Patent Publication Number: US-2020283108-A1

Title: Arrangement for Displaying the Airflow Conditions Around the Sails and the Procedure for its Application

Description:
The present invention relates to an arrangement for displaying the airflow conditions around the sails, including a wind sensor device, a central device and a signal transmission device, and at least one of the wind sensor devices is a built-in wind sensor device mounted on the sail. The subject of the invention is also the procedure to observe the airflow conditions around the sails, with the built-in wind sensor devices fixed on the sail, to describe the flow with the measurement data, and based on the measurement data to support the crew in navigating the boat. 
     In order to achieve the optimal sailing performance (speed, angle to the wind, safe sailing, etc.) the sails of the boat should be set such a way, that the sum vector of forces arising on the sails always has the proper direction, point of application and size. This vector is determined by the 3D shape of sails by the given (apparent) wind direction and force. The shape of the sails is set by the crew using the rig and ropes of the boat, considering the sailing environment conditions. Instruments normally used on sailboats give sufficient information about the boat speed, direction and speed of the apparent wind (as the sum of real wind and leading wind) and the rudder angle. However, the spatial form of the sails and its deviation from the optimal shape can be estimated only as a rule of thumb and based on the actual sailing performance by the sailing crew. Telltales (thin yarns or tapes fixed on proper points of sail) are simple and cheap aids for trimming of sails. As long as there is an undisturbed flow along the sail, the telltales will stream horizontally aft, pointing towards the stern, without fluttering. When the airflow is disturbed due to wrong trim, the telltales at that location will start to flutter. 
     In case the reliable and frequent monitoring of telltales can be provided, a system can be set up for processing such data, supporting the sailing crew in optimal setting of sails and optimizing the sailing performance of the boat. 
     With the current techniques the following solutions are known. 
     The Dutch patent document with publication number NL 8803205 introduces the traditionally used, clearly “mechanical” windvane. 
     The British GB 2105846 B patent document introduces an optical measurement arrangement to sense the distortion of a bluff body in fluid flow. By analysing the interferometric image of the beam of optical radiation reflected by the internal body wall, the distortion can be sensed. 
     In the US patent document with publication number U.S. Pat. No. 3,654,807 from 1972, D. S. Deskey applies thermistor sensors placed on both sides of the sail. The wind flow along the sensors cool the sensors in the function of airflow speed and characteristics, so the change of the detected temperature difference indicates the change in wind angle too, and the system provides information for the crew accordingly. The crew should give manual input on the control panel about the actual sailing maneuver, this makes the system operation complicated. Other conditions that impacts the sensor temperature, like light/shadow conditions, rain etc. can cause inaccuracy. 
     The patent document of J. V. Man, from the USA, with the publication number U.S. Pat. No. 3,763,703 A, from 1973 is based on sensing the air pressure on both sides of the sail. Leading flexible tubes from aneroid barometers to specific point of the sails, the air pressure at these points can be measured, and information can be gained to adjust sail settings. The measured data does not provide information about the real airflow conditions, e.g. turbulences. More measurement points would be necessary, but this would make complicated the deployment and operation of the system. 
     In 1999, in the USA patent document with publication number U.S. Pat. No. 5,877,415 A, L. Kruse patented a solution which detects the vertical angle of the telltales, and provides feedback for the crew about it. The measurement of the angle is performed by rotation sensors at the fixing point of the telltales. This solution can not detect the fluttering of telltales, therefore it can provide only a partial support for sail adjustments. Essentially the same solution is described in the patent of J. Leboff in 2014, from the USA, under publication number US 20140260593 A1, with the same limitations. 
     The international patent number WO 2009066013 A1 submitted by D. Voisin et al in 2010 describes a solution, where the telltale is connected to the sail by a flexible tape. The tape is deformed according to the movement of the telltale, and force gauges deployed on the tape convert this deformation to electronic signals. The status of the telltale can be determined by these provided signals. This solution is not able to track the accurate status of the telltale, as the deformation of the tape is limited by the sensors fixed on the tape, so this way mainly the direction of the telltale can be determined. This solution can not accurately measure the fluttering and doubling back of the telltale. 
