Autonomous Robot Radar Imaging for Precise Obstacle Detection
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Solution Overview
Problem
Autonomous moving objects, such as mobile cleaning robots and robotic lawn mowers, face challenges in accurately detecting obstacles using single radar sensors due to ambiguity in object localization and complexity associated with multi-antenna arrays, especially in real-world environments with multi-path fading.
Innovation Solution
The implementation of a radar-based system with a single radar sensor that uses synthetic aperture radar processing to create a virtual array of antennas by acquiring a sequence of radar responses at different positions, allowing for reliable obstacle detection and avoidance without the need for trilateration or multi-antenna arrays, using the motion of the robot to enhance signal resolution and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple distance sensors are used in combination with trilateration, then object localization accuracy is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple radar responses acquired at different positions along the movement path into a single synthetic aperture radar image. By merging the spatial information from sequential measurements, the system achieves accurate object localization without requiring multiple simultaneous sensors or complex trilateration algorithms.
Solution Approach 2:
The patent introduces the time dimension by acquiring radar responses at multiple positions along the movement path. This temporal-spatial dimension allows the single sensor to synthesize the information that would otherwise require multiple simultaneous sensors, resolving the ambiguity in object localization.
2Measurement precision
If beamforming techniques are used with multiple receiver antennas, then spatial resolution is improved, but device complexity and cost increase
Solution Approach 1:
The patent creates a virtual array of receiver antennas by copying the radar response at different positions along the movement path. This synthetic aperture approach replicates the spatial sampling that would require physical multiple antennas, achieving the same angular resolution without the hardware complexity.
Solution Approach 2:
The patent replaces the mechanical system of multiple physical antennas with a computational approach using a single moving sensor. The motion of the robot substitutes for the static multi-antenna array, and signal processing replaces the hardware complexity.
3Device complexity
If a single radar sensor with wide pattern is used, then device simplicity is maintained, but object localization accuracy deteriorates due to large ambiguity
Solution Approach 1:
The patent transforms the static single-sensor system into a dynamic one by moving the sensor along the movement path. The motion provides varying observation angles that resolve the angular ambiguity inherent in wide-pattern single-sensor systems, maintaining simplicity while improving accuracy.
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
This approach enables robust and accurate obstacle detection and navigation in complex environments, allowing for the separation of obstacles likely to collide from those not likely to collide, and detects obstacles above the movement path, providing improved decision-making for changing the robot's movement path.
Implementation Method 1
a radar sensor mounted on the autonomous moving object and configured to scan a volume in front of the object during a movement of the object along a movement path
Data Source
AI summary
The disclosure relates to an autonomous moving object comprising: a radar sensor configured to scan a volume in front of the object, and a radar signal processor configured to: acquire a sequence of radar responses, each radar response of the sequence being acquired at a different position of the autonomous moving object, and perform synthetic aperture radar processing of at least parts of the acquired sequence of radar responses to obtain a synthetic aperture radar image representing response amplitude as a function of at least distance and angle with respect to the radar sensor, the autonomous moving object further comprising: a controller configured to detect presence of a potential obstacle within a pre-defined sub-volume in front of the autonomous moving object by analyzing the synthetic aperture radar image and, in response to detecting presence of a potential obstacle, output a control command configured to cause a changed movement of the autonomous moving object.