Virgilio Mattoli

Design of a biomimetic robotic octopus arm

This paper reports the rationale and design of a robotic arm, as inspired by an octopus arm. The octopus arm shows peculiar features, such as the ability to bend in all directions, to produce fast elongations, and to vary its stiffness. The octopus achieves these unique motor skills, thanks to its peculiar muscular structure, named muscular hydrostat. Different muscles arranged on orthogonal planes generate an antagonistic action on each other in the muscular hydrostat, which does not change its volume during muscle contractions, and allow bending and elongation of the arm and stiffness variation. By drawing inspiration from natural skills of octopus, and by analysing the geometry and mechanics of the muscular structure of its arm, we propose the design of a robot arm consisting of an artificial muscular hydrostat structure, which is completely soft and compliant, but also able to stiffen. In this paper, we discuss the design criteria of the robotic arm and how this design and the special arrangement of its muscular structure may bring the building of a robotic arm into being, by showing the results obtained by mathematical models and prototypical mock-ups.

SPIRAL: A novel biologically-inspired algorithm for gas/odor source localization in an indoor environment with no strong airflow

This work describes the design and experimental results of an algorithm, designed to localize a gas source in an indoor environment with no strong airflow by using an autonomous agent. This condition exacerbates the patchiness and intermittency of odor distribution, typical of turbulent flows in the presence of strong mean flows. Furthermore, no information about the wind can be used to detect the position of the source. In the approach proposed here, the robot moves along spirals. A spiral can be reset and a new one started, based on the information acquired about gas distribution. This enables the robot to get close to the ejecting source, without relying on airflow measurements. Results from experiments are also described and discussed, to assess the efficiency of the proposed method.

Preparation, characterization and in vitro testing of poly (lactic-co-glycolic) acid/barium titanate nanoparticle composites for enhanced cellular proliferation

The recent advancements in tissue engineering and, more in general, in cell-based applications, has led to an ever increasing interest toward new materials for sustained cell proliferation and differentiation. Here, the preparation and the characterization of scaffolds based on poly(lactic-co-glycolic) acid / barium titanate nanoparticle composites are presented. In vitro testing on H9C2 cell line demonstrates how the presence of the nanoparticles positively affects both the proliferation and the differentiation of this muscle-like cell line. Finally, the possibility to obtain porous scaffold and, therefore, an actual 3D culture system, is introduced.

A Biologically-Inspired Algorithm Implemented on a new Highly Flexible Multi-Agent Platform for Gas Source Localization

This paper presents the design of a biologically-inspired algorithm, as well as the design and development of a new highly flexible multi-agent platform for a cooperative robotic system, to be applied to the localization of a gas source in an indoor environment with no strong airflow. The platform consists of a central PC and a variable number of robots. The robots cooperate, can communicate with each other, even when exchanging complex messages, and present a swarm-like behavior, which optimizes the gas localization task. The inexpensive, multipurpose, scalable, highly flexible platform whose use is discussed in this paper investigates the efficiency of bio-inspired cooperative algorithms, to detect the odor source location

Localizing multiple gas/odor sources in an indoor environment using bayesian occupancy grid mapping

This paper addresses the problem of autonomous localization of multiple gas or odor sources in an indoor environment with no strong airflow. In our approach, a robot iteratively builds an occupancy grid map from successive measurements of odor concentration. The resulting map shows the probability of each discrete cell in the map containing an active plume source. Our method is based on a recent adaptation of Bayesian occupancy grid mapping (OGM) to the chemical plume source localization problem. We present experimental results that demonstrate the utility of the approach.

Biomechatronic design and development of a legged rat robot

This paper describes the biomechatronic design of a legged rat robot, to be used in experiments on rat behavior. The rat robot has been designed so as to possess leg and body motion similar to those of real rats and to show the capability of rat-like simple behaviors, like walking and pushing a lever. The rat robot has 4 legs with 3 DOF (2 active and 1 passive) for each leg and 1 additional DOF allowing robot spine torsion. A cable and pulley mechanism allows the two front legs of the robot to perform manipulation tasks like pushing levers and buttons in a smooth and natural way, as not only the geometry and mass of the legs are similar to those of real rats, but also because the cables act, from an anatomical and physiological point of view, like the triceps muscle with the knee tendon structure. An interaction experiment, using our rat robot and two different real rats (control and experimental subject) has been conducted to verify the capability of the robotic rat to interact and teach simple tasks to the real rat.

