SAIL – the system architecture for intralogistics from VDI / VDMA
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“Innovation and Standardization” is the title of a working group of the Intralogistics Forum of the German Engineering Federation (VDMA), which brings together renowned machine and facility manufacturers, IT companies, warehouse logistics specialists, sorting specialists, and equipment and component manufacturers. The working group has set itself the goal of creating added value for users and suppliers of intralogistics systems and system components by creating standards. The result of the work so far is the system architecture for intralogistics – SAIL.
Projects in intralogistics are largely interdisciplinary and require a high degree of cooperation from all companies involved – from the planners to the suppliers, to the system operators. The success or failure of a project, therefore, depends not only on the quality of individual products or developments but decisively on the systematic and sustainable cooperation of all disciplines.
SAIL – the objective
SAIL results from standardization efforts of the Forum Intralogistics within the VDMA with the aim of achieving effective cooperation between project partners of individual crafts by means of cross-supplier architecture concepts. The core functions of an intralogistics system are systematized and standard control functions and interfaces (between the functions) are defined. Logistics systems via SAIL are based on standardized functional components, which, due to their harmonization across suppliers, enable easier integration of different systems. The respective system provider is left to decide on the individual distribution of functions to different control levels since SAIL is platform-neutral.
Note from the editor
SAIL is never considered in its entirety in project planning; rather, the ideas written down serve today as a source of inspiration for the new digital and above all automated approaches known to us. The most recent edition dates from 2016 (German source: VDI/VDMA 5100 sheet 1:2016-05).
SAIL – the components of materials handling equipment
The materials handling equipment according to SAIL is built up from various components. Each component (C) can be assigned to materials handling technology function. The components serve to encapsulate the functions during modeling.
Conveying Element C:CE
A ‘Conveying Element’ is the smallest unit. It consists of a drive for the main conveying direction, the drives for the branching conveying directions as well as the corresponding sensor technology. It only has the function Facility Control F:FC (system control).
Conveying Group C:CG
A Conveying Group is characterized by the fact that it operates a group of Conveying Elements with the function Facility Control F:FC. It is therefore a group of Conveying Elements that together can form a complex facility structure, which outwardly represents a so-called branching point. Accordingly, the conveying group has a directional decision instance Direction Control F:DC with the corresponding operating parameters.
Conveying Segment C:CS
A Conveying Segment is characterized by the fact that it provides the function Mission Management F:MM (transport order management) for a group of Conveying Groups.
Conveying Area C:CA
A Conveying Area consists of a group of Conveying Segments for which it provides the coordinating function of the resource Utilization F:RU.
SAIL – Innovation via standardized functions
The segmentation of an intralogistics system according to functions enables platform-independent modeling with reusable building blocks. In contrast to the formerly common breakdown into different facility levels, the focus of the modeling is now on the actual logistics and not on the process. A reduction of complexity and a hierarchization inevitably result as a secondary effect. Inspired by object-oriented programming, which has already led to a paradigm shift in other areas, SAIL transfers this approach to the modeling of intralogistics systems.
Decisive for the mental planning process of the facility constructors are the following conceptual steps/h3>
- Primary facility segmentation by function and not by level
- Encapsulation of the found functions in components
- Standardization of the interfaces of individual components
- Provision of standardized control components analogous to available mechanical components
This results in the following functions (as listed above)
- Direction Control F:DC
- Facility Control F:FC
- Mission Management F:MM
- Resource Utilization F:RU
- Transport Coordination F:TC
SAIL – the function: Direction Control F:DC
The Direction Control F:DC function decides whether and in which direction a transport object should be conveyed at a decision point. This is done on the basis of defined operating parameters and any motion task data available for the transport object that is currently located at this point.
For identifiable transport objects, the transport order must be considered for each directional decision. Depending on the size of the facility, the structure of the motion tasks and the available storage possibilities, the determination of the direction of travel from the motion task is more or less complex. In order to always guarantee a fast reaction time, the determination of the data is carried out by the function Mission Management F:MM (transport order management).
In the case of unidentified transport objects, there must at least be a confirmation that it is an unknown transport object (UFO). If this is the case, it can usually already be decided where this UFO is to be transported. If UFOs are to be handled situationally and thus according to non-trivial strategies, a corresponding target request must be made to an external instance Resource Utilisation F:RU. If it is an identifiable transport object, but which has no driving task (fare dodger), the treatment is based on fixed programmed rules or on a parameterizable directional instruction. The same applies if the transport order management has a transport order for a transport object, but this transport order does not provide special directional instruction.
