Camera-based heliostat tracking controller

Abstract

Systems and methods for a heliostat directing incident sun light to a receiver based on an estimate or predicted receiver location and an imaged sun location

1 . A system for directing incident radiation from a source to a target, the system comprising:
 a reflector for reflecting the incident radiation, the reflector having an optical axis and at least one angle of rotation;   an imager attached to the reflector;   a tracking controller coupled to the imager; and   one or more actuators connected to the reflector and in communication with a tracking controller;   wherein the tracking controller comprises a processor configured to:
 i) receive image data from the imager; 
 ii) detect a source projection onto the image sensor 
 iii) determine an estimated target location relative to the imager based on predetermined target locations and at least one actuator position; and 
 iv) generate one or more actuator commands based on the received image data and the estimated target location. 
   
     
     
         2 . The system of  claim 1 , wherein the processor is further configured to receive at least one of: a first actuator position and a second actuator position; and determine an estimated target location on the image sensor based on a set of predetermined target locations and at least one received actuator position. 
     
     
         3 . The system of  claim 1  wherein the imager comprises a camera having a single neutral density lens filter. 
     
     
         4 . A heliostat for directing incident light to a receiver, the heliostat comprising:
 a mirror for reflecting the incident light, the mirror having an optical axis substantially perpendicular to the mirror and at least one angle of rotation;   an imager mounted to the mirror; and   a tracking controller in communication with the imager; and   one or more actuators in communication with the tracking controller;   wherein the tracking controller comprises a processor configured to:
 i) locate one or more image points corresponding to the center of the sun's projection on the imager; 
 ii) estimate at least one point on the imager corresponding to the receiver based on at least one actuator position; and 
 iii) generate one or more actuator commands to at least one reflector angle actuator to dispose the optical axis of the mirror between the one or more image points corresponding to the sun based on the image data from the imager and the at least one point corresponding to the receiver based on at least one actuator position. 
   
     
     
         5 . The system of  claim 4  wherein the imager comprises a camera having a single neutral density lens filter. 
     
     
         6 . The heliostat of  claim 4  wherein the tracking controller is further configured to: receive at least one actuator motor position; and determine an estimated target location based on a set of predetermined target locations and the received at least one actuator position. 
     
     
         7 . A method of tracking the sun with a heliostat comprising an imager mounted to a mirror, the method comprising:
 determining one or more image points corresponding to the sun in a captured image;   estimating one or more image points corresponding to a receiver based on a least one actuator position;   actuating the mirror in one or more angular directions to improve the antipodal arrangement of the determined one or more image points corresponding to the sun and the estimated one or more image points corresponding to the receiver.   
     
     
         8 . The method of  claim 7  wherein the step of actuating the mirror further comprises at least one command based in part on a search based on a manhattan method. 
     
     
         9 . The method of  claim 7  further comprising:
 generating a lookup table based on captured image points of a receiver and at least one actuator position. 
 
     
     
         10 . The method of  claim 7  wherein the step of estimating one or more image points corresponding to a receiver is based on a least one actuator position and the generated lookup table based on captured image points of a receiver and the at least one actuator position.