Underactuated robotics: A review <s> UR hand <s> This research presents a multi-fingered hand and computer control system intended for research in dextrous manipulation. The hand mechanism is based on an anthropomorphic configuration with four identical fingers. Each finger has four degrees of freedom actuated by four DC servomotors. The fingers, palm and mechanical interface to a robotic arm are separate components of a modular design allowing the hand to be highly dexterous and flexible. Each finger is a compact module with eight position sensors, and all the four actuators are integrated into the mechanical structure of the finger module. Position control has been implemented using a DSP based computer controller. Experimental results validate that the basic functionality and requirements of the hand system were achieved. <s> BIB001 </s> Underactuated robotics: A review <s> UR hand <s> Abstract This paper describes the mechanical features of an experimental, multiple finger, prosthetic hand which has been designed for children in the 7–11 year age group. Conventional prosthetic hands exist for this age group, but they have limited mechanical function. The experimental hand presented is able to perform passive adaptive grasp, that is, the ability of the fingers to conform to the shape of an object held within the hand. During grasping, the four fingers and thumb are able to flex inwards independently, to conform to the shape of the object. This passive design is simple and effective, not requiring sensors or electronic processing. The adaptive grasp system developed here results in a hand with reduced size and weight compared to other experimental hands, and has increased mechanical function and cosmetic appearance compared to conventional prosthetic hands. <s> BIB002 </s> Underactuated robotics: A review <s> UR hand <s> Current prosthetic hands are basically simple grippers with one or two degrees of freedom, which barely restore the capability of the thumb-index pinch. Although most amputees consider this performance as acceptable for usual tasks, there is ample room for improvement by exploiting recent progresses in mechatronic design and technology. This paper focus on an innovative approach for the design and development of prosthetic hands based on underactuated mechanisms. Furthermore, it describes the development and a preliminary analysis of a first prototype of an underactuated prosthetic hand. <s> BIB003 </s> Underactuated robotics: A review <s> UR hand <s> Among social infrastructure technologies, robot technology (RT) is expected to play an important role in solving the problems of both decrease of birth rate and increase of elderly people in the 21st century, specially but not only in Japan. In order to achieve this objective, the new generation of personal robots should be capable of a natural communication with humans by expressing human-like emotion. In this sense, human hands play a fundamental role in communication, because they have grasping, sensing and emotional expression ability. This paper presents the recent results of the collaboration between the Takanishi Lab of Waseda University, Tokyo, Japan, and the Arts Lab of Scuola Superiore Sant'Anna, Pisa, Italy, and ROBOCASA. In this paper, the development of a novel anthropomorphic hand for humanoid robotics RCH-1 (ROBOCASA Hand No.1) and its integration into a humanoid robotic platform, named WE-4RII (Waseda Eye No.4 Refined II) is presented. <s> BIB004 </s> Underactuated robotics: A review <s> UR hand <s> Commercially available prosthetic hands are simple grippers with one or two degrees of freedom; these pinch type devices have two rigid fingers in opposition to a rigid thumb. This paper focuses on an innovative approach for the design of a myoelectric prosthetic hand. The new prosthesis features underactuated mechanisms in order to achieve a natural grasping behavior and a good distribution of pinching forces. In this paper it is shown that underactuation allows reproducing most of the grasping behaviors of the human hand, without augmenting the mechanical and control complexity. <s> BIB005 </s> Underactuated robotics: A review <s> UR hand <s> This paper presents the design of a new underactuated finger. The main characteristic of this two-degree-of-freedom / one-actuator finger is to be force-isotropic. This means that the intensity of the forces exerted at the center of each phalanx, on the grasped object, are identical. Until now, this characteristic was observed on some underactuated fingers for some very specific configurations only (mainly when the phalanxes were lined up). With the proposed finger, this characteristic remains true whatever the configuration of the phalanxes is. <s> BIB006 </s> Underactuated robotics: A review <s> UR hand <s> This paper presents recent results aimed at developing a functional prosthetic hand characterized by an EMG-control and by a simple and low cost fabrication technology. In order to overcome some limitations of current prosthetic hands mainly related to the poor functionality and controllability, the prosthetic hand has been designed following a biomechatronic approach based on biologically-inspired design solutions. The core of the project described in this paper is the