Patent Publication Number: US-2023139512-A1

Title: Device and method of protecting item based on serving order

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of International Application No. PCT/KR2022/012581 designating the United States, filed on Aug. 23, 2022, in the Korean Intellectual Property Receiving Office and claiming priority to Korean Patent Application No. 10-2021-0148733, filed on Nov. 2, 2021, and Korean Patent Application No. 10-2021-0150690, filed on Nov. 4, 2021, in the Korean Intellectual Property Office, the disclosures of which are incorporated by reference herein in their entireties. 
    
    
     BACKGROUND 
     1. Field 
     Certain example embodiments relate to a method of protecting an item based at least on a serving order. 
     2. Description of Related Art 
     Recently, driven by the advancement of electronics technology, various types of electronic devices have been developed and distributed. In stores, cafes, restaurants, and the like, electronic devices, such as kiosks and robots, that replace humans have been actively used. The electronic devices may perform operations, such as processing an order requested by a customer and delivering the order to a customer. 
     However, there has also been a constant demand for a method of efficiently delivering ordered food to satisfy many customers and providing a consistent service to many customers such that an electronic device, such as a robot, may perform labor rather perfectly, thus replacing humans. A needed method may efficiently deliver ordered food and a service item by a few robots while satisfying many customers. 
     SUMMARY 
     Example embodiments of the disclosure may provide an electronic device that allows an employee to put cooked food on a robot without considering a serving order and a table a table location. 
     The electronic device may provide a service that allows a customer of a table to take ordered food only without taking food of another table. 
     The electronic device may provide a solution for exactly delivering food to a certain table while serving food items to a plurality of tables simultaneously and for preventing or reducing the likelihood of food of another table from being taken. 
     According to various example embodiments, an electronic device may include a plurality of serving trays each configured to accommodate an item; a driver configured to move the electronic device; a memory configured to store computer-executable instructions; and a processor (including processing circuitry) configured to execute the computer-executable instructions by accessing the memory, in which the computer-executable instructions are configured to, based on items on the plurality of serving trays and pieces of order information of a plurality of destinations, determine a serving order in which the items on the plurality of serving trays need to be delivered, and while an item is delivered to one destination among the plurality of destinations, provide protection for a serving tray to which a serving order subsequent to a serving order of the one destination is mapped. 
     According to various example embodiments, a method implemented by a processor may include, based at least on items on a plurality of serving trays and pieces of order information of a plurality of destinations, determining a serving order in which the items on the plurality of serving trays need to be delivered, and while an item is delivered to one destination among the plurality of destinations, providing protection for a serving tray to which a serving order subsequent to a serving order of the one destination is mapped. 
     The electronic device may perform serving by automatically identifying a serving order for each tray although an employee puts cooked food on a robot without considering a serving order and a table position. 
     The electronic device may exactly deliver food to a certain table while serving food items to a plurality of tables simultaneously and may prevent or reduce the likelihood of wrong delivery by preventing or reducing the likelihood of access to food of another table. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features, and advantages of certain embodiments of the present disclosure will be more apparent from the following detailed description, taken in conjunction with the accompanying drawings, in which: 
         FIG.  1    is a block diagram illustrating an electronic device in a network environment according to various example embodiments; 
         FIG.  2    is a diagram illustrating an electronic device implemented as a serving robot according to various example embodiments; 
         FIGS.  3  and  4    are flowcharts each illustrating a method of protecting an item, according to various example embodiments; 
         FIG.  5    is a diagram illustrating item matching according to various example embodiments; 
         FIG.  6    is a diagram illustrating determining a serving order according to various example embodiments; 
         FIG.  7    is a diagram illustrating protecting a serving tray based on a serving order, according to various example embodiments; 
         FIGS.  8  and  9    are diagrams each illustrating sequential delivery of items protected based on a serving order according to various example embodiments; 
         FIG.  10    is a diagram illustrating detecting invasion of an unauthorized object, according to various example embodiments; 
         FIGS.  11 - 17    are diagrams illustrating a protection module according to various example embodiments; 
         FIG.  18    is a diagram illustrating protection based on a direction of an electronic device according to various example embodiments; and 
         FIG.  19    is a flowchart illustrating a processing method of a serving error according to various example embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, various example embodiments will be described in greater detail with reference to the accompanying drawings. When describing the example embodiments with reference to the accompanying drawings, like reference numerals refer to like elements and a repeated description related thereto will be omitted. 
       FIG.  1    is a block diagram illustrating an electronic device  101  in a network environment  100  according to various example embodiments. Referring to  FIG.  1   , the electronic device  101  in the network environment  100  may communicate with an electronic device  102  via a first network  198  (e.g., a short-range wireless communication network), or communicate with at least one of an electronic device  104  or a server  108  via a second network  199  (e.g., a long-range wireless communication network). According to an example embodiment, the electronic device  101  may communicate with the electronic device  104  via the server  108 . According to an example embodiment, the electronic device  101  may include a processor  120  including processing circuitry, a memory  130 , an input module  150 , a sound output module  155 , a display module  160 , an audio module  170 , and a sensor module  176 , an interface  177 , a connecting terminal  178 , a haptic module  179 , a camera module  180 , a motor  187 , a power management module  188 , a battery  189 , a communication module  190 , a subscriber identification module (SIM)  196 , or an antenna module  197 . In some example embodiments, at least one (e.g., the connecting terminal  178 ) of the above components may be omitted from the electronic device  101 , or one or more other components may be added in the electronic device  101 . In some example embodiments, some (e.g., the sensor module  176 , the camera module  180 , or the antenna module  197 ) of the components may be integrated as a single component (e.g., the display module  160 ). 
     The processor  120  may execute, for example, software (e.g., a program  140 ) to control at least one other component (e.g., a hardware or software component) of the electronic device  101  connected to the processor  120 , and may perform various data processing or computation. According to an example embodiment, as at least a part of data processing or computation, the processor  120  may store a command or data received from another components (e.g., the sensor module  176  or the communication module  190 ) in a volatile memory  132 , process the command or the data stored in the volatile memory  132 , and store resulting data in a non-volatile memory  134 . According to an example embodiment, the processor  120  may include a main processor  121  (e.g., a central processing unit (CPU) or an application processor (AP)) or an auxiliary processor  123  (e.g., a graphics processing unit (GPU), a neural processing unit (NPU), an image signal processor (ISP), a sensor hub processor, or a communication processor (CP)) that is operable independently of, or in conjunction with the main processor  121 . For example, when the electronic device  101  includes the main processor  121  and the auxiliary processor  123 , the auxiliary processor  123  may be adapted to consume less power than the main processor  121  or to be specific to a specified function. The auxiliary processor  123  may be implemented separately from the main processor  121  or as a part of the main processor  121 . Each processor herein includes processing circuitry. 