Design and development of biomimetic quadruped robot for behavior studies of rats and mice

This paper presents the design and development of a novel biomimetic quadruped robot for behavior studies of rats and mice. Many studies have been performed using these animals for the purpose of understanding human mind in psychology, pharmacology and brain science. In these fields, several experiments on social interactions have been performed using rats as basic studies of mental disorders or social learning. However, some researchers mention that the experiments on social interactions using animals are poorly-reproducible. Therefore, we consider that reproducibility of these experiments can be improved by using a robotic agent that interacts with an animal subject. Thus, we developed a small quadruped robot WR-2 (Waseda Rat No. 2) that behaves like a real rat. Proportion and DOF arrangement of WR-2 are designed based on those of a mature rat. This robot has four 3-DOF legs, a 2-DOF waist and a 1-DOF neck. A microcontroller and a wireless communication module are implemented on it. A battery is also implemented. Thus, it can walk, rear by limbs and groom its body. Key word: Biomimetics, Quadruped robot, Experiments with animals

Development of the hybrid wheel-legged mobile robot WR-3 designed to interact with rats

This paper presents the design and development of a bio-inspired mobile robot called WR-3 (Waseda Rat No.3), as an experimental tool to study social interaction between rats and robots. According to the motion analysis of rats, their motion can be divided into two phases: moving and interaction. Therefore, a novel hybrid mechanism in which wheels are used for moving and legs are used for interaction has been designed to actuate the WR-3. Consequently, the robot can move at a high speed using its wheels and reproduce the rats interaction using its legs and other parts. Based on the dimension and body structure of a mature rat, WR-3 has been designed with dimensions of 240×70×90[mm] and is the same shape as a rat. It consists of 18 DOFs in total: two 1-DOF wheels, four 3-DOF legs (including passive DOFs), a 2-DOF waist, and a 2-DOF neck. Preliminary interaction experiments with rats demonstrate that WR-3 is capable of reproducing interactions such as following, rearing, grooming, mounting, etc. similar to a real rat.

Explorative Particle Swarm Optimization method for gas/odor source localization in an indoor environment with no strong airflow

This paper presents an algorithm to localize a gas source by using a swarm of robots in a large indoor environment without the presence of a relevant wind. The algorithm is composed of two different phases: an exploration phase aiming at finding a clue of the presence of a gas source and a localization phase to detect the emitting source. We propose a modified version of the particle swarm optimization (PSO) algorithm, called explorative particle swarm optimization (EPSO), as a strategy of movement for the swarm of robots during the localization phase. The introduced modifications point at avoiding multiple gas samplings in nearby locations, in this way increasing the exploration of the area and limiting the possibility for the swarm of being trapped in local maxima. Results from computer simulations are reported and discussed. They show that, in these environmental conditions, the proposed algorithm improves the performance of the standard PSO and can be a viable solution in localizing a chemical source.

Development of a novel quadruped mobile robot for behavior analysis of rats

In the domain of psychology and medical science, many experiments have been conducted referring to research on animal behaviors, to study the mechanism of mental disorders and to develop psychotropic drugs to treat them. Rodents such as rats are often chosen as experimental subjects in these experiments. However, according to some researchers, the experiments on social interactions using animals are poorly- reproducible. Therefore, we consider that the reproducibility of these experiments can be improved by using a robotic agent that interacts with an animal subject. We have developed a novel quadruped rat-inspired robot, the WR-2 (Waseda Rat No.2), based on the dimension and body structure of a mature rat. It is capable of reproducing the behaviors such as walking, mounting, rearing and grooming of the rat.