Patent Publication Number: US-2021175755-A1

Title: Monitor system and power supply control method

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of China application serial no. 201911256258.7, filed on Dec. 10, 2019. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a monitor technique for a drone, and particularly relates to a monitor system and a power supply control method for a drone. 
     2. Description of Related Art 
     In various industries, monitor techniques are used to monitor equipment, buildings, or other assets. Research institutions may monitor animals or ecosystems under watch. In addition, government institutions may monitor roads, parks, or entrances/exits. To rule out human factors, automatic monitoring has been applied nowadays. Automatic monitoring equipment is installed at a specific location to monitor the surroundings. Automatic monitoring equipment may include drones and charging equipment. However, since charging equipment is commonly installed outdoor, and the charging plates thereof are usually metallic, the charging plates may be humidified or rusted due to weather factors, or foreign objects may fall onto the charging plates. All these situations may affect charging efficiency and result in unexpected power consumption and temperature rising. Besides, drones may be insufficiently charged, or are unable to be fully charged within a fixed time period, which results in extra charging time and consequently affects the frequency and efficiency for executing assignments. 
     The information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Further, the information disclosed in the Background section does not mean that one or more problems to be resolved by one or more embodiments of the invention was acknowledged by a person of ordinary skill in the art. 
     SUMMARY OF THE INVENTION 
     The invention provides a monitor system and a charging control method, which detect an abnormal condition and report the abnormal condition or compensate for a power supply loss resulting from the abnormal condition. 
     In order to achieve one or a portion of or all of the objects or other objects, an embodiment of the invention provides a monitor system including a base station, an image capture apparatus, and a processor. The base station includes a charging apparatus including a power supply connector and a power source coupled to and outputting power through the power supply connector. The image capture apparatus shoots the power supply connector to obtain a shot image. The processor determines a foreign object distribution on the power supply connector according to the shot image and sends a warning message according to the foreign object distribution. The foreign object distribution relates to foreign objects formed on the power supply connector. 
     In order to achieve one or a portion of or all of the objects or other objects, an embodiment of the invention provides a power supply method including: shooting a power supply connector of a base station to obtain a shot image, wherein the base station is configured to charge a drone; determining a foreign object distribution on the power supply connector according to the shot image; and sending a warning message according to the foreign object distribution, wherein the foreign object distribution is related to a foreign object formed on the power supply connector. 
     Based on the above, in the monitor system and the power supply control method according to the embodiments of the invention, whether power supply of the power supply connector at the base station is affected by a foreign object or other abnormal conditions is determined through image identification, and the timing of the charging mode or the magnitude of the power supply voltage is adjusted accordingly, so as to compensate for the power supply loss resulting from the abnormal condition. Accordingly, the charging efficiency is facilitated, and the chance of fully charging the drone becomes higher. 
     In order to make the aforementioned and other features and advantages of the invention comprehensible, several exemplary embodiments accompanied with figures are described in detail below. 
     Other objectives, features and advantages of the invention will be further understood from the further technological features disclosed by the embodiments of the invention wherein there are shown and described preferred embodiments of this invention, simply by way of illustration of modes best suited to carry out the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
         FIG. 1  is a schematic diagram illustrating a monitor system according to an embodiment of the invention. 
         FIG. 2  is a block diagram illustrating a drone according to an embodiment of the invention. 
         FIG. 3  is a block diagram illustrating a remote server according to an embodiment of the invention. 
         FIG. 4  is a block diagram illustrating a base station according to an embodiment of the invention. 
         FIG. 5  is a flowchart illustrating a power supply control method according to an embodiment of the invention. 
         FIG. 6  is a flowchart illustrating foreign object identification according to an embodiment of the invention. 
         FIG. 7  is a flowchart illustrating connection confirmation according to an embodiment of the invention. 
         FIG. 8  is a flowchart illustrating power supply compensation according to an embodiment of the invention. 
         FIG. 9  is a flowchart illustrating power supply compensation according to another embodiment of the invention. 
