Fabio Pini

A systematic approach to the engineering design of a HRC workcell for bio-medical product assembly

Human Robot Collaboration (HRC) have proved to be effective if compared to traditional hybrid automation in assembly tasks, especially when human-like sensitivity and high quality are required. However, a rigorous engineering design is mandatory in order to successfully apply HRC to Industry. Academy and Industry are asked to jointly work for exploiting the technical opportunities given by robots and humans. Scientific literature often describes the application of HRC in manufacturing but rarely presents systematic engineering design approaches. The present paper investigates and describes the systematic design of a HRC workcell for assembling bio-medical products. Moreover, productivity and profitability of the developed solution are evaluated and discussed.

An Offline Programming Method for the Robotic Deburring of Aerospace Components

Deburring of aerospace components is a complex task in case of large single pieces designed and optimized to deliver many mechanical functions. A constant high quality requires accurate 3D surface contouring operations with engineered tool compliance and cutting power. Moreover, aeronautic cast part production is characterized by small lot sizes with high variability of geometries and defects. Despite robots are conceived to provide the necessary flexibility, reconfigurability and efficiency, most robotic workcells are very limited by too long programming and setup times, especially at changeover. The paper reports a design method dealing with the integrated development of process and production system, and analyzes and compares a CAD-based and a digitizer-based offline programming strategy. The deburring of gear transmission housings for aerospace applications serves as a severe test field. The strategies are compared by the involved costs and times, learning easiness, production downtimes and machining accuracy. The results show how the reconfigurability of the system together with the exploitation of offline programming tools improves the robotic deburring process.

Integration of CAM off-line programming in robot high-accuracy machining

Actual industrial robotic systems offer performance to effectively cope with the requirements in manufacturing dealing with flexibility and quality. However, their known limits in accuracy do not allow to extend their field of application to high-accuracy machining, actually covered by state-of-the-art CNC machine tools. The European Project COMET has recently proposed an approach to develop a robotic reconfigurable workcell with enhanced accuracy for machining, through the full integration of different theoretical models, technological solutions and manufacturing strategies. The present paper presents and demonstrates the effectiveness of a demo reconfigurable machining workcell for one of its possible configurations, based on CAM off-line programming. In particular, an experimental campaign has been designed and realized in order to discuss the dimensional and geometrical quality obtained for an aluminium automotive part in comparison with quality and costs offered by a standard 5-axis CNC machine tool.

A Calibration Method for the Integrated Design of Finishing Robotic Workcells in the Aerospace Industry

Industrial robotics provides high flexibility and reconfigurability, cost effectiveness and user friendly programming for many applications but still lacks in accuracy. An effective workcell calibration reduces the errors in robotic manufacturing and contributes to extend the use of industrial robots to perform high quality finishing of complex parts in the aerospace industry. A novel workcell calibration method is embedded in an integrated design framework for an in-depth exploitation of CAD-based simulation and offline programming. The method is composed of two steps: a first offline calibration of the workpiece-independent elements in the workcell layout and a final automated online calibration of workpiece-dependent elements. The method is finally applied to a robotic workcell for finishing aluminum housings of aerospace gear transmissions, characterized by complex and non-repetitive shapes, and by severe dimensional and geometrical accuracy demands. Experimental results demonstrate enhanced performances of the robotic workcell and improved final quality of the housings.

Evaluation of operator relief for an effective design of HRC workcells

In recent years, Human Robot Cooperation (HRC) has found an increasing adoption in manufacturing, especially to help humans in the execution of manual assembly tasks. An effective employment of HRC encompasses human relief from exhausting operations. Therefore, the design of cooperative solutions should be developed accordingly to ergonomic aspects. The present work proposes an approach to support the integration of ergonomic evaluation of manual operations in the design of HRC solution, based on modelling and simulation of the human body along the manufacturing tasks. The proposed modified model integrates the ergonomic metrics and returns a fatigue level along the working shift scheduling. A real manual assembly of biomedical products has been selected to validate the proposed approach. As a result, the suggested fatigue model provides an objective ergonomic evaluation of manual operations which verifies the impact of the HRC solution on the production goals.

Dynamic Identification of Industrial Robots from Low-Sampled Data

This paper proposes a fast and on-site method for the dynamic identification of industrial robots from low-sampled position and torque data. Owing to the basic architecture of the employed controller, only trapezoidal-velocity trajectories can be enforced for identification purposes. Differently from previous literature, where this kind of trajectories were performed with limited joint velocities and range of motions, the procedure proposed hereafter is characterized by fast movements performed on wide angular ranges. Furthermore, in order to identify the influence of friction without deriving complex friction models, a novel method is outlined that decouples frictional torques from gravitational, centrifugal and inertial ones. Finally, although multiple experiments of different kinds have been performed, inertial parameters are determined in one singular step, thus avoiding possible error increase due to sequential identification algorithms.

Offline workpiece calibration method for robotic reconfigurable machining platform

Recent trends in industrial manufacturing impose the adoption of changeable systems, based on reconfigurable and flexible equipment. In this scenario, industrial robotics platforms are central to design highly reconfigurable systems. A Robotic Reconfigurable Machining Platform (RRMP), as defined, is a modular architecture for robotic workcells, designed in order to exploit the flexibility features of robots and extend their field of application to high precision machining. RRMP calibration is a key task, which involves calibration of tools, workpieces and peripherals. However, state-of-the-art calibration methods and tools lead to hardly predictable system downtime, which impacts the reconfiguration phase. A novel method to perform the workpiece calibration is proposed for the reduction of the reconfiguration efforts in RRMPs. The method is addressed through a full integration with a virtual environment for robot simulation and programming. The method is finally applied to an industrial case study and compared to the most widely diffused online approach.