     The auxiliary processor  123  may control at least some of functions or states related to at least one (e.g., the display module  160 , the sensor module  176 , or the communication module  190 ) of the components of the electronic device  101 , instead of the main processor  121  while the main processor  121  is in an inactive (e.g., sleep) state or along with the main processor  121  while the main processor  121  is an active state (e.g., executing an application). According to an example embodiment, the auxiliary processor  123  (e.g., an ISP or a CP) may be implemented as a portion of another component (e.g., the camera module  180  or the communication module  190 ) that is functionally related to the auxiliary processor  123 . According to an example embodiment, the auxiliary processor  123  (e.g., an NPU) may include a hardware structure specified for artificial intelligence model processing. An artificial intelligence model may be generated by machine learning. Such learning may be performed by, for example, the electronic device  101  in which artificial intelligence is performed, or performed via a separate server (e.g., the server  108 ). Learning algorithms may include, but are not limited to, for example, supervised learning, unsupervised learning, semi-supervised learning, or reinforcement learning. The artificial intelligence model may include a plurality of artificial neural network layers. An artificial neural network may include, for example, a deep neural network (DNN), a convolutional neural network (CNN), a recurrent neural network (RNN), a restricted Boltzmann machine (RBM), a deep belief network (DBN), and a bidirectional recurrent deep neural network (BRDNN), a deep Q-network, or a combination of two or more thereof, but is not limited thereto. The artificial intelligence model may additionally or alternatively, include a software structure other than the hardware structure. 
     The memory  130  may store various data used by at least one component (e.g., the processor  120  or the sensor module  176 ) of the electronic device  101 . The various data may include, for example, software (e.g., the program  140 ) and input data or output data for a command related thereto. The memory  130  may include the volatile memory  132  or the non-volatile memory  134 . 
     The program  140  may be stored as software in the memory  130 , and may include, for example, an operating system (OS)  142 , middleware  144 , or an application  146 . 
     The input module  150 , which may include input circuitry, may receive a command or data to be used by another component (e.g., the processor  120  including processing circuitry) of the electronic device  101 , from the outside (e.g., a user) of the electronic device  101 . The input module  150  may include, for example, a microphone, a mouse, a keyboard, a key (e.g., a button), or a digital pen (e.g., a stylus pen). 
     The sound output module  155  may output a sound signal to the outside of the electronic device  101 . The sound output module  155  may include, for example, a speaker or a receiver. The speaker may be used for general purposes, such as playing multimedia or playing record. The receiver may be used to receive an incoming call. According to an example embodiment, the receiver may be implemented separately from the speaker or as a part of the speaker. 
     The display module  160  may visually provide information to the outside (e.g., a user) of the electronic device  101  (e.g., a user). The display module  160  may include, for example, a control circuit for controlling a display, a hologram device, or a projector and control circuitry to control a corresponding one of the display, the hologram device, and the projector. According to an example embodiment, the display module  160  may include a touch sensor adapted to sense a touch, or a pressure sensor adapted to measure an intensity of a force incurred by the touch. 
     The audio module  170  may convert a sound into an electric signal or vice versa. According to an example embodiment, the audio module  170  may obtain the sound via the input module  150  or output the sound via the sound output module  155  or an external electronic device (e.g., an electronic device  102  such as a speaker or a headphone) directly or wirelessly connected to the electronic device  101 . 
     The sensor module  176  may detect an operational state (e.g., power or temperature) of the electronic device  101  or an environmental state (e.g., a state of a user) external to the electronic device  101 , and generate an electric signal or data value corresponding to the detected state. According to an example embodiment, the sensor module  176  may include, for example, a gesture sensor, a gyro sensor, an atmospheric pressure sensor, a magnetic sensor, an acceleration sensor, a grip sensor, a proximity sensor, a color sensor, an infrared (IR) sensor, a biometric sensor, a temperature sensor, a humidity sensor, or an illuminance sensor. 
     The interface  177  may support one or more specified protocols to be used for the electronic device  101  to be coupled with the external electronic device (e.g., the electronic device  102 ) directly (e.g., wiredly) or wirelessly. According to an example embodiment, the interface  177  may include, for example, a high-definition multimedia interface (HDMI), a universal serial bus (USB) interface, a secure digital (SD) card interface, or an audio interface. 
     The connecting terminal  178  may include a connector via which the electronic device  101  may be physically connected to an external electronic device (e.g., the electronic device  102 ). According to an example embodiment, the connecting terminal  178  may include, for example, an HDMI connector, a USB connector, an SD card connector, or an audio connector (e.g., a headphone connector). 
     The haptic module  179  may convert an electric signal into a mechanical stimulus (e.g., a vibration or a movement) or an electrical stimulus which may be recognized by a user via his or her tactile sensation or kinesthetic sensation. According to an example embodiment, the haptic module  179  may include, for example, a motor, a piezoelectric element, or an electric stimulator. 
     The camera module  180  may capture a still image and moving images. According to an example embodiment, the camera module  180  may include one or more lenses, image sensors, image signal processors, or flashes. 
     A driving module may drive the electronic device  101 . The driving module may include the motor  187  and a wheel connected to the motor  187 . In  FIG.  2    to be described below, illustrated is an example of a pair of wheels spaced and disposed along an axis (e.g., a lateral axis) perpendicular to a driving direction (e.g., a longitudinal axis) at a bottom center of the electronic device  101 , but examples are not limited thereto. The disposition and number of wheels of the motor  187  of the driving module may vary depending on a design. 
     The power management module  188  may manage power supplied to the electronic device  101 . According to an example embodiment, the power management module  188  may be implemented as, for example, at least a part of a power management integrated circuit (PMIC). 
     The battery  189  may supply power to at least one component of the electronic device  101 . According to an example embodiment, the battery  189  may include, for example, a primary cell which is not rechargeable, a secondary cell which is rechargeable, or a fuel cell. 
     The communication module  190  may support establishing a direct (e.g., wired) communication channel or a wireless communication channel between the electronic device  101  and the external electronic device (e.g., the electronic device  102 , the electronic device  104 , or the server  108 ) and performing communication via the established communication channel. The communication module  190  may include one or more communication processors that are operable independently of the processor  120  (e.g., an AP) and that support a direct (e.g., wired) communication or a wireless communication. According to an example embodiment, the communication module  190  may include a wireless communication module  192  (e.g., a cellular communication module, a short-range wireless communication module, or a global navigation satellite system (GNSS) communication module) or a wired communication module  194  (e.g., a local area network (LAN) communication module, or a power line communication (PLC) module). A corresponding one of these communication modules may communicate with the external electronic device  104  via the first network  198  (e.g., a short-range communication network, such as Bluetooth™, wireless-fidelity (Wi-Fi) direct, or infrared data association (IrDA)) or the second network  199  (e.g., a long-range communication network, such as a legacy cellular network, a 5G network, a next-generation communication network, the Internet, or a computer network (e.g., a LAN or a wide area network (WAN)). These various types of communication modules may be implemented as a single component (e.g., a single chip), or may be implemented as multi components (e.g., multi chips) separate from each other. The wireless communication module  192  may identify and authenticate the electronic device  101  in a communication network, such as the first network  198  or the second network  199 , using subscriber information (e.g., international mobile subscriber identity (IMSI)) stored in the SIM  196 . 
