Pool Cleaning Robot Depth Control via Pressure Feedback

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Solution Overview

Problem

Conventional swimming pool cleaning robots face difficulties in reliably reaching the water line and maintaining uniform cleaning, especially when the filter is clogged or the robot's mass increases due to debris, affecting its ability to climb walls and maintain consistent depth.

Innovation Solution

Incorporating a pressure sensor to determine the robot's depth of immersion and using servo-control means to adjust driving and guiding parameters, ensuring consistent depth and reliable water line access, regardless of filter status or surface adhesion, through PID or other regulation systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the robot uses fixed driving parameters calibrated for clean filter conditions, then it can operate simply without complex control systems, but it fails to reliably reach the water line when the filter is clogged or mass increases

Engineering Contradiction:
Improveability to reach water lineVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a feedback control system where a pressure sensor continuously measures the robot's depth and feeds this information to a controller. The controller adjusts driving parameters (pump power, motor speed) based on the depth feedback to maintain the robot at the water line, ensuring reliable operation regardless of filter clogging or mass changes.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent transitions from fixed, static driving parameters to dynamic, adaptive parameters. The control system continuously modifies pump power and motor speed based on real-time depth measurements, allowing the robot to adapt to changing conditions such as filter clogging and mass increase throughout the cleaning cycle.

Inventive Principle:
Principle #15Dynamics

2Productivity

If the robot maintains fixed driving parameters throughout the cleaning cycle, then energy consumption is predictable and simple, but cleaning uniformity deteriorates as the filter fills and robot mass increases

Engineering Contradiction:
Improvecleaning uniformityVSAvoidparameter adjustment system
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The pressure sensor provides continuous depth feedback to the control system, which adjusts driving parameters to maintain consistent cleaning performance. This feedback loop ensures that the robot compensates for mass increases due to filter filling, maintaining cleaning uniformity throughout the operation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent dynamically changes operating parameters (pump power, motor speed) based on robot depth and cleaning conditions. The control system modifies these parameters in real-time to maintain optimal cleaning performance, transitioning from fixed parameters to adaptive parameter control.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If additional weights or floats are added to correct wall-climbing behavior, then the robot can adapt to different pool surfaces, but the installation becomes complex and requires additional resources

Engineering Contradiction:
Improveadaptability to pool surfacesVSAvoidinstallation simplicity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent replaces mechanical adjustment methods (adding weights or floats) with an electronic control system. The pressure sensor and controller dynamically adjust pump power and motor speed to achieve proper wall-climbing behavior, eliminating the need for physical modifications and simplifying installation.

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

Solution Approach 2:

The robot automatically adjusts its own operating parameters to adapt to different pool surfaces and conditions. The control system self-regulates pump power and motor speed based on depth feedback, eliminating the need for external installation of weights or floats by users.

Inventive Principle:
Principle #25Self-service

4Duration of action of stationary object

If the robot operates with a blocked filter, then it can continue cleaning without interruption, but the increased mass and reduced thrust prevent it from reaching the water line

Engineering Contradiction:
Improvecontinuous operation timeVSAvoidability to reach water line
Core Design Contradiction:
Duration of action of stationary objectVSReliability

Solution Approach 1:

The control system dynamically adjusts pump power and motor speed in response to depth feedback. When the filter becomes blocked and mass increases, the system automatically increases driving parameters to compensate, maintaining the ability to reach the water line throughout continuous operation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The pressure sensor continuously monitors depth and provides feedback to the controller. When depth deviations occur due to filter blocking and mass increase, the feedback loop triggers parameter adjustments that restore proper water line reaching capability, enabling uninterrupted operation.

Inventive Principle:
Principle #23Feedback

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

The solution enables the robot to consistently reach and follow the water line, ensuring uniform pool cleaning and adapting to varying conditions, such as filter clogs, by adjusting its operating parameters based on pressure readings, thus improving its behavior and cleaning efficiency.

Implementation Method 1

a pressure sensor making it possible to determine the immersion depth of the cleaning robot in a pool basin, on the basis of a measurement of the ambient pressure of the robot

Methodology Applied
Scientific EffectPressure measurement: Pressure Gradient

Implementation Method 2

the power of the pumping device being controlled so as to guide the cleaning robot to a predetermined immersion depth

Methodology Applied
Scientific EffectHydraulic thrust: Hydraulic Press

Implementation Method 3

a pumping device that provides a directed hydraulic flow to impart vertical thrust to the roller

Methodology Applied
Scientific EffectHydraulic flow thrust: Hydraulic Press

Implementation Method 4

maintaining the robot at the waterline to ensure cleaning is usually achieved by using the balance between Archimedes' principle and the robot's weight when it is at the waterline

Methodology Applied
Scientific EffectArchimedes' principle (buoyancy): Archimedes' Principle (Buoyancy)

Data Source

PatentEP3408471B1Swimming pool cleaning robot and method for using same
Publication Date: 2020.03.04 ZODIAC POOL CARE EURO
  • EP3408471B1 patent drawingFigure 1~2
  • EP3408471B1 patent drawingFigure 3a~3b
  • EP3408471B1 patent drawingFigure 4a~4b

AI summary

The invention relates to swimming pool cleaning robot (10) comprising: a body (11); at least one hydraulic circuit through which a liquid flows between at least one liquid inlet (13) and at least one liquid outlet (14), said hydraulic circuit including at least one means for separating debris suspended in the liquid; pumping means for driving the liquid through the hydraulic circuit; means for driving and guiding the cleaning robot on a surface; and means for controlling the operating parameters of the means for driving and guiding the cleaning robot (10). The control means comprise a pressure sensor (21) that can be used to determine the immersion depth of the cleaning robot in a swimming pool, and means for automatically controlling the measured pressure on the basis of a set value.