Self-Moving Mower Speed Control on Downhill Slopes

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Solution Overview

Problem

Automatic lawn mowers often fail to safely navigate slopes due to excessive speed, leading to potential safety hazards and poor cutting performance, as they may not be able to timely turn or reverse when approaching borders.

Innovation Solution

A self-moving device equipped with a detection unit (such as an accelerometer, tachometer, or inclinometer) that alternates the acceleration of the device by adjusting the drive motor's working current to maintain speed within a preset range, preventing excessive speed when descending slopes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the automatic lawn mower moves fast to improve productivity, then the working efficiency is improved, but the safety and stability deteriorate due to inability to turn around or reverse in time when detecting border

Engineering Contradiction:
Improveworking efficiencyVSAvoidsafety
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The control module applies preliminary anti-action by detecting acceleration changes that indicate slope descent and proactively reducing motor output power before the lawn mower reaches border detection zones. This preventive measure ensures the device can stop or turn around safely within the available distance, eliminating the safety risk associated with high-speed operation while maintaining productivity through controlled acceleration management.

Inventive Principle:
Principle #9Preliminary anti-action

2Productivity

If the automatic lawn mower moves fast to improve productivity, then the working efficiency is improved, but the cutting quality deteriorates due to poor lawn cutting when moving too fast

Engineering Contradiction:
Improveworking efficiencyVSAvoidcutting quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The system implements dynamics by continuously monitoring acceleration parameters and dynamically adjusting motor output power in real-time. When acceleration exceeds the preset threshold indicating slope descent, the control module reduces power to maintain speed within the optimal range for quality cutting. This dynamic adjustment ensures consistent cutting quality across varying terrain conditions while maximizing productivity through intelligent power management.

Inventive Principle:
Principle #15Dynamics

3Speed

If the automatic lawn mower descends slope to move forward, then the speed increases to improve productivity, but the stability deteriorates due to excessively high speed causing unsafe operation

Engineering Contradiction:
Improvemovement speedVSAvoidoperational stability
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The system employs feedback control by using the detection unit to monitor acceleration parameters and feed this information back to the control module. When the detected acceleration exceeds the preset threshold, indicating slope descent causing excessive speed, the control module responds by reducing motor output power. This closed-loop feedback mechanism maintains operational stability by keeping speed within safe limits while allowing productivity improvements through controlled acceleration on suitable terrain.

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

This solution ensures the device maintains a safe and stable speed, preventing border crossings and ensuring proper lawn cutting by intermittently braking or adjusting acceleration based on detected parameters.

Implementation Method 1

the detection unit comprises at least one of an accelerometer, a tachometer, an inclinometer, and a gyroscope

Methodology Applied
Scientific EffectAccelerometer: Accelerometer

Implementation Method 2

the detection unit comprises at least one of an accelerometer, a tachometer, an inclinometer, and a gyroscope

Methodology Applied
Scientific EffectTachometer:

Implementation Method 3

a movement module, mounted at the housing, and driven by a drive motor to enable the self-moving device to move

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3584661B1Automatic working system, self-moving apparatus and control method thereof
Publication Date: 2023.03.08 POSITEC POWER TOOLS (SUZHOU) CO LTD
  • EP3584661B1 patent drawingFigure 1
  • EP3584661B1 patent drawingFigure 2
  • EP3584661B1 patent drawingFigure 3

AI summary

The present invention relates to a self-moving device, moving and working in a working region, and including: a housing; a movement module, mounted at the housing, and driven by a drive motor to enable the self-moving device to move; a control module, controlling movement and working of the self-moving device; and a detection unit, electrically connected to the control module, and detecting a movement and/or status parameter of the self-moving device, where when the detection unit detects that the movement and/or status parameter of the self-moving device satisfies a preset condition, the control module alternately decreases and increases an acceleration of the movement of the self-moving device, so as to keep a speed of the movement of the self-moving device in a preset range. The beneficial effect of the present invention is as follows: When the self-moving device descends a slope, an acceleration of the movement of the self-moving device is alternately decreased and increased to keep a speed of the movement of the self-moving device in a preset range, thereby avoiding a series of problems such as safety hazards that occur because the speed of the movement of the self-moving device is excessively high.