Development of Robotic Hands: The UB Hand Evolution G. Palli, U. Scarcia, C. Melchiorri and G. Vassura Dipartimento di Elettronica, Informatica e Sistemistica Universit` a di Bologna, 40136 Bologna, Italy {gianluca.palli, umberto.scarcia, claudio.melchiorri, gabriele.vassura}@unibo.it Abstract— This video presents the evolution of the robotic hands, called UB Hands (University of Bologna Hands), de- veloped at the Laboratory of Automation and Robotics of the University of Bologna during more than 25 years of research in this field. Starting from the UB Hand I, the first robot hand prototype developed in our labs, the different design solutions and philosophies that have been followed toward the innovative UB Hand IV, also called DEXMART Hand, recently developed within the DEXMART project are presented. Remarkable characteristics of the UB Hands are also the whole hand manipulation capabilities, the ability of reconstructing the contact forces over the whole hand surface as in the case of the UB Hand II, and the presence of force/tactile sensors as in the UB Hand IV. Moreover, the use of soft covers for the emulation of the human tissue characteristics has been studied, and the adoption of innovative design concepts based on compliant structures has been introduced in the UB Hand III and IV. I. SUMMARY At the University of Bologna, since the end of the ’80, researchers have been engaged in the design and devel- opment of dexterous hands for industrial applications. Our research activity aims at reproducing the grasping and ma- nipulation capabilities of humans by developing innovative solutions concerning the mechanical design, the sensory equipment and the actuation system for the implementation of anthropomorphic robotic hands with improved reliability, functionality and reduced complexity and cost, considering also aspects related to safety during the interaction with humans. The only common characteristic among the several versions of the robotic hands developed at the University of Bologna is the actuation system based on remotely located actuators and tendon-based transmission. This design choice inspired by the biological model allows the reduction of the overall device complexity and volume, but introduces several issues that have been solved at control level also by means of a suitable sensory equipment, obtaining in this way intelligent grasping and manipulation devices. In 1988, financed by IBM Italy, a device with two parallel fingers, an opposible thumb and a palm has been developed. This robot hand were called UB Hand I. The phalanges were controller by artificial muscles, tendons and a controller, represented respectively by DC-motors, steel cables and a complex system of calculators and electronic equipments. The results of this project were a milestone for the research in this area, and a number of theoretical and experimental issues have been raised, which originated several interesting collaborations. As soon as the project with IBM finished, researchers from the University of Bologna where financed by the Italian government, and they stared to design new concepts in order to solve some of the critical aspect that affected the UB Hand I. The UB Hand II [1], [2] was revolutionary again. The kinematic structure was confirmed. It was introduced the wrist articulation, which has two degrees of freedom, a bend and a roll. The entire actuation system was embedded in the forearm. A great effort was made to integrate the arm and the hand both at an hardware and at a software level. Within the SICURA project, engineers started to investi- gate alternative design concepts for anthropomorphic robotic hands, which can safely interact with humans. Several pro- totypes of compliant joints were analyzed and evaluated. Simplification of the structure, the mechanisms and the control strategies were stressed. The robot hand prototype developed within this project has been called UB Hand III [3]. In 2008 the University of Bologna participated at the DEXMART project [4], funded by the European commis- sion. Its goal was to fill the gap between to use of robot industrial environments and the their use in everyday human and unstructured environments. Innovative technologies and solutions for the actuation system and the sensors were studied. The twisted string concept [5], based on twisting quickly a double wire to transform a rotational force in a linear tension, with intrinsic compliance and high trans- mission ratio. For the tactile, angular and force sensors, the potentialities of rapid prototyping have been exploited, together with the use of optical components, leading to inexpensive and reliable solutions. The final result of the project was the UB Hand IV, also called the DEXMART Hand [6], [7]. 2012 IEEE/RSJ International Conference on Intelligent Robots and Systems October 7-12, 2012. Vilamoura, Algarve, Portugal 978-1-4673-1735-1/12/S31.00 ©2012 IEEE 5456