Brush with pressure sensor
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Solution Overview
Problem
Robotic vacuum cleaners often falsely detect entanglement with obstructions due to increased current draw from thick carpets, leading to unnecessary shutdowns and potential damage, as the current increase can be triggered by factors other than actual entanglement.
Innovation Solution
A surface cleaning device equipped with a rotatable brush featuring a pressure sensor system, comprising a projecting blade connected to a tactile sensor via a flexible member, which actuates a processor to respond to entanglement by altering the brush's operation only after sustained pressure exceeds a threshold, preventing false detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current draw is used to detect entanglement, then entanglement detection capability is improved, but false detection increases due to thick carpet conditions
Solution Approach 1:
A pressure sensor is introduced as an intermediary detection device between the brush and the obstruction. The pressure sensor directly measures the physical contact force between the brush and potential obstructions, providing a more reliable detection signal that is not influenced by carpet thickness or motor load variations, thereby eliminating false detections while maintaining accurate entanglement detection
Solution Approach 2:
The electrical measurement system (current draw monitoring) is replaced with a mechanical measurement system (pressure sensor). The pressure sensor provides direct mechanical measurement of contact force between the brush and obstructions, which is more accurate and less prone to false positives compared to indirect electrical measurements that are affected by varying operational conditions
2Productivity
If brush operates continuously on thick pile carpet, then cleaning productivity is maintained, but false entanglement detection occurs due to increased power requirements
Solution Approach 1:
The pressure sensor serves as an intermediary that directly detects physical contact with obstructions, independent of the power requirements for moving the brush through thick carpets. This allows the brush to operate continuously on various carpet types without false shutdowns, maintaining productivity while ensuring reliable obstruction detection
Solution Approach 2:
The detection parameter is changed from electrical (current draw) to mechanical (contact pressure). This parameter change makes the detection system insensitive to variations in power requirements caused by different carpet types, allowing continuous operation on thick pile carpets without triggering false entanglement detections
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 differentiates between actual entanglement and increased load conditions, such as thick carpets, reducing false shutdowns and ensuring continuous operation while protecting the device from damage.
Implementation Method 1
a pressure sensor comprising a projecting blade extending along the length of the shaft connected thereto by a flexible member attached to a tactile sensor. When pressure around the brush reaches a predetermined threshold, the projecting blade will force the connecting flexible member to compress and actuate the tactile sensor
Data Source
AI summary
A method for detecting entanglement of an object with a brush of a surface cleaning device includes collecting sensor readings indicative of an operational status of the brush of the surface cleaning device using at least one sensor, detecting entanglement of an object with the brush when a magnitude of the sensor readings exceeds a predetermined threshold for a predetermined amount of time using a motor controller of the brush, notifying a processor of the surface cleaning device of the detected entanglement using the motor controller, and actuating an action in response to the detected entanglement using the processor.