Paolo Corradi

Symbiotic robot organisms: REPLICATOR and SYMBRION projects

Cooperation and competition among stand - alone swarm agents can increase the collective fitness of the whole system. An interesting form of collective system is demonstrated by some bacteria and fungi, which can build symbiotic organisms. Symbiotic communities can enable new functional capabilities which allow all members to survive better in their environment. In this article we show an overview of two large European projects dealing with new collective robotic systems which utilize principles derived from natural symbiosis. The paper provides also an overview of typical hardware, software and methodological challenges arose along these projects, as well as some prototypes and on-going experiments available on this stage.

Micromanipulation, communication and swarm intelligence issues in a swarm microrobotic platform

Abstract Rapid advancements of both microsystem technology and multi-agent systems have generated a new discipline, arising from the fusion of microrobotics technologies and of swarm intelligence theories. Microrobotics contributes with new capabilities in manipulating objects in the microscale and in developing miniaturized intelligent machines, while swarm intelligence supplies new algorithms allowing sets of simple robotic agents to solve complex tasks. A microrobotic swarm that is able to collectively achieve a cleaning task in an arena has been developed. This paper presents a novel platform for microrobotic swarms with the goal to apply swarm intelligence results to practical micromanipulation tasks and describes in details two main features of the platform: an optical communication strategy between the microrobotic agents, in order to share information and to coordinate swarm actions, and a micromanipulation technique–based on electrostatic phenomena–which can be performed by each microrobotic agent.

An Integrated Triangulation Laser Scanner for Obstacle Detection of Miniature Mobile Robots in Indoor Environment

The miniaturization of an autonomous robot requires the integration of components that not only need to satisfy strict spatial constraints, but also need to demonstrate useful functionalities and performance, while demanding low power. For miniaturized autonomous robots that aim at exploring unknown environments, sensors for navigation and for the understanding of basic geometrical features of the environment are of utmost importance for a robots survival and mission. This paper presents a miniaturized triangulation laser scanner that was developed and characterized for use on a 10 × 10 × 10 cm3 robot. The optimal configurations of the laser sensor on two sides of the robot are discussed, and measurement formulas as well as theoretical resolution are deduced. For indoor applications, the measurement range of the system runs from approximately 80 mm, with 1 mm resolution, up to 600 mm, with 12 mm resolution. The aim of the work is to demonstrate the possibility of extracting basic information from the robot surroundings by means of small, simple, low-power, and low-cost demanding devices, which, in addition, can be scaled down in order to equip even smaller robots.

Evaluation of building technology for mass producible millimetre-sized robots using flexible printed circuit boards

Initial tests of a building technology for a compact three-dimensional mass producible microrobot are presented. The 3.9 × 3.9 × 3.3 mm3 sized prototype robot represents a microsystem with actuators, sensors, energy management and integrated electronics. The weight of a folded robot is 65 mg and the total volume is less than 23 mm3. The design of the interfaces of the different modules in the robot, as well as the building technology, is described. The modules are assembled using conductive adhesive with industrial surface mounting technology on a thin double-sided flexible printed circuit board. The final shape of the microrobots is achieved by folding the flexible printed circuit board twice. Electrical and mechanical studies are performed to evaluate the assembly and it is concluded that the technology can be used for this type of microsystem. Several issues using the presented assembly technique are identified and addressed.

A Miniaturized Mechatronic System Inspired by Plant Roots for Soil Exploration

This paper describes the principles and theoretical investigations, supported by experimental measurements, aimed at designing and developing a novel mechatronic system for soil exploration, inspired by the apical part of the plant roots, named apex. Each single plant root has to move through the substrate, orienting itself along the gravity vector and locating water and nutrients. In the same way, the mechatronic apex can steer in all directions and it embeds a gravity sensor, a soil moisture gradient detector, as well as the electronics for sensory data acquisition and steering control. A bio-inspired algorithm reproducing the gravitropism and hydrotropism behaviors, typical of plants, was developed and tested on a purposive prototype of the mechatronic apex system, actuated by hydraulic pumps. Moreover, the design and testing of a novel bio-inspired osmotic actuator module, composed of three cells separated by couples of osmotic and ion-selective membranes, is also presented. Preliminary prototypes developed in acrylic material for testing the gravitropism and hydrotropism behaviors are shown.

