Search

CN-121973605-A - Virtual sun shield control method

CN121973605ACN 121973605 ACN121973605 ACN 121973605ACN-121973605-A

Abstract

The invention provides a virtual sun shield control method, which comprises the steps of constructing a glare risk field for quantifying the visual interference intensity of sunlight on each point on a curved surface of a windshield to a driver based on a curved surface equation of the windshield and the current sun direction of the vehicle, determining a glare center point on the curved surface of the windshield according to the glare risk field and the position of the driver's eye point, generating a dynamic sun shield area by taking the glare center point as the center, determining a target light transmittance field of an electrochromic cell array on the windshield according to the glare risk field and the dynamic sun shield area, and driving the electrochromic cell array based on the target light transmittance field. The invention can effectively eliminate the interference of the core glare, simultaneously maintain the permeability of the whole visual field of the windshield to the maximum extent, and remarkably improve the visual comfort and safety of driving.

Inventors

  • YANG QINGCHUN

Assignees

  • 惠州华阳通用电子有限公司

Dates

Publication Date
20260505
Application Date
20251224

Claims (10)

  1. 1. An intelligent sunshade control method for a vehicle, comprising: constructing a glare risk field for quantifying the visual interference intensity of sunlight at each point on the curved surface of the windshield on the basis of a curved surface equation and the current solar direction of the windshield of the vehicle; determining a glare center point on the curved surface of the windshield according to the glare risk field and the position of the driver's eye point; Generating a dynamic sunshade area by taking the center point of the glare as the center, and And determining a target light transmittance field of the electrochromic cell array on the windshield according to the glare risk field and the dynamic sunshade area, and driving the electrochromic cell array based on the target light transmittance field.
  2. 2. The method according to claim 1, wherein prior to constructing the glare risk field, the method further comprises the step of establishing a system coordinate system comprising: A vehicle coordinate system with an origin located at the center of a rear axle of the vehicle for describing physical properties fixed to the vehicle body; an eye point coordinate system having an origin at an average value of positions of eyes of a driver and a coordinate axis direction parallel to the vehicle coordinate system, and The geographic coordinate system is defined based on longitude and latitude and course angle by taking the current position of the vehicle as an origin and is used for calculating the relative position of the sun; Wherein all calculations are ultimately unified under the vehicle coordinate system.
  3. 3. The method of claim 2, wherein constructing the glare risk field comprises: acquiring an equation z=f (x, y) of the curved surface of the windshield and a corresponding unit normal vector field; according to the current time, the geographic position and the course angle of the vehicle, calculating a direction unit vector of the sun under the coordinate system of the vehicle at the current moment; acquiring a sight line direction vector of a driver under the vehicle coordinate system; Calculating a dot product of the solar direction unit vector and the unit normal vector field to obtain a transmission attenuation factor, and And calculating the glare risk field based on the transmission attenuation factor, the sun direction unit vector, the sight line direction vector and the real-time measured solar irradiance.
  4. 4. A method according to claim 3, characterized in that the glare risk field G (x, y) is calculated by the following formula: Wherein U is solar irradiance, Is the unit vector of the direction of the sun, (X, y) is a curved surface unit normal vector, Gamma is a transmittance attenuation coefficient, and epsilon θ is a zero-removal constant, which is a line-of-sight direction vector.
  5. 5. A method according to claim 3 or 4, wherein determining the glare center point comprises: calculating an intersection point of a ray in the sun direction unit vector direction and the curved surface of the windshield from the eye point position of the driver; And determining the intersection point as the glare center point.
  6. 6. The method of claim 5, wherein generating the dynamic sun-shading area comprises: calculating a principal curvature of the windshield curved surface at the glare center point; Adaptively determining lengths of a major half axis and a minor half axis of an elliptical region based on the principal curvature, a glare risk value at the glare center point and a preset glare risk threshold value, wherein a major axis direction of the elliptical region is configured as a horizontal direction; determining a rotation angle of the elliptical area based on an azimuth angle of the solar direction in a horizontal plane, and And generating an elliptic equation by taking the glare central point as a center and combining the length of the long half shaft, the length of the short half shaft and the rotation angle to define the dynamic sunshade area.
  7. 7. The method of claim 6, wherein determining the target light transmittance field comprises: determining a base transmittance according to weber-fishena law according to the current solar irradiance; and calculating the target light transmittance field through a Gaussian attenuation function based on the basic light transmittance, the elliptic equation value of the dynamic sunshade area and the glare risk field, so that the light transmittance in the dynamic sunshade area is reduced, and the area edge is smoothly transited.
  8. 8. The method of claim 7, wherein driving the array of electrochromic cells based on the target transmittance field comprises: Determining a target driving voltage field according to the target light transmittance field and the voltage-light transmittance characteristics of the electrochromic material; Determining a required current density field based on the target driving voltage field and the current voltage of the electrochromic cell, and Integrating the current density field for the curved surface area covered by each electrochromic driving unit and combining the sun shading weight calculated based on the glare risk field and the dynamic sun shading area to obtain the driving current value of the unit.
  9. 9. The method of claim 8, wherein the array of electrochromic cells is divided into a rectangular grid of M rows by N columns, each cell is provided with an independent or addressable drive circuit, and the central processor sends the calculated cell drive current values to the corresponding drive circuits to perform control.
  10. 10. The method according to any one of claims 1-9, wherein the method is applied to a vehicle equipped with an electrochromic windshield, by dynamically adjusting the light transmittance of different areas of the windshield, it is achieved that the overall view of the driver is maximally preserved while suppressing sun glare in a specific direction.

