Pulse ranging device and method, and automatic cleaning apparatus having same
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Solution Overview
Problem
Current laser distance sensors using time of flight (TOF) ranging methods face challenges in accurately measuring short distances due to signal superposition, leading to dead zones and reduced precision in obstacle detection for autonomous cleaning devices.
Innovation Solution
A pulse ranging apparatus and method that includes an emitting unit, a receiving unit, a threshold comparator, a time delay unit, and a distance determination unit, which emits an optical pulse, receives and processes the reflected signal, delays the trigger signal to prevent superposition, and calculates distance based on the time of flight, effectively eliminating dead zones and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If TOF ranging method is used with continuous pulse emission, then long ranging scope and high long-distance precision are achieved, but signal superposition occurs at short distances causing dead zones and reduced measurement precision
Solution Approach 1:
The patent applies periodic action by controlling the laser emitter to emit optical pulses at specific intervals rather than continuously. The pulse emission is synchronized with the timing unit to ensure that each pulse is emitted only after the previous pulse's reflected signal has been fully received and processed, eliminating signal superposition and dead zones while maintaining long ranging capability
Solution Approach 2:
The patent implements preliminary action through the time delay unit and timing unit, which prepare and coordinate the pulse emission schedule in advance. The system calculates the expected flight time of optical pulses and sets the pulse emission timing accordingly, ensuring that new pulses are only emitted when the measurement cycle is complete, thus preventing signal overlap before it occurs
2Productivity
If optical pulse emission frequency is increased to improve measurement speed, then productivity is improved, but signal superposition and dead zones increase reducing measurement precision
Solution Approach 1:
The patent employs feedback through the timing unit and time delay unit, which continuously monitor the measurement cycle status and adjust pulse emission timing accordingly. The system uses the measured flight time information to feedback control the pulse emission schedule, ensuring optimal measurement speed while maintaining precision by dynamically adjusting emission intervals based on actual ranging conditions
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 solution enhances the accuracy and range of distance measurement, particularly in short-distance scenarios, by preventing signal superposition and allowing for precise obstacle detection, thereby improving the navigation and cleaning efficiency of autonomous cleaning devices.
Implementation Method 1
The optical pulse flies at a speed of light
Implementation Method 2
the laser emitter emits an optical pulse, which hits an object and is reflected back
Implementation Method 3
a receiver including a photoelectric sensor. During ranging, the laser emitter emits an optical pulse, which hits an object and is reflected back, and is received by the receiver
Data Source
AI summary
A pulse ranging apparatus, includes: an emitting unit configured to emit an optical pulse signal; a receiving unit configured to receive a reflected optical pulse signal by an obstacle, and convert it into an electrical signal; a threshold comparator, configured to compare the electrical signal with a preset threshold and to generate a pulse trigger signal according to a comparison result; a time delay unit configured to delay the pulse trigger signal by a preset time length to generate a delay trigger signal; a timing unit, configured to determine a time of flight of the optical pulse signal according to an emitting time of the optical pulse signal, a generating time of the delay trigger signal, and a delay of the preset time length; and a distance determination unit configured to determine a distance between the pulse ranging apparatus and the obstacle according to the time of flight.