Lidar Pulse Timing Compensation for Motor Dynamics
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Solution Overview
Problem
Lidar systems face challenges in maintaining consistent pulse timing due to motor dynamics and varying target distances, leading to inefficient data collection and power usage.
Innovation Solution
A method and system that adjust the pulse rate of light pulses in a lidar system based on scan speed and target orientation, allowing for faster pulse rates when scanning peripherally and slower rates when scanning directly ahead to compensate for motor dynamics and ensure optimal data collection and power management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a constant pulse rate is used regardless of scan speed, then the system is simple to control, but data resolution and pixel density become inconsistent across different scanning regions
Solution Approach 1:
The pulse rate is made dynamic by adjusting it according to the scan speed at different positions. The controller modifies the pulse rate in real-time based on the scanner's position and velocity, using higher pulse rates when scan speed decreases (at turnaround points) and lower pulse rates when scan speed is higher (in mid-scan regions), thereby maintaining consistent data resolution across the field of regard.
Solution Approach 2:
The system changes the pulse rate parameter dynamically based on scan speed variations. By monitoring the scanner's position and calculating the instantaneous scan speed, the controller adjusts the pulse rate parameter to compensate for speed variations, ensuring uniform spatial sampling density across different scanning regions.
2Productivity
If the pulse rate is increased to compensate for slower scan speed at turnaround points, then data collection efficiency improves, but power consumption increases
Solution Approach 1:
The pulse rate is adjusted locally based on the scanner's position in the field of regard. Higher pulse rates are applied only in specific regions where scan speed is slower (near turnaround points), while lower pulse rates are used in regions where scan speed is higher (mid-scan areas). This localized adjustment maintains data collection efficiency without unnecessarily increasing power consumption across the entire scanning cycle.
Solution Approach 2:
Instead of using a uniformly high pulse rate throughout the scanning cycle, the system applies partial action by increasing the pulse rate only when and where needed (at turnaround points where scan speed decreases). This avoids excessive power consumption while still ensuring adequate data collection efficiency in the critical regions.
3Productivity
If the scanner operates at high speed throughout the entire scan cycle, then productivity increases, but motor dynamics cause timing errors and reduced measurement precision
Solution Approach 1:
The system dynamically adjusts the pulse rate to match the scanner's instantaneous speed. During mid-scan regions where the scanner moves at high speed, lower pulse rates are used to maintain productivity. Near turnaround points where the scanner decelerates and changes direction, the pulse rate is increased to compensate for the reduced scan speed and maintain timing accuracy, thus resolving the contradiction between productivity and measurement precision.
4Measurement precision
If a higher pulse rate is used during deceleration phases, then pixel density remains consistent, but the system complexity increases
Solution Approach 1:
The controller uses feedback from the scanner's position information to determine the instantaneous scan speed and adjust the pulse rate accordingly. By continuously monitoring the scanner's position and calculating the derivative to obtain speed information, the system automatically adjusts the pulse rate to maintain consistent pixel density without requiring complex manual calibration or additional hardware components.
Data Source
AI summary
To compensate for motor dynamics in a scanner in a lidar system, a light source transmits light pulses at a variable pulse rate in accordance with a scan speed of the scanner. More specifically, the pulse rate may be directly related to the scan speed so that the light source transmits light pulses uniformly across a field of regard. A controller may determine the scan speed and provide a control signal to the light source adjusting the pulse rate accordingly.