         FIG. 10  is a flowchart illustrating power supply setting adjustment according to an embodiment of the invention. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which are shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as “top,” “bottom,” “front,” “back,” etc., is used with reference to the orientation of the Figure(s) being described. The components of the invention can be positioned in a number of different orientations. As such, the directional terminology is used for purposes of illustration and is in no way limiting. Unless limited otherwise, the terms “connected,” “coupled,” and “mounted” and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings. Besides, the terminology “signal” may refer to as at least one current, voltage, charge, temperature, data, electromagnetic wave, or any other one or more signal. 
       FIG. 1  is a schematic diagram illustrating a monitor system  1  according to an embodiment of the invention. Referring to  FIG. 1 , the monitor system  1  includes, but is not limited to, a drone  10 , a monitor server  30 , and a base station  50 . 
       FIG. 2  is a block diagram illustrating the drone  10  according to an embodiment of the invention. Referring to  FIG. 2 , the drone  10  includes, but is not limited to, a battery  11 , a charging connector  13 , a communication transceiver  15 , and a processor  19 . 
     The battery  11  may be a lithium battery, a fuel battery, a nickel-cadmium battery, a nickel-hydrogen battery, or other rechargeable batteries. 
     The charging connector  13  may be various connectors such as a terminal, a socket, a port, a pin, a plug, etc. The charging connector  13  is connected with the battery  11  and is configured to be connected with an external power source (e.g., an electric power grid, a power converter, or other power supply apparatuses) to charge the battery  11 . 
     The communication transceiver  15  may be a transceiver compatible with a wireless communication technology, such as Wi-Fi, Bluetooth, fourth generation (4G) mobile communication technology, or mobile communication technologies of other generations. 
     The processor  19  is coupled to the battery  11  and the communication transceiver  15 , and may be a central processing unit (CPU), a micro-controller, a chip programmable controller, an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), other similar components, or a combination thereof. In the embodiment, the processor  19  is configured to control all the operations of the drone  10 . 
     In an embodiment, the drone  10  further includes an image capture apparatus  14 . The image capture apparatus  14  is coupled to the processor  19 . The image capture apparatus  14  may be an apparatus such as a camera, a video camera, etc., and may include a component such as an image sensor (e.g., a charge coupled device (CCD), a complementary metal-oxide-semiconductor (CMOS), etc.), an optical lens, an image control circuit, etc. In the embodiment of the invention, the image capture apparatus  14  is configured to shoot toward the external environment. For example, the image capture apparatus  14  shoots toward a location extending outward from the charging connector  13 . 
       FIG. 3  is a block diagram illustrating a remote server  30  according to an embodiment of the invention. Referring to  FIG. 3 , the remote server  30  includes, but is not limited to, a communication transceiver  35  and a processor  39 . The remote server  30  may be an electronic apparatus such as a desktop computer, a notebook computer, servers of various types, a smart phone, a tablet computer, etc. 
     Reference for details of implementing the communication transceiver  35  is directed to the description about the communication transceiver  15  and relevant details will not be repeated in the following. In some embodiment, the communication transceiver  35  may also be compatible with the Ethernet, an optic fiber network, or other types of wired communication networks. The communication transceiver  35  may directly communicate with the communication transceiver  15  or forward information of the communication transceiver  15  via another relay apparatus (e.g., the base station  50 , another base station, or a router, etc.). 
     The processor  39  is coupled to the communication transceiver  35 . Reference for details of implementing the processor  39  is directed to the description about the processor  19  and relevant details will not be repeated in the following. In the embodiment, the processor  39  is configured to control all the operations of the the remote server  30 . 
       FIG. 4  is a block diagram illustrating the base station  50  according to an embodiment of the invention. Referring to  FIG. 4 , the base station  50  includes, but is not limited to, a charging apparatus  51 , a communication transceiver  55 , and a processor  59 . 
