Title: Decentralized multi-arm planning

Author of the experiment: Alessandro Marino & Jolanda Coppola

Description: A two-layer decentralized framework for kinematic control of cooperative and collaborative multi-robot systems is developed and tested. The motion of the system is specified at the workpiece level, by adopting a task-oriented formulation for cooperative tasks. The first layer computes the motion of the single arms in the system. In detail, the control unit of each robot computes the end-effector motion references in a decentralized fashion on the basis of the knowledge of the assigned cooperative task and the motion references computed by its neighbors. Then, in the second layer, each control unit computes the reference joint motion of the corresponding manipulator from the end-effector reference motion.

Setup: 2 Comau SmartSix robots installed at the Automatica Laboratory of University of Salerno.


Title: Cooperative drilling of aeronautic hybrid stacks

Author of the experiment: Alessandro Marino

Description: The proposed technology consists in a general robot architecture and a cooperative drilling process using only standard low-cost robots and off-the-shelf components. A first robot is in charge of drilling the hybrid stack, while a second manipulator ensures the right clamping force between the parts of the stack. Both robots are equipped with force control capabilities to control the generalized forces raising during the interaction with the stack. Thanks to the adoption of a fuzzy inference system, the tuning of the force controllers might be carried out by operators that have knowledge of the drilling process but not of control system technology.

Setup: 2 Comau SmartSix robots equipped with force/torque sensors installed at the Automatica Laboratory of University of Salerno.


Title: Cooperative impedance

Author of the experiment: Alessandro Marino

Description: This is a video showing experiments on impedance control for cooperative manipulators. Dexterous manipulation of objects with two robot hands require a suitable cooperation between the robots. Control of the absolute motion of the object as well as of the internal forces shall be ensured. Also, the interaction between the environment and the object to be manipulated should be taken into account. A general impedance control scheme was adopted, which encompasses a centralized impedance control strategy aimed at conferring a compliant behavior at the object level, and a decentralized impedance control, enforced at the end-effector level, aimed at avoiding large internal loading of the object. The overall control scheme is based on a two-loops arrangement, where a simple PID inner motion loop is adopted for each manipulator. Reference: F. Caccavale, P. Chiacchio, A. Marino, L. Villani: Six-DOF impedance control of dual-arm cooperative manipulators, IEEE/ASME Trans. Mechatron. 13, 576-586 (2008).


Title: Cooperative harbour patrolling

Author of the experiment: Alessandro Marino

Description: Three Surface marine vehicles, entirely designed and assembled by the staff of the Dynamical Systems and Ocean Robotics Laboratory (DSOR-Lab) of the ISR/IST (Instituto Superior Tecnico/Institute for Systems and Robotics) of Lisbon, are adopted. The Medusa vehicles were used to perform the patrolling mission at the Parque Expo site in Lisbon. Patrolling is here interpreted within the framework of the sampling problem. To be applied in practice, several realistic constraints and the time/spatial variance of the information are explicitly taken into account. The proposed approach is well rooted in the concepts of Voronoi tessellations and Gaussian Processes. Each robot, based only on local information, computes the next point to visit according to a given performance criteria.

Setup: 3 surface marine vehicles at the ISR/IST (Instituto Superior Tecnico/Institute for Systems and Robotics).


Title: Cooperative harbour patrolling

Author of the experiment: Alessandro Marino

Description: Three Surface marine vehicles, entirely designed and assembled by the staff of the Dynamical Systems and Ocean Robotics Laboratory (DSOR-Lab) of the ISR/IST (Instituto Superior Tecnico/Institute for Systems and Robotics) of Lisbon, are adopted. The Medusa vehicles were used for the patrolling mission. Patrolling is here interpreted within the framework of the sampling problem. To be applied in practice, several realistic constraints and the time/spatial variance of the information are explicitly taken into account. The proposed approach is well rooted in the concepts of Voronoi tessellations and Gaussian Processes. Each robot, based only on local information, computes the next point to visit according to a given performance criteria.


Title: Cooperative harbour patrolling

Author of the experiment: Alessandro Marino

Description: The Folaga is 2m length and 30Kg weight and with an autonomy of 8 h; it is able to navigate on the sea surface with its own propulsion system; it dives vertically, exploiting ballast and attitude changes. The motion is due to propulsion jet-pumps or to a propeller at the vehicle stern (both options are available). Underwater communication is allowed by WHOI micro-modem based on the Texas Instrument TMS320C5416 DSP able to transmit at about 80 bps. The Folaga vehicles were used for the patrolling mission. Patrolling is here interpreted within the framework of the sampling problem. To be applied in practice, several realistic constraints and the time/spatial variance of the information are explicitly taken into account. The proposed approach is well rooted in the concepts of Voronoi tessellations and Gaussian Processes. Each robot, based only on local information, computes the next point to visit according to a given performance criteria. The scenario used for tests is the Gulf of La Spezia, Italy, and in particular the NATO Undersea Research Center. The volume to patrol is 150×120×4m box 1m below sea level.

