Networked Control Time-Delay Compensation Using PSO-FNN Prediction

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Solution Overview

Problem

Current networked control systems (NCS) lack effective methods for accurately predicting and compensating time-delays, which severely impact system performance.

Innovation Solution

An NCS time-delay compensation method based on predictive control using a fuzzy neural network (FNN) optimized by a particle swarm optimization (PSO) algorithm, combined with an implicit proportional-integral-based generalized predictive control (PIGPC) algorithm, to predict and compensate time-delays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional control methods are used in NCS, then the system structure is simple, but time-delay prediction accuracy is low and compensation effectiveness is poor

Engineering Contradiction:
Improvetime-delay prediction accuracyVSAvoidcontrol system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The control system is segmented into distinct functional modules: PSO algorithm module for optimization, FNN module for prediction, and PIGPC module for compensation. Each module performs a specific function, allowing the complex time-delay compensation task to be divided into manageable components that can be developed and optimized independently while maintaining overall system effectiveness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts key parameters including prediction horizon, control horizon, forgetting factor, and penalty factors based on system conditions. The PSO algorithm optimizes FNN parameters such as connection weights and membership function parameters, enabling the system to adapt to varying time-delay characteristics and improve prediction accuracy under different operating conditions.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If FNN is optimized by traditional BP algorithm, then the implementation is simple, but prediction accuracy is lower and convergence is slower

Engineering Contradiction:
Improveprediction accuracyVSAvoidcalculation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The traditional BP algorithm (gradient-based mechanical optimization) is replaced with the PSO algorithm (swarm intelligence approach). PSO uses a population-based search mechanism that explores the parameter space more efficiently, avoiding local minima and achieving faster convergence with higher prediction accuracy, though requiring more computational resources per iteration.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The PSO algorithm performs preliminary optimization of FNN parameters before actual prediction tasks. By pre-optimizing connection weights and membership function parameters using training data, the system prepares the FNN in advance for accurate predictions, reducing the need for repeated optimizations during real-time operation.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If explicit GPC algorithm is used, then the control strategy is straightforward, but calculation time is long and real-time performance is poor

Engineering Contradiction:
Improvereal-time control performanceVSAvoidcalculation time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The explicit GPC algorithm's computationally intensive components are extracted and replaced. Specifically, the explicit calculation of future control moves is replaced with an implicit iterative approach that solves for control increments more efficiently. The system extracts only the essential prediction and compensation functions, removing unnecessary computational overhead while maintaining control effectiveness.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The control algorithm transitions from a static explicit GPC approach to a dynamic implicit PIGPC approach. The implicit formulation allows the controller to adaptively adjust control actions based on current system state and predicted time-delay, with iterative refinement that converges to optimal solutions. This dynamic approach improves real-time performance by focusing computational effort only where needed.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS11543787B2Networked control system time-delay compensation method based on predictive control
Publication Date: 2023.01.03 QINGDAO UNIV OF TECH
  • US11543787B2 patent drawing
  • US11543787B2 patent drawing
  • US11543787B2 patent drawing

AI summary

The present invention discloses a networked control system (NCS) time-delay compensation method based on predictive control. The method comprises the following steps: (1) acquiring random time-delay data in an NCS, and preprocessing the data; (2) predicting the current time-delay by using a fuzzy neural network (FNN) optimized by a particle swarm optimization (PSO) algorithm; (3) compensating the predicted time-delay by using an implicit proportional-integral-based generalized predictive control (PIGPC) algorithm; (4) determining whether a preset work end time is up according to a clock in the NCS; if yes, ending the process; if no, returning to step (2). The method disclosed by the present invention can accurately predict and effectively compensate the NCS time-delay and has excellent development prospect.