Coverage Robot Obstacle Approach and Brush Disentanglement Control
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Solution Overview
Problem
Autonomous coverage robots face challenges in navigating and cleaning surfaces without continuous human guidance, particularly in avoiding obstacles and disentangling from entangling soft media like strings or cords, which can lead to operational interruptions.
Innovation Solution
The autonomous coverage robot is equipped with a chassis, a drive system, an edge cleaning head, and a controller that monitors motor current to reverse bias the edge cleaning head motor when entanglement is detected, allowing the robot to continue cleaning while disentangling, and incorporates sensors for obstacle detection and navigation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the robot continues to maneuver across the floor when entanglement is detected, then cleaning coverage is maintained, but the cleaning head may become damaged or the robot may stall
Solution Approach 1:
The system applies preliminary anti-action by detecting entanglement conditions through motor current monitoring and proactively reversing the cleaning head rotation before damage or stalling occurs. The controller reverses bias the edge cleaning head motor when a spike or elevated current is detected, preventing the harmful effect of continued operation under entanglement while maintaining overall productivity by resuming normal operation after disentanglement.
2Reliability
If the robot stops to disentangle the cleaning head, then damage is prevented, but cleaning coverage is interrupted
Solution Approach 1:
The system maintains continuity of useful action by keeping the robot's forward motion and cleaning operations ongoing while only reversing the cleaning head rotation to disentangle. The independent control allows the drive system to continue maneuvering the robot across the floor while the brush control process handles disentanglement, ensuring minimal interruption to overall cleaning coverage.
Solution Approach 2:
The control system is segmented into independent processes: the drive system controls robot motion while the brush control process independently manages cleaning head rotation. This segmentation allows the robot to continue forward movement and cleaning coverage while the cleaning head rotation is temporarily reversed for disentanglement, resolving the contradiction between preventing damage and maintaining productivity.
3Reliability
If the cleaning head rotates in reverse to unwind entanglement, then disentanglement is achieved, but cleaning effectiveness is reduced
Solution Approach 1:
The system uses periodic action by applying reverse bias to the cleaning head motor in short bursts or transient periods when entanglement is detected, rather than continuous reverse rotation. The controller monitors motor current and applies reverse bias only when needed (when a spike or elevated current is detected), allowing the cleaning head to resume normal forward rotation afterward. This periodic reverse action achieves disentanglement while minimizing impact on overall cleaning effectiveness.
Data Source
AI summary
An autonomous coverage robot includes a drive system, a bump sensor, and a proximity sensor. The drive system is configured to maneuver the robot according to a heading (turn) setting and a speed setting. The bump sensor is responsive to a collision of the robot with an obstacle in a forward direction. A method of navigating an autonomous coverage robot with respect to an object on a floor includes the robot autonomously traversing the floor in a cleaning mode at a full cleaning speed. Upon sensing a proximity of the object forward of the robot, the robot reduces the cleaning speed to a reduced cleaning speed while continuing towards the object until the robot detects a contact with the object. Upon sensing contact with the object, the robot turns with respect to the object and cleans next to the object, optionally substantially at the reduced cleaning speed.