     The international patent number WO 2011110602 A1 WP of S. Rakoczy and T. McGuinness in 2011 describes a solution where the telltale is placed on an electronic unit fixed on the sail. 4 transceiver/receiver infrared blocks are placed at different heights in front of the telltale. Light impulses frequently transmitted by the IR block are reflected by the telltale, therefore the fluttering or steady streaming state of the telltale can be determined. The system is mentioned in the invention only as a sail entry monitoring solution. Should the solution be used for mainsail mid telltale, more IR blocks would be necessary, because in this case the telltales are moving in much wider angle range. However, this would make the size of the unit much bigger. The applicability of the solution is heavily impacted by weather conditions, e.g. direct sunlight or heavy rain. The IR blocks should be kept clean continuously, or at least should be cleaned regularly. Due to the method of operation the electronic unit has a minimal size (80×40×8 mm according to the patent text). This can negatively influence the performance and operation of the sails in case of several telltales. 
     The aim of the invention is to eliminate the problems of the previous solutions and to create such device and the related procedure, which can make the sail trimming more precise and effective by automatic monitoring of the status of telltales mounted on the sails of the boat, furthermore can provide support to making the necessary adjustments while providing continuous information. 
     The invention is based on the recognition that if the arrangement is carried out according to claim  1 , then a more advantageous invention will be created. 
     Such recognition allows us to free the crew of the boat from continuous watching of the sails, so the busy, tired or less experienced crew can achieve better sailing performance. Part of the invention is the recognition, that by applying purely electronic units under unfavourable environmental conditions (bad weather, low visibility) that can generally arise during sailing, we can achieve the above specified requirements. Furthermore, we realized that by digitizing units and devices, we can achieve much more sensitive and accurate results compared to visual observation, not to mention that we can do it faster, and thus evaluation becomes more efficient with the help of information technology, using electronic measuring instruments. 
     According to the objective set, the most general embodiment of the invention can be realised as specified in claim  1 . The most general form of the application procedure is described in the procedure main claim. Various modes of the invention embodiments are described in the sub claims. 
     The feature of the invention is that the built-in wind sensor device contains electronic units and is connected to the central device. Data connection between units can have many ways, the signal transmitter devices can be for example galvanic connection, optic cable, wireless data connection (e.g. Wi-Fi), or any possible combination of these. The communication protocol can be NMEA 0183 or NMEA 2000 used in marine industry or any other standardized or proprietary protocol. 
     The invention can be used to log the workload of sails, as well. The controller device on the sail can store the measured parameters, that can be read/acquired by the manufacturer afterwards. These data can be used for product support and development. 
     Another embodiment can be that the controller device is placed between the built-in wind sensor device and the central device, and the devices are connected by the transmitter. The controller device is then dedicated to the control, create, transmit and process the built-in wind sensor devices. Specific system components can be functionally merged or detached, for example the central device can take over the function of controllers, and for example the digital signal processing can be performed by the dedicated units integrated in the built-in wind sensor devices. In a preferred embodiment the controller devices are directly connected (e.g. via Bluetooth or Wi-Fi) to external, general-purpose smart devices that trigger the central device (for example, smartphones, tablets, desktop or portable personal computers). 
     Another embodiment can be when the built-in wind sensor device contains a moving unit, an accelerometer unit, a transmitter unit, a controller unit and a converter unit, and at least one of the accelerometer units is fixed on the moving unit. For example, taking advantage of the size of the micro-electromechanical sensing devices (MEMS), the current state of the flow can be observed by means of a device mounted on the moving unit. By processing actual 3D acceleration data the degree of fluttering of the moving unit can be determined, while the position related to the geomagnetic field unequivocally indicates the doubling back. The accelerometer measures the actual 3D acceleration values, therefore it senses the direction of Earth gravitation, so the angle of telltale can be calculated. It also senses the occurring acceleration in any directions so the fluttering degree and direction of the telltale can be calculated. For the sake of higher accuracy and reliability a reference accelerometer can be fixed on or near the controller unit, i.e. on the sail. Errors caused by tilt of the boat and the waves can be eliminated by comparison of measurements done by the two accelerometer units. In case the controller unit equipped by accelerometer unit is fixed in itself on the edge of the sail, the sensor can detect the luffing/fluttering of the sail e.g. on spinnaker or gennaker too. 
     Another embodiment includes an external wind sensor device, a rudder sensor device and a graphical user interface (GUI) connected to the central device. The external wind sensor device may include any membrane, pressure gauge or flow rate measuring device, but it may also be identical with the built-in wind sensor devices, however, not mounted on a sail but on the tip of the mast. The rudder sensor device is preferably a digital incremental rotation detector or any other shaft rotation encoding device, but can also be a linear (e.g., laser) telemeter, observing the distance of a point of a rudder to the hull. The GUI is preferably implemented by an electronic screen, through which direct graphical and text guidance can be given on how to make the settings. 
     In another embodiment the built-in wind sensor device comprises a magnetic sensor unit and a magnet, and at least one of the magnetic sensor units is located on the moving unit. 
