Automated Stacker Cranes: A Two-Step Storage Reallocation Process for Enhanced Service Efficiency

Automated storage and retrieval systems (AS/RS) play a key role in improving the performance of automated manufacturing systems, warehouses, and distribution centers. In the modern manufacturing industry, the term (AS/RS) refers to various methods under computer control for storing and retrieving loads automatically from defined storage locations. Using an (AS/RS) is not considered a value-added activity. Therefore, the longer (AS/RS) travels, the more expensive the warehousing process becomes. This paper presents an algorithm for minimizing total travel distance/time between input/output (I/O) stations. The proposed algorithm is used to manage the storage and retrieval orders on warehouse shelves in class-based storage on the storage racks. It contains two steps: the first step is to evacuate some storage compartments (locations) near the I/O station; in the second step, some tote bins are reallocated to compartments closer to the I/O station. Among the features of this algorithm are mechanisms that determine the number of reallocated tote bins, which tote bins to reallocate, and in which direction (toward the I/O station or away from it). A simulation model using R software developed specifically for this purpose was used to validate the suggested method. Based on the results, the new method can reduce the service time per order by about 10% to 20%, depending on parameters like the number of orders and the height of the storage rack.

Robot Operations for Pine Tree Resin Collection

A robotic technology consisting of an industrial robot mounted on an autonomous rover used to tap slash pine trees and collect their oleoresin for processing is introduced, and the technological challenges related to the robotic operations are discussed in detail. Unlike the case of industrial automated manufacturing systems where the relative position between the tool and workpiece can be controlled within a few hundredths of a millimeter accuracy, when used in highly unstructured environments characteristic to forestry or agriculture, the positioning accuracy between the industrial robot and the target on which it operates can be much lower than the accuracy required for the operation of the industrial robot. The paper focuses on presenting the robotic operations necessary for drilling three converging boreholes in the pine tree, spraying the boreholes with chemicals, inserting a plastic tube with pre-attached collection bag in one borehole and inserting two plugs in other two boreholes. The challenges related to performing these robotic operations in conditions of large variations in the actual shape of the pine tree trunk and variations in the relative position between the robot and the pine tree after the autonomous vehicle positions itself in front of the tree are presented. The technical solutions used to address these challenges are also described. The strategies used to programmatically adjust the robot toolpath based on detection of the borehole entry points and on the measurement of the insertion force are presented.

A Coloured Petri Net- and D* Lite-Based Traffic Controller for Automated Guided Vehicles

Mobile robots, such as Automated Guided Vehicles (AGVs), are increasingly employed in automated manufacturing systems or automated warehouses. They are used for many kinds of applications, such as goods and material handling. These robots may also share industrial areas and routes with humans. Other industrial equipment (i.e., forklifts) could also obstruct the outlined routes. With this in mind, in this article, a coloured Petri net-based traffic controller is proposed for collision-free AGV navigation, in which other elements moving throughout the industrial area, such as humans, are also taken into account for the trajectory planning and obstacle avoidance. For the optimal path and collision-free trajectory planning and traffic control, the D* Lite algorithm was used. Moreover, a case study and an experimental validation of the suggested solution in an industrial shop floor are presented.

Multiobjective Heuristic Scheduling of Automated Manufacturing Systems Based on Petri Nets

In practice, automated manufacturing systems usually have multiple, incommensurate, and conflicting objectives to achieve. To deal with them, this paper proposes an extend Petri nets for the multiobjective scheduling of AMSs. In addition, a multiobjective heuristic A* search within reachability graphs of extended Petri nets is also proposed to schedule these nets. The method can obtain all Pareto-optimal schedules for the underlying systems if admissible heuristic functions are used. Finally, the effectiveness of the method is illustrated by some experimental systems.

Virtual commissioning of automated manufacturing systems — Quality-handling station case study

The aim of the contribution is to create an event-controlled simulation of an automated production system using selected simulation software according to analyses and creation PLC control program compatible with human-machine control interface (HMI) visualization. The programmer can test the control program without the need for additional hardware on a virtual model of the machine. This method is called as a Virtual Commissioning method. The question is whether these new digital technologies are beneficial in the development process of new machines. The theoretical part of the contribution deals with the evaluation of the current state of knowledge in the field of virtual commissioning systems from the perspective of the Industry 4.0 concept and the use of principles taken from the technology of digital twins for analysing the possibilities of productive support of simulation, programming and visualization of control. For the Virtual Commissioning of the Quality-handling station from a flexible production system. It was chosen Tecnomatix Process simulating software for the developing of the Digital Twin of the station that is suitable for the connection of the logical behaviour inputs and outputs of the Digital Twin to the PLCSIM emulator. The main goal is to create a functional PLC program, so that in the second phase the process of virtual commissioning can be tested by the Software-the-Loop method. The preparation of the simulation model consists in a sample of the control station model of the production system, the process of creating kinematic bonds, behaviour model, creating control signals in the Tecnomatix Process Simulate program. Programming procedure and acquaintance with control means in the Simatic Manager program, selection of communication interface and creation of control visualization. In the final work, validation is performed and evaluation supports the objectives and the results confirmed the benefits of the Virtual Commissioning tool.