Mobile Robot Debris Bin Pneumatic Flap Door for Reduced Contact Forces

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Solution Overview

Problem

Existing mobile robots face challenges in efficiently evacuating debris from their bins due to issues with debris bin door mechanisms and the lack of efficient evacuation systems that minimize contact forces and maximize air flow during the evacuation process.

Innovation Solution

A mobile robot equipped with a debris bin featuring a door unit with a semi-spherical support structure and a flap that opens in response to air pressure, connected by a biasing mechanism such as a torsion spring, and an evacuation station with a control system that uses negative air pressure to evacuate debris through a removable conduit system, optimizing the evacuation process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a door mechanism is used to seal the exhaust port, then debris containment is improved, but mechanical complexity and contact forces increase

Engineering Contradiction:
Improvedebris containmentVSAvoiddoor mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the traditional mechanical door mechanism with a pneumatically actuated flap system. The flap is driven by air pressure differential rather than mechanical actuators, reducing mechanical complexity and contact forces. The flap pivots on a simple hinge mechanism and is controlled by directing compressed air to either side of the flap, eliminating the need for complex motors, gears, or linkages that would be required for a conventional door mechanism.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses compressed air to actuate the flap door. A compressor generates pressurized air that is directed through nozzles to the appropriate side of the flap to open or close it. The air pressure creates a force differential that moves the flap against the hinge spring, providing reliable debris containment through pneumatic actuation rather than mechanical means.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Reliability

If a conventional door mechanism is used, then sealing is achieved, but evacuation time and power consumption increase

Engineering Contradiction:
Improvesealing effectivenessVSAvoidevacuation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces slow mechanical door actuation with rapid pneumatic flap response. The compressed air system can open and close the flap in fractions of a second compared to the seconds required for mechanical door mechanisms. This rapid cycling capability significantly reduces the time required for each evacuation cycle while maintaining effective sealing when the flap is closed.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs periodic opening and closing of the flap in synchronization with the compressor cycles. The flap is opened briefly during compressor operation to allow debris evacuation, then quickly closed to maintain sealing. This periodic action optimizes the balance between evacuation efficiency and sealing effectiveness, minimizing the time the system is open while ensuring complete debris removal during each cycle.

Inventive Principle:
Principle #19Periodic action

3Ease of manufacture

If a fixed door mechanism is used, then construction is simple, but adaptability to different evacuation conditions is reduced

Engineering Contradiction:
Improveconstruction simplicityVSAvoidadaptability to evacuation conditions
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent transforms the static door mechanism into a dynamic, actively controlled flap system. The flap can rapidly change its position in response to varying air pressure conditions, allowing the system to adapt to different evacuation requirements. The hinge spring provides continuous passive force while the pneumatic actuation provides active control, creating a dynamically responsive system that can adjust to changing conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameters of the sealing mechanism by using air pressure as the control variable instead of mechanical position. By varying the air pressure applied to different sides of the flap, the system can adaptively control the flap position and sealing force. This allows the same simple mechanical structure to operate under varying pressure conditions and adapt to different evacuation scenarios.

Inventive Principle:
Principle #35Parameter changes

4Productivity

If the flap is positioned to maximize opening area, then air flow is improved, but contact forces with external objects increase

Engineering Contradiction:
Improveair flow efficiencyVSAvoidcontact forces with external objects
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent positions the flap and its pivot mechanism entirely within the debris bin structure. The hinge axis is located inside the bin, and the flap rotates within the bin's internal volume. This nested arrangement ensures that even when the flap is fully open to maximize the exhaust port opening area for optimal air flow, the flap and its mechanism remain confined within the bin boundaries and cannot contact external objects, eliminating the harmful contact forces.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 ensures efficient debris evacuation with reduced contact forces, improved air flow, and adaptive control of evacuation time, minimizing power consumption and noise, while allowing for easy cleaning and maintenance of the debris bin and evacuation station components.

Implementation Method 1

a flap configured to move, in response to air pressure at the exhaust port, between a closed position to cover the exhaust port and an open position to open a path between the chamber and the exhaust port

Methodology Applied
Scientific EffectAir pressure: Pressure Increase

Implementation Method 2

a motor that is responsive to commands from the control system to remove air from the canister and thereby generate negative air pressure in the canister to evacuate the debris bin by suctioning the debris from the debris bin

Methodology Applied
Scientific EffectNegative air pressure (suction): Suction

Data Source

PatentEP3313255B1Evacuation station
Publication Date: 2020.06.17 IROBOT CORP
  • EP3313255B1 patent drawingFigure 1
  • EP3313255B1 patent drawingFigure 2
  • EP3313255B1 patent drawingFigure 3~4

AI summary

A mobile robot includes a body configured to traverse a surface and to receive debris from the surface, and a debris bin within the body. The debris bin includes a chamber to hold the debris received by the mobile robot, an exhaust port through which the debris exits the debris bin; and a door unit over the exhaust port. The door unit includes a flap configured to move, in response to air pressure at the exhaust port, between a closed position to cover the exhaust port and an open position to open a path between the chamber and the exhaust port. The door unit, including the flap in the open position and in the closed position, is within an exterior surface of the mobile robot.