     The feature of the application is, that the built-in wind sensor device is connected to the central device, and the built-in wind sensor device uses an electric unit. During the application of the invention, the workload of the sails, the measured data can be easily logged by recording the data series provided by the electronic devices on electronic data storage equipment. The data storage device can be integrated into the central device or another device of the arrangement or can be connected as a separate device to the arrangement. 
     Another feature of the application can be, that the electronic signals of the built-in wind sensor device are processed and evaluated before the central device, and forward such data to the central device. The acceleration or magnetic field force signals are appropriately processed by the fast Fourier-transformation (Fast Fourier Transformation—FFT), or could be processed directly. For processing the high amount of information, artificial intelligence, e.g. neural network can be applied as well. 
     The application may also be functioning by measuring the acceleration values at the points of the built-in wind sensor device moving and stationary, compared to the sail, and calculating the flow around the sail with the calculated acceleration difference. On the acceleration values, before calculating the difference, we preferably use the low pass filter, or average them for certain sampling time periods (so called windows). When measuring 3D acceleration values, the motion of the moving unit of the built-in wind sensor device can already be characterized by the acceleration values measured at the primary, i.e. the moving active point and the reference, i.e. the measurement point on the sail, from which for example by numeric integration the position can also be calculated. 
     Another form of application can be when the characteristics of the air flow far from the sail and unforced and also the angle of the rudder are measured. 
     Another form of application is when the deviation from the geomagnetic direction is measured at the moving point of the built-in wind sensor device compared to the sail, and also measure the deviation from the geomagnetic direction at the point of the built-in wind sensor device stationary compared to the sail. 
    
    
     
       The invention will now be described in more detail with reference to the embodiment examples, using figures. 
       The figures describe the followings: 
         FIG. 1  shows a typical embodiment of the arrangement, 
         FIG. 2  shows a typical embodiment of the wind sensor device, while 
         FIG. 3  shows another possibly embodiment of the wind sensor device, with magnetic sensor units added, 
         FIG. 4  shows the preferred embodiment of the magnetic sensor units, 
         FIG. 5  shows the draft of the typical, digital embodiment of processing the accelerating signals from the wind sensor devices, 
         FIG. 6  shows a possible embodiment of processing the magnetic sensor signals from the wind sensor devices, 
         FIG. 7  shows a possible embodiment of GUI, 
         FIG. 8  shows the suggestions and instructions transmitted to the crew via the GUI, and finally 
         FIG. 9  shows the example of using GUI, in a status not requiring intervention but providing general information. 
     
    
    
       FIG. 1  gives a draft overview of the arrangement. The  200   b  built-in wind sensor devices mounted on the  100   b  jib, the  200   a  built-in wind sensor devices mounted on the  100   a  mainsail leech, and the  200   c  built-in wind sensor devices mounted on the middle of the  100   a  mainsail are fixed at the usual places of  100   a  mainsail and  100   b  jib. The  200   a ,  200   b  and  200   c  built-in sensor devices are connected by flexible and strain resistant wires to  300   a  and  300   b  signal transmitters, typically to  100   a  and  100   b  cables running along the sails. The  300   a  and  300   b  signal transmitters forward the signals from  200   a ,  200   b ,  200   c ,  450  and  460  sensor devices to the  400   a  and  400   b  controller devices.  400   a  and  400   b  controller devices collect and analyse the direct data from  200   a ,  200   b  and  200   c  built-in wind sensor devices, and they establish the status of the individual  201  moving units (degree and direction of flutter, etc.). The information from  400   a  and  400   b  controller devices progresses to  600  central device with display (GUI). The  600  central device represents the control and information unit for the sailing crew, and provides system integration to other external units of the boat. The figure presents  450  external wind direction sensor and  460  rudder sensor, connected to  600  central unit. The  600  central device provides network connection to remote systems (e.g. mobile Internet connection), and connection with other smart devices (e.g. Wi-Fi connection with mobile phones). 
       FIG. 2  presents the structural set-up of  100   b  jib and  200   b  and  100   a  mainsail mid  200   c  built-in wind sensor devices. The  202   a  MEMS acceleration sensor unit is deployed at the end of the  201  moving unit, preferably a flexible tape. The MEMS unit is connected to the sail-mounted  204  controller unit through the  203  signal transmitter unit, a light and flexible cable along the tape. The  201  moving unit itself is fixed to  204  controller unit, i.e. indirectly to  100   a  and  100   b  sails. The signals coming from MEMS unit are forwarded by  205  converter unit to the  100   a ,  100   b  sail and  400   a ,  400   b  controller device, via the  300   a ,  300   b  transmitter device. The  202   b  reference MEMS accelerometer unit in the  204  controller unit provides reference data bout the movement and position of the boat (sail), to eliminate the errors caused by tilt of the boat and the waves. 
