Elevator Car Dimension Estimation from Lidar Maps with Mirrors
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Solution Overview
Problem
Existing lidar systems often provide erroneous or imprecise measurements of elevator car dimensions due to the presence of mirrors, which distort the detected environment, hindering accurate navigation and maintenance by robots.
Innovation Solution
A method involving the use of a lidar sensor to create a virtual 2-dimensional map of the elevator car, defining a starting area within the real dimensions, and extending a rectangular area orthogonally until it reaches the actual walls, while considering prior knowledge and iterative positioning to ensure accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a lidar sensor is used to detect the environment in an elevator car, then the robot can obtain information about positions and dimensions of floors, elevator doors, and elevator cars, but mirrors in the elevator car cause erroneous observations and imprecise measurements
Solution Approach 1:
The patent introduces an intermediary processing step between the lidar sensor and the robot's navigation system. A computing device processes the raw lidar data to identify and filter out erroneous observations caused by mirror reflections. The system uses the known rectangular geometry of elevator cars as a reference model to distinguish valid wall surfaces from reflected images, thereby mediating between the problematic sensor output and the required accurate navigation information.
Solution Approach 2:
The system implements feedback by continuously comparing the detected environment with the expected rectangular geometry of the elevator car. When discrepancies are detected (such as impossible geometric configurations or inconsistent distance measurements), the system adjusts its interpretation of the lidar data to conform to the known structural constraints, thereby correcting errors introduced by mirror reflections through iterative validation.
2Productivity
If conventional methods are used for elevator maintenance testing, then all functions can be tested, but technicians spend a lot of time and efforts traveling throughout the building
Solution Approach 1:
The patent enables the elevator system to perform self-diagnosis and self-testing functions. A robot equipped with sensors and actuators autonomously navigates the elevator car, tests various functions (door operations, lighting, communication systems), and collects maintenance data without requiring constant human intervention. This self-service capability significantly reduces technician travel time while maintaining comprehensive testing coverage.
Solution Approach 2:
The patent replaces the mechanical presence of human technicians with an automated robotic system. The robot uses sensors (lidar, cameras, contact sensors) and programmable actuators to perform functions that traditionally required physical human actions, such as pressing buttons, opening doors, and inspecting components. This substitution eliminates the time loss associated with technician travel while maintaining thorough maintenance testing.
3Ease of operation
If the robot needs precise information about elevator car dimensions for social navigation, then the robot can avoid disturbing passengers, but lidar systems provide erroneous observations due to mirrors
Solution Approach 1:
The system performs preliminary processing of lidar data to establish the accurate rectangular boundaries of the elevator car before the robot begins its navigation tasks. By pre-processing the environmental information and filtering out mirror-induced errors in advance, the robot receives clean, reliable dimensional data that enables proper social navigation behavior without requiring complex real-time corrections during movement.
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 method allows for precise determination of elevator car dimensions, enhancing the accuracy of robot navigation and maintenance operations by correcting for mirror distortions.
Implementation Method 1
a lidar sensor for determining information about a surrounding of the robot
Implementation Method 2
the virtual 2-dimensional map represents reflection surfaces from which laser light emitted by the lidar sensor is reflected
Data Source
AI summary
A method for determining estimated real dimensions of an elevator car by: acquiring a virtual 2-dimensional map of the car based on data provided by a lidar sensor, the map representing reflection surfaces from which laser light emitted by the sensor is reflected; defining a rectangular starting area at a position located within the real dimensions of the car; successively extending the area by one pixel in each of four extension directions orthogonal to edges of the area, and when any pixel in one of the extension directions corresponds to one of the reflection surfaces in the map, stopping extending the area in this extension direction and successively extending the area by one pixel in each of the remaining extension directions the area is extended to a maximum in all the extension directions; and determining the fully extended rectangular area as the estimated real dimensions of the car.