Mobile Platform Obstacle Detection via Sensor Fusion
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Solution Overview
Problem
Existing obstacle detection methods for mobile platforms, such as ultrasound and time-of-flight sensing, face limitations like limited range, sensitivity to small objects, and interference from ambient light, making them inadequate for fast-moving objects and varied environments.
Innovation Solution
A mobile platform control system that combines time-of-flight and ultrasound sensing to accurately detect distance and speed, using phase-shift processes and stereopsis for real-time obstacle avoidance, integrating multiple sensors for redundancy and robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ultrasound-based obstacle detection is used, then the device is simple and cost-effective, but the detection range is limited (less than five meters) and sensitivity to small objects is poor
Solution Approach 1:
The patent combines ultrasound sensors with time-of-flight sensors to create a hybrid detection system. The ultrasound sensors provide short-range detection with high precision, while time-of-flight sensors extend the detection range to long distances. This merging of two different sensing technologies resolves the contradiction between device simplicity and detection range by integrating complementary sensor types that work together to cover both near and far detection needs.
2Measurement precision
If time-of-flight sensing is used, then long detection range and high resolution are achieved, but strong ambient light reduces signal-to-noise ratio and mirror-like objects cause signal variation
Solution Approach 1:
The patent introduces ultrasound sensors as an intermediary detection method to complement time-of-flight sensing. When time-of-flight sensors experience degraded performance due to ambient light interference or reflective surfaces, the ultrasound sensors serve as an alternative detection pathway. The system uses the intermediary ultrasound modality to maintain reliable obstacle detection in conditions where optical sensing becomes unreliable.
Solution Approach 2:
The system dynamically changes detection parameters by switching between or weighting different sensing modalities based on environmental conditions. When ambient light levels are high or reflective surfaces are detected, the system adjusts by relying more heavily on ultrasound detection parameters rather than time-of-flight parameters, effectively adapting to changing environmental conditions to maintain measurement precision.
3Device complexity
If single sensor type is used for obstacle detection, then device complexity is low, but reliability for fast-moving objects is insufficient due to limited detection range or sensitivity
Solution Approach 1:
The patent merges ultrasound sensors and time-of-flight sensors into an integrated obstacle detection system. This combination provides redundancy where each sensor type can compensate for the other's limitations. For fast-moving objects, the extended detection range of time-of-flight sensors provides early warning, while ultrasound sensors provide reliable short-range detection, together achieving high reliability without requiring overly complex individual sensor systems.
Solution Approach 2:
The system implements beforehand cushioning by using the extended detection range of time-of-flight sensors to detect obstacles at long distances before they become critical threats. This early detection provides a time buffer that allows the mobile platform to prepare avoidance maneuvers. The redundant sensor system cushions against detection failures, ensuring that if one sensor type misses an obstacle, the other can still provide warning.
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
Enhances obstacle detection accuracy and range, enabling effective avoidance of obstacles in diverse environments, including fast-moving objects, by leveraging the strengths of both time-of-flight and ultrasound sensing while mitigating their individual limitations.
Implementation Method 1
Time-of-flight (ToF) sensing, an alternative technique, can acquire obstacle distances based on a travel time of emitted light to and from the obstacle
Implementation Method 2
ultrasound-based obstacle detection has limited detection range
Implementation Method 3
ultrasound-based obstacle detection
Data Source
AI summary
A system for operating a mobile platform using distance and speed information and methods for making and using same. The system includes a time-of-flight sensor and an ultrasound sensor for measuring a distance between the mobile platform and an obstacle and a processor for integrating the sensed measurements and controlling the mobile platform. The distance measured by the time-of-flight sensor can be determined via a phase shift method. The time-of-flight sensor can also be used to measure a speed of the mobile platform by imaging a reference point at different times and using stereopsis to ascertain the displacement. Distances and speeds measured using the time-of-flight and ultrasound sensors can be integrated to improve measurement accuracy. The systems and methods are suitable for use in controlling any type of mobile platform, including unmanned aerial vehicles and advantageously can be applied for avoiding collisions between the mobile platform and the obstacle.