     The charging apparatus  51  includes, but is not limited to, a power source  511 , a power supply connector  512 , and a power controller  515 . The power source  511  may be an electric power grid, a generator, a solar energy system, a battery identical to or similar with the battery  11 , or a combination of two or more of the aforementioned. The power supply connector  512  may be various connectors such as a terminal, a socket, a port, a pin, a plug, a charging board, etc., and may be connected with the charging connector  13  of the drone  10 , and is electrically connected with the power source  511 . The power controller  515  may be a processor, a chip, or a circuit, and the power controller  515  is connected with the power source  511  and the power supply connector  512 , so that the power source  511  supplies power to a connected external apparatus (e.g., the drone  10  or other electronic apparatuses) through the power supply connector  512 . 
     Reference for details of implementing the communication transceiver  55  is directed to the description about the communication transceiver  35  and relevant details will not be repeated in the following. The communication transceiver  55  may directly communicate with the communication transceiver  15  and/or the communication transceiver  35  or forward information of the communication transceiver  15 ,  35  via another relay apparatus (e.g., a base station, or a router, etc.). 
     The processor  59  is coupled to the charging apparatus  51  and the communication transceiver  55 . Reference for details of implementing the processor  59  is directed to the description about the processor  19  and relevant details will not be repeated in the following. In the embodiment, the processor  59  is configured to control all the operations of the base station  50 . 
     In an embodiment, the base station  50  further includes an image capture apparatus  54 . Reference for details of implementing the image capture apparatus  54  is directed to the description about the image capture apparatus  14  and relevant details will not be repeated in the following. In the embodiment of the invention, the image capture apparatus  54  is configured to shoot the power supply connector  512 . 
     To make the operation procedures of the embodiments of the invention more understandable, several embodiments will be described in the following to explicate the operation flow of the monitor system  1  according to the embodiments of the invention. In the following, the method according to the embodiments of the invention is described with reference to the respective apparatuses in the monitor system  1  and the components or modules therein. The respective steps in the method may be adjusted based on the actual situation, and shall not be limited to those described herein. Besides, for the ease of description, the processor  59  of the base station  50  will be described as an example in the following and serve as the main operating component. However, some operations at the processor  59  may also be executed by the processor  19  of the drone  10  or the processor  39  of the remote server  30 , and relevant signals or data may be transmitted or received through the communication transceivers  15 ,  35 , and  55 . 
       FIG. 5  is a flowchart illustrating a power supply control method according to an embodiment of the invention. Referring to  FIG. 5 , the processor  59  shoots the power supply connector  512  of the base station  50  by using the image capture apparatus  14  or  54 , so as to obtain a shot image (Step S 510 ). In an embodiment, the processor  59  may control the image capture apparatus  14 ,  54  to shoot at any time, at a predetermined time, or depending on a trigger operation (e.g., a remote control signal, the drone  10  traveling to a location at a predetermined distance, or detecting a specific humidity or wind speed level, etc.). The shot image captured by the image capture apparatus  14 ,  54  includes the power supply connector  512 . 
     In another embodiment, when the drone  10  travels to a location at a predetermined distance (e.g., 10, 5, or 3 meters) from the base station  50 , the processor  19  of the drone  10  may also shoot the power supply connector  512  of the base station  50  by using the image capture apparatus  14  or  54 . For example, the distance between the drone  10  and the base station  50  may be detected by using a component such as an infrared sensor, a distance sensor, a radio transceiver, etc. 
     The processor  59  determines a foreign object distribution on the power supply connector  512  according to the shot image (Step S 530 ). In an embodiment, the foreign object distribution relates to foreign objects formed on the power supply connector  512 . The foreign objects may be oxides or hydroxides formed through oxidization (i.e., rusting) of the surface material of the power supply connector  512 , leaves, dust, or objects other than the device body of the base station  50 . The foreign objects may affect the charging condition. For example, the charging efficiency may decrease, which makes the battery  11  unable to be charged to a certain power capacity level or results in rising of temperature, etc. In the embodiment of the invention, the foreign objects and the distribution thereof are detected by automated optical inspection (AOI) or other image identification technologies. 
