Patent Publication Number: US-2019187457-A1

Title: Heliostat system

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of priority of U.S. provisional application No. 62/607,536, filed Dec. 19, 2017, the contents of which are herein incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a heliostat and, more particularly, to a heliostat for home use. 
     A heliostat is a device that includes a mirror, usually a plane mirror, which turns so as to keep reflecting sunlight toward a predetermined target, compensating for the sun&#39;s apparent motions in the sky. 
     Some individuals prefer to have sunlight directed into their house to improve living conditions. Heliostats are predominantly used for industrial purposes. Such heliostats are large, expensive, and require multi-disciplinary expertise to install and operate. Therefore, industrial heliostats are not very practical for a normal consumer who prefers sunlight directed through an average sized window. Certain heliostats that are for normal consumer purposes use consumer-grade technologies, but they are too unreliable to be useful. 
     As can be seen, there is a need for a heliostat that can be purchased at a reasonable cost and operated with reasonable ease. 
     SUMMARY OF THE INVENTION 
     In one aspect of the present invention, a heliostat system comprises: a frame; a mirror coupled to the frame; a first actuator configured to rotate the mirror about a horizontal axis relative to the frame; a second actuator configured to rotate the mirror about a vertical axis relative to the frame; an angle indicator comprising data indicating an angle of the mirror relative to the frame; a time keeper; and a computing system comprising a processor, a memory, and a wireless communications interface, wherein the processor calculates a sun position using the time keeper, determines an approximate mirror angle to reflect sunlight towards a target by utilizing the sun position, a location of the frame, and an approximate alignment of the frame relative the target, automatically adjusts the mirror to the approximate mirror angle based on the angle indicator by activating the first and second actuators, manually adjusts the mirror from the approximate mirror angle to an angle that reflects the sunlight to the target by wirelessly receiving a manual input from a remote device via the wireless communications interface if the mirror is not reflecting the sunlight to the target at the approximate mirror angle, and refines subsequent approximate mirror angles based on the manual input. 
     These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an embodiment of the present invention, shown in use; 
         FIG. 2  is a perspective view of an embodiment of the present invention; 
         FIG. 3  is a section view of the present invention, taken along line  3 - 3  in  FIG. 2 ; 
         FIG. 4  is a section view of the present invention, taken along  4 - 4  in  FIG. 2 ; and 
         FIG. 5  is detailed section view of an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following detailed description is of the best currently contemplated modes of carrying out exemplary embodiments of the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims. 
     The present invention includes a low cost and easy to setup consumer purpose heliostat. A heliostat tracks the sun to reflect sunlight into the house through an opening, for example, a window. The present invention includes a heliostat that utilizes sophisticated algorithms to eliminate the need for expensive high precision mechanical parts used in existing heliostats. The present invention is easily setup by leveraging a smartphone graphics user interface (GUI), wireless connections, computational power, built-in global positioning system (GPS), accelerometer, gyroscope, compass, and camera to calculate and program the heliostat&#39;s location and its alignment. The heliostat of the present invention operates autonomously without need for external power by a combination of mechanical, electrical, and on-board firmware inter-works such that the power requirement can be fully met by small, inconspicuous, low power solar panels. 
     Referring to  FIGS. 1 through 5 , the present invention includes a heliostat  10 . The heliostat  10  includes a frame  41 , a mirror  18  coupled to the frame  41 , a first actuator  51  configured to rotate the mirror  18  about a horizontal axis relative to the frame  41 , a second actuator  53  configured to rotate the mirror  18  about a vertical axis relative to the frame  41 , an angle indicator  22 ,  38  including data indicating an angle of the mirror  18  relative to the frame  41 , a time keeper, and a computing system  56 . The computing system  56  includes a processor, a memory, and a wireless communications interface. 
     The computing system  56  of the present invention calculates a sun position using the time keeper and determines an approximate mirror angle to reflect sunlight  16  towards a target  12 ,  14  by utilizing the sun position, a location of the frame, and an approximate alignment of the frame relative the target. The computing system  56  then automatically adjusts the mirror  18  to the approximate mirror angle based on the angle indicator  22 ,  38  by activating the first and second actuators  51 ,  53 . The computing system  56  may then manually adjusts the mirror  18  from the approximate mirror angle to an angle that reflects the sunlight  16  to the target  12 ,  14  by wirelessly receiving a manual input from a remote device  58  via the wireless communications interface if the mirror  18  is not reflecting the sunlight  16  to the target  12 ,  14  at the approximate mirror angle. Subsequent approximate mirror angles are refined based on the manual input. 
     The present invention may include a system that includes the heliostat  10  and the remote device  58 . The remote device  58  may be a smart device, such as a smart phone or tablet. Alternatively, the remote device  58  may be a desktop or laptop. The remote device  58  includes a user Interface to control the heliostat  10 , a processor, a memory, and a wireless communication interface. The remote device  58  may further include positional sensing and imaging system. The positional sensing and imaging system may include, a global positioning system (GPS), an accelerometer, a gyroscope, a compass, and a camera. Data transfer between the remote device  58  and the computing system  56  of the heliostat  10  is done over a wireless communications channel, such as BLUETOOTH ®, a wireless network, or the Internet. 
