Digital twin model development applied to 5 axis gantry stacker

Flat glass represents one of the key materials employed in important market slices, like constructions and automotive, due to its recyclability and its intrinsic characteristics. The production process plays an important role in the efficiency and the fulfillment of the market demand. Bottero S.p.A. is one of the leading companies in the glass technology and it is the principal partner of this research. An upcoming problem that will be faced in this industry is the combination of shorter time-to-market required and delays in the supply chain which leads to limited design and validation phases. To overcome this challenge, the solution is the development of a digital twin for virtual commissioning. The digital twin represents an emerging technology for a digital and intelligent design. This model is a virtual copy of the complete system capable of monitoring, simulating processes, predicting possible outcomes and optimizing the re-think of the automation unit at all the phases of the design. The machinery under investigation is a 5-axis gantry stacker whose main purpose is the loading and unloading of glass sheets from the line conveyor to the storage racks. Mechanically, it is composed by a gantry portal on which a bridge can translate on wheels along the line direction. A carriage then slides perpendicularly on the bridge guides. A lifting piston governed by a chain mechanism then perform the movement in height. In the end, two motors define the rotation along the z axis and the tilting movement along the x axis. From an electrical and automation point of view, the system is composed principally by two control units: a CPU (Siemens ET200SP) that performs the control algorithms on the IO coming from the operator (console and HMI), the processing line and the pneumatic commands for glass suction and blowing; the second component is a Motion Control Unit (Siemens SIMOTION D425-2) which governs the axis motion, synchronism and trajectory definition. Once programmed the software codes, the interconnections between the subsystems are required and the SIMIT simulation software is the responsible for the different signals travelling in the machinery. With this software, it is possible to emulate the several instances of control units and investigate the response of the automation system to the several Input tests. The final element of the digital twin is the definition of a proper multi-body model. From the CAD design, two simple MatLab models were developed investigating several aspects of the kinematics and dynamics of the machine. With the help of the Robotic Matlab Toolbox, it is possible to analyse the definition of the pose of the robot with an interactive GUI and, once defined the working environment, a collision check can be performed with the several robot configurations considered during the trajectory definition. With the SimScape model, instead, a trajectory planning analysis is developed considering the exploitation of the drive parameters, cycle time and dynamic response of the system. The solutions analysed are the polynomial cubic and quintic, the harmonic functions and the piece-wise trajectories (trapezoidal and double-S). This project represents the beginning of the digital twin concept and it will be further developed with the interconnection with the native Siemens multi-body designer, capable of interacting with the IO and the automation. This digital twin has the power to show the complete design process under a newer, brighter light.