Iterative Learning Control for LiDAR Memory and Convergence

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Solution Overview

Problem

LiDAR systems face challenges with high memory requirements and slow convergence times due to large error tables and iterative learning controller tables, particularly when reconfiguring scanning profiles, such as when a vehicle's pitch changes relative to the horizon.

Innovation Solution

Implementing iterative learning control methods that pre-learn feedforward tables and approximate error tables and iterative learning controller tables using piecewise functions, reducing memory needs and accelerating convergence by determining iterative learning functions based on reference profiles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If iterative learning control uses large error tables and iterative learning controller tables, then measurement precision and control accuracy are improved, but memory requirements increase and convergence time increases

Engineering Contradiction:
Improvecontrol accuracyVSAvoidmemory requirements
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent transforms discrete lookup tables into continuous piecewise function representations. Instead of storing numerous discrete error values and learning coefficients in large tables, the system uses mathematical functions with parameters that can be evaluated continuously, significantly reducing memory requirements while maintaining control accuracy.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a simplified mathematical model (piecewise function) that copies the essential behavior of the complex lookup tables without retaining their full data structure. This functional copy captures the error correction characteristics while using minimal memory compared to the original tables.

Inventive Principle:
Principle #26Copying

2Measurement precision

If iterative learning control uses large error tables and iterative learning controller tables, then measurement precision and control accuracy are improved, but convergence time increases

Engineering Contradiction:
Improvecontrol accuracyVSAvoidconvergence time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

By changing from discrete table lookups to continuous piecewise function evaluations, the system achieves faster convergence. The mathematical functions can be evaluated more efficiently than table lookups, and the continuous nature of the functions allows for smoother error correction and faster adaptation to changing conditions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent pre-computes and stores the piecewise function parameters during system initialization or offline calibration. This preliminary action allows the system to use pre-processed mathematical models during real-time operation, reducing the computational burden and accelerating convergence compared to computing error corrections on-the-fly from large tables.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If LiDAR system reconfigures scanning profiles (e.g., vehicle pitch changes), then adaptability is improved, but convergence time increases due to large error tables

Engineering Contradiction:
Improvereconfiguration capabilityVSAvoidconvergence time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The piecewise function representation allows for efficient reconfiguration by simply changing the function parameters or selecting different function segments rather than reloading large error tables. This enables rapid adaptation to new scanning profiles or vehicle attitudes with minimal convergence time.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system dynamically adjusts the piecewise function parameters or selected functions based on the current operating conditions (e.g., vehicle pitch angle). This dynamic adaptation allows the system to quickly respond to changing requirements without the delay of processing large static tables, achieving fast convergence during reconfiguration.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS20240219568A1Iterative learning control
Publication Date: 2024.07.04 MICROVISION INC
  • US20240219568A1 patent drawing
  • US20240219568A1 patent drawing
  • US20240219568A1 patent drawing

AI summary

A system includes a light emitter configured to emit light pulses. The system includes a controller configured to control positions of the emitted light pulses based on a selected reference profile. The controller includes an iterative learning controller configured to provide an error correction signal based on one or more iterative learning functions that correspond to the selected reference profile. The system includes a detector configured to provide one or more detection signals in response to a detection of a return pulse corresponding to at least one of the emitted light pulses.