Multi-Chamber Hydraulic Actuator Control Without Throttling Loss

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Solution Overview

Problem

Conventional hydraulic systems experience energy losses and vibrations due to throttling control, which affects the precision and efficiency of force control in actuators with multiple working chambers.

Innovation Solution

The implementation of a hydraulic system using quick proportional valves with low pressure loss for non-throttled control, allowing stepless control of hydraulic fluid flow and synchronization of proportional valves to manage pressure levels and force steps in multi-chamber linear actuators, thereby reducing energy consumption and minimizing vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If throttling control is used to adjust pressure level in working chambers, then force magnitude can be controlled continuously, but energy losses occur due to throttling of hydraulic fluid flow

Engineering Contradiction:
Improveforce controlVSAvoidenergy losses
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The hydraulic system divides the actuator into multiple working chambers (first and second working chambers) that can be controlled independently. Each chamber receives hydraulic fluid at different pressure levels through separate control valves, allowing the total force to be controlled by combining discrete force components from each chamber without requiring continuous throttling of a single flow path.

Inventive Principle:
Principle #1Segmentation

2Stress or pressure

If conventional control valves are used for pressure control, then pressure level can be adjusted, but losses occur in hydraulic output due to throttling

Engineering Contradiction:
Improvepressure levelVSAvoidhydraulic output
Core Design Contradiction:
Stress or pressureVSProductivity

Solution Approach 1:

The system dynamically switches between different pressure levels in the working chambers by controlling the opening and closing of control valves. Instead of maintaining continuous pressure adjustment through throttling, the system transitions between discrete pressure states, thereby reducing energy losses while maintaining effective pressure control.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If pressure levels vary in multiple working chambers simultaneously, then force steps can be generated, but unnecessary variation or vibration occurs in the sum force of the actuator

Engineering Contradiction:
Improveforce stepsVSAvoidsum force stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The control system coordinates the operation of control valves so that when one valve opens to increase pressure in a chamber, another valve closes to maintain or reduce pressure in other chambers. This preliminary coordination prevents simultaneous pressure variations that would cause force vibrations, ensuring smooth transitions between force steps.

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach results in significant energy savings and enhanced control of loads by eliminating unnecessary variations and vibrations in the sum forces generated by the actuator, enabling precise control of force steps and efficient energy recovery within the system.

Implementation Method 1

The proportional valve is a control valve in which the volume flow of hydraulic fluid may be controlled in a stepless manner, and in which the cross-sectional area of the flow path, that is, the opening of the proportional valve, may be controlled in a stepless manner

Methodology Applied
Scientific EffectFluid flow control through variable cross-sectional area:

Implementation Method 2

The proportional valve is electrically controlled and is based on a proportional magnet. The proportional valve is controlled by a control signal which is proportional to the opening.

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 3

The pressure of the hydraulic fluid in the system acts on the effective area of the working chamber and generates a force acting on the load via the actuator

Methodology Applied
Scientific EffectHydraulic pressure force: Pascal's Law

Data Source

PatentEP3365560B1A hydraulic system and method for controlling a hydraulic system
Publication Date: 2021.07.21 NORRHYDRO
  • EP3365560B1 patent drawingFigure 1
  • EP3365560B1 patent drawingFigure 2
  • EP3365560B1 patent drawingFigure 3~4

AI summary

A hydraulic system and a method comprising a linear actuator 23 for generating discrete sum forces, chambers A-D for generating discrete force components, at least two charging circuits 3,4 configured to maintain predetermined pressure levels of hydraulic fluid, independent control interfaces 9-16 configured to open and close connections of the first and second charging circuits to the chambers, and an electronic control unit 50 for controlling the control interfaces. At least two control interfaces are proportional valves which are used as shut-off valves and are independently switchable to the open and closed positions in a controlled manner. Moreover, non-throttled control and secondary control are implemented in the hydraulic system and the method.