Pool Cleaner Stair Detection to Prevent Water Ejection

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Robotic pool cleaners lack the capability to identify and navigate stairs, leading to potential ejection of pool water and debris, which can be problematic due to reduced traction and safety concerns.

Innovation Solution

A pool cleaner equipped with a controller that utilizes tilt and depth sensors to detect stair ascension and descension, maintaining a stair count, and reversing direction when reaching the highest permissible stair to prevent water ejection and ensure safe operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the pool cleaner operates autonomously to clean pool surfaces, then cleaning effectiveness is improved, but the ability to identify and navigate stairs is lost, causing water ejection and safety issues

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidstair navigation capability
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent replaces mechanical stair-detection mechanisms with electronic sensor systems (tilt sensors, depth sensors) and computational processing. The controller uses sensor data to identify stair geometries, calculate ascent angles, and determine when to reverse direction, substituting physical mechanical detection with electronic sensing and algorithmic processing.

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

Solution Approach 2:

The patent introduces sensors as intermediary devices between the pool cleaner and the stair structure. Tilt sensors measure the angle of the cleaner relative to the horizontal plane, while depth sensors measure distance to the pool surface. These intermediaries translate physical stair characteristics into electrical signals that the controller can process for navigation decisions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Area of stationary object

If the pool cleaner ascends stairs without detection capability, then cleaning coverage is improved, but traction is reduced and water is ejected from the pool

Engineering Contradiction:
Improvecleaning coverageVSAvoidwater ejection and reduced traction
Core Design Contradiction:
Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent implements a feedback control system where sensors continuously monitor the pool cleaner's position, orientation, and depth. The controller processes this feedback information to detect stair ascension events by analyzing changes in tilt angle and depth measurements. Based on this feedback, the controller automatically triggers reverse-direction propulsion to prevent water ejection and maintain safe operation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary detection of stair geometries and ascent angles before the harmful effects occur. By continuously monitoring tilt and depth data, the system identifies approaching stairs and calculates ascent parameters in advance, allowing the controller to prepare and execute reverse-direction propulsion before water ejection or traction loss occurs.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If the pool cleaner uses sensors to detect stairs, then stair navigation safety is improved, but device complexity increases

Engineering Contradiction:
Improvestair navigation safetyVSAvoidsensor and controller complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent designs the sensor system and controller to perform multiple functions beyond just stair detection. The same tilt sensors and depth sensors used for stair identification also provide information for navigation, positioning, and operational control. The controller integrates stair-detection algorithms with existing navigation logic, allowing a single system to handle both stair safety and general pool cleaning operations without requiring entirely separate specialized components.

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

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 pool cleaner to autonomously navigate pool stairs without ejection of water, maintaining pool cleanliness and safety by preventing liquid from being sprayed outside the pool, thus maintaining the pool's water level and preventing slippery surfaces.

Implementation Method 1

a tilt sensor, wherein the controller is configured to detect ascending or descending a stair of the stairway in accordance with a sensed tilt of the pool cleaner

Methodology Applied
Scientific EffectGravitation: Gravitation

Implementation Method 2

a depth sensor, wherein the controller is configured to detect ascending or descending a stair of the stairway in accordance with a depth of the pool cleaner below a waterline of the liquid in the pool

Methodology Applied
Scientific EffectHydrostatic pressure: Pressure Gradient

Implementation Method 3

a pump for drawing liquid from the pool into the housing through an inlet and expelling the liquid through an outlet when the pool cleaner is submerged in the pool

Methodology Applied
Scientific EffectPumping: Pump

Implementation Method 4

a filter for trapping debris that is in the indrawn liquid

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Data Source

PatentEP3567188B1Pool cleaner with stair identification capability
Publication Date: 2021.04.14 AQUATRON ROBOTIC TECH LTD
  • EP3567188B1 patent drawingFigure 1A~1B
  • EP3567188B1 patent drawingFigure 2~3
  • EP3567188B1 patent drawingFigure 4

AI summary

A pool cleaner for cleaning a pool includes a housing, a pump for drawing liquid from the pool into the housing through an inlet and expelling the liquid through an outlet when the pool cleaner is submerged in the pool, a filter for trapping debris that is in the indrawn liquid, and a propulsion system for propelling the pool cleaner along a submerged surface within the pool. A controller is configured to determine a position of the pool cleaner on a stairway of the pool, and to control the propulsion system to stop ascending the stairway when the pool cleaner is determined to have ascended to a highest permissible stair of the stairway.