Floor Cleaner Brush Motor Torque Control for Lifted-Nozzle Safety
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Solution Overview
Problem
Floor cleaning devices with rotating brushes pose safety risks when the nozzle is lifted, as they can suck in fingers, hair, or clothing, and powerful motors can cause injury, while existing solutions like stopping or reducing motor speed decrease cleaning performance and motor lifespan.
Innovation Solution
A controller that detects whether the nozzle is in contact with the floor or lifted, adjusting the torque threshold of the brush motor to prevent injury without stopping or significantly reducing speed, maintaining cleaning performance by limiting torque when the nozzle is lifted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the brush motor is stopped when the nozzle is lifted, then safety is improved, but cleaning performance and motor lifespan deteriorate due to frequent stopping and starting
Solution Approach 1:
The patent changes the control parameter from binary (on/off) to continuous variable (speed threshold). When the nozzle is lifted, the controller reduces the upper threshold value for brush speed, allowing the motor to operate at lower speeds rather than stopping completely. This resolves the contradiction by maintaining safety through speed limitation while preserving motor continuity and cleaning capability.
Solution Approach 2:
The patent implements dynamic speed threshold adjustment based on nozzle position. The controller continuously monitors nozzle contact status and dynamically modifies the speed threshold parameter accordingly - high threshold when contacting floor, low threshold when lifted. This dynamic adaptation allows the system to optimize both safety and performance in real-time.
2Object-affected harmful factors
If the brush motor is stopped when the nozzle is lifted, then safety is improved, but motor lifespan deteriorates due to frequent starting and stopping
Solution Approach 1:
The patent changes the operational state from complete stop to reduced-speed operation. By lowering the speed threshold rather than stopping the motor, the system eliminates frequent start-stop cycles that stress the motor, thereby extending lifespan while maintaining safety through speed limitation when the nozzle is lifted.
Solution Approach 2:
The patent prepares for potential safety issues by having a reduced speed threshold ready to activate immediately when nozzle lift is detected. This pre-prepared lower threshold acts as a cushion, allowing smooth transition to safe operating conditions without abrupt motor shutdown and subsequent restart stress.
3Object-affected harmful factors
If the brush speed is reduced when the nozzle is lifted, then safety is improved, but cleaning performance deteriorates
Solution Approach 1:
The patent implements dynamic threshold adjustment rather than fixed speed reduction. The controller adapts the upper threshold based on real-time nozzle position detection - maintaining high thresholds during floor contact for optimal cleaning, and switching to low thresholds when lifted for safety. This dynamic approach preserves cleaning performance when needed while ensuring safety when appropriate.
Data Source
AI summary
The present invention relates to a controller for controlling a floor cleaning device that comprises a nozzle configured to contact a floor, a rotatable brush arranged at the nozzle, a brush motor configured to drive the brush to rotation, and a nozzle detector configured to detect whether the nozzle contacts the floor or is lifted from the floor. The controller being configured to control the rotation of the brush by means of the brush motor; and to decrease an upper threshold of a parameter related to a torque of the brush motor, if the nozzle detector detects that the nozzle is lifted from the floor.