SAIL – the function: Facility Control F:FC
The Facility Control F:FC function (system control) directly operates the facility. It implements all decisions necessary for the intrinsic safety of the facility and the execution of a transport step. It is at this level that the decision is made as to whether or not a transport step can be carried out. Usually, only the release of the subsequent conveyor is considered. The direction in which the transported goods are to be conveyed is given to the system control as a result of the Direction Control F:DC function.
SAIL – the function: Mission Management F:MM
The Mission Management F:MM function provides the relevant data (see also Information in Intralogistics) of the motion task for the Direction Control F:DC function. Its most important task is to provide information about the identification of the decision point and the transport object to determine whether a directional instruction is available and what its characteristics are. This process places high demands on the response time. In addition, this functional group is responsible for creating, changing and deleting transport orders if this is required by the ordering function Resource Utilisation F:RU. The tasks of F:RU do not place high demands on the reaction speed.
When responding to a directional request, the transport order is first determined by the identification number of the transport object. If this function is routable, the presence of the final destination of the transport is sufficient for determining the direction. Mission Management then determines the concrete transport direction itself. If this function is not routable, the system searches in the transport order to see whether an instruction is given for the current point. If yes, this is transmitted, if no, this fact is transmitted instead. This gives the user the freedom, depending on the requirements, to choose the appropriate implementation for very simple motion tasks with only the specification of the final destination or with one or more point/direction value pairs.
SAIL – the function: Resource Utilization F:RU
The function Resource Utilization F:RU knows the current occupancy status of the transport systems, their possible transport capacities and structure, the existing transport orders as well as the necessary strategy parameters for the utilization of free resources. Here it is decided which of several competing transport objects may use a free resource. This results in the assignment of a new transport order to the function Mission Management F:MM (transport order management) or the change/deletion of an existing transport order. The function group Resource Utilization F:RU also uses the parameterization of the decision points in the function group Direction Control F:DC (direction decision) to follow its operating strategies.
SAIL – the function group: Transport Coordination F:TC
The function group Transport Coordination F:TC is the interface to the surrounding systems not belonging to the material flow control system. These systems order their transports from the function group Transport Coordination F:TC and receive all relevant data and status information from it. The function group Transport Coordination F:TC is responsible for ensuring that all transports ordered from it are completed at the right time and in the right place. Even with a large number of transport orders (high load operation), the appropriate operating strategies must be determined. For example, functions for grouping and sequencing several transport orders are also located here. To achieve maximum utilization, the availabilities of all areas and systems are considered and taken into account in the load control for individual transport systems. In the function group Transport Coordination F:TC the organization of collective transports, rounds and batch formations also takes place.
SAIL – the advantages
All in all, the high degree of reuse of the encapsulated functions of SAIL offers a clear cost advantage through reduced adaptation effort, higher standardization, a more mature implementation level and shorter commissioning times.
Advantages for the operator
- Transparency of all functions down to the last encoder
- No project risk of interface adaptation
- Architecture harmonization
- Shortened project duration
- Safe operation
- Simplified Service
- Increased system availability due to clear functional separation in the operating phase
- Flexibility for later plant modification
- Low-risk interchangeability of functionally defined sub-trade or components in the modernization phase (retrofit)
Advantages for the project leads
- Increased planning intelligence through uniform and clear definition of terms and communication methods
- A simple implementation of customer requirements
- Customer states what he wants, supplier states what he delivers
- Project partners communicate on the same basis
- Architecture harmonization as a cost brake
- Implied benefits through reusable standardized components
- Lower project costs with high solution quality
- A modular view of the facility in the planning phase
- Transparent function evaluation in the procurement phase
- Clear separation of functions in interdisciplinary cooperation during the realization phase
- Clear interface definition at the module boundaries during the realization phase
Summary – SAIL
SAIL (System Architecture for Intralogistics) is a solution developed in the Intralogistics Forum of the VDMA to create standards for intralogistics systems and system components; this creates added value for both their users and their suppliers. Standardization ensures that all trades can work together systematically and smoothly in the long term. This has many advantages, especially in intralogistics projects that are highly interdisciplinary. SAIL has a particularly innovative character since an intralogistics system is not divided into individual system levels; instead, it is broken down by function.