Lawn Mower Robot Ultrasonic Obstacle Avoidance Control

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Solution Overview

Problem

Conventional lawn mowers require manual operation, leading to labor costs and inefficiencies, as users often need to hire workers to maintain lawns, and existing autonomous solutions do not effectively manage obstacle interactions, potentially causing damage.

Innovation Solution

A lawn mower robot equipped with ultrasonic sensors and a control method that senses obstacles, decelerates, and adjusts direction to minimize impact, allowing for efficient navigation and obstacle avoidance while maintaining lawn cutting operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the lawn mower robot drives at normal velocity without deceleration, then productivity is improved, but the degree of impact upon collision with obstacles increases

Engineering Contradiction:
Improvelawn mowing efficiencyVSAvoidimpact degree on robot and obstacles
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The robot performs preliminary sensing of obstacles using ultrasonic sensors before reaching them, and executes deceleration in advance based on the sensed distance. This preliminary action allows the robot to maintain higher overall speed while reducing impact upon collision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The robot applies counter-action (deceleration) in advance when an obstacle is detected, opposing the forward motion before collision occurs. This preliminary anti-action reduces the impact force while allowing the robot to quickly resume normal speed after passing the obstacle.

Inventive Principle:
Principle #9Preliminary anti-action

2Object-affected harmful factors

If the lawn mower robot decelerates upon sensing obstacles, then the degree of impact is reduced, but productivity decreases due to frequent speed changes

Engineering Contradiction:
Improveimpact degree on robot and obstaclesVSAvoidlawn mowing efficiency
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The robot applies deceleration partially and selectively only when obstacles are detected at specific distance thresholds, rather than continuously decelerating. This partial action minimizes the impact reduction benefit while limiting productivity loss to only necessary moments.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The robot dynamically adjusts its velocity based on real-time obstacle detection results. The speed changes from normal velocity to decelerated velocity and back are executed smoothly and quickly, optimizing the balance between safety and productivity.

Inventive Principle:
Principle #15Dynamics

3Reliability

If the lawn mower robot stops and changes direction upon collision, then obstacle avoidance is improved, but time loss increases

Engineering Contradiction:
Improveobstacle avoidance capabilityVSAvoidtime for direction change
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The robot rushes through the obstacle avoidance maneuver by executing quick direction changes immediately after collision detection, rather than stopping completely for extended periods. This skipping approach minimizes time loss while ensuring reliable obstacle avoidance.

Inventive Principle:
Principle #21Skipping (Rushing through)

Solution Approach 2:

The robot performs preliminary sensing and deceleration before collision occurs, which reduces the severity of collision and allows for faster post-collision recovery and direction change, thereby reducing overall time loss.

Inventive Principle:
Principle #10Preliminary action

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 reduces labor costs by automating lawn maintenance and minimizes damage to the robot and obstacles by effectively sensing and navigating around them, ensuring safe and efficient lawn mowing.

Implementation Method 1

a first sensing unit (32) for sensing an obstacle (400) located within a work area

Methodology Applied
Scientific EffectUltrasonic wave emission and detection: Ultrasound

Data Source

PatentEP2939513B1Lawn mower robot and control method thereof
Publication Date: 2019.11.06 LG ELECTRONICS INC
  • EP2939513B1 patent drawingFigure 1A~1B
  • EP2939513B1 patent drawingFigure 2
  • EP2939513B1 patent drawingFigure 3

AI summary

Disclosed are a lawn mower robot and a control method thereof. The control method includes sensing whether or not an obstacle is present during driving at a normal velocity, decelerating the lawn mower robot, when the obstacle is sensed, sensing whether or not the lawn mower robot collides with the obstacle in the decelerated state, and differently driving the lawn mower robot if a collision of the lawn mower robot with the obstacle is sensed and if a collision of the lawn mower robot with the obstacle is not sensed.