Rotatable Optical Obstacle Detection for Self-Propelled Floor Cleaners

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Solution Overview

Problem

Existing automatically movable devices, such as floor dust collectors, face challenges in effectively detecting obstacles and navigating within a room due to limitations in their obstacle detection systems, particularly in covering a wide peripheral area and reacting to objects and room boundaries.

Innovation Solution

The use of rotatable optical measurement methods like phase correlation, time-of-flight measurement, or heterodyne methods for the transmitter and receiver units, where the central beam intersects or coincides with the axis of rotation, enabling detection ranges of over 20 cm and allowing for early reaction to obstacles and improved room orientation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the transmitter and receiver units are made stationary, then the device structure is simple, but the detection range and ability to cover wide peripheral area is limited

Engineering Contradiction:
Improvedetection coverage areaVSAvoidstructure complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by making the transmitter and receiver units rotatable about a vertical axis instead of stationary. This allows the optical measurement system to scan a wide peripheral area (180° to 270° or more) and achieve all-round detection coverage, directly resolving the contradiction between detection coverage area and structural simplicity.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If the central beam is offset from the axis of rotation, then the beam can cover a wider area, but the detection precision and accuracy are reduced

Engineering Contradiction:
Improvedistance measurement accuracyVSAvoiddetection coverage area
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent applies asymmetry in the optical path design where the central beam is deliberately offset from the rotation axis in the transmitting unit, while in the receiving unit the central beam coincides with the rotation axis. This asymmetric arrangement allows the beam to sweep across a wide area during rotation while maintaining precise measurement capability when the beam returns to the central position.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent resolves the contradiction by introducing temporal dimension through rotation. The beam path is arranged so that during rotation, the central beam passes through different positions relative to the rotation axis, creating a sweeping detection pattern that covers wide area while maintaining measurement precision at key positions in the rotation cycle.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Length of stationary object

If optical measurement methods are used, then the detection range is extended beyond 20 cm, but the device is more susceptible to electromagnetic interference

Engineering Contradiction:
Improvedetection rangeVSAvoidelectromagnetic interference susceptibility
Core Design Contradiction:
Length of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by using different optical measurement methods (phase correlation, time-of-flight, or heterodyne methods) that operate at different wavelengths and modulation frequencies. This allows optimization of the detection system to achieve ranges beyond 20 cm while selecting parameters that are less susceptible to specific electromagnetic interference sources in the operating environment.

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

This solution enables the device to detect obstacles and room boundaries at greater distances, facilitating early reaction and improved navigation within a room, with the optical measurement methods providing accurate distance measurements and reducing interference from electromagnetic sources.

Implementation Method 1

the transmitter and receiver units are based on one of the optical measurement methods phase correlation, time-of-flight measurement or heterodyne method

Methodology Applied
Scientific EffectTime-of-flight measurement: Time of Flight

Implementation Method 2

the transmitter and receiver units are based on one of the optical measurement methods phase correlation, time-of-flight measurement or heterodyne method

Methodology Applied
Scientific EffectPhase correlation: Phase Modulation

Implementation Method 3

the transmitter and receiver units are based on one of the optical measurement methods phase correlation, time-of-flight measurement or heterodyne method

Methodology Applied
Scientific EffectHeterodyne method: Heterodyne

Data Source

PatentEP2236069B1Self-propelled device, in particular self-propelled dust collection device
Publication Date: 2019.12.25 VORWERK & CO INTERHOLDING GMBH
  • EP2236069B1 patent drawingFigure 1~2
  • EP2236069B1 patent drawingFigure 3
  • EP2236069B1 patent drawingFigure 4~5

AI summary

The invention relates to an automatically movable device, in particular an automatically movable floor dust collecting device (1), with electrically driven wheels (3), a device housing and preferably a dust collection container, the device (1) being provided with an obstacle detection system (10) which consists of optical transmitter and receiver units (11, 12) and wherein elements are provided for beam deflection, with at least some of the transmitter and receiver units (11, 12) being arranged so as to be rotatable by 180° or more for all-round detection. In order to improve the obstacle detection of an automatically moving device of the type in question, it is proposed that the transmitter and receiver units (11, 12) be based on one of the optical measuring methods phase correlation, light propagation time measurement or heterodyne method.