Gaussian process model continuously updates the value function approximation based on observed system behavior. The model incorporates statistical uncertainties from previous iterations and uses this feedback to refine the control strategy, creating a closed-loop adaptation mechanism that improves performance while managing complexity through probabilistic reasoning.
Data Source
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AI summary
The invention relates to a method for operating an actuator regulation system (45) which is designed to regulate a regulation variable (x) of an actuator (20) to a pre-definable nominal variable (x), the actuator regulation system (45) being designed to generate a correcting variable according to a variable (θ) characterising a regulation strategy (π), and to control the actuator (20) according to said correcting variable (u), the variable (θ) characterising the regulation strategy (π) being determined according to a value function (V*).