Digital Twin Development for Serial Manipulators: Data Driven Optimized Planning and Sequencing of Tasks
The first task occurs at the smart warehouse
and trolley docking area. The warehouse is
equipped with a piezoelectric weighing
machine for each part to obtain the real-
time stock update. The inventory data is
connected and integrated with an ERP
system via an IoT platform. When the raw
material stock level hits below the minimum
setting, the required stock replenishing alert
appears at the ERP, and the purchasing
process for required materials is initiated.
The material transportation is performed by
an AGV between the warehouse and
assembly line via the docking stations. The
trolley carries the gearbox parts, and the
AGV transports the trolley to any desired
location on the shop floor. The trolley is
prepared by a warehouse operator to be
secured and fetched by an AGV from the
docking area once the shaft assembly starts.
The computer vision system with an
intelligent part recognition system is
equipped above the trolley to monitor the
parts located there. The recognition system
can identify the part types and count the
quantity. It is also integrated with the IoT
platform and notifies the operator at the
warehouse dashboard to replenish the parts
on the trolley if needed. The transportation
of sub-assembly parts for the customized
order only starts when the second task, the
configurations of the specific sub-assembly
process, is ready.
Based on this MMC concept and method,
the authors identify a use case of DT
application related with the gearbox
production line. A customized sale order,
which contains the combination of shaft sub-
assemblies consisted in a gearbox, is
received from a customer to deliver in a
high-priority setting. There are three types
of shaft sub-assemblies: output, input and
transfer. The production manager applies
the MMC concept-based DT model in
planning, simulating, monitoring, controlling
and executing the resources of the
production line to fulfill such a customized
order.
Explanation of workflow, components,
technologies
When a high-priority sale order of the
combination of shaft sub-assemblies is
received, the production manager requires
planning, simulating, monitoring, verifying
and executing the necessary tasks to fulfill
the order efficiently with minimum
interruption on the full gearbox production
line. In order to achieve this business need,
the manager utilizes the MMC DT model
which requires developing two adaptable
functions—collecting
necessary
raw
materials and picking, placing and
assembling shaft assembly parts. The assets
and their connections involved in this
operation are described in Figure 6. Hence,
the digital architecture of production is
modified with the Cobot Digital Twin
application as in Figure 7.
- 34 -
November 2019