Robotics of human movements

The construction of robotic systems that can move the way humans do, with respect to agility, stability and precision, is a necessary prerequisite for the successful integration of robotic systems in human environments. We explain human-centered views on robotics, based on the three basic ingredients (1) actuation; (2) sensing; and (3) control, and formulate detailed examples thereof

Development and testing of a pyro-driven launcher for harpoon-based comet sample acquisition

The CORSAIR (COmet Rendezvous, Sample Acquisition, Investigation, and Return) mission is a proposal for the fourth NASA New Frontiers program. It belongs to the Comet Surface Sample Return mission theme which focuses on acquiring and returning to Earth a macroscopic sample from the surface of a comet nucleus. CORSAIR uses a harpoon-based Sample Acquisition System (SAS) with the spacecraft hovering several meters above the comet surface. This stand-off strategy overcomes disadvantages of systems using drills or shovels. Since comets are low gravity objects, these techniques would require anchoring before sampling, which is not necessary here. Moreover, the harpoon-based system allows for acquiring several samples from different locations on the comet maximizing the scientifc output of the mission. Each SAS assembly consists of a pyro-driven launcher, a Sample Acquisition and Retrieval Projectile (SARP) and a retraction system using a deployable composite boom structure. In order to collect enough cometary material, the launcher has to provide the required kinetic energy to the SARP. Due to high energy densities, pyrotechnically actuated devices ultimately reduce the overall system mass and dimensions. Here, an overview of the development, design and testing of the launcher is given. Furthermore, the launcher theory is introduced explaining the entire reaction chain: initiation -> gas dynamics -> SARP motion

The hand of the {DLR} Hand Arm System: Designed for interaction

Physical human-robot interaction implies the intersection of human and robot workspaces and intrinsically favors collision. The robustness of the most exposed parts, such as the hands, is crucial for effective and complete task execution of a robot. Considering the scales, we think that the robustness can only be achieved by the use of energy storage mechanisms, e.g. in elastic elements. The use of variable stiffness drives provides a low-pass filtering of impacts and allows stiffness adjustments depending on the task. However, using these drive principles does not guarantee the safety of the human due to the dramatically increased dynamics of such system. The design methodology of an antagonistically tendon-driven hand is explained. The resulting hand, very close to its human archetype in terms of size, weight, and, in particular, grasping performance, robustness, and dynamics, is presented. The hyper-actuated hand is a research platform that will also be used to investigate the importance of mechanical couplings and, in future projects, be the basis of a simplified hand that would still perform daily manipulation tasks

Approaching Human Performance - The Functionality-Driven Awiwi Robot Hand

Humanoid robotics have made remarkable progress since the dawn of robotics. So why don't we have humanoid robot assistants in day-to-day life yet? This book analyzes the keys to building a successful humanoid robot for field robotics, where collisions become an unavoidable part of the game. The author argues that the design goal should be real anthropomorphism, as opposed to mere human-like appearance. He deduces three major characteristics to aim for when designing a humanoid robot, particularly robot hands: _ Robustness against impacts _ Fast dynamics _ Human-like grasping and manipulation performance Instead of blindly copying human anatomy, this book opts for a holistic design me-tho-do-lo-gy. It analyzes human hands and existing robot hands to elucidate the important functionalities that are the building blocks toward these necessary characteristics.They are the keys to designing an anthropomorphic robot hand, as illustrated in the high performance anthropomorphic Awiwi Hand presented in this book. This is not only a handbook for robot hand designers. It gives a comprehensive survey and analysis of the state of the art in robot hands as well as the human anatomy. It is also aimed at researchers and roboticists interested in the underlying functionalities of hands, grasping and manipulation. The methodology of functional abstraction is not limited to robot hands, it can also help realize a new generation of humanoid robots to accommodate a broader spectrum of the needs of human society

Feedback linearization and simultaneous stiffness-position control of robots with antagonistic actuated joints.

In this paper, the dynamic model of a robot with antagonistic actuated joints is presented, and the problem of full linearization via static state feedback is analyzed. The use of transmission elements with nonlinear relation between the displacement and the actuated force allows to control both the position and the stiffness of each joint. The main advantage of this actuation modality is that the achieved stiffness becomes same mechanical characteristic of the system and it is not the result of an immediate control action as in the classical impedance control scheme. Different examples of implementation of this kind of devices are known in literature, even if limited to one single joint and the application of antagonistic actuated kinematic chains in the field of robotic hand design is under investigation. After a brief review of the dependence of the properties of antagonistic actuation on the transmission elements characteristics, a scheme for simultaneous stiffness-position control of the linearized system is presented. Finally, simulation results of a two-link antagonistic actuated arm are reported and discussed

Approaching human performance: The functionality driven Awiwi robot hand

Humanoid robotics have achieved a remarkable state in recent years. Nowadays humanoids can walk stairs, serve coffee, throw and catch balls and interact with human beings. However, most of these demonstrations and applications take place in well known environments or even in surroundings that have been adapted to the robots capabilities and needs. However, in order to assist the human in every day tasks, the robot has to operate in (partially) unknown environments in most cases. In these unknown environments and in interaction with moving obstacles as well as human beings, collision avoidance is vague notion. Consequently, this dissertation hypothesizes that the operation of humanoid robots outside of environments dedicated to operate the robots implies that robots have to be able to complete tasks even in case of collision. This especially applies to robot hands, since they are the most exposed and fragile part of a humanoid robot. Humanoid robots have to be anthropomorphic in sense of providing not only human-like appearance but also human characteristics. In particular they have to provide: Robustness against impacts, fast dynamics, human-like grasping and manipulation performance To achieve this robustness and fast dynamics, from the author's point of view, a paradigm change has to be done . Future robots have to be able to store energy as suggested by T. Morita [Morita et al. 1999]. In this thesis the anthropomorphic Awiwi Hand is developed, which provides human-like robustness and dynamics as well as grasping performance. To achieve these characteristics, the human anatomy as well as existing robot hands are analyzed. The goal of this analysis is to derive the functionalities needed to achieve real anthropomorphism rather than to blindly copy the human being. These abstract functionalities are then implemented to a robotic hand. The achieved anthropomorphic characteristics of the Awiwi Hand are demonstrated in several experiments. The Awiwi Hand is able to withstand the impact of a 500 g hammer at high velocity without any damage. It can still keep objects firmly grasped even when struck by an 750 g object at a speed of approximately 4 m/s. The energy stored in the elastic elements of its antagonistic drive train allows the fingers of the hand to achieve a maximum finger speed of approximately 3500 grad/