       FIG. 6  is a flowchart illustrating foreign object identification according to an embodiment of the invention. Referring to  FIG. 6 , the processor  59  performs a gray-scale process on the shot image and determines a foreign object area of the foreign object according to a corresponding gray-scale value of the power supply connector  512  in the shot image having been subjected to the gray-scale process (Step S 610 ). Specifically, it is assumed that the brightness of the foreign object is different from that of the power supply connector  512 , and a gray-scale image can reflect difference in brightness. The processor  59  may record the corresponding gray-scale value of the power supply connector  512  in advance, sets a gray-scale tolerance range according to the gray-scale value, and sets an object corresponding to a gray-scale value out of the gray-scale tolerance range in the shot image as a foreign object. The processor  59  may further mark the location and the range identified as a foreign object in the gray-scale shot image. The total of the corresponding ranges of the foreign objects is considered as the foreign object area, and the proportion taken up by the foreign object area in the shot image may be set as an area proportion. 
     It should be noted that, in addition to identifying an object based on gray-scale difference, there are still various ways for identifying an object. For example, a foreign object may be identified by using a classifier based on machine learning, by image feature comparison, etc. In addition, based on practical needs, the processor  59  may also perform an image process on the shot image, such as denoising, color processing, edge detection, image enhancement, etc. The embodiments of the invention do not intend to impose a limitation on this regard. 
     Then, the processor  59  determines whether the area proportion is greater than an area threshold (Step S 630 ). The area threshold may be a fixed value (e.g., 10%, 25%, or 30%, etc.) Alternatively, the area threshold may also be dynamically adjusted based on a special weather condition (e.g., raining for multiple days, a predetermined high temperature, a predetermined humidity level, a predetermined wind speed, etc.) or a remote setting (e.g., one from the remote server  30 ). If the area proportion is greater than the area threshold, the processor  59  determines that the current foreign object distribution has affected the charging condition. If the area proportion is not greater than the area threshold, the processor  59  determines that the current foreign object distribution is still within the tolerance range. 
     The processor  59  may further send a warning message according to the foreign object distribution (Step S 550 ). In the embodiment of  FIG. 6 , the processor  59  determines the area proportion taken up by foreign objects of the foreign object distribution with respect to the entirety or a portion of the area of the power supply connector  512 . If the area proportion is greater than the area threshold, the processor  59  may send a warning message (Step S 650 ). The processor  59  may further send a warning message in the form of a text message, an e-mail, a push notification, etc., to the remote server  30  or other external apparatuses through the communication transceiver  55 , or the processor  59  may send a warning message in the form of sounds, images, or glittering colors through a speaker, a display, or an illumination apparatus. 
     In another embodiment, the foreign object distribution is related to the location where the charging connector  13  and the power supply connector  512  contact each other. The processor  59  may perform image identification on a specific location or range in the shot image. If the location or range corresponding to the location where the charging connector  13  and the power supply connector  512  contact each other contains a foreign object or the proportion taken up by the foreign object exceeds a threshold, the processor  59  may send a warning message. 
     It should be noted that, in other embodiments, the processor  19 ,  39  may receive the shot image taken by the image capture apparatus  14 ,  54  and further determine the foreign object distribution in the shot image. 
     After the drone  10  lands on the base station  50 , the base station  50  may charge the drone  10 . The embodiment of the invention is mainly related to a charging mechanism where the charging terminals (i.e., the charging connector  13  and the power supply connector  512 ) of the drone  10  and the base station  50  contact each other. 
       FIG. 7  is a flowchart illustrating connection confirmation according to an embodiment of the invention. Referring to  FIG. 7 , the processor  59  may determine whether the charging connector  13  of the drone  10  is connected with the power supply connector  512  according to the battery voltage of the battery  11  (Step S 710 ). The power controller  515  includes a detection circuit for the battery voltage. The processor  59  may determine whether the battery voltage of the battery  11  can be measured/read or whether the value thereof falls within a tolerance range (which may relate to the range between the lowest battery voltage and the highest battery voltage of the battery  11 , but may be adjustable according to other needs) through the power controller  515 , so as to verify a connection state. If the battery voltage can be measured/read or the value thereof falls within the tolerance range, the processor  59  confirms that the charging connector  13  has been connected with the power supply connector  512 . For example, the charging connector  13  are two pins extending outward from the main body of the drone  10 , and the power supply connector  512  are two charging boards disposed on a platform of the base station  50  and exposed to the external environment. When the pins and the charging boards directly contact each other, the power controller  515  may read the value of the battery voltage. Alternatively, if the battery voltage cannot be measured/read, or the value thereof does not fall within the tolerance range, the processor  59  determines that the charging connector  13  is not connected with the power supply connector  512  and performs Step S 710  repetitively at a fixed or arbitrary interval until the charging connector  13  is connected with the power supply connector  512 . 