     The frame  41  of the present invention may include a chassis  40  with mounting holes  42 . The frame  41  may be mounted to the surface of the earth using the mounting holes  42 . The frame  41  is mounted to face the target  12 ,  14 . The target  12 ,  14  of the present invention may be a window  12  of a house  14 . 
     The location of the frame  41  is determined by placing the remote device  58  on the mirror  18 , in which the global positioning system records the location. The approximate alignment of the frame  41  relative to the target  12 ,  14  is determined by placing the remote device  58  on the mirror  18 , in which the accelerometer measures a 2-axis inclination of the mirror  18 . A first image is captured with the camera of a shadow of itself (remote device  58 ). The accelerometer, the gyroscope, and the compass are used to calculate horizontal directional angle of the sun with respect to the frame  41  using the first image. A second image is captured with the camera of the target  12 ,  14 , in which the accelerometer, the gyroscope, and the compass are used to calculate elevation of the target  12 ,  14 , and the horizontal directional angle of the target  12 ,  14  with respect to frame  41 . The computing system  56  wirelessly receives the location of the frame  41  and the approximate alignment of the frame  41  relative to the target  12 ,  14  from the remote device  58 . 
     In certain embodiments, the first actuator  51  includes a first gear  36 , a first gear arm  30  disposed along the vertical axis and fixedly coupled to the first gear  36 , and a first motor  43  driving the first gear  36 . The first actuator  51  may further include a first gear box  32  housing a first drive shaft  34  coupled to a first spur gear  35  and a first worm gear shaft  54  with a first worm gear  52  interlocked with the first spur gear  35  and the first gear  36 . The first motor  43  drives the first drive shaft  34  which rotates the first spur gear  35 , which rotates the first worm gear  52 , which rotates the first gear  36 , turning the mirror  18  about the vertical axis. The second actuator  53  includes a second gear  24 , a second gear arm  28  disposed along the horizontal axis and fixedly coupled to the second gear  24  and the mirror  18  by a bracket  26 . A second motor  45  drives the second gear  24 . The second actuator  53  may further include a second gear box  44  housing a second drive shaft  46  coupled to a second spur gear  37  and a second worm gear shaft  50  with a second worm gear  48  interlocked with the second spur gear  37  and the second gear  24 . The second motor  45  drives the second shaft  46  which rotates the second spur gear  37 , which rotates the second worm gear  48 , which rotates the second gear  24 , turning the mirror  18  about the horizontal axis. The computing system  56  sends a first signal  70  to the first motor  43  and a second signal  68  to the second motor  45  when the angle of the mirror is to be adjusted  18 . 
     The gearboxes  32 ,  44  are self-locking, and thereby prevent the mirror  18  from moving unless the gears  24 ,  36  are driven. The second actuator  53  interfaces between the mirror  18  and the first actuator  51 . The second actuator  53  tilts the mirror  18  upward and downward. The first actuator  51  interfaces between the second actuator  53  and the chassis  40 . The first actuator  51  spins both the second actuator  53  and the mirror  18  from side to side. The self-locking mechanism in the self-locking gearboxes  32 ,  44  uses the self-locking property of the worm gears  48 ,  52 . The worm gears  48 ,  52  and spur gears  35 ,  37  in the gearboxes  32 ,  44  reduces the speed of the motors  43 ,  45 . The motors  43 ,  45  engage the spur gears  35 ,  37 , which in turn engages the worm gears  48 ,  52 . The heliostat frame  41  refers to a vector frame defined by the Azimuth at angle 0 and Zenith at angle 0. 
     In certain embodiments, the present invention uses a solar panel  20 . The solar panel  20  may be coupled to the mirror  18 . The solar panel  20  is electrically connected to a battery and the battery powers the computing system  56  and the first and second actuators  51 ,  53 . 
     The angle indicator  22 ,  38  may include a first disc  38  disposed along the first gear  36 . The first disc  38  includes an outer edge having a plurality of markers indicating a fixed incremental angle change along the vertical axis. A first optical sensor  72  sends signals  64  to the computing system  56  to indicate a change in angle of the mirror  18  relative to the frame  41  along the vertical axis. A second disc  22  disposed along the second gear  24  and includes an outer edge having a plurality of markers indicating a fixed increment angle change along the horizontal axis. A second optical sensor  74  sends signals  60  to the computing system  56  to indicate a change in angle of the mirror  18  relative to the frame  41  along the horizontal axis. The outer edge of the first disc  38  and the second disc  22  may each further include a plurality of angle code patterns indicating an angle of the mirror  18  relative to the frame  41  along the vertical axis and the horizontal axis. The optical sensors  72 ,  74  read the plurality angle code patterns of the first disc  38  and the second disc  22 . The first optical sensor  72  sends signals  66  to the computing system  56  to indicate an angle of the mirror  18  relative to the frame  40  along the vertical axis. A second optical sensor  74  sends signals  62  to the computing system  56  to indicate an angle of the mirror  18  relative to the frame  40  along the horizontal axis. 