fabrication of a compliant under-actuated prosthetic hand: the structure of the hand (both palm and fingers) is moulded as a soft polymeric single part with compliant joints and embedded tendon driven underactuated mechanism for providing adaptive grasp. In order to make user trials, the hand is equipped with simple but functional EMG-based control of the single motor incorporated in the hand, and is integrated with a prosthesis socket. The paper presents the biomechatronics design, the fabrication process, the integration of the prosthetic device and first experimental results. <s> BIB007 </s> Underactuated robotics: A review <s> UR hand <s> This paper details the design and operation of the BarrettHand BH8-250, an intelligent, highly flexible eight-axis gripper that reconfigures itself in real t ime to conform securely to a wide variety of part shapes without tool-change interruptions. The grasper brings enormous value to factory automation because it: reduces the required number and size of robotic work cells (which average US$90,000 each - not including the high cost of footprint) while boosting factory throughput; consolidates the hodgepodge proliferat ion of customized gripper-jaw shapes onto a common programmab le p latform; and enables incremental process imp rovement and accommodates frequent new-product introductions, capabilit ies deployed instantly via software across international networks of factories. <s> BIB008 </s> Underactuated robotics: A review <s> UR hand <s> The present paper refers to the design of a robotic hand named RL1 hand. This robotic hand has 3 articulated fingers, which adapt themselves to the object that is being held. The fingers movement and auctioning are made through one direct current motor. The control is done through simple commands and can be sent from any computer, as a string of characters. One special characteristic this robotic hand has is that its mechanism, its electronic control and its 250 gr weight actuator are all embodied in the ASIBOT Robot. This arm was developed to help disable people or people with special needs. Apart from the topics described, the paper also refer to a theoretical study made to optimize the size and localization of the underactuated fingers' pulleys in order to exploit the most of the strength made by the tendon. Thanks to this study, better results would significantly improve these fingers' design <s> BIB009 </s> Underactuated robotics: A review <s> UR hand <s> Manipulator kinematics refers the analytical study of the motion of manipulator, such as positions, velocities, and accelerations of the links of a manipulator. As formulating the suitable kinematics models for a manipulator is very crucial for analyzing the behavior of manipulators and light weight design of manipulators, many researches have been focused on it in recent decades with a result of many valuable contributions. However, current researches always focus on rigid manipulator, while the manipulator is always a rigid-flexible coupling multibody system, which can affect the accuracy of kinematics analysis and numerical simulation. This paper proposed a model of kinematics analysis of manipulator based on rigid-flexible coupling virtual prototyping. After a model of manipulator kinematics based on the D-H method was proposed, rigid-flexible coupling virtual prototyping-based kinematics simulation and numerical simulation was then put forward. The kinematical experiment is carried out based on manipulator physical prototyping, which demonstrates that the accuracy of the kinematics calculation and the rationality of design based on rigid-flexible coupling virtual prototyping. The design of a five-degrees-of-freedom manipulator is given as an example, which demonstrates that the methodology is obviously helpful to manipulator design. <s> BIB010 </s> Underactuated robotics: A review <s> UR hand <s> Dynamics is concerned with the study of forces and torques and their effect on motion. As formulating the suitable dynamics models for an offshore crane is very crucial for analyzing the behavior and lightweight design, many researches have been focused on it in recent decades with a result of many valuable contributions. However, current researches always focus on rigid crane, while the crane is always a rigid-flexible coupling multibody system, which can affect the accuracy of dynamic analysis. This paper proposed a model of dynamics analysis of an offshore crane based on rigid-flexible coupling virtual prototyping. After the structure and performance parameters of the 800-ton offshore crane were introduced, rigid-flexible coupling virtual prototyping-based dynamics analysis and numerical simulation were then put forward. The dynamics experiment is carried out based on offshore crane physical prototyping, and experimental results indicate successful lifting load with predetermined boom angle, which demonstrates that the accuracy of the dynamics analysis is based on rigid-flexible coupling virtual prototyping. The design of an offshore crane is given as an example which demonstrates that the methodology is obviously helpful to offshore crane design. <s> BIB011 </s> Underactuated robotics: A review <s> UR hand <s> With the present gap between engineering design and