     If the charging connector  13  is connected with the power supply connector  512 , the processor  59  determines whether to charge the power source  511  of the drone  10  through the charging apparatus  51  (Step S 730 ). In an embodiment, the processor  59  may determine whether to charge the battery  11  through the power source  511  according to a battery state of the battery  11 . The battery state may be related to the power capacity level of the battery  11 , the individual voltages of a plurality of cells in the battery  11 , or the voltage differences from one another among the cells. For example, the charging condition may be that the power capacity level of the battery  11  is lower than a charging threshold (e.g., 10%, 20%, or 80% of the power capacity), the voltage of any one or a predetermined number or more of the cells is within a voltage safety range (which may be related to a value between the lowest battery voltage level and the highest battery voltage level of the battery  11 , but may be adjusted according to other needs), or the voltage difference from any one of the battery cells or the voltage differences from one another among a predetermined number or more of the cells are within the voltage difference safety range. 
     It may be set to jointly take all the charging conditions into consideration or to only take some of the charging conditions into consideration. In the case where all the charging conditions are jointly taken into consideration, the processor  59  notifies the charging apparatus  51  to not charge the battery  11  if any of the charging conditions is not met. Specifically, when the power capacity level of the battery  11  is higher than the charging threshold, the processor  59  may consider the battery  11  as not requiring to charge and notifies the charging apparatus  51  to not charge the battery  11 . Alternatively if the voltage of a cell is not within the voltage safety range, and/or the voltage difference between cells is not within the voltage difference safety range, the processor  59  may consider the battery  11  as abnormal and notifies the charging apparatus  51  to not charge the battery  11 . In some embodiments, when the battery  11  is abnormal (e.g., the case where the voltage of a cell is not within the voltage safety range, and/or the voltage difference between cells is not within the voltage difference safety range), the processor  59  may further send a warning message to the remote server  30  or other external apparatuses through the communication transceiver  55 . Reference for details of sending the warning message is directed to the description about sending a warning message due to the foreign object distribution and relevant details will not be repeated in the following. 
     Meanwhile, if all the charging conditions are jointly taken into consideration, when the charging conditions are all met, e.g., the power capacity level of the battery  11  is lower than the charging threshold, the voltages of the cells are within the battery safety range, and the voltage difference between the cells is within the voltage difference safety range, the processor  59  notifies or controls the charging apparatus  51  to charge the battery  11  (i.e., start charging) (Step S 750 ). For example, the charging apparatus  51  turns on a charging switch. However, it is also possible to consider only some of the charging conditions to determine whether to charge the battery  11  through the power source  511 , such as only considering the power capacity level of the battery  11 , only considering the voltages of the cells, or only considering the voltage difference between the cells. However, the disclosure is not limited thereto. 
     It should be noted that, in other embodiments, the processor  19 ,  39  determines whether the connection state between the charging connector  13  and the power supply connector  512  and the charging condition is met by receiving the reading result of the power controller  515  through the communication transceiver  15 ,  35 . Besides, in some embodiments, it is also possible that the processor  59  directly starts charging when the charging connector  13  is connected with the power supply connector  512 . 
     Then, when the charging connector  13  is connected with the power supply connector  512 , the processor  59  determines an abnormal condition at the power supply connector  512  according to an electrical characteristic exhibited during charging the battery  11  by the power source  511 . In an embodiment, the abnormal condition relates to the foreign objects formed on the power supply connector  512 . The foreign objects may be oxides or hydroxides formed through oxidization (i.e., rusting) of the surface material of the power supply connector  512 , leaves, dust, or objects other than the device body of the drone  10 . In another embodiment, the abnormal condition relates to damages to the power supply connector  512 . Such damage includes, for example, corrosion, breakage, loss, etc., of the power supply connector  512 . 