       FIG. 3  illustrates a possible set-up of  200   a  built-in wind sensor device, performing the function of the  100   a  mainsail leech telltale, in the state when the air flow makes the telltale double back. The difference between this set-up and  FIG. 2  is, that the  204  controller unit takes the function of batten as well, furthermore, at the end of  200   a  wind sensor device there is the  210   a  magnetic sensor unit, i.e. a 3D MEMS magnetic field sensor. The  210   a  magnetic field sensor unit can determine its own direction (and of the  201  moving unit at the same time) related to the  220  geomagnetic direction. A  210   b  reference magnetic field sensor unit is located on or near the  204  control unit, i.e. on the  100   a  mainsail entry, in order to eliminate local magnetic field effects and to achieve higher accuracy. The direction of the  201  moving unit can be accurately determined by the comparison of the measured values coming from the two,  210   a  and  210   b  magnetic field sensor units, including the case if the telltale doubles back because of the airflow. 
     An other possible set-up of  200   a  built-in wind sensor device mounted on  100   a  mainsail leech is shown by  FIG. 4 . In this set-up  230  magnet, i.e. permanent or electromagnet is mounted on or near  204  controller unit, i.e. on  100   a  mainsail entry. If based on the signals of  210   a  magnetic sensor unit, the distance reduction between  230  magnet and moving  210   a  magnetic field sensor is detected, the conclusion can be drawn that  201  moving unit is doubling back. 
       FIG. 5  shows how the data provided by  200   a ,  200   b  and  200   c  built-in wind sensor devices are digitally processed by  400   a  and  400   b  controller devices. The units described here, representing part of the process, could be implemented as a separate hardware unit or as a software function.  200   a ,  200   b  and  200   c  built-in wind sensor devices transfer the sampled acceleration data along x-y-z axes (3D) to  400   a  and  400   b  controller devices, in a specific timeframe, coming from measurements of both the primary  202   a  accelerometer on the  201  moving unit and the reference  202   b  accelerometer. From the measurements by the primary  202   a  accelerometer unit the primary  1000   a  data series, from the data by the reference  202   b  accelerometer unit the reference  1000   b  data series are produces. In order to determine the 3D direction of  201  moving unit, as the first step, the acceleration data measured along axes (x-y-z, x R -y R -z R ) (x a , y a  and z a  based on primary  202   a  accelerometer unit, x aR , y aR , z aR  based on  202   b  accelerometer unit) are processed by  1100  low pass filter unit. The average acceleration values are provided as the result of the filtering, corresponding with the vector of the Earth gravitation. The  1150  subtracting unit subtracts from the averages of the accelerations along the x a , y a , z a  primary axle, from the averages along the reference axle x aR , y aR , z aR , related to the appropriate axles, the 3D angle of the resultant vector provides the position of the  201  moving unit, which is calculated by the  1200  3D angle calculating unit. Periodic functions of time are provided by x a , y a , z a  signals in case of  201  moving unit, and the degree and characteristic of fluttering can be determined by the parameters of these functions. For evaluation, the spectrum of the signals (discrete frequency components) serves as the basis. For this purpose  1300  spectrum analysis on the digital data series of the acceleration signals, i.e. FFT shall be performed. The resulting X a , Y a , Z a  discrete spectrums are compared with the pre-stored sample spectrum by  1400  comparison unit, and determines the fluttering characteristics of  201  moving unit based on this comparison. The composite output of  400   a  and  400   b  controller devices is provided by  1500  evaluation unit, using the  201  moving units angle and fluttering data. The  1500  evaluation unit receives the doubling back status information from  1600  leech port in case of  200   a  built-in wind sensor devices, provided by  1250  doubling back calculating unit. 
       FIG. 6  follows the processing of the signals of the  200   a  built-in wind sensor device, as leech telltale. The units described here, representing part of the process, could be implemented as a separate hardware unit or as a software function. The signals from primary and reference  210   a  and  210  by magnetic sensor units placed in  200   a  built-in wind sensor device can be processed by the liftering and subtracting applied for processing the acceleration signals, thereby recognising the relative position of the two,  210   a  and  210   b  magnetic sensor units, i.e. the doubling back. The magnetic field forces along the primary axles (x-y-z, x R -y R -z R )x m , y m , z m  and the magnetic field forces along axle X mR , y mR , Z mR  are averaged by  1100  low pass filter unit, and  1150  subtraction unit calculates the given differences by the angles.  1250  doubling back calculating unit computes angle data, which provides doubling back information to signal input of  1600  leech of  400   a  and  400   b  controller devices. In case of the embodiment example using 230 magnet in  200   a  and  200   b  built-in wind sensor devices presented on  FIG. 4 , the simple binary signal from  210   a  magnetic sensor unit provides information about the doubling back of  201  moving unit, towards  1600  leech signal input. 
