Systems and methods of use of optical odometry sensors in a mobile robot
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Solution Overview
Problem
Mobile robots face difficulties in navigating environments with varying surfaces, such as deep carpets and sand, where traditional position determining devices struggle due to changes in surface distance and irregularities, leading to inaccurate odometry data.
Innovation Solution
A mobile robot equipped with an optical odometry sensor system featuring a telecentric lens and recessed camera configuration, capable of capturing images of a tracking surface at multiple distances, combined with gyroscope and wheel odometry data, to estimate distance and direction traveled, and a navigation application that compares data from different sensors to ensure accurate pose determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditional position determining device is used, then the device structure is simple, but the measurement precision deteriorates on surfaces with varying distances and irregularities
Solution Approach 1:
The sensor system is segmented into multiple independent components: optical odometry camera, wheel odometry sensors, and gyroscope. Each sensor captures different aspects of motion, and their data is fused to achieve high measurement precision without requiring a single complex sensor
Solution Approach 2:
Multiple sensor data sources (optical flow from camera, wheel rotation data, and gyroscope orientation data) are merged through sensor fusion algorithms to produce a unified, accurate pose estimate. This combination compensates for individual sensor limitations and maintains precision across varying surface conditions
2Area of stationary object
If the camera is positioned close to the surface, then the field of view is narrow, but the depth of field is limited
Solution Approach 1:
The system dynamically adapts to varying distances between the camera and tracking surface by using a telecentric lens design that maintains a extended depth of field. This allows the camera to capture features at multiple distances simultaneously, ensuring reliable focus regardless of surface irregularities or robot body movement
Solution Approach 2:
The telecentric lens transforms the optical geometry to achieve a extended depth of field, effectively adding a dimensional tolerance to the focusing capability. This allows the system to maintain measurement reliability across a range of distances rather than requiring precise single-point focus
3Reliability
If wheel odometers are used for odometry, then the device complexity is low, but the reliability deteriorates on surfaces where direct mechanical contact is not maintained
Solution Approach 1:
The optical odometry camera acts as an intermediary that measures surface features and optical flow to determine robot motion, replacing the need for direct mechanical contact between wheels and surface. This intermediary optical measurement method provides reliable odometry on surfaces where wheel contact is unreliable
Solution Approach 2:
The system replaces the mechanical wheel odometry measurement with an optical measurement system. Instead of relying on mechanical wheel rotation and surface contact, the camera captures optical flow patterns to infer robot motion, eliminating the need for direct mechanical contact while maintaining measurement reliability
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 system provides reliable odometry data across diverse surfaces by maintaining focus over a wide range of distances and integrating multiple sensor inputs, enhancing navigation accuracy and autonomy in complex environments.
Implementation Method 1
an optical odometry camera including a telecentric lens configured to capture images of a tracking surface beneath the body and having a depth of field that provides a range of viewing distances at which a tracking surface is captured in focus
Implementation Method 2
having a depth of field that provides a range of viewing distances at which a tracking surface is captured in focus from a first distance within the recessed structure to a second distance below the underside of the mobile robot body
Implementation Method 3
an optical odometry sensor system positioned within a recessed structure on an underside of the body and configured to output optical odometry data
Implementation Method 4
The mobile robot can comprise a gyroscope configured to output gyroscope measurement data
Data Source
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AI summary
Systems and methods for use of optical odometry sensor systems in a mobile robot. The optical odometry sensor system is positioned within a recessed structure on an underside of the mobile robot body and configured to output optical odometry data. The optical odometry sensor system includes an optical odometry camera that includes a telecentric lens configured to capture images of a tracking surface beneath the body and having a depth of field that provides a range of viewing distances at which a tracking surface is captured in focus from a first distance within the recessed structure to a second distance below the underside of the mobile robot body.