     The wireless communication module  192  may support a 5G network after a 4G network, and a next-generation communication technology, e.g., a new radio (NR) access technology. The NR access technology may support enhanced mobile broadband (eMBB), massive machine type communications (mMTC), or ultra-reliable and low-latency communications (URLLC). The wireless communication module  192  may support a high-frequency band (e.g., a mmWave band) to achieve, e.g., a high data transmission rate. The wireless communication module  192  may support various technologies for securing performance on a high-frequency band, such as, e.g., beamforming, massive multiple-input and multiple-output (MIMO), full dimensional MIMO (FD-MIMO), an array antenna, analog beam-forming, or a large scale antenna. The wireless communication module  192  may support various requirements specified in the electronic device  101 , an external electronic device (e.g., the electronic device  104 ), or a network system (e.g., the second network  199 ). According to an example embodiment, the wireless communication module  192  may support a peak data rate (e.g., 20 Gbps or more) for implementing eMBB, loss coverage (e.g., 164 dB or less) for implementing mMTC, or U-plane latency (e.g., 0.5 ms or less for each of downlink (DL) and uplink (UL), or a round trip of 1 ms or less) for implementing URLLC. 
     The antenna module  197  may transmit or receive a signal or power to or from the outside (e.g., the external electronic device) of the electronic device  101 . According to an example embodiment, the antenna module  197  may include a slit antenna, and/or an antenna including a radiating element including a conductive material or a conductive pattern formed in or on a substrate (e.g., a printed circuit board (PCB)). According to an example embodiment, the antenna module  197  may include a plurality of antennas (e.g., array antennas). In such a case, at least one antenna appropriate for a communication scheme used in a communication network, such as the first network  198  or the second network  199 , may be selected by, for example, the communication module  190  from the plurality of antennas. The signal or the power may be transmitted or received between the communication module  190  and the external electronic device via the at least one selected antenna. According to an example embodiment, another component (e.g., a radio frequency integrated circuit (RFIC)) other than the radiating element may be additionally formed as a part of the antenna module  197 . 
     According to various example embodiments, the antenna module  197  may form a mmWave antenna module. According to an example embodiment, the mmWave antenna module may include a PCB, an RFIC disposed on a first surface (e.g., a bottom surface) of the PCB or adjacent or proximate to the first surface and capable of supporting a designated a high-frequency band (e.g., the mmWave band), and a plurality of antennas (e.g., array antennas) disposed on a second surface (e.g., a top or a side surface) of the PCB, or adjacent or proximate to the second surface and capable of transmitting or receiving signals in the designated high-frequency band. 
     At least some of the above-described components may be coupled mutually and communicate signals (e.g., commands or data) therebetween via an inter-peripheral communication scheme (e.g., a bus, general purpose input and output (GPIO), serial peripheral interface (SPI), or mobile industry processor interface (MIPI)). 
     According to an example embodiment, commands or data may be transmitted or received between the electronic device  101  and the external electronic device  104  via the server  108  coupled with the second network  199 . Each of the external electronic devices  102  and  104  may be a device of the same type as or a different type from the electronic device  101 . According to an example embodiment, all or some of operations to be executed by the electronic device  101  may be executed at one or more of the external electronic devices  102 ,  104 , and  108 . For example, if the electronic device  101  needs to perform a function or a service automatically, or in response to a request from a user or another device, the electronic device  101 , instead of, or in addition to, executing the function or the service, may request one or more external electronic devices to perform at least part of the function or the service. The one or more external electronic devices receiving the request may perform the at least part of the function or the service requested, or an additional function or an additional service related to the request, and may transfer an outcome of the performing to the electronic device  101 . The electronic device  101  may provide the outcome, with or without further processing of the outcome, as at least part of a reply to the request. To that end, a cloud computing, distributed computing, mobile edge computing (MEC), or client-server computing technology may be used, for example. The electronic device  101  may provide ultra low-latency services using, e.g., distributed computing or mobile edge computing. In an example embodiment, the external electronic device  104  may include an Internet-of-things (IoT) device. The server  108  may be an intelligent server using machine learning and/or a neural network. According to an example embodiment, the external electronic device  104  or the server  108  may be included in the second network  199 . The electronic device  101  may be applied to intelligent services (e.g., smart home, smart city, smart car, or healthcare) based on 5G communication technology or IoT-related technology. 
     The electronic device according to various example embodiments may be one of various types of electronic devices. The electronic device may include, for example, a portable communication device (e.g., a smartphone), a computer device, a portable multimedia device, a portable medical device, a camera, a wearable device, or a home appliance device. According to an example embodiment of the disclosure, the electronic device is not limited to those described above. 
     It should be appreciated that various example embodiments of the present disclosure and the terms used therein are not intended to limit the technological features set forth herein to particular example embodiments and include various changes, equivalents, or replacements for a corresponding example embodiment. In connection with the description of the drawings, like reference numerals may be used for similar or related components. It is to be understood that a singular form of a noun corresponding to an item may include one or more of the things, unless the relevant context clearly indicates otherwise. As used herein, “A or B”, “at least one of A and B”, “at least one of A or B”, “A, B or C”, “at least one of A, B and C”, and “A, B, or C,” each of which may include any one of the items listed together in the corresponding one of the phrases, or all possible combinations thereof. Terms such as “first”, “second”, or “first” or “second” may simply be used to distinguish the component from other components in question, and do not limit the components in other aspects (e.g., importance or order). It is to be understood that if an element (e.g., a first element) is referred to, with or without the term “operatively” or “communicatively”, as “coupled with,” “coupled to,” “connected with,” or “connected to” another element (e.g., a second element), it means that the element may be coupled with the other element directly (e.g., wiredly), wirelessly, or via at least a third element. 
     As used in connection with various example embodiments of the disclosure, the term “module” may include a unit implemented in hardware, software, or firmware, and may interchangeably be used with other terms, for example, “logic,” “logic block,” “part,” or “circuitry”. A module may be a single integral component, or a minimum unit or part thereof, adapted to perform one or more functions. For example, according to an example embodiment, the module may be implemented in a form of an application-specific integrated circuit (ASIC). 
     Various example embodiments as set forth herein may be implemented as software (e.g., the program  140 ) including one or more instructions that are stored in a storage medium (e.g., an internal memory  136  or an external memory  138 ) that is readable by a machine (e.g., the electronic device  101 ) For example, a processor (e.g., the processor  120 ) of the machine (e.g., the electronic device  101 ) may invoke at least one of the one or more instructions stored in the storage medium, and execute it. This allows the machine to be operated to perform at least one function according to the at least one instruction invoked. The one or more instructions may include a code generated by a complier or a code executable by an interpreter. The machine-readable storage medium may be provided in the form of a non-transitory storage medium. Here, the term “non-transitory” simply means that the storage medium is a tangible device, and does not include a signal (e.g., an electromagnetic wave), but this term does not differentiate between where data is semi-permanently stored in the storage medium and where the data is temporarily stored in the storage medium. 
     According to an example embodiment, a method according to various example embodiments of the disclosure may be included and provided in a computer program product. The computer program product may be traded as a product between a seller and a buyer. The computer program product may be distributed in the form of a machine-readable storage medium (e.g., compact disc read only memory (CD-ROM)), or be distributed (e.g., downloaded or uploaded) online via an application store (e.g., PlayStore™), or between two user devices (e.g., smart phones) directly. If distributed online, at least part of the computer program product may be temporarily generated or at least temporarily stored in the machine-readable storage medium, such as memory of the manufacturer&#39;s server, a server of the application store, or a relay server. 
     According to various example embodiments, each component (e.g., a module or a program) of the above-described components may include a single entity or multiple entities, and some of the multiple entities may be separately disposed in different components. According to various example embodiments, one or more of the above-described components may be omitted, or one or more other components may be added. Alternatively or additionally, a plurality of components (e.g., modules or programs) may be integrated into a single component. In such a case, according to various example embodiments, the integrated component may still perform one or more functions of each of the plurality of components in the same or similar manner as they are performed by a corresponding one of the plurality of components before the integration. According to various example embodiments, operations performed by the module, the program, or another component may be carried out sequentially, in parallel, repeatedly, or heuristically, or one or more of the operations may be executed in a different order or omitted, or one or more other operations may be added. 
       FIG.  2    is a diagram illustrating an electronic device implemented as a serving robot according to various example embodiments. 
     An electronic device  210  (e.g., the electronic device  101  of  FIG.  1   ) may be implemented as a serving robot, as illustrated in  FIG.  2   . For example, the electronic device  101  may be a public mobile robot, which is a serving robot configured to autonomously drive and visit a plurality of destinations (e.g., a table). The electronic device  101  may establish communication with an order server  220  (e.g., the server  108  of  FIG.  1   ) and receive, from the order server  220 , information related to orders of customers of the plurality of destinations. 
     The order server  220  may manage order information of each destination. For example, the order server  220  may correct order information (e.g., point-of-sale (POS) data) on a customer of each destination from the electronic device  210  and/or an external device (e.g., a mobile terminal of the customer, a tablet terminal of an employee, and a kiosk terminal). The order information may include seated information, order receiving information, ordered menu information, and serving information. Seated information of each destination may include identification information (e.g., a table number) of the destination, whether a customer sits in the destination, and the number of seated customers. Order receiving information of each destination may include whether a customer seated in the destination places an order and the time of the order. Ordered menu information of each destination may include a type of item ordered by a seated customer at the destination and the number of ordered items. Serving information of each destination may include whether each item ordered from each destination has been served. In addition, the order information may include a side item (e.g., a side menu item) accompanying an ordered main item (e.g., a main dish), a special order (e.g., whether additional tableware is needed), additional food, whether a customer is a customer with a reservation, the number of visits of the customer, and whether the customer is a very-important-person (VIP) customer. 
     The electronic device  210  may include a display module  211  (e.g., the display module  160  of  FIG.  1   ), a camera module  212  (e.g., the camera module  180  of  FIG.  1   ), a lighting module  213 , a serving tray  214 , a sensor module  215  (e.g., the sensor module  176  of  FIG.  1   ), a sound output module  216  (e.g., the sound output module  155  of  FIG.  1   ), a communication module  218  (e.g., the communication module  190  of  FIG.  1   ), and a driver  219  (e.g., the motor  187  of  FIG.  1   ). In addition, the electronic device  210  may include a protection module  250  and tray light  260 . Although in  FIG.  2   , the sensor module  215 , the sound output module  216 , the communication module  218 , and the driver  219  are illustrated as being included in a base driving platform  217 , examples are not limited thereto. The base driving platform  217  may further include a battery (e.g., the battery  189  of  FIG.  1   ) and a power management module (e.g., the power management module  188  of  FIG.  1   ). 
     The display module  211  may visually output information related to item delivery to at least one of a user and a customer. For example, the display module  211  may output visual information (e.g., text and an image) that guides to an item to be delivered to a destination where the electronic device  210  reaches. The display module  211  may output visual information that guides to an item to be protected at the destination. 
     In addition, the electronic device  210  may further include an input module (e.g., the input module  150  of  FIG.  1   ) integrated with the display module  211 . The electronic device  210 , through the input module, may receive at least one of a touch input and a voice input from at least one of a user and a customer. 
     The camera module  212  may be disposed to face each serving tray. For example, in  FIG.  2   , the camera module  212  may face a serving tray from the ceiling facing the serving tray. In other words, the camera module  212  may have a viewing angle for capturing the serving tray. The camera module  212  may capture an image including an item (e.g., food) on the serving tray. A processor (e.g., the processor  120  of  FIG.  1   ) of the electronic device  210 , based on an image captured by the camera module  212 , may recognize a type (e.g., a food type) of item on each serving tray and the number of items (e.g., the number of food items). An example of an item herein is mainly described as food, but examples are not limited thereto, and the item may be such things as tableware. 
     The lighting module  213  may be a module for projecting light onto a serving tray. The lighting module  213 , when the electronic device  210  reaches a target destination to which a target item on a serving tray needs to be delivered, may light up the serving tray and the target item on the serving tray. 
     Each serving tray (e.g., the serving tray  214 ) may be a tray for accommodating an item. Although in  FIG.  2    three serving trays are illustrated as being spaced and in a direction perpendicular to the ground, the number and structure of the serving tray  214  may not be limited thereto and may vary depending on a design. At least one serving tray among a plurality of serving trays may be on the same surface as another serving tray. The electronic device  210  may include one or more serving trays (e.g., the serving tray  214 ). 
     The sensor module  215  may include a sensor for driving the electronic device  210 . For example, the sensor module  215  may include one or a combination of two or more of a light detection and ranging (LiDAR) sensor, a depth sensor (e.g., a time-of-flight (TOF) sensor), and an ultrasonic sensor. The electronic device  210 , through the sensor module  215 , may set a driving route by detecting an object and a background around the electronic device  210  and perform a maneuver for avoiding an obstacle. 
     The sound output module  216  may output, to a customer, a sound signal (e.g., voice guidance) for indicating information (e.g., the name and amount of a currently delivered item) related to item delivery. The sound output module  216  may record a sound signal (e.g., guidance to a customer) to be delivered from a user to the customer and a sound signal (e.g., a request from the customer) to be delivered from the customer to the user. In  FIG.  2   , for example, a speaker of the sound output module  216  is illustrated as being at a lower part of the electronic device  210 , and a microphone of the sound output module  216  may be integrated with the display module  211 . 
     The communication module  218 , including communication circuitry, may establish wired or wireless communication with the order server  220 . For example, the communication module  218  may receive POS data from the order server  220 . The communication module  218 , when a target item has been delivered by the electronic device  210 , may report the completed delivery of the target item (e.g., served food) to the order server  220 . In addition, the communication module  218  may establish communication with another terminal (e.g., a wearable device) of a user other than the order server  220 . The communication module  218  may transfer an anomaly detected by the electronic device  210  to the other terminal of the user. 
     The driver  219  may move the electronic device  210 . The driver  219  may include a motor and/or wheels. The driver  219  may move the electronic device  210  forward and backward and rotate the electronic device  210  on the ground by driving the motor. 
     The protection module  250 , including a protector, may provide protection for an item on the serving tray  214 . The protection module  250  may physically prohibit, restrict, or prevent or reduce the likelihood of invasion of an object (e.g., the hand of a third person) unauthorized to access a tray space in which an item is placed and the placed item. For example, the protection module  250  may physically, partially at least, prevent or reduce the likelihood of unauthorized physical access to the item on the serving tray  214 . The protection module  250  may cover at least some of the tray space including the serving tray  214  by actuating a protection guard. The protection module  250  may be configured to cover one or a combination of two or more of one side (e.g., one side based on a driving axis) of the tray space, both sides (e.g., both sides based on the driving axis) of the tray space, and all the sides of the tray space. As another example, the protection module  250  may move or fix a serving tray. The protection module  250  may provide individual protection for each of the plurality of serving trays. As described below, the protection module  250  may provide protection for some items at a destination and release the protection sequentially in a serving order. Examples of the protection module  250  may be described below with reference to  FIGS.  11  through  17   . 
     The tray light  260  may refer to light (e.g., a light-emitting diode) on at least one side of a tray. The tray light  260  may provide feedback based on lighting up a serving tray corresponding to a destination at which the electronic device  210  arrives. Although  FIG.  2    illustrates an example where the tray light  260  is on one side (e.g., the left side) of the electronic device  210  based on a driving axis (e.g., a longitudinal axis) of the electronic device  210  examples are not limited thereto, and the tray light  260  may be on both sides of the electronic device  210  based on the driving axis of the electronic device  210 . The tray light  260  may output light of a first color (e.g., green) when an item on a tray is allowed to be delivered at each destination and may output light of a second color (e.g., red) when the delivery is restricted. 
     The electronic device  210  may serve simultaneously prepared items (e.g., simultaneously cooked food items) in a service space (e.g., a restaurant) to multiple destinations (e.g., multiple tables) in one drive. The electronic device  210 , even when a user (e.g., an employee), who does not consider a serving order, randomly places items on serving trays, may visit destinations in the serving order by identifying an item on each serving tray. In addition, the electronic device  210 , when a plurality of items is on each serving tray (e.g., the serving tray  214 ), may prevent or reduce the likelihood of, through a protection operation (e.g., a warning output and a physical protection operation), a customer of another destination from unloading a target item to be delivered to a target destination. 
       FIGS.  3  and  4    are flowcharts each illustrating a method of protecting an item, according to various example embodiments. 
     In operation  310 , an electronic device (e.g., the electronic device  101  of  FIG.  1   ), based on items on a plurality of serving trays and order information of a plurality of destinations, may determine a serving order in which the items on the plurality of serving trays need to be delivered. 
     For example, in operation  411 , the electronic device may sense the items on the plurality of serving trays. The electronic device may obtain an image of an item on a certain serving tray through a camera sensor installed on each of the plurality of serving trays. The electronic device, by analyzing a captured image of an item, may identify a type and quantity of an item in each image. For example, the electronic device may determine a type and quantity of an item by comparing a captured image of each serving tray with an item image (e.g., a food image) by each menu item in an items database (e.g., a restaurant food database) on a service space. The electronic device may determine, based on the captured image described above, whether an item is on each serving tray. Sensing an item is described below with reference to  FIG.  5   . However, the sensing of the item is not limited to the foregoing example, and information on an item on each serving tray may be provided based on an input from a user. 
     In operation  412 , the electronic device may match order information to an item on each serving tray. The electronic device, as described above, may receive POS data from an order server. The electronic device may match order information at each destination among the POS data with an identified item on each serving tray. The order information may include, for example, information on an order time, a destination identifier (e.g., a table number), an item type (e.g., a food type), a served item, and an unserved item. The electronic device, based on the order information, may determine a destination to which an item on each serving tray needs to be delivered. Matching order information to an item is described below with reference to  FIG.  6   . 
     In operation  413 , the electronic device may determine a serving order for each tray based on the order information. The serving order may refer to an order in which items placed in the electronic device need to be delivered. For example, when the electronic device accommodates a second item of a second order subsequent to a first item of a first order, the electronic device may deliver the first item of the first order first to a first destination, and subsequently, the second item of the second order to a second destination. A protection order for serving trays may be determined based on the serving order described above. For example, each serving tray may be protected at a destination of a serving order preceding a serving order of the serving tray. In other words, the electronic device may determine to protect a serving tray mapped to a serving order posterior to a serving order of a visited destination. 
     In operation  320 , the electronic device, while an item is delivered to a first (e.g., one) destination among the plurality of destinations, may provide protection for a serving tray to which a serving order subsequent to a serving order of the first (e.g., one) destination is mapped. In operation  421 , the electronic device may perform a protection operation on a serving tray not in a current serving order. 
     For example, the electronic device may perform a non-physical protection operation. The electronic device, when detecting an unauthorized attempt to unload an item, may perform a warning operation upon access. The electronic device may monitor an action (e.g., an entry of hands, gloves, and tongs to a tray space) of another customer taking an item (e.g., food). The electronic device may output one or a combination of two or more of a warning sound, speech, and lighting for warning of accessing. The non-physical protection operation is described below with reference to  FIG.  10   . As another example, the electronic device may perform a physical protection operation. The electronic device may protect a serving tray in a serving order subsequent to a serving order of a reserved destination by driving at least one of a protection guard and a serving tray through a protection module. The electronic device may release protection for a serving tray of which an item needs to be delivered at the reserved destination and maintain protection for serving trays accommodating the remaining items. For reference, the electronic device may individually perform the non-physical and physical protection operations described above or may simultaneously perform a combination of the non-physical and physical protection operations. 
     The electronic device may visit a plurality of destinations sequentially based on a serving order. 
     In operation  430 , the electronic device may notify a customer of a serving tray accommodating an item corresponding to a reserved destination. For example, the electronic device may light up the serving tray by activating a lighting module corresponding to the serving tray mapped to the reserved destination. In addition, the electronic device may activate tray light of the serving tray. The electronic device may turn on the tray light in the first color. The electronic device may output at least one of an image and sound signals that guide to a serving tray accommodating an item delivered at a destination together with the lighting operation described above. 
       FIG.  5    is a diagram illustrating item matching according to various example embodiments. 
     An electronic device  500  (e.g., the electronic device  101  of  FIG.  1   ), in response to an item being on at least one serving tray among the plurality of serving trays, may identify the item on the serving tray. For example, the electronic device  500  may capture images  510  through a camera sensor on each serving tray. 
     The electronic device  500  may compare the captured images  510  with an items database  590  of a service space. The electronic device  500 , by comparing the captured images  510  and the items database  590 , may generate an identification result on an item on each serving tray. The identification result may be a result of identifying an item on each serving tray and may include, for example, a name of the identified item. The items database  590  may include a list of items provided to customers in a service space and may include, for example, an item name (e.g., a menu item name) and an item image (e.g., a food image). In the example illustrated in  FIG.  5   , the electronic device  500  may recognize pastas from images captured in first and second serving trays and recognize steak from an image captured in a third serving tray. The electronic device  500  may determine that the pastas are respectively placed on the first and second serving trays and the steak is placed on the third serving tray. 
       FIG.  6    is a diagram illustrating determining a serving order according to various example embodiments. 
     An electronic device (e.g., the electronic device  101  of  FIG.  1   ), based on pieces of order information of a plurality of destinations and an identification result of an item, may map a serving tray accommodating the item among a plurality of serving trays to one destination among the plurality of destinations. The electronic device may generate a mapping result  620  that maps each serving tray to a destination to which an item on each serving tray needs to be delivered. For example, the electronic device may compare items  610  identified in the plurality of serving trays with order information  615 . 
     In the example illustrated in  FIG.  6   , the order information  615  may include information on an order time, a serving order, a destination identifier  615   a  (e.g., a table number and a table name), a name  615   b  and a quantity of an ordered item, a special order requested by a customer, and a served item  615   c  at a destination. An example illustrated is that a customer at table C ordered steak and customers at tables B and E each ordered a pasta. In the mapping result  620 , a first serving tray accommodating a pasta may be mapped to table B, a second serving tray accommodating another pasta may be mapped to table E, and a third serving tray accommodating steak may be mapped to table C. The electronic device, when a plurality of items having the same name are respectively on a plurality of serving trays, may map a destination of a preceding serving order to an upper serving tray of the plurality of serving trays and a destination of a subsequent serving order to a lower serving tray. Accordingly, when a user places items regardless of serving orders, a customer at a destination to which an item is to be delivered first may be served the item from a position (e.g., a high position) where the item is rather conveniently picked up. 
     The electronic device, based on a mapping result of a serving tray and pieces of order data of a plurality of destinations, may determine a serving order of a serving tray accommodating an item. For example, the electronic device, based on time information related to delivery of an item from the pieces of order information of the plurality of destinations, may determine a serving order  630  of a plurality of items on a plurality of serving trays. The electronic device, based on order times of the plurality of serving trays, may determine a serving tray accommodating an item ordered first to have a prior serving order. In the example illustrated in  FIG.  6   , an order from table C is received at 11:30, an order from table B is received at 11:35, and an order from table E is received at 11:36. The electronic device may determine the serving order  630  for table C to be a first priority, for table B to be a second priority, and for table E to be a third priority. However, determining the serving order  630  may not be limited to the foregoing example and may vary depending on a design. 
       FIG.  7    is a diagram illustrating protecting a serving tray based on a serving order, according to various example embodiments. 
     An electronic device  700  (e.g., the electronic device  101  of  FIG.  1   ) may determine a serving tray to be protected based on the serving order determined as described with respect to  FIG.  6   . Protection tray information  710  may indicate a serving tray to be protected based on a serving order. The electronic device  700 , when delivering a target item to a target destination, may determine serving trays mapped to a serving order subsequent to a serving order of the target destination to be protection targets. For example, according to the protection tray information  710  illustrated in  FIG.  7   , the electronic device  700 , for delivering steak to table C, may deactivate protection of a third serving tray  723  corresponding to table C. The electronic device  700  may activate protection for a first serving tray  721  and a second serving tray  722  each accommodating pastas to be respectively delivered to tables B and E and may maintain the activated protection until reaching a destination corresponding to each of the first and second serving trays  721  and  722 . 
     For reference, as an example of a protection module, a bar-shaped guard as a protector is illustrated. However, examples are not limited thereto, and various examples of the protection module are described below with reference to  FIGS.  11  through  17   . 
     Each embodiment herein may be used in combination with any other embodiment(s) herein. 
       FIGS.  8  and  9    are diagrams each illustrating sequential delivery of items protected based on a serving order according to various example embodiments. 
     An electronic device (e.g., the electronic device  101  of  FIG.  1   ), in response to a target item reaching a target destination, may provide a guide for indicating a serving tray accommodating the target item. For example, the electronic device, as the guide for indicating a serving tray accommodating the target item, may perform one or a combination of two or more of activation of light on one side of the serving tray accommodating the target item, activation of light for lighting up the target item, an output of visual information for describing the target item on a display, and an output of auditory information for describing the target item. 
     For example, in  FIG.  8   , the electronic device may deliver steak to table C as examples described above with reference to  FIGS.  5 ,  6 , and  7   . The electronic device, in response to reaching table C, through a display module  810 , may guide a customer by visually outputting that the steak is on a third serving tray. In addition, the electronic device may output light  820  through a lighting module to the third serving tray accommodating the steak. The electronic device may also emit light  830  on one side of the third serving tray. 
     The electronic device, in response to the target item reaching the target destination, may release protection for the serving tray accommodating the target item. For example, a plurality of destinations may include a first destination and a second destination corresponding to a serving order subsequent to the first destination. In the example illustrated in  FIG.  8   , the first destination may be table C and the second destination may be table B or E. The electronic device, based on a user&#39;s input, may activate a protection module (including a protector) of a first tray mapped to the first destination and a protection module of a second tray mapped to the second destination. The user&#39;s input may be an input for instructing initiation of protection or driving. The electronic device, in response to initiating driving for item delivery, may activate the protection modules of the first and second trays respectively mapped to the first and second destinations. The electronic device, in response to reaching the first destination, while maintaining the activation of the protection module of the second tray, may deactivate the protection module of the first tray. In the example illustrated in  FIG.  8   , the electronic device having reached table C, which is the first destination, may deactivate a protection module of the third serving tray accommodating the steak. 
     In addition, the electronic device, in response to detecting unloading of the target item having been on the serving tray at the target destination, may determine that the target item has been delivered. For example, in the example illustrated in  FIG.  9   , a customer may unload the steak at table C, which is the target destination. The electronic device, while staying at the target destination, may monitor, through a camera sensor, the serving tray mapped to the target destination. The electronic device, in response to detecting removal of the target item from the serving tray through the camera sensor, may determine that the target item has been delivered. When the delivery has been completed, the electronic device may turn off tray light  930  on one side of the serving tray and light  920  of a lighting module facing an upper side of the serving tray. The electronic device may output, to a customer, a serving completion notification on a display module  910 . The electronic device may transmit, to an order server, data (e.g., a destination identifier, a name of served item, and a quantity) related to the serving completion notification. 
     In addition, the electronic device, in response to reaching the second destination, may deactivate the protection module of the second tray. For example, in the example illustrated in  FIG.  9   , the electronic device, in response to reaching a second destination, which is table B, may activate light  950  of a first serving tray mapped to table B and tray light  960  and deactivate a protection module. The electronic device may provide information on an item to be delivered on a display module  940 . The electronic device may open a bar-shaped guard that has covered some of a tray space of the first serving tray mapped to table B. 
     The electronic device, by repeating the operations described above with reference to  FIGS.  8  and  9    when visiting each destination sequentially, may provide the delivery of and protection for an item. 
       FIG.  10    is a diagram illustrating detecting invasion of an unauthorized object, according to various example embodiments. 
     An electronic device may provide a non-physical protection operation. The electronic device, while a target item is delivered to one destination among the plurality of destinations, may sense access of things  1080  in a detection region defined based on a serving tray accommodating another item in a serving order subsequent to a serving order of the target item. The electronic device, through a view of a camera sensor  1010  facing each serving tray, may monitor object invasion to a serving tray mapped to a subsequent serving order to a current destination. The camera sensor  1010  may have a viewing range  1011  that is wider than a region  1090  in which an item may be on a serving tray. The electronic device may detect whether there are things  1080  (e.g., hands, gloves, and tongs) in the view range  1011  around a placed item. 
     The electronic device, in response to sensing access of things in a detection region, may perform a protection operation on another item. The electronic device, as the protection operation on the other item, may perform one or a combination of two or more of auditory information warning of wrongful taking of the other item, visual information warning of wrongful taking of the other item, and turning on light on one side of a serving tray. For example, the electronic device may output first color light from light on one side of a serving tray accommodating the target item and output second color light from light on one side of the serving tray accommodating the other item, wherein the second color light is different from the first color light. As another example, the electronic device, when detecting object invasion, may change color of light of all the serving trays to light  1022  of the second color (e.g., red). The electronic device may output a warning image (e.g., a warning emoji face) on a display module  1021  and may output a warning sound and warning speech. The non-physical protection operation described above may be provided with a physical protection operation. 
     The electronic device, in response to the things  1080  disappearing without wrongfully taking an item and the item being left intact, may determine that food safety is secured for a serving tray. The electronic device may determine that an abnormal situation has ended. The electronic device may display a screen, which had been output before the abnormal situation occurred, on a display module  1031  and may change the color of the tray light to light  1032  of a first color (e.g., green). The electronic device may output sound and speech (e.g., the speech of “Food is on its way”) for indicating safety of an item. Accordingly, the electronic device may provide feedback that the item is safe to a user and a customer. 
     The electronic device, in response to the things  1080  being outside the view range  1011  and wrongfully taking an item, may determine that the item on a serving tray  1091  has been wrongfully taken. The electronic device may call a user and a manager in this error situation according to the description to be provided below with reference to  FIG.  19   . 
       FIGS.  11  through  17    are diagrams illustrating a protection module (including a protector) according to various example embodiments. 
       FIG.  11    illustrates a protection operation based on a bar-shaped guard  1110 . An electronic device (e.g., the electronic device  101  of  FIG.  1   ) may further include a protection module configured to drive the bar-shaped guard  1110  movably disposed along an axis  1193  perpendicular to a surface of a serving tray from at least one side of each of the plurality of serving trays. Although  FIG.  11    illustrates an example of disposing the bar-shaped guard  1110  on one side of each of the serving trays, examples are not limited thereto. The bar-shaped guard  1110 , as an example of a protector, may be on both sides based on a driving axis (e.g., a longitudinal axis  1191 ) of the electronic device. For example, the surface of the serving tray may be a surface defined by the longitudinal axis  1191  and a lateral axis  1192  of the electronic device. 
     The electronic device, in response to initiating protection of an item on the serving tray, may raise the bar-shaped guard  1110  along the axis  1193  perpendicular to the surface of the serving tray. The electronic device, in response to terminating the protection of the item on the serving tray, may accommodate the bar-shaped guard  1110  in a bar-shaped groove  1120  by lowering the bar-shaped guard  1110  along the axis  1193  perpendicular to the surface of the serving tray. The bar-shaped guard  1110  may be configured to be movable along an inner rail along the axis  1193 , and a protection module, in response to an electrical signal based on whether each serving tray is protected, may perpendicularly move the bar-shaped guard  1110  through a power transmission structure including one or a combination of two or more of a linkage connected to a motor, a chain, a belt, and a thread structure. 
       FIG.  12    illustrates a protection module configured to move a serving tray. The protection module may further include a protection module configured to move each of the plurality of serving trays along one axis of the electronic device. For example, the electronic device may slide a serving tray along a lateral axis  1292  of the electronic device. The lateral axis  1292  may be an axis perpendicular to a vertical axis  1293  and a longitudinal axis  1291  of the electronic device. 
     The electronic device, while a target item is delivered to a target destination, may move a serving tray accommodating the target item, among the plurality of serving trays, along one axis in one direction. The electronic device, at the target destination, may move, along the axis in an opposite direction to the direction, another serving tray accommodating another item different from the target item. For example, the electronic device may slide a serving tray  1210  mapped to the target destination to a customer and move the remaining serving trays  1220  away from the customer. The electronic device may explicitly guide a customer to a serving tray accommodating an item to be delivered by activating a lighting module and tray light, for example, for the serving tray  1210  that moved forward to the customer. The electronic device may intuitively notify a customer of an item to be delivered and at the same time, may decrease the customer&#39;s accessibility by moving an item of which delivery is restricted away from the customer. 
       FIGS.  13 ,  14 , and  15    each illustrate a protection operation using a partition guard. The electronic device may further include a protection module configured to drive a partition guard configured to open and close at least some tray space of each of a plurality of serving trays. The electronic device, while a target item is delivered to a target destination, may open a tray space corresponding to a serving tray accommodating the target item, among the plurality of serving trays. The electronic device, while the target item is delivered, may close at least some tray space corresponding to a serving tray accommodating another item. The partition guard may be implemented with one or a combination of two or more of materials including a mesh type, a perforation type, an orgami type, a curtain type, a sliding door type, a comb pattern type, a chain type, and a fabric type. For example, the partition guard may be configured with a mesh-type material and to be movable through a slide structure. The partition guard may include a transparent or translucent material such that the inside of a tray space may be seen. The partition guard of a mesh-type material may ensure ventilation for food preservation, prevent or reduce the likelihood of obstruction of food confirmation from steam or dew condensation, protect food items from pests, and block inflow of matter, dust, and saliva of customers from other tables. 
     In  FIG.  13   , the partition guard, when closed, may cover some area of one side of a tray space of each serving tray. For example, the height of the partition guard along a vertical axis  1393  may be lower than the height of the tray space of each serving tray along the vertical axis  1393 . For example, a closed partition guard  1310  may cover a half of one side of a tray space. The closed partition guard  1310  may decrease a customer&#39;s accessibility to an item. The partition guard may be configured to be rotatable based on an axis parallel to a longitudinal axis  1391  and/or lateral axis  1392 , and the protection module may open or close the partition guard by rotating the partition guard. The partition guard may have a rotatable hinge structure. The partition guard may open at a destination to which food needs to be delivered. A customer may explicitly recognize, through an opened partition guard  1311 , that a placed item is allowed to be taken. 
     In  FIG.  14   , a partition guard  1411 , before an electronic device drives to a destination, may be invisibly included. The partition guard  1411  may have a type and a size that may entirely cover one side of a tray space. The partition guard  1411  may be spaced apart from another and accommodated along a lateral axis  1492  of the electronic device on both sides of the electronic device based on a longitudinal axis  1491  of the electronic device. Partition guards disposed on both sides of the electronic device each may have a sliding hinge structure. The electronic device, in response to determining a serving tray to be protected, may move a partition guard  1412  along a vertical axis  1493  of the electronic device toward the serving tray to be protected. The electronic device may maintain a position of a partition guard  1413  that arrives at the serving tray to be protected. When another serving tray is additionally determined to be a protection target, the electronic device may extend a partition guard  1414 . For example, the electronic device may stack a plurality of partition guards and sequentially move each of the plurality of partition guards or may extend a partition guard configured with an elastic material. 