       FIG. 7 , as the GUI embodiment, presents the screen where the status of all  200   a ,  200   b  and  200   c  built-in wind sensor devices are displayed directly in symbolic form. The screen displays both the  100   b  jib and the  100   a  mainsail.  201  moving units streaming aft due to undisturbed airflow are represented by  2001  horizontal straight lines, the windward one is the continuous line, the leeward (which is on the other side of the sail from the helm) is the dashed line. Telltales that require attention are highlighted by  2002  ellipse shape frames. The fluttering  201  moving unit, as the telltale (due to turbulences) is represented by  2003  curvy line. The setting of the optimum shape of the sail is supported by the fact, that the status of the  201  moving units positioned in the stable airflow are indicated by  2004  straight, oblique symbols. 
       FIG. 8  shows the embodiment of the GUI, supporting the less experienced crew with direct instructions. Separately for the sails, small  2100   a  and  2100   b  sail icons indicate if the symbols next to them apply to  100   a  mainsail or to  100   b  jib. In normal case the icons are in green colour, in case of required intervention the colour of  2100   a  and  2100   b  sail icon first changes to yellow than red. Blinking  2200   a  dashed line at  100   b  jib indicates that depth of the sail profile should be decreased. Similarly blinking  2200   b  dashed line shows that leech twist of  100   b  jib should be increased. Blinking  2201  arrow indicates that the  100   a  mainsail should be eased, additionally  2200   c  blinking dashed line shows that  100   a  main leech twist should be closed. 
       FIG. 9  presents the embodiment within GUI, displaying a case of required intervention only for one sail.  2200   d  blinking dashed line indicates the required increase of profile depth of  100   b  jib,  2201  blinking arrow shows that the jib should be tightened. In this case the  2100   a  sail icon of the  100   a  main sail is green, and the nearby field is, as no intervention is necessary. 
     When applying the invention, it provides the crew with a constant, automatic flow monitoring of the sails according to the desired result and, in accordance with the embodiments shown, provides support to the crew, in real time. 
     The arrangement and process offers several advantages. As a general advantage, the skipper is provided with continuous and accurate feedback about the sail profile, therefore higher speed can be achieved. Better performance can be achieved at lower wind speed; usage of engine can be avoided resulting in fuel saving and more environment friendly sailing. One advantage of the invention is that it is able to evaluate the real 3D motion of the moving unit, hence the fast and complex changes of airflow can be tracked. Another advantage is, that it is able to display the flow conditions in real time, reliably and at any widely used type of sails. Further advantages of the invention are the followings. Both the sensor devices and the processors in the central and controller devices, processing the data provided by sensors are available on the market in big quantity and at favourable price. The system can be operated reliably in extreme weather conditions and does not require any special maintenance. By processing accurate data coming from the sensor devices, a much more sensitive system can be set up in comparison with the traditional visual observation. The MEMS acceleration sensor provides precise, high resolution, 3D acceleration data. Based on these, even movements of the moving unit invisible to the naked eye can be detected. Timely warning can be provided e.g. in case of accidental gybe (when sailing downwind the mainsail gets hit by a wind shift), such event is responsible for big part of the sailing accidents. 
     The system can provide early warnings about the necessary changes of sail settings, so they can be implemented with minimal loss of time, therefore higher speed can be achieved. This advantage is realized at both manual and automatic boat control. By this solution the sailboat crew can be relieved from continuous watching of telltales and reliable feedback can be provided in bad weather conditions and low visibility, as well. The system can give input to the autopilot, so in favourable conditions automatic keeping of optimal angle to apparent wind can be provided. Electric winches can be connected as well to the system, so automatic setting of sails can be realized based on data provided by the telltales. Real time monitoring of sail profile in tense conditions is very important in regattas, among different angles of apparent wind and at all types of sails applied. Data provided by the system can be integrated to other sailing support systems well. 
     The field of application of the invention is the systems for sailing and boat crew support. 
     Further to the above examples, and within the patent protection, the invention can be realized in other embodiment and manufacturing procedure.