Actuator Cylinder Descent Control With Load-Adaptive Valve Opening

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Solution Overview

Problem

Existing control systems for actuator cylinders in hydraulic applications face issues with instability, response delay, pressure spikes, and varying movement speeds due to non-adjustable valve openings, leading to potential instability and cavitation.

Innovation Solution

A control system that automatically adjusts the rate of load descent based on the magnitude of the load and its position relative to the operating machine, using proportional solenoid valves and electronic control units to regulate pilot pressure and prevent sudden accelerations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a simple hydraulic balancing valve is used with non-adjustable opening control, then the system structure is simple and cost is low, but the valve undergoes abrupt opening causing instability of movement and response delay

Engineering Contradiction:
Improvevalve control structureVSAvoidmovement stability
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The patent applies dynamics by making the valve opening control adjustable rather than fixed. The electro-proportional valve allows dynamic adjustment of the opening degree based on operating conditions, enabling the system to adapt to varying loads and positions while maintaining stability and preventing abrupt openings.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of valve opening control from non-adjustable to adjustable via electronic control. By varying the opening degree parameter dynamically based on load magnitude and position, the system achieves stable movement without requiring complex mechanical damping devices.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If a damping device is inserted to reduce abrupt opening, then movement stability improves, but pressure spikes occur in fast movements and activation delay increases

Engineering Contradiction:
Improvemovement stabilityVSAvoidactivation delay
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The patent replaces the mechanical damping device with an electronic control system. Instead of using physical damping elements that cause delays and pressure spikes, the system uses an electro-proportional valve controlled by electronic signals to achieve smooth valve opening without the drawbacks of mechanical damping.

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

Solution Approach 2:

The patent implements feedback control where the control unit continuously monitors the position of the load and the magnitude of the load, then adjusts the valve opening accordingly. This closed-loop feedback system eliminates activation delay while maintaining stability by dynamically optimizing the valve opening based on real-time conditions.

Inventive Principle:
Principle #23Feedback

3Object-affected harmful factors

If pilot pressure limiting systems and shutoff valves are introduced to prevent cavitation, then cavitation is prevented, but the system complexity increases and movement speed varies with load

Engineering Contradiction:
Improvecavitation preventionVSAvoidvalve system complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent makes the electro-proportional valve multi-functional by enabling it to simultaneously control valve opening, prevent cavitation, and maintain consistent movement speed across varying loads. This single valve performs multiple functions that previously required separate components, reducing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent uses dynamic control of the electro-proportional valve to adapt to varying load conditions. The valve opening is continuously adjusted based on load magnitude and position, preventing cavitation under all operating conditions while maintaining consistent movement speed, eliminating the need for fixed pilot pressure limiting systems.

Inventive Principle:
Principle #15Dynamics

4Use of energy by moving object

If externally line-driven valves are used for movement control, then power consumption is reduced and precise movements are achieved, but different speed of movement occurs when load varies and cavitation can be triggered

Engineering Contradiction:
Improvepower consumptionVSAvoidmovement speed consistency
Core Design Contradiction:
Use of energy by moving objectVSSpeed

Solution Approach 1:

The patent implements feedback control where the control unit monitors load magnitude and position, then dynamically adjusts the electro-proportional valve opening to maintain consistent movement speed across varying loads. This feedback mechanism ensures speed consistency while preserving the energy efficiency of externally line-driven valve operation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent dynamically changes the valve opening parameter based on real-time measurements of load and position. This parameter adjustment maintains consistent movement speed under varying load conditions while preserving the energy efficiency of the externally line-driven valve system.

Inventive Principle:
Principle #35Parameter changes

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

Ensures safe and stable load descent by limiting speeds according to load weight and distance, preventing sudden movements and cavitation, while maintaining efficient operation.

Implementation Method 1

said control system includes a proportional solenoid valve (32, 38) configured to regulate a pilot pressure to be supplied to said retaining system (30) in order to adjust an opening degree of the retaining system (30)

Methodology Applied
Scientific EffectHydraulic pressure control: Hydraulic Press

Implementation Method 2

an actuator cylinder (10) configured to allow a direct or indirect displacement of a load (C3)... a first feed conduit (20) of said first chamber (11)... a second feed conduit (21) of said second chamber (12)

Methodology Applied
Scientific EffectHydraulic force transmission: Hydraulic Press

Data Source

PatentEP4325068B1Control system for an actuator cylinder
Publication Date: 2025.10.08 ROBERT BOSCH GMBH
  • EP4325068B1 patent drawingFigure 1
  • EP4325068B1 patent drawingFigure 2
  • EP4325068B1 patent drawingFigure 3

AI summary

The present invention relates to a Method for adjusting a control system for an actuator cylinder (10) of an operating machine, said actuator cylinder having a first and a second chamber (11, 12), a piston (13) separating said first chamber (11) from said second chamber (12), said system comprising a first feed conduit (20) of said first chamber (11) of said cylinder (10), a second feed conduit (21) of said second chamber (12) of said cylinder (10), wherein an increase in the volume of said second chamber (12) causes a load supported by said cylinder (10) to descend downwardly wherein said first feed conduit (20) and said second feed conduit (21) are connectable to a distribution valve (100) configured to control a feed operation and a discharge operation of said first feed conduit (20) and said second feed conduit (21), said control system comprising a retaining system (30) positioned along said first supply conduit (20) and configured to open a passage for a fluid coming from said distribution valve (100) and directed to said first chamber (11) if the pressure difference between the pressure of said fluid coming from said distribution valve (100) and the pressure in said first chamber (11) exceeds a first predetermined value, and wherein said retaining system (30) is configured to regulate the flow of fluid exiting said first chamber (11) and directed to said distribution valve (100) according to a signal provided to said retaining system (30); said method comprising the following steps: a. Receiving an information corresponding to a request for descent of said load (C3); b. Send to said restraint system (30) a signal for the descent of said load (C3); c. Adjust said restraint system (30) so as to execute said descent of said load according to said signal received by said restraint system (30) in said step b.; wherein said signal provided to said retaining system (30) during said step b. takes into consideration the weight of said load (C3) or a quantity dependent thereon so that the descent of said load (C3) meets at least one predetermined criterion.