edited by: Nestor E. Nava Rodríguez
One of the main objectives of the robotic is to make the systems able to interact, modify, transmit and receive information from the human environment. They reach the possibility to replace the human being in simple and basic functions with better results. In this way, robotic hands play a relevant role since they can perform different tasks, such as holding and manipulating, reaching visual communication and obtaining direct contact with the environment, interacting and even modifying it. When we refer to robotic hands the first thing that comes up to our mind is a robotic system that tries to imitate, in the closest way, the skills and shapes that human hands have. There are many different robotic hands and each of them marks a determined improvement in a specific aspect, due to new technology used in its development, since it has been designed from an innovative mechanic system or mechanism. Technology and mechanics applied to robotics help in improving faster. These two concepts, as it is going to be detailed in this Chapter, must be closely related because the efficient use of one of them depends on the improvement of the other. Basing in our classification, it is possible to divide robotic hands in to two types: the multi-actuated robotic hands, directed by technology and helped by special mechanisms, and the underactuated robotic hands, focused on complex and innovative mechanic systems. The second classification adds a new system concept that allows generating several and independent tasks fulfilled with only one actuator, referring to a new generation of robotic hands able to manipulate in a more dextrous way. In this Chapter, robotic hands will be analysed from its technological and mechanical aspects. First, there will be a brief explanation of robotic hands that have incorporated innovative mechanisms or new technology. Afterwards, the Chapter will focus on functional problems that can be found in the robotic hands development. Finally, some solutions will be detailed through mechanical systems and how they can affect the development of new robotic hands, studying the case of underactuated architectures.