analysis, designers are often hindered in their efforts to explore design alternatives and ensure product robustness. This paper is devoted to parameter constraint graph approach-based dynamic information association and integration between the design model and analysis model. After the description of the gap between design and analysis is analyzed, the modeling and representation method of the product parameter constraints model are proposed. With the help of a product virtual prototyping element model, it can be simplified to a product parameter constraint graph to support an integrated model for multidisciplinary virtual prototyping of complex products. An integrated design and analysis method based on the parameter constraint graph approach is proposed based on the parameterized design method for analysis. The decoupling method of parameter constraints for multidisciplinary virtual prototyping is also discussed in detail in five steps. The integrated design and analysis of an automatic pipe racking robot in an offshore platform are given as an example, which demonstrates that the methodology is obviously helpful in improving the associability of design-analysis models. <s> BIB012 </s> Underactuated robotics: A review <s> UR hand <s> The characteristic features of underactuated finger are compact structure, large grasping force, and simple operation. It has a wide application prospect in the fields of industrial robot, humanoid... <s> BIB013 </s> Underactuated robotics: A review <s> UR hand <s> This paper develops a mathematical analysis of contact forces for the under-actuated finger in a general under-actuated robotic hand during grasping. The concept of under-actuation in robotic grasp... <s> BIB014 </s> Underactuated robotics: A review <s> UR hand <s> Fatigue failure is defined as the progressive degradation of the strength of a structural component during the manufacturing of machine tools. As the increasing demands for high product quality result in a continuing need to achieve improvements in fatigue reliability on machining tools, many researches have been focused on it in recent decades with a result of many valuable contributions. However, current researches always focus on the fatigue analysis of rigid components, and the dimension change, necessary design, and optimization are lacked, while the component of a product is always a rigid-flexible coupling multi-body system, which could affect the accuracy and reliability of fatigue analysis, and parameterization help designers see each dimension change. This paper proposed a process of component fatigue analysis based on rigid-flexible coupling virtual prototyping. In this paper, a crankshaft in the cold heading machine is taken as an example to show the rigid-flexible coupling fatigue analysis process in detail. After the parameterization of the crankshaft is proposed, the static analysis and optimization of the crankshaft is carried out. The dynamics analysis for rigid-flexible coupling of the cold heading components is also proposed. The fatigue analysis for the crankshaft is discussed in detail. The crankshaft in the cold heading machine is given as an example, which demonstrates that the methodology is obviously helpful to fatigue analysis and simulation. The physical prototyping is also carried out to demonstrate the fatigue reliability. The crankshaft of cold heading machine is given as an example, which demonstrates that the methodology is obviously helpful to fatigue analysis and simulation. <s> BIB015 </s> Underactuated robotics: A review <s> UR hand <s> Abstract Space robotics is taken as one of the most promising approaches for on-orbit servicing missions. The underactuated non-holonomic parallel mechanism is a new direction of parallel space robotics, with small volume, lightweight, low cost, low energy consumption, and high flexibility. The existing methods on type synthesis could not generate underactuated non-holonomic parallel mechanisms with the introduction of the non-holonomic spherical pairs in parallel mechanisms. This paper is devoted to type synthesis of underactuated parallel mechanisms with spherical motion pattern accompanied by the generation of the non-holonomic spherical pairs in parallel mechanisms with spherical motion pattern. After the introduction of the traditional roller-sphere contact, this paper proposes a novel roller-sphere contact. After this paper provides the type synthesis of parallel mechanisms with spherical motion pattern, it puts forward the generation method of non-holonomic spherical pairs in parallel underactuated mechanisms with spherical motion pattern. The non-holonomic underactuated joint mechanism of a space robot for on-orbit servicing operations is taken as an example to demonstrate the proposed method. <s> BIB016 </s> Underactuated robotics: A review <s> UR hand <s> Abstract Continuum mechanisms have recently been used in various manipulator designs, often for medical applications. Instead of forming manipulators, a multi-backbone continuum mechanism, in a composed configuration, can be alternatively used as a transmission unit to generate an arbitrary number of translating outputs that are linearly combined from two independent inputs. This CCM (Composed Continuum