     The computing system  56  steps the motors  43 ,  45  in fixed incremental steps using the angle coding system described above. In this way, the computing system  56  keeps track of the angle incremented for each of the motors  43 ,  45 . The computing system  56  is also able to verify the angle correctness of each axis of the mirror  18  whenever an axis movement makes sufficiently differentiable code pattern change in the angle coding system for that axis. If angle verification fails for some reason, further movement of the angle coding system eventually produces a uniquely identifiable angle code pattern to allow the computing system  56  to establish a valid angle code. For the axis that has angle limits, the angle coding system prevents the computing system  56  from driving the actuators  51 ,  53  beyond that. 
     The user interface of the remote device  58  provides GUI to the user. Using the steps mentioned above, the computing system  56  calculates the exact location and approximate alignment of the mirror  18 , the elevation of the target  12 ,  14 , and the relative horizontal directional angle between the mirror direction, the sun direction, and the target direction. The calculated result is then sent over the wireless communications channel to program the computing system  56 . The computing system  56  derives the approximate alignment of the heliostat frame  41  from the approximate alignment of the mirror  18 . The computing system  56  calculates the sun position using the time from the time keeper. Using the sun position, the exact location and approximated alignment of the heliostat frame  41 , and the approximated alignment of the intended target  12 ,  14 , the computing system  56  calculates the approximate mirror angles. The computing system  56  then steps the motors  43 ,  45  to their respective calculated angles. 
     Since the heliostat frame alignment is approximated, the reflected sunlight  16  may not hit the intended target. The user through the user interface and over the wireless communication, can command the computing system  56  to step the motors  43 ,  45  to nudge the reflected sunlight  16  into the intended target  12 ,  14 . Once that happens, the position of the sun and the mirror  18  angles establishes the exact condition whereby the sunlight  16  reflects exactly on target. Over time, the sunlight  16  may drift away since the heliostat frame  41  alignment is approximated. Using the same process as before, the user can again nudge the reflected sunlight  16  into the intended target  12 ,  14 . There are now two exact conditions whereby the sunlight  16  reflects exactly on target  12 ,  14 . The remote device  58  may use these two conditions to refine the heliostat frame alignment approximation. The refined alignment approximation is then sent over the wireless channel to program into the computing system  56 . By iterating this process, more and more exact conditions further refine the heliostat frame  41  alignment approximation. With the exact location and with refinement of heliostat frame  41  alignment approximation refined over time with sun at different positions in the sky, the computing system  56  alone keeps calculating the angle of the sun periodically using the time keeper, keeping the sunlight  16  on intended target  12 ,  14 . 
     The user interface may allow the user to add more targets besides the first target  12 ,  14  using the above mentioned steps. The user interface may further allow targets  12 ,  14  to be scheduled and manipulated in various ways. For example, the user may direct the heliostat  10  to sweep reflected sunlight  16  from one target to another, and another. The user interface may further allow more than one heliostats  10  to be operated. 
     The heliostat  10  could be placed anywhere in the line of sight outside the window  14 , skylight, or any opening through which the person would like to have sunlight  16  reflected by the heliostat  10  into the house  12 . If it is not possible to place the heliostat  10  in the line of sight, a reflective surface may be placed in its stead, and the heliostat  10  placed in a way such that reflection from it could be bounced off the reflective surface and through window  14 . The heliostat  10  could be place at any distance from the window  14  depending on the size of the window  14 . 
     The present invention could be used with any device that needs to track the sun, such as a photo-voltaic array or some other solar products. The present invention could be used in photography, movie making, or some artistic uses that benefit from natural light. The present invention could be used for Solar cooking, baking bricks, scaled down power generation, or uses that benefit from concentration of heat. The present invention could be used for indoor planting, green house, or some other indoor farming that could benefit from natural light. 
     Any of the non-precision manufactured elements throughout the present invention could be replaced with a precision element either with precision manufacturing or manufacturing screening. Adding a communications repeater separate from the main unit can increase the distance of the communications channel, which then allows the user to be further away from the heliostat  10 . A component may be added to the smartphone to let the user take a picture with the camera of the horizon. The smartphone can then calculate the entire annual range of the sun and present it to the user through the user interface. The user can then decide from the picture if the place the user stood is a good heliostat installation spot. One or more components in smart phone like gyroscope and compass, accelerometer, and GPS, could be shuffled into the heliostat  10  to link directly with the computing system  56 . The worm gears and spur gears chain sequence can be interchanged or reconfigured. The self-locking worm gear could be place anywhere in the chain of speed reducing spur gears. The gear ratios could be re-configured. 
     It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims.