## 3 System Design
### Functional Design of the Platform  
The system functions comprised four main parts: resource management and configuration module, order management module, operation and maintenance mode module and user management module. The functional architecture is shown in Figure 3.  
Figure 3: System functional structure.  
Figure 2: Overall design structure diagram of the platform.  
Order management information mainly refers to sorting out customer information in order to create a maintenance request order after maintenance requests sent by the agricultural machinery operator have been received. The customer information is sorted out, including information such as the location, cause and type of the reported fault, and is then used to conveniently allocate maintenance resources to the harvester in order to provide maintenance.  
There are two main operation and maintenance modes in maintenance scenarios: service network maintenance and scheduling maintenance. Service network maintenance sends a query to the agricultural machine operators, displays the maintenance resources available in the service area through the app, and provides information on the available maintenance network for agricultural machine operators, as well as the available spare parts available in the current area. Maintenance scheduling mainly provides regional maintenance network information, maintenance personnel information, and information on replacement spare resources with respect to the fault maintenance location reported by the agricultural machinery operators. Agricultural machinery operators are able to choose between active maintenance and prompt maintenance using the platform.  
As the main core of the platform, the resource management and configuration module includes the information on the execution of service for the entire maintenance scenario, including information on maintenance personnel, service vehicles, spare parts, etc. The typical maintenance service mode is that in which maintenance personnel drive a maintenance service vehicle to the location of the failure with the spare parts corresponding to the required maintenance in accordance with the report describing the faulty agricultural machinery and order information received by the app. Multiple orders will generally be assigned to maintenance personnel. A dynamic optimization algorithm was used to optimize the order, maintenance route and time required for service provision, and service operation and maintenance work were carried out in consideration of the minimum maintenance cost.  
User management is performed with reference to the information on personnel included in the operation and maintenance platform, including information regarding the quantity of spare parts produced by the first-level manufacturer of agricultural machinery, information regarding increases or decreases in the configuration of each service unit, and the details of collaborative operation and maintenance at all levels, including the spare parts available from the spare parts center library, the spare parts production library and the regional configuration service library.  
Evaluation refers to customers' evaluation of the operation and maintenance service process, where the commencement of the maintenance task is signalled by order generation. On the basis of the fault resolution time and the maintenance cost involved in the service process, agricultural machine operators are able to evaluate the tasks through the app in order to provide feedback for the platform. The evaluation information serves to represent the level of the quality of the maintenance operation and the star rating given to the maintenance personnel and service provider.