Robotic Mower Cover Movement Detection

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Solution Overview

Problem

Existing robotic lawnmowers are error-prone due to their detection systems, which fail to accurately differentiate between obstacles and operator handling movements, leading to potential accidents and inefficient control mechanisms.

Innovation Solution

A self-propelled robotic lawnmower with a detection device that utilizes a movable cover as a mechanical sensor, featuring a sensor arrangement with Hall and magnetic sensors, allowing for precise detection of cover movements and differentiation between types, sizes, and directions of movements, connected to a controller for enhanced safety and control measures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a sensor system is used to detect cover movements, then the ability to detect movements is improved, but the reliability of differentiation between obstacles and operator handling deteriorates

Engineering Contradiction:
Improvedetection precisionVSAvoiddifferentiation reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The detection device is divided into multiple independent sensors (acceleration sensor, rotation sensor, position sensor) that detect different aspects of cover movement. Each sensor provides specific data about movement characteristics, allowing the control system to analyze and differentiate between various movement types more reliably.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system transitions from single-point detection to multi-dimensional analysis by combining data from multiple sensors measuring different parameters (acceleration, rotation, position). This dimensional expansion enables the system to distinguish between subtle movement patterns of obstacles versus operator handling more accurately.

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

2Measurement precision

If multiple sensors are used to improve detection accuracy, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvemovement detection precisionVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Multiple sensors (acceleration sensor, rotation sensor, position sensor) are integrated into a single detection device unit that is coupled to both the cover and the chassis. This merging approach consolidates the sensor system while maintaining comprehensive detection capabilities, reducing overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The detection device serves multiple functions simultaneously: it detects cover movements, determines movement directions, identifies movement types, and provides data for control decisions. This multi-functionality reduces the need for separate dedicated systems for each function.

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

3Reliability

If the detection device is coupled to both cover and chassis, then detection reliability is improved, but construction costs increase

Engineering Contradiction:
Improvedetection reliabilityVSAvoidconstruction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The detection device is designed as an integrated unit that combines multiple sensors and coupling mechanisms into a single assembly. This merged design reduces the total number of separate components and assembly steps, thereby lowering construction costs while maintaining reliable multi-point detection.

Inventive Principle:
Principle #5Merging (Combining)

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 provides improved sensitivity and reliability in detecting movements, reducing construction and control costs, and enabling targeted reactions to ensure safe operation and efficient movement, distinguishing between collisions and operator handling.

Implementation Method 1

The detection system incorporates a Hall sensor to detect lateral deflections of the cover

Methodology Applied
Scientific EffectHall effect: Hall Effect

Implementation Method 2

a sensor arrangement with Hall and magnetic sensors, allowing for precise detection of cover movements

Methodology Applied
Scientific EffectMagnetic field detection: Magnetic Field

Data Source

PatentEP2687077B1Robotic mower
Publication Date: 2017.12.27 AL-KO KOBER SE
  • EP2687077B1 patent drawingFigure 1
  • EP2687077B1 patent drawingFigure 2
  • EP2687077B1 patent drawingFigure 3

AI summary

The machine (1) has a support (14) for a resting cover (3) i.e. cover, that is movable on a chassis (2), and a detection device (5) i.e. safety device, co-acting with the chassis and the cover for detection of movements of the cover. The support comprises multiple bearing points that are arranged to the chassis. The detection device is functionally and locally separately arranged from the bearing points. The detection device comprises a compact sensor arrangement with multiple sensors with different acquisition directions. The sensor arrangement comprises lifting and separate moving sensors.