Mechanism), applicable in other design scenarios, is applied as mechanical postural synergies of an anthropomorphic robotic hand. In this hand, three actuators actuate the CCM in its coordinated motion mode to drive the eleven hand joints according to two synergy inputs to form synergy-based hand poses in a pre-grasp phase. Then, the CCM closes the fingers in its synchronized motion mode. Joint-level compliance was selectively introduced based on a statics analysis to help achieve the stable grasping and pinching of many daily life objects. The compliance calculation, postural synergy synthesis, system descriptions and experimental characterizations of this hand with Compliant Mechanical Postural Synergy (the CoMPS hand) are expounded. The efficacy of the hand, demonstrated by the experimental results, can inspire its use as a prosthesis, as a training device for synergy control, or in a humanoid robot, showing the potentials of the proposed CCM. <s> BIB017 </s> Underactuated robotics: A review <s> UR hand <s> The reliability analysis is a quantification of the sources of failures in a product, with emphasis on the most significant contributors towards the overall product unreliability. As the reliability analysis of complex products is very crucial for analyzing the behavior of the products, many researches have been focused on it in recent decades with a result of many valuable contributions. However, current researches always focus on rigid product, while the product is always a rigid-flexible coupling multibody system, which could affect the accuracy of reliability analysis. This paper is devoted to virtual prototyping-based approach to a fuzzy Failure Mode, Effects, and Criticality Analysis (FMECA) with the consideration of rigid-flexible coupling virtual prototyping model. This paper discussed proposed approach in detail with three steps: the traditional FMECA method, the fuzzy FMECA method, and the rigid-flexible coupling-based analysis for FEMCA. The cold heading machine is given as an example which demonstrates that the methodology is helpful to reliability analysis. The physical prototyping is also carried out to demonstrate the product reliability. <s> BIB018
Experts have studied different types of robotic hands to achieve object capture and processing. Several successful designs for human and nonhuman hands have been developed in the past. The Stanford/Jet Propulsion Laboratory (JPL) Hand  was a representative robot at that time and now. The dexterous hand has three fingers for a total of nine DOFs. The Stanford/JPL hand's contribution to the multi-finger hand is the multi-joint, multi-DOF modular structure design, and more important. It has completely introduced sensor systems such as position, touch, and force for the first time. Therefore, the era of multifingering perception of the external environment began. And the first step of the actual grasping operation of the multi-finger hand was created. Both the German Aerospace Center I (DLR I) Hand and the German Aerospace Center II (DLR II) Hand  are multi-sense, sensory integrated, mechatronic multi-finger dexterous hands. The DLR I hand transmission mode and the large number of analog signals have led to a reduction in reliability and an increase in maintenance difficulty. Based on the DLR I dexterous hand, the DLR II dexterous hand is more powerful and more reliable. It is considered to be the best dexterity in the world at the time. The BUAA Hand BIB001 has high flexibility of movement and strong force sensing capability. All actuators are integrated into the finger module based on the modular design strategy. Based on the kinematics and mechanical design of Manus Colobi, Colobi Hand 45 is a robot developed for industrial applications. Barrett Hand BIB008 is a multi-finger programmable gripper with great flexibility. It protects target objects of different sizes, shapes, and orientations. The Tokyo University of Agriculture and Technology (TUAT)/Karlsruhe Hand 47 possesses 20 DOFs and is driven by one actuator which could be placed into or around the hand. The Turin Hand 48 is a pneumatic hand consisting of four fingers and an opposite thumb. The features of adaptive grasp, curling fingers, and a rotational thumb have increased the mechanical functionality of this Toronto/Bloorview MacMillan (TBM) BIB002 Hand that exceeds the traditional prosthesis. The strengthening and stretching for rheumatoid arthritis of the hand (SARAH)  was developed as a potential tool for special purpose manipulators on the International Space Station. It is suitable for adaptive and reconfigurable space applications. Because the springs are placed inline with the actuators and fingers, the Massachusetts Institute of Technology Hand 51 exhibits a low mechanical impedance. This low impedance increases the mechanical robustness of the hand, allowing people to safely operate the hand in environments that are not well known. The RoboCasa Hand-I (RCH-I) BIB004 is a new type of human hand that could be integrated with a humanoid robot platform. It enhances communication between robots and humans. Wu et al.  proposed an equivalent mechanism for deducing the underactuated finger mechanism under different gripping conditions based on the principle of minimum damping. Liu