Mobile Robot Laser Layout for Detecting Holes and Stairs
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Solution Overview
Problem
Mobile robots equipped with horizontally-oriented laser sensors struggle to detect and avoid obstacles that are parallel to the floor or not at the same height as the scanning plane, such as positive obstacles like tables or negative obstacles like holes and stairs, leading to frequent collisions.
Innovation Solution
A system comprising non-horizontally oriented lasers, a memory, a laser controller, and a propulsion system that converts laser readings into three-dimensional coordinates to identify and avoid obstacles by determining minimum and maximum heights within a tolerance profile, allowing the mobile robot to detect and navigate around both positive and negative obstacles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If horizontally-oriented laser sensors are used to scan the area in the mobile robot's direction of travel, then the system can detect obstacles that extend from the floor in a substantially perpendicular direction, but the system fails to detect obstacles that are parallel to the floor or not at the same height as the scanning plane
Solution Approach 1:
The patent introduces a vertically-oriented laser sensor that scans in a vertical plane perpendicular to the floor, adding a new dimensional perspective to obstacle detection. This vertical scanning dimension complements the existing horizontal scanning capability, enabling the system to detect both vertical obstacles (tables, chairs) and horizontal obstacles (floor gratings, gaps) that were previously undetectable
2Adaptability or versatility
If multiple vertically-oriented or randomly-oriented lasers are attached to the mobile robot to detect obstacles parallel to the floor and holes, then the system can detect a broader range of obstacles, but the cost of installing, using and maintaining the multiplicity of expensive lasers becomes prohibitively high
Solution Approach 1:
The patent employs a single vertically-oriented laser sensor that performs multiple detection functions: it detects horizontal obstacles parallel to the floor, identifies gaps and holes in the floor, and determines the robot's position relative to the floor plane. This multi-functional approach replaces what would otherwise require multiple specialized sensors, reducing system complexity and cost while maintaining comprehensive obstacle detection capability
3Measurement precision
If multiple vertically-oriented or randomly-oriented lasers are used to detect obstacles, then the system can detect obstacles parallel to the floor, but an unacceptably high number of false positives arise from gratings in the floor which do not necessarily need to be avoided
Solution Approach 1:
The patent implements a feedback mechanism where the vertically-oriented laser sensor continuously scans the vertical plane and the system compares successive readings to distinguish between temporary variations (false positives from floor gratings) and genuine obstacles. The controller analyzes patterns in the laser return data, using feedback from multiple measurements to filter out false positives while maintaining detection of actual hazards
Solution Approach 2:
The system changes the scanning parameters of the vertically-oriented laser, varying the scan angle and position across different vertical planes. By analyzing how obstacle reflections change with these parameter variations, the system can distinguish between static genuine obstacles and transient false positives caused by floor gratings or surface irregularities
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
Effectively prevents mobile robots from colliding with obstacles by accurately detecting and mapping three-dimensional coordinates of obstacles, reducing false positives and enhancing navigation safety across varied environments.
Implementation Method 1
laser readings into three-dimensional coordinates
Implementation Method 2
horizontally-oriented laser sensors to scan the area in the mobile robot's direction of travel and to detect potential obstacles
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
Embodiments of the present invention provide methods and systems for ensuring that mobile robots are able to detect and avoid negative obstacles, such as gaps or holes in the floor, or a flight of stairs in a physical environment that are typically hard to detect because the obstacles do not exist in the same plane or planes as the mobile robot's horizontally-oriented obstacle detecting lasers. Thus, the invention provides negative obstacle avoidance systems for mobile robots.