Setup: 2 underwater vehicles from Graal Tech.


Title: Decentralized fault-detection and accomodation for multi-robot systems

Author of the experiment: Alessandro Marino

Description: The vehicles in the video are Khepera III robots The proposed solution for distributed fault tolerant control of multi-agent systems is based on a distributed observer-controller schema where each robot, by communicating only with its direct neighbors, is able to estimate the overall state of the system. Such an estimate is then used by the controllers of each robot to achieve global missions as, for example, centroid and formation tracking. The information exchanged among the observers is also used to compute residual vectors that allow each robot to detect failures on anyone of the teammates, even if not in direct communication. The proposed strategy considers both recoverable and unrecoverable actuator faults. When the robots are subject to unrecoverable faults, the faults are isolated from anyone of the teammates by means of a distributed fault detection and isolation strategy; then, the faulty robots are removed from the team and the mission is rearranged. University of Cassino and Southern Lazio: http://webuser.unicas.it/lai/robotica/ University of Basilicata: http://www2.unibas.it/automatica/ University of Salerno: http://www.automatica.unisa.it/ Reference: Arrichiello, Filippo; Marino, Alessandro; Pierri, Francesco Observer-Based Decentralized Fault Detection and Isolation Strategy for Networked Multirobot Systems IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY. Vol. 23. Pag.1465-1476, 2015.


Title: Decentralized formation control for multi-robot systems

Author of the experiment: Alessandro Marino

Description: The team is composed by 5 Khepera III mobile robots and a base station set-up by the robotic group of University of Cassino. Each robot and the base station have on-board a Korebot II board with a basic linux os that allows to execute autonomous navigation algorithms. The default equipment of the robots is composed by several infrared sensors, 5 sonar and a wifi communication device. Moreover, depending on the specific mission, the robots can be equipped with on-board usb webcam, or with an Hokuyo URG Laser Scanner. The robots are used to test decentralized control algorithms for multi-robot systems. In fact, the Null-Space-based Behavioral control (NSB) has been extended to the control of decentralized multi-robot systems. University of Cassino and Southern Lazio: http://webuser.unicas.it/lai/robotica/ University of Basilicata: http://www2.unibas.it/automatica/ University of Salerno: http://www.automatica.unisa.it/ Reference: G. Antonelli and F. Arrichiello and F. Caccavale and A. Marino, Decentralized time-varying formation control for multi-robot systems, The International Journal of Robotics Research, vol.33, n.7, pp. 1029--1043, 2014.


Title: Multi-robot patrolling

Author of the experiment: Alessandro Marino

Description: Multirobot systems can execute missions more efficiently than a single robot or can accomplish tasks not executable by a single one; moreover, they offer increased tolerance to possible vehicle faults, provide flexibility to task execution, and can take the advantages of distributed sensing and actuation. A behavior-based approach, namely the Null-Space-based Behavioral control (NSB), aimed at guiding a mobile robots platoon has been adopted. The approach, using a hierarchy based logic to combine multiple conflicting tasks, is able to fulfill or partially fulfill each task according to their position in the hierarchy. This control technicque was used to perform the decentralized patrolling mission. The basic idea is to define elementary behaviors and then combine them in a consistent way to form a set of high-level actions in the NSB framerwork. The approach was experimente on a setub composed by three Pioneer 3DX robots. They are 0.44 m long, 0.38 m wide, and 0.22 m tall, having a two-wheel drive along with a passive caster, equipped with two rings of sonars (8 front and 8 rear), a SICK laser range-finder, a pan-tilt-zoom color camera, onboard computation on a PC104 stack and Player control software.


Title: Multi-robot patrolling

Author of the experiment: Alessandro Marino

Description: Multi-robot systems can execute missions more efficiently than a single robot or can accomplish tasks not executable by a single one; moreover, they offer increased tolerance to possible vehicle faults, provide flexibility to task execution, and can take the advantages of distributed sensing and actuation. A behavior-based approach, namely the Null-Space-based Behavioral control (NSB), aimed at guiding a mobile robots platoon has been adopted. The approach, using a hierarchy based logic to combine multiple conflicting tasks, is able to fulfill or partially fulfill each task according to their position in the hierarchy. This control technique was used to perform the decentralized patrolling mission. The basic idea is to define elementary behaviors and then combine them in a consistent way to form a set of high-level actions in the NSB framework. The approach was experimented on a setubp composed by three Pioneer 3DX robots. They are 0.44 m long, 0.38 m wide, and 0.22 m tall, having a two-wheel drive along with a passive caster, equipped with two rings of sonars (8 front and 8 rear), a SICK laser range-finder, a pan-tilt-zoom color camera, onboard computation on a PC104 stack and Player control software.