Hydraulic Servo Pressure Control via Excitation-Based Auto Tuning

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Solution Overview

Problem

Current methods for determining control parameters of hydraulic systems, particularly those with servo drives, are time-consuming, user-dependent, and lack precision, requiring manual iterative tuning and relying on experienced personnel, which is inefficient and prone to errors due to insufficient knowledge of system dynamics.

Innovation Solution

A method that automates the determination of control parameters by applying an excitation signal to the target speed of a servo drive, measuring the resulting system pressure, and calculating the control parameters based on the system dynamics, allowing for quick, accurate, and reproducible parameterization independent of the user, enabling identification of unknown hydraulic systems and adaptation to changing conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual iterative tuning is used to determine control parameters, then control parameters can be adjusted, but the process is time-consuming and requires experienced personnel

Engineering Contradiction:
Improvecontrol parameter accuracyVSAvoidparameter determination time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs self-identification by automatically determining control parameters through excitation signal application and system response measurement, eliminating the need for manual tuning by experienced personnel while maintaining high accuracy

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The manual mechanical tuning process is replaced by an automated electronic identification system that uses excitation signals, sensors, and computational algorithms to determine control parameters automatically

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

2Ease of operation

If manual tuning is used, then control parameters can be set, but the process is user-dependent and lacks reproducibility

Engineering Contradiction:
Improveparameter setting simplicityVSAvoidparameter determination reproducibility
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system performs self-identification with consistent, reproducible results by automatically measuring system response to excitation signals and computing control parameters through standardized algorithms, eliminating user-dependent variability

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system transforms the subjective, variable manual tuning process into an objective, standardized automated process by changing from human judgment to systematic measurement and computation of control parameters

Inventive Principle:
Principle #35Parameter changes

3Productivity

If pressure surges are used for system identification, then parameterization can be performed, but the method is not well suited for rapid and exact parameterization

Engineering Contradiction:
Improveparameterization speedVSAvoidsystem dynamics identification accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

Instead of waiting for natural pressure surges to occur, the system applies predetermined excitation signals in advance to deliberately provoke system responses that are optimal for identification, enabling both speed and accuracy

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses periodic excitation signals with specific frequencies to systematically explore system dynamics across different frequency ranges, enabling comprehensive and accurate identification of system characteristics

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3602210B1Method for determining closed-control parameters for a hydraulic system
Publication Date: 2021.05.19 B&R IND AUTOMATION GMBH
  • EP3602210B1 patent drawingFigure 1~2b
  • EP3602210B1 patent drawingFigure 3~4a
  • EP3602210B1 patent drawingFigure 4b~5

AI summary

In order to carry out largely automated parameterisation of the closed-loop control parameters for closed-loop control of a hydraulic system comprising a servo drive, a method and a device for determining the closed-loop parameters of a closed-loop control unit of the hydraulic system are specified, wherein an actual system pressure of a hydraulic consumer of the hydraulic system is closed-loop controlled by means of a predefined set point rotational speed of a servo drive, wherein an actual rotational speed of the servo drive follows the predefined set point rotational speed, wherein an excitation signal is applied to the setpoint rotational speed, and the actual system pressure which is set here is measured, the dynamics of the hydraulic system are acquired from the actual rotational speed and/or the setpoint rotational speed and the actual system pressure, and the closed-loop control parameters are calculated from the acquired dynamics.