Bio-inspired grasp control in a robotic hand with massive sensorial input

The capability of grasping and lifting an object in a suitable, stable and controlled way is an outstanding feature for a robot, and thus far, one of the major problems to be solved in robotics. No robotic tools able to perform an advanced control of the grasp as, for instance, the human hand does, have been demonstrated to date. Due to its capital importance in science and in many applications, namely from biomedics to manufacturing, the issue has been matter of deep scientific investigations in both the field of neurophysiology and robotics. While the former is contributing with a profound understanding of the dynamics of real-time control of the slippage and grasp force in the human hand, the latter tries more and more to reproduce, or take inspiration by, the nature’s approach, by means of hardware and software technology. On this regard, one of the major constraints robotics has to overcome is the real-time processing of a large amounts of data generated by the tactile sensors while grasping, which poses serious problems to the available computational power. In this paper a bio-inspired approach to tactile data processing has been followed in order to design and test a hardware–software robotic architecture that works on the parallel processing of a large amount of tactile sensing signals. The working principle of the architecture bases on the cellular nonlinear/neural network (CNN) paradigm, while using both hand shape and spatial–temporal features obtained from an array of microfabricated force sensors, in order to control the sensory-motor coordination of the robotic system. Prototypical grasping tasks were selected to measure the system performances applied to a computer-interfaced robotic hand. Successful grasps of several objects, completely unknown to the robot, e.g. soft and deformable objects like plastic bottles, soft balls, and Japanese tofu, have been demonstrated.

Optical Networking in a Swarm of Microrobots

Swarm Microrobotics aims to apply Swarm Intelligence algorithms and strategies to a large number of fabricated miniaturized autonomous or semi-autonomous agents, allowing collective, decentralized and self-organizing behaviors of the robots. The ability to establish basic information networking is fundamental in such swarm systems, where inter-robot communication is the base of emergent behaviors. Optical communication represents so far probably the only feasible and suitable solution for the constraints and requirements imposed by the development of a microrobotic swarm. This paper introduces a miniaturized optical communication module for millimeter-sized autonomous robots and presents a computer-simulated demonstration of its basic working principle to exploit bio-inspired swarm strategies.

An optical system for communication and sensing in millimetre-sized swarming microrobots

Microrobotic technology underlines the concept of top–down fabrication of autonomous or semi-autonomous robotic systems, with the final aim to produce autonomous micromachines. For millimetre-sized robots, all the sub-component modules must be conceived and designed as minimal components able to accomplish a specific basic task, and each of them consequently represents a fundamental part in the whole microrobotic system. Communication and sensing modules, in particular, are indispensable to the microrobot in order to physically interact with its neighbours and the surrounding environment, a fundamental feature for multi-agent or swarm robotic systems. At present, there exist no communication and sensing modules suitable to be integrated in millimetre-sized microrobots that fulfil the requirements of the application discussed in this paper. The objective of the paper is to present the development of an integrated and scalable miniaturized optical system for communication and sensing in swarming microrobots that are among the smallest ever reported. The system consists of optoelectronic devices in a die form, which are assembled on a substrate and encompassed in a mirroring polymeric structure. The final experimental results demonstrate the effectiveness of the optical module, and potential methods for further improving the system performance are finally proposed.

An optical interface for inter-robot communication in a swarm of microrobots

It is described the optical communication interface for short-range communications of robots in a microrobotic swarm between thousands of units. The robots, of 27 mm3-size, will be deployed in an arena of A4 sheet size with controlled illumination conditions. The communication between robots is done via IR light. The interface can handle variations of IR background light from point to point in the arena, deals with robot different orientation and distance, i.e., the amplitude of the signal to be detected, and with interferences of other robots. The interface has been designed to manage the low energy available in the robot.

A Micro-Optical Transducer for Sensing Applications

This article describes the design, development, and characterization of a miniaturized optical system that works as a part of a hybrid flexible system, where electrical signals, generated by tactile micro-sensors, are computed by a microcontroller driving the micro-optical transducer. The whole module was conceived to be mass-produced for sensing applications where flexibility and thickness of the sensing network are primary requirements, e.g., skin-like sensing structures for robotics. The fabricated micro-optical system fulfilled application requirements, demonstrating also appealing features and optical performances as a basic general-purpose optical terminal.