The use of robots in waste processing plants can significantly improve the processing of recyclables. Such robots need sophisticated visual and manipulation skills to be able to work in the extremely heterogeneous, complex, and unpredictable waste sorting industrial environment. This article considers the implementation of an autonomous robotic system for the categorization and physical sorting of recyclables according to material types. In particular, it focuses on the development of a low-cost computer vision module based on deep learning technologies to identify and sort items. To facilitate further research endeavors, the data set of recyclable images and a group of image processing scripts for object identification, masking, and synthetic placement against multiple backgrounds are available in an open source GitHub repository (https://github.com/kskmar/ReSort-IT.git). The deep-trained computer vision module is integrated with a robotic system that undertakes the physical separation of recyclables. The composite system is deployed in a waste processing plant, where it is successfully assessed in recyclable sorting under difficult and demanding industrial conditions.

Robotic Waste Sorting Technology: Toward a Vision-Based Categorization System for the Industrial Robotic Separation of Recyclable Waste

Incorporating robots into industrial settings is not a new concept, but their use in the waste recycling industry is critical. Recently AI-assisted robots are used to support waste sorting and improve the quantity and quality of recovered materials. This article aims to study and apply a new transfer paradigm for recyclable sorting using Delta robots, which is based on replacing the usual Pick-and-Place process with the much faster Pick-and-Toss process. Current robotic sorting systems can sort one item per second, Pick-and-Toss intends to significantly advance this score. We quantitatively and qualitatively assess the tossing approach by comparing it to Pick-and-Place, in terms of accuracy and robustness, both in simulation and on a real waste sorting lab-setup equipped with an ABB-IRB360 Delta robot. Overall, the Pick-and-Toss approach proves to be a powerful mechanism that succeeds faster sorting of waste streams in comparison to the standard Pick-and-Place procedure.

Robotic Pick-and-Toss Facilitates Urban Waste Sorting *

In manufacturing systems, pick-up operations by vacuum grippers may fail owing to manufacturing errors in an object’s surface that are within the allowable tolerance limits. In such situations, manual interference is required to resume system operation, which results in considerable loss of time as well as economic losses. Although vacuum grippers have many advantages and are widely used in the industry, it is highly difficult to directly monitor the current machine status and provide appropriate recovery feedback for stable operation. Therefore, this paper proposes a method to detect the success or failure of a suction operation in advance by analyzing the amount of outlet air pressure in the Venturi line. This was achieved by installing an air pressure sensor on the Venturi line to predict whether the current suction action will be successful. Through empirical experiments, it was found that downward movements in the z-axis of the vacuum gripper can easily rectify a faulty gripper suction operation. Real-time monitoring results verified that predictive process adjustment of the pick-up operation can be performed by modifying the z-position of the vacuum gripper.

Predictive Process Adjustment by Detecting System Status of Vacuum Gripper in Real Time during Pick-Up Operations

Robotic process automation (RPA) is automating various job processes in many offices. However, most existing RPA systems automate only processes that are performed on computers. It is highly desirable to develop physical RPA systems that incorporate real robots to automate physical job processes. When developing physical RPA systems, handling paper is particularly important because many physical office jobs involve handling paper documents. However, it is not easy for robots to handle paper because paper is fragile. To address this issue, we propose an electroadhesive paper gripper in this study. The use of electroadhesion enables a robot to handle paper in a simple, non-destructive, and quiet manner. We provide (1) a mechanism for lifting a sheet of paper without accurate control of robot hands, (2) a mechanism for a small gripper to hold a large sheet of paper without bending it, and (3) a method for quickly releasing a sheet of paper. Furthermore, we apply the proposed paper gripper to a document-sorting robot. The robot that we have developed automatically arranges a given stack of paper documents in a predetermined order (e.g., alphabetical or numerical). Experimental results show the validity of the paper gripper and the sorting robot. 

An Electroadhesive Paper Gripper With Application to a Document-Sorting Robot

Recyclebot – using robots for sustainable plastic recycling

A variety of real-world robotic applications assume reliable grasping mechanisms to facilitate the effective management of objects. Vacuum technology has been frequently used for the development of end of arm tools for industrial robotic applications. Besides its effectiveness, the vacuum technology may occasionally face issues when the surface of the object to grasp is full of cavities or has an arbitrary non-flat shape. The present work studies the development of vacuum gripping mechanism for industrial environments, by assessing the importance of the vacuum generator technology, the use of shock absorber and the plasticity of the suction cup. The vacuum system is integrated in the end-effector of a delta-robot that is used for sorting recyclable wastes, thus providing the opportunity to assess vacuum performance on difficult and demanding situations. The obtained results show that the use of different vacuum generators has rather minimal effect on the performance of the composite system. On the opposite side, the use of the shock absorber and the plasticity of the suction cup may greatly affect system performance, especially for gripping objects with complex surfaces. To overcome the relevant issues, we have implemented a custom made suction cup that significantly facilitates gripping, even for dirty and oily objects. The composite system has been tested on a realistic recyclable waste sorting scenario with high success rates in gripping recyclable objects.

Emmanouil Papadakis

Papers

On the Use of Vacuum Technology for Applied Robotic Systems