Grasp compliance control with underactuated robotic hand

Mathematical methods and tool to analize and to study the grasping of parallel robot. Study of compliance matrix of a grasped object. Application of studied methods on a DLR Han

An experimental analysis of abrasive water jet engraving of Italian marbles / Analisi sperimentale del processo di marcatura su marmi italiani tramite getto d’acqua ad alta pressione con abrasivo

English: This article concerns characterizing and optimizing the process of water-jet engraving on stone materials through experimental analysis. The purpose is to find possible relationships between work parameters for an abrasive water-jet and the geometrical parameters created by grooves. Samples of White Carrara and Perlato of Coreno marbles were used in testing. An optical profilometer was used to measure the transversal profile of the groove, objectively characterized by a number of measurements described in the article, including two parameters of visual quality. Statistical analysis made it possible to indicate optimal settings to enter on the basis of desired results; for example, increases in width, depth or the degree of groove contrast. Italian: Questo articolo affronta la caratterizzazione e ottimizzazione del processo di incisione di materiali lapidei mediante water jet attraverso un’analisi sperimentale. La finalità è trovare possibili relazioni tra parametri impostati per la lavorazione, tramite idrogetto con abrasivo, e parametri geometrici ricavati dai solchi. Per questo studio sono stati analizzati dei campioni di marmo Bianco di Carrara e di Perlato di Coreno. Per mezzo di un profilometro ottico è stato possibile misurare il profilo trasversale del solco, caratterizzato in maniera oggettiva tramite alcune misure descritte nell’articolo, inclusi due parametri di qualità visiva. Attraverso un’analisi statistica è stato possibile indicare le impostazioni ottimali da settare in base al risultato desiderato: es. aumento della larghezza, profondità o livello di contrasto del solco

Underactuated Robotic Fish Control: Maneuverability and Adaptability Through Proprioceptive Feedback

Bioinspired robotics is a promising technology for minimizing environmental disruption during underwater inspection, exploration, and monitoring. In this research, we propose a control strategy for an underactuated robotic fish that mimics the oscillatory movement of a real fish’s tail using only one DC motor. Our control strategy is bioinspired to Central Pattern Generators (CPGs) and integrates proprioceptive sensory feedback. Specifically, we introduced the angular position of the tail as an input control variable to integrate a feedback into CPG circuits. This makes the controller adaptive to changes in the tail structure, weight, or the environment in which the robotic fish swims, allowing it to change its swimming speed and steering performance. Our robotic fish can swim at a speed between 0.18 and 0.26 body lengths per second (BL/s), with a tail beating frequency between 1.7 and 2.3 Hz. It can also vary its steering angular speed in the range of 0.08 rad/s, with a relative change in the curvature radius of 0.25 m. With modifications to the modular design, we can further improve the speed and steering performance while maintaining the developed control strategy. This research highlights the potential of bioinspired robotics to address pressing environmental challenges while improving solutions efficiency, reliability and reducing development costs

Advanced grasping with the Pisa/IIT softHand

This chapter presents the hardware, software and overall strategy used by the team UNIPI-IIT-QB to participate to the Robotic Grasping and Manipulation Competition. It relies on the PISA/IIT SoftHand, which is underactuated soft robotic hand that can adapt to the grasped object shape and is compliant with the environment. It was used for the hand-in-hand and for the simulation tracks, where the team reached first and third places respectively

An experimental analysis of laser engraving on marble / Analisi sperimentale del processo di marcatura laser su marmo

Questo articolo affronta la caratterizzazione e ottimizzazione del processo di incisione di materiali lapidei tramite fascio laser attraverso un’analisi sperimentale. La finalità è trovare possibili relazioni tra parametri impostati per la lavorazione e parametri geometrici ricavati dai solchi. Per questo studio sono stati analizzati dei campioni di marmo Bianco di Carrara. Per mezzo di un profilometro ottico è stato possibile misurare il profilo trasversale del solco, caratterizzato in maniera oggettiva con alcune misure descritte nell’articolo, inclusi due parametri di qualità visiva. Attraverso un’analisi statistica è possibile indicare le impostazioni ottimali da settare in base al risultato desiderato: es. aumento della larghezza, profondità o livello di contrasto del solco. English: This article deals with characterizing and optimizing the process of engraving stone materials with a laser beam through experimental testing. The purpose of testing was to find possible relations between the parameters set for work and the geometric parameters gotten from the grooves. For this study we tested samples of White Carrara marble. By means of an optical profilometer it was possible to measure the cross section of the groove, objectively characterized by a number of measurements described in the article including two parameters of visual quality. Through statistical analysis it was possible to indicate optimal settings to use on the basis of the results desired; for example, increasing the width, depth or contrast level of the groove

Low-Cost and Accurate Reconstruction of Postures via IMU

In this chapter, we present an approach to reconstruct the pose of serial kinematic chain that aims at reconciling the two previously described, and could be defined as an intermediate way of tackling the problem, see Figure 30.1c. Inspired by (b), we apply to each link of the chain with an inertial measurement unit (IMU), thus estimating its orientation via a quaternion. Then considering the relative orientation of a link with respect another one, and knowing the geometry and the topology of the joint between two links, we are able to compute the joint angles value

Low-cost, fast and accurate reconstruction of robotic and human postures via IMU measurements

In this paper, we present a method to reconstruct the configurations of kinematic trees of rigid bodies not using measurements of relative angles (such as, e.g. rotary encoders at joints) but absolute posture sensors (such as IMUs) along with suitable filter algorithms. We argue that the relatively larger inaccuracies shown by absolute sensors can be compensated by suitable processing, such as a passive complementary filters exploiting the Mahony-Hamel formulation. The proposed method is applicable to systems where measurements of relative angles is not feasible or convenient, or where the joint kinematics are not lower pairs: for example, human body parts or soft robotic devices. In the paper, we make explicit reference to the reconstruction of posture of the compliant, underactuated Pisa/IIT SoftHand. Quantitative comparisons with ground truth data in grasping tests are used to validate the proposed method. The resulting hardware design is mechanically robust, cheap and can be easily adapted to robotic hands with different structures, as well as to sensorizing gloves for studying human grasping strategies

An experimental analysis of abrasive water jet engraving of Italian marbles / Analisi sperimentale del processo di marcatura su marmi italiani tramite getto d’acqua ad alta pressione con abrasivo

This article concerns characterizing and optimizing the process of water-jet engraving on stone materials through experimental analysis. The purpose is to find possible relationships between work parameters for an abrasive water-jet and the geometrical parameters created by grooves. Samples of White Carrara and Perlato of Coreno marbles were used in testing. An optical profilometer was used to measure the transversal profile of the groove, objectively characterized by a number of measurements described in the article, including two parameters of visual quality. Statistical analysis made it possible to indicate optimal settings to enter on the basis of desired results; for example, increases in width, depth or the degree of groove contrast