et al.  designed a scalable underactuated cable truss-type mechanical gripper that could be used in the field of space robots. Xu et al. BIB017 proposed a combined continuous mechanism for anthropomorphic robots, which could generate any number of translational outputs by linearly combining two independent inputs. Most of the available multi-fingered prototypes have a large amount of DOFs, complex actuation, and high cost. Most of these hands are still used to enhance applications, laboratory tests, or research projects. However, it could be used availably in industrial and nonindustrial applications even in the market, such as the Barrett Hand, SARAH Hand, and Robosoft Hand. Many robotic hands focus on simulating the overall appearance and movement of a biologic hand, while ignoring other equally important features, such as size, weight, and real-time control. Those traditional manipulators (such as those in Qian and Zhang  ) are relatively complex, large, and heavy. It is difficult to install on robots as large as humans. Based on the manipulator kinematics model of D-H method, He et al. BIB010 proposed kinematics simulation and numerical simulation based on rigid-flexible coupled virtual prototype. Taking the design of the five DOFs manipulator as an example, it is proved that the method obviously contributes to the lightweight design of the manipulator. The rigid-flexible multi-body system is a hot topic in recent years. Based on the rigid-flexible coupled virtual prototype, He et al. BIB012 BIB011 BIB018 BIB015 carried out modeling, simulation analysis, and numerical simulation for different types of prototypes. This method is of great significance for the mechanical design and dynamic analysis control of multi-body systems in the future. The traditional robotic hands are also very expensive and difficult to manufacture and maintain. Because the robotic hand has many DOFs, drivers and control systems are large and difficult to control. In a sense, a robotic hand with more DOF is more dexterous. And the DOF directly determines the ability of the hand to bend around the object and adapt to the shape of the object. How to reduce volume, weight, and power costs is an important aspect of designing robotic hands. Therefore, designing a robotic hand that drives less becomes an interesting direction. However, it becomes a challenge that how to design a robotic hand with feature of compact, low cost, and easy operation but still keep the number of DOF to support the ability of grasp adaptively different objects. A popular research method uses the underactuated mechanism of the finger. A new type of fully rotating joint linkagebased underactuated mechanism is proposed. A new method based on the minimum resistance law to realize the equivalent mechanism under different contact conditions of the finger is proposed. And the kinematics analysis based on the equivalent mechanism was given. BIB013 Gao et al. BIB016 proposed a 3-RRS (R represents a rotating pair and S stands for spherical side) parallel mechanism based on the generation of underactuated parallel joints that is shown in Figure 9 . Ha et al. BIB014 developed a mathematical analysis model of contact forces for the underactuated finger in a general UR hand during grasping. By using springs and mechanical constraints, the underactuated concept in robotic grip allows the hand to adjust itself to an irregularly shaped object without complex control strategies and sensors and with actuators less than DOFs. Based on comprehensive domestic and foreign literature, the mechanisms commonly used for underactuated finger design schemes are differential mechanism (seesaw mechanism, t-pipe mechanism, movable pulley mechanism, connecting rod mechanism, planetary wheel mechanism, etc.), compatible mechanism (generally composed of springs, tendons, and some flexible materials), trigger mechanism, passive mechanism, and so on. The underactuated finger of the tension drive (or friction wheel drive) could only achieve a small grip. In order to realize underactuated humanoid fingers with compact structure and large grasping force, underactuated linkage mechanism is generally used to design and make robot fingers. Currently, there are two main types of underactuated finger mechanisms, namely, tendon-actuated mechanisms and linkage-based mechanisms.  A typical tendon drive mechanism makes it easy to build a compact structure. However, the tendon drive mechanism could only exert a small grip. Another disadvantage of the tendon system was that they were strongly influenced by friction and elasticity.  Massa et al. BIB003 and Carrozza et al. BIB005 studied the tendon mechanism of the underactuated prosthetic hand. The optimal design issues associated with pulley diameter and position were discussed. BIB009 Two DOFs/one actuator referred to an isotropic force characteristic. BIB006 Here, the isotropy of force means that the strength of the force applied to the center of each phalanx and the object being grasped is the same. Dechev et al. BIB002 described a prosthetic hand with a passive adaptive gripping mechanism-TBM Hand. Carrozza et al. BIB007 also gave some preliminary results regarding the tendon-driven underdrive mechanism and the compliant joint prosthesis.