     The abnormal condition may affect the charging condition. For example, the charging efficiency may decrease, which makes the battery  11  unable to be charged to a certain power capacity level or results in rising of temperature, etc. The charging condition may be represented by the electrical characteristic exhibited during charging the battery  11  by the power source  511 . In other words, in addition to determining the foreign object distribution according to image identification, in the embodiments of the invention, the abnormal condition may also be read and determined through the association between the abnormal condition and the electrical characteristic. 
       FIG. 8  is a flowchart illustrating power supply compensation according to an embodiment of the invention. Referring to  FIG. 8 , in an embodiment, the electrical characteristic includes an impedance value. According to findings through experiments and actual situation, the abnormal condition at the power supply connector  512  may result in an increase in the impedance value thereof. The power controller  515  may respectively read the battery voltage of the battery  11 , the power supply voltage of the power supply connector  512  (e.g., the voltage of any conductive substance at the power supply connector  512 ), and the power supply current of the power supply connector  512  (e.g., the current of any conductive substance at the power supply connector  512  or the output current of the power source  511 ), and the processor  59  determines the impedance value of the power supply connector  512  according to the voltage difference between the battery voltage and the power supply voltage of the power supply connector  512  and the power supply current of the power supply connector  512  (Step S 810 ). The processor  59  may determine whether to send a warning message according to a difference between the impedance value and an impedance threshold. The impedance threshold may be a predetermined value and related to the impedance value measured when the abnormal condition with foreign objects is not present at the power supply connector  512  (but may still be adjusted according to other needs). Since the occurrence of the abnormal condition may result in an increase in impedance value, the processor  59  may determine whether the impedance value is greater than the impedance threshold (i.e., the difference) (Step S 820 ). 
     If the impedance value is not greater than the impedance threshold, the processor  59  may determine the impedance value of the power supply connector  512  again at the next time when the power supply connector  512  is connected with the charging connector  13  (return to Step S 810 ). Alternatively, if the impedance value is greater than the impedance threshold, the processor  59  determines that the abnormal condition occurs and sends a warning message accordingly (Step S 830 ). Reference for details of sending the warning message is directed to the description about sending a warning message due to the foreign object distribution and relevant details will not be repeated in the following. 
     It should be noted that, in some embodiments, the processor  59  sets the condition where the impedance value is not equal to the impedance threshold as the condition where the difference thereof does not meet the normal condition. Besides, in other embodiments, the processor  19 ,  39  determines whether the abnormal condition occurs by receiving the reading result about the impedance value read by the power controller  515  or the processor  59  through the communication transceiver  15 ,  35 . 
     When the abnormal condition occurs, the base station  50  may initiate a charging compensation mechanism. In an embodiment, the power controller  515  adjusts the power supply setting of the power source  511  (e.g., the output voltage/current of the power source  511 , the switching condition of the charging mode of the power source  511 , or the choice on the charging mode, etc.) according to the electrical characteristic (e.g., the impedance value of the power supply connector). The power supply setting affects the electrical characteristic. Specifically, due to the increase in impedance value, the power supplied by the power source  511  may be additionally consumed due to the foreign object or other damages. If the current and/or voltage provided by the power source  511  is still maintained at the initial power supply setting (e.g., a default value with no change made to the power supply setting related to the default value), the output power provided to the battery  11  may be insufficient (compared with the output power without the abnormal condition). Comparatively, if the power supply setting of the power source is changed, and the output power provided by the charging apparatus  51  is increased, the power supply loss (e.g., the insufficient output voltage/current of the power source  511 , or the insufficient output power, etc.) resulting from the voltage difference between the battery voltage of the battery  11  and the power supply voltage of the power supply connector  512  may be compensated by adopting the adjusted power supply setting. 