Description

Virtual sun shield control method Technical Field The invention relates to the technical field of auxiliary driving, in particular to a virtual sun shield control method. Background The traditional mechanical sun shield has a plurality of inherent defects, and severely restricts driving safety and comfort experience. Firstly, the biggest disadvantage is that the function and safety contradict that the sun shield can shield glare when put down, but permanently physically shields the front or side view of the part, so that a visual blind area is easily formed under complex traffic conditions, and potential safety hazards are formed. Secondly, the intelligent operation is lacking, the driver is required to manually and frequently start and stop and rotate, the operation is complicated in the light and dark alternate road sections (such as tunnel groups and boulevards), and the driving attention is dispersed. Finally, the function of the glass is single and stiff, and only has two states of complete shielding or complete permeation, so that gradient adjustment cannot be performed according to the glare intensity, and complex glare caused by the curved surface of the windshield and changing along with time and azimuth cannot be dealt with. The Electrochromic (EC) material provides possibility for breaking through the limitations, can control the continuous change of the light transmittance through voltage, and lays a technical foundation for realizing an intelligent, accurate and automatic electronic virtual sun shield. Disclosure of Invention The invention provides a virtual sun shield control method, which aims to overcome the defects in the prior art, and can be used for effectively eliminating core glare interference, simultaneously keeping the permeability of the whole visual field of a windshield to the maximum extent and remarkably improving the visual comfort and safety of driving. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: The invention provides a virtual sun shield control method, which comprises the following steps: constructing a glare risk field for quantifying the visual interference intensity of sunlight at each point on the curved surface of the windshield on the basis of a curved surface equation and the current solar direction of the windshield of the vehicle; determining a glare center point on the curved surface of the windshield according to the glare risk field and the position of the driver's eye point; Generating a dynamic sunshade area by taking the center point of the glare as the center, and And determining a target light transmittance field of the electrochromic cell array on the windshield according to the glare risk field and the dynamic sunshade area, and driving the electrochromic cell array based on the target light transmittance field. In particular, before constructing the glare risk field, the method further comprises the step of establishing a system coordinate system comprising: A vehicle coordinate system with an origin located at the center of a rear axle of the vehicle for describing physical properties fixed to the vehicle body; an eye point coordinate system having an origin at an average value of positions of eyes of a driver and a coordinate axis direction parallel to the vehicle coordinate system, and The geographic coordinate system is defined based on longitude and latitude and course angle by taking the current position of the vehicle as an origin and is used for calculating the relative position of the sun; Wherein all calculations are ultimately unified under the vehicle coordinate system. Specifically, constructing the glare risk field includes: acquiring an equation z=f (x, y) of the curved surface of the windshield and a corresponding unit normal vector field; according to the current time, the geographic position and the course angle of the vehicle, calculating a direction unit vector of the sun under the coordinate system of the vehicle at the current moment; acquiring a sight line direction vector of a driver under the vehicle coordinate system; Calculating a dot product of the solar direction unit vector and the unit normal vector field to obtain a transmission attenuation factor, and And calculating the glare risk field based on the transmission attenuation factor, the sun direction unit vector, the sight line direction vector and the real-time measured solar irradiance. Specifically, the glare risk field G (x, y) is calculated by the following formula: Wherein U is solar irradiance, Is the unit vector of the direction of the sun,(X, y) is a curved surface unit normal vector,Gamma is a transmittance attenuation coefficient, and epsilon θ is a zero-removal constant, which is a line-of-sight direction vector. Specifically, determining the glare center point includes: calculating an intersection point of a ray in the sun direction unit vector direction and the curved surface of the windshield from the