# How the iRobot Roomba Automatically Cleans Floors Without Falling Down Stairs > A 2002 patent describing an autonomous floor-cleaning robot that uses sensors to navigate rooms, avoid cliffs like stairs, and sweep debris into a removable bin. - **Patent:** US 6883201 - **Original title:** Autonomous floor-cleaning robot - **Owner:** iRobot Corp - **Granted:** 2005 - **Status:** Public domain (expired) - **Times cited:** 215 - **Field:** consumer_electronics, mechanical, ai_ml ## What it does This patent describes an autonomous robot that cleans floors by combining a motive system for movement, a vacuum, and a primary brush assembly. It features a side brush that reaches beyond the robot's main body to pull dirt into the cleaning path. The robot uses a sensor system, specifically a cliff detector, to identify stairs or ledges and prevent itself from falling. When a cliff is detected, the control system automatically adjusts the robot's speed and direction to escape the area and resume cleaning. ## What it does NOT cover - Does not cover non-robotic manual vacuum cleaners or push-brooms. - Does not cover cleaning systems that rely on external navigation markers or beacons installed in a room. - Does not cover robots that use cameras or visual mapping (SLAM) to navigate, as this patent focuses on tactile and cliff sensors. - Does not cover robots that utilize liquid-based mopping systems as their primary cleaning mechanism. ## The clever bit The innovation lies in the integration of a side brush that extends beyond the chassis, combined with a control system that treats 'cliffs' as a distinct sensor event requiring a specific escape maneuver rather than just a standard obstacle. ## Real-world examples 1. Original iRobot Roomba models 2. Roomba 400 series 3. Early autonomous vacuum cleaners ## Why it matters This patent is a foundational document for the modern consumer robotics industry. It established the core behavioral logic—such as the 'bounce' mode and cliff avoidance—that allowed the original iRobot Roomba to become a household staple. It effectively defined the 'bump-and-go' navigation style that dominated the market for over a decade. ## Frequently asked questions ### What does How the iRobot Roomba Automatically Cleans Floors Without Falling Down Stairs cover? A 2002 patent describing an autonomous floor-cleaning robot that uses sensors to navigate rooms, avoid cliffs like stairs, and sweep debris into a removable bin. ### Who owns patent US 6883201? iRobot Corp owns this patent, granted in 2005. ### When does this patent expire? This patent has expired and is now in the public domain — anyone can use the invention freely. ### What is patent US 6883201 cited by? This patent has been cited by 215 later patents that build on its ideas. ### What problem does this patent solve? This patent is a foundational document for the modern consumer robotics industry. It established the core behavioral logic—such as the 'bounce' mode and cliff avoidance—that allowed the original iRobot Roomba to become a household staple. It effectively defined the 'bump-and-go' navigation style that dominated the market for over a decade. ### What does this patent NOT cover? Does not cover non-robotic manual vacuum cleaners or push-brooms. **Full plain-English explainer:** https://patentbrief.org/patent/us/6883201/roomba-autonomous-vacuum **Original patent:** https://patents.google.com/patent/US6883201 --- _Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._ ## Related patents Semantically similar inventions in the PatentBrief corpus: - [How James Spangler Invented the First Portable Electric Vacuum Cleaner](https://patentbrief.org/patent/us/889823/vacuum-cleaner-spangler) — A 1908 patent for a portable suction-based cleaning device that combined a rotating brush with a fan to lift dust into a bag. - [How Self-Driving Cars Detect Dirty Lidar Sensors](https://patentbrief.org/patent/us/12130389/methods-and-systems-for-detecting-sensor-occlusions) — Waymo's 2024 patent on a self-driving car system that uses two scans from a rotating Lidar sensor to spot dirt or obstructions on its lens. - [How a Robot System Finds and Picks Specific Items from Mixed Storage](https://patentbrief.org/patent/us/11107174/autonomous-picking-from-mixed-pallets) — Target's patent describes a robotic system that travels through a warehouse to find a specific item on a shelf with many different products, temporarily holding other items it picks up by mistake before returning them. - [Robot Design for Carrying Objects While Walking](https://patentbrief.org/patent/us/12246441/torso-protrusion-for-robotic-manipulation-of-objects-and-related-technology) — This patent describes a robot with a torso, legs, arms, and a special forward-extending protrusion designed to help it carry objects while it walks. - [How a Spinning Lidar Sensor Creates 3D Maps](https://patentbrief.org/patent/us/10613201/three-dimensional-lidar-sensor-based-on-two-dimensional-scanning-of-one-dimensio) — This patent describes a 3D Lidar sensor that uses a laser bar for one-dimensional sensing and a spinning part to scan in two dimensions, all inside a static outer case with a special window.