     In an embodiment, the power supply setting includes a switching condition for two charging modes. The two charging modes include a constant current (CC) mode and a constant voltage (CV) mode, and the switching condition includes a threshold voltage. The initial power supply setting of the charging mechanism may be that the power controller  515  is maintained at the CC mode, i.e., the output current of the power source  511  is maintained at a constant value. The output current under the CC mode may be the maximum output current, an output current greater than that under the CV mode, or other values of the power source  511 , thereby charging rapidly and consequently reducing charging time. In addition, when the power supply voltage of the power supply connector  512  is greater than the threshold voltage (i.e., the switching condition), the power controller  515  may switch from the CC mode to the CV mode (i.e., the output voltage of the power source  511  is maintained at a constant value). The abnormal condition at the power supply connector  512  may result in an increase in the supply voltage thereof. In addition, compared with the case without the abnormal condition, the power supply voltage at the time when the abnormal condition occurs reaches the threshold voltage sooner, so the charging time under the CC mode is reduced. That is, the time of rapid charging is shortened. Changing the current mode/rapid charging time affects the charging efficiency. The power controller  515  may adjust the threshold voltage according to the voltage difference between the battery voltage and the power supply voltage (Step S 840 ). In an embodiment, the power controller  515  adopts the sum of the voltage difference and the threshold voltage as a new threshold voltage, so that the time maintained under the CC mode increases. For example, the voltage difference is 1V, and the threshold voltage is 24V, then the new threshold voltage is 25V. Compared with the original threshold voltage, it takes a longer time for the supply voltage to reach the new threshold voltage. Accordingly, the charging time under the CC mode is increased. In another embodiment, the power controller  515  may add a predetermined value (which may be related to the proportion of the voltage difference or be a fixed value) to the threshold voltage, so as to obtain the new threshold voltage. For example, the threshold voltage is 30V, then the new threshold voltage is 32V, 35V, or 36V. 
     It should be noted that, according to different battery properties, the effect of rapid charging may only be exhibited when the CC mode is adopted with the battery capacity level at a specific percentage (e.g., 70% or 80%) or lower. Therefore, the remaining power in the battery  11  may also be taken into consideration in deciding the new threshold voltage. 
     In another embodiment, the power supply setting includes the output voltage of the power source  511 . The power controller  515  may adjust the output voltage according to the voltage difference to change the power supply voltage (Step S 750 ). After the power supply voltage reaches the threshold voltage so the power source  511  switches to the CV mode, the power controller  515  may increase the output voltage of the power source  511  to raise the battery voltage of the battery  11  to an expected voltage level and thereby compensate for power supply loss (e.g., increasing the chance of fully charging the battery  11 ). 
     In addition to initiating the compensation mechanism according to the impedance value, in an embodiment, the electrical characteristic includes a voltage difference, and the processor  59  may determine the voltage difference between the battery voltage of the battery  11  and the power supply voltage of the power supply connector  512  and determine whether to send a warning message according to a difference between the voltage difference and a difference threshold. According to findings through experiments and actual situation, the abnormal condition at the power supply connector  512  may result in an increase in the voltage difference between the power supply voltage thereof and the battery voltage. The difference threshold may be a predetermined value and related to the power supply voltage measured when the abnormal condition with foreign objects is not present at the power supply connector  512  (but may still be adjusted according to other needs). Since the occurrence of the abnormal condition may result in an increase in voltage difference, the processor  59  may determine whether the voltage difference is greater than the difference threshold (i.e., the difference). 
     If the voltage difference is not greater than the difference threshold, the processor  59  may determine the voltage difference again at the next time when the power supply connector  512  is connected with the charging connector  13 . Alternatively, if the voltage difference is greater than the difference threshold, the processor  59  determines that the abnormal condition occurs and sends a warning message accordingly. Reference for details of sending the warning message is directed to the description about sending a warning message due to the foreign object distribution and relevant details will not be repeated in the following. 
     It should be noted that, in other embodiments, the processor  19 ,  39  determines whether the abnormal condition occurs by receiving the reading result about the voltage difference read by the power controller  515  or the processor  59  through the communication transceiver  15 ,  35 . 
     Meanwhile, the power controller  515  may also adjust the power supply setting of the power source  511  according to the voltage difference between the battery voltage and the power supply voltage of the power supply connector  512 . In other words, the charging compensation mechanism is initiated.  FIG. 9  is a flowchart illustrating power supply compensation according to another embodiment of the invention. Referring to  FIG. 9 , in an embodiment, the power controller  515  may adjust the threshold voltage according to the voltage difference (Step S 910 ). Reference for details about Step S 910  is directed to the descriptions about Step S 840  and relevant details will not be repeated in the following. Besides, in another embodiment, the power controller  515  may also adjust the output voltage according to the voltage difference (Step S 930 ). Reference for details about Step S 930  is directed to the descriptions about Step S 850  and relevant details will not be repeated in the following. 
     It should be noted that the time points for sending the warning message and adjusting the power supply setting are not limited to the order in the embodiments of  FIGS. 8 and 9 , and it is also possible that the processor  59  only performs one of sending the warning message and adjusting the power supply setting. Besides, the power supply setting is not limited to the two charging modes, and it is possible that the power controller  515  only adjusts the output voltage and/or the output current. 
     Besides, in the process of executing the charging compensation mechanism, the embodiments of the invention further provide a fool-proof mechanism.  FIG. 10  is a flowchart illustrating power supply setting adjustment according to an embodiment of the invention. Referring to  FIG. 10 , the power controller  515  may determine whether an adjustment command (e.g., changing the threshold voltage, or changing the adjustment command of the output voltage) relating to compensating for the power supply loss within a set time (e.g., 500 ms, one second, or three seconds, etc.) (Step S 1010 ). When the power controller  515  receives the adjustment command from the processor  19 ,  39 , or  59  within the set time, the power controller  515  may set the power supply setting according to the adjustment command setting (Step S 1030 ). For example, the power controller  515  performs Step S 740 , S 750 , S 810 , or S 830  to change the threshold voltage or output voltage. Alternatively, when the power controller  515  does not receive the adjustment command within the set time, the power controller  515  may adjust the power supply setting to a default value (Step S 1050 ). The default value is related to the power supply setting remaining unchanged. For example, the power controller  515  does not change the threshold voltage or the output voltage. Accordingly, a communication error which results in an erroneous operation can be avoided. 
     In view of the foregoing, the monitor system and the power supply control method according to the embodiments of the invention can automatically determine (through image identification and/or electrical characteristic) the abnormal condition at the power supply connector, send a warning message when the abnormal condition occurs, and/or further compensate for the power supply loss. In this way, it is ensured that the drone can be charged normally, which prevents flight safety issues such as power shortage from happening. 
     The foregoing description of the preferred embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form or to exemplary embodiments disclosed. Accordingly, the foregoing description should be regarded as illustrative rather than restrictive. Obviously, many modifications and variations will be apparent to practitioners skilled in this art. The embodiments are chosen and described in order to best explain the principles of the invention and its best mode practical application, thereby to enable persons skilled in the art to understand the invention for various embodiments and with various modifications as are suited to the particular use or implementation contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents in which all terms are meant in their broadest reasonable sense unless otherwise indicated. Therefore, the term “the invention”, “the present invention” or the like does not necessarily limit the claim scope to a specific embodiment, and the reference to particularly preferred exemplary embodiments of the invention does not imply a limitation on the invention, and no such limitation is to be inferred. The invention is limited only by the spirit and scope of the appended claims. Moreover, these claims may refer to use “first”, “second”, etc. following with noun or element. Such terms should be understood as a nomenclature and should not be construed as giving the limitation on the number of the elements modified by such nomenclature unless specific number has been given. The abstract of the disclosure is provided to comply with the rules requiring an abstract, which will allow a searcher to quickly ascertain the subject matter of the technical disclosure of any patent issued from this disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Any advantages and benefits described may not apply to all embodiments of the invention. It should be appreciated that variations may be made in the embodiments described by persons skilled in the art without departing from the scope of the invention as defined by the following claims. Moreover, no element and component in the disclosure is intended to be dedicated to the public regardless of whether the element or component is explicitly recited in the following claims.