       FIG.  15    illustrates an example of individually disposing a partition guard at a height corresponding to each serving tray. The electronic device may invisibly accommodate a movable partition guard  1511  at a front end of the electronic device based on a longitudinal axis  1591  of the electronic device. The electronic device may move a partition guard through a sliding hinge structure  1512 . The electronic device may move a partition guard  1513  corresponding to a serving tray accommodating a protection target. The electronic device may prevent or reduce the likelihood of an unauthorized customer from accessing an item by closing a tray space through a moved partition guard  1514 . For reference, an example of moving a partition guard to one side of the electronic device is illustrated in  FIG.  15   , but examples are not limited thereto, and a partition guard may be deployed on both sides based on the longitudinal axis  1591  of the electronic device. The longitudinal axis  1591  of the electronic device may be a driving axis of the electronic device and may be, for example, perpendicular to a vertical axis  1593  and a horizontal/lateral axis  1592  of the electronic device. 
     For reference, the protection module described with reference to  FIGS.  11  through  15    may move a protection guard on only one side or both sides of the electronic device based on a longitudinal axis of the electronic device. The electronic device reaching each destination may identify a direction of a destination to which an item is to be served, based on a longitudinal axis of the electronic device, and may drive a protection guard in the identified direction. As another example, the electronic device may rotate a body of the electronic device based on a vertical axis such that a side of the electronic device from which a customer at a destination may be comfortably served may face the customer. 
       FIG.  16    illustrates an operation of fixing an edge  1630  on a serving tray  1610 . The electronic device may further include a protection module configured to drive a fixer  1620  configured to fix the edge  1630  of each of a plurality of serving trays. The electronic device, while a target item is delivered to a target destination, may unfix the edge  1630  of a serving tray accommodating the target item and maintain the edge  1630  of another serving tray accommodating another item, fixed. An unlocked fixer  1621  may unlock the edge  1630 . The fixer  1620  may hold the edge  1630  by mechanically locking a vertical height of a latch hung on the edge  1630 . Accordingly, the electronic device may prevent or reduce the likelihood of another customer from unrightfully taking another item by locking the edge  1630 , where the other item is placed. 
       FIG.  17    illustrates an operation of raising and lowering a serving tray along a vertical axis. 
     The electronic device may further include a protection module configured to protect a plurality of serving trays by accommodating the plurality of serving trays in a protection space defined by a protection guard and move the plurality of serving trays along an axis perpendicular to the plurality of serving trays. The protection guard configured with a transparent, translucent, or mesh material may be disposed along the edges of the electronic device, and serving trays accommodated inside the protection guard may be observed from outside. The protection guard may be implemented as a portion of a housing of the electronic device. 
     In  FIG.  17   , a shared tray  1701 , which is a tray accommodating a shared item (e.g., tableware) provided for ease of access to all customers, may be disposed above the protection space  1710 . A serving tray accommodating a main item (e.g., a main dish) may be accommodated inside the protection space  1710  defined by the protection guard, and thus, the main item may be protected. Accordingly, the hygiene, freshness, and temperature of the main item may be maintained during the delivery of the main item. 
     The electronic device, in response to reaching a target destination, may expose a serving tray accommodating a target item by elevating the serving tray higher than the protection space  1710 . For example, the electronic device may elevate a first serving tray  1721  higher than the protection space  1710  at a first destination. The electronic device may elevate a second serving tray  1722  higher than the protection space  1710  at a second destination. The second serving tray  1722  may be lower than the first serving tray  1721 , and the first and second serving trays  1721  and  1722  may be uniformly elevated and lowered together. 
       FIG.  18    is a diagram illustrating protection based on a direction of an electronic device according to various example embodiments. 
     An electronic device (e.g., the electronic device  101  of  FIG.  1   ) may further include a protection module that may selectively prevent or reduce the likelihood of entry of an object from both sides of a plurality of serving trays based on one axis (e.g., a driving axis or a longitudinal axis) of the electronic device. 
     For example, the electronic device, in response to the electronic device reaching a target destination to which a target item is to be delivered, may provide protection to a side corresponding to the target destination based on the axis of the electronic device in a serving tray accommodating the remaining items different from the target item. The electronic device, when reaching a destination, may recognize a serving direction at the destination, deploy a protection guard in the recognized serving direction, rotate in a direction for serving, and provide an item. 
       FIG.  18    illustrates an example of sequentially visiting tables C, B, and E from a starting position  1801  by the electronic device. An electronic device  1881  reaching table C by driving along a first route  1811  may recognize that table C is on the right side of the electronic device based on a driving axis of the electronic device. The electronic device  1881  may activate a protection guard  1821  on the right side of the electronic device based on the driving axis of the electronic device. A protection module of a third serving tray accommodating an item to be delivered may be deactivated. An electronic device  1882 , in response to completed delivery to table C, may drive along a second route  1812  and reach table B. The electronic device  1882  may recognize that table B is on the left side of the electronic device based on a driving axis of the electronic device. The electronic device  1882  may activate a protection guard  1822  on the left side of the electronic device. A protection module of a first serving tray accommodating an item to be delivered may be deactivated. An electronic device  1883  may reach table E along a third route  1813 . Because table E is on the left side of the electronic device  1883 , the electronic device  1883  may provide an item to a customer by deactivating a protection module on the left side of a second serving tray. 
       FIG.  19    is a flowchart illustrating a processing method of a serving error according to various example embodiments. 
     As described above, an electronic device (e.g., the electronic device  101  of  FIG.  1   ), when a serving error that an item to be served is wrongfully taken or lost occurs, may call a manager. 
     In operation  1910 , the electronic device may recognize a serving error (e.g., wrong delivery). For example, the electronic device may determine that a serving error occurs in response to at least one of the cases when a destination identifier does not match a destination and when an item is lost at a different destination from a serving order. 
     In operation  1920 , the electronic device may inform a customer of the serving error. For example, the electronic device may inform a customer at a destination that an item is not an item ordered from the destination through one or a combination of two or more of visual information, auditory information, and tactile information. 
     In operation  1930 , the electronic device may request a customer to return an item. The electronic device, in response to a target item being unloaded before arriving at a target destination, may request a customer of another destination to return the target item. The electronic device may output one or a combination of two or more of visual information, auditory information, and tactile information for requesting the customer to return the item to a serving tray. 
     In operation  1940 , the electronic device may sense whether the item is returned within a certain time. For example, the electronic device may monitor that the same item is re-detected on the serving tray within a threshold time from when recognizing the serving error and informing the customer of the serving error. 
     In operation  1950 , the electronic device, in response to sensing that the target item is not returned, may call a manager (e.g., user). The electronic device, when recognizing that an item is completely missing, may call a manager to a destination by transferring a notification message to a terminal (e.g., a mobile phone and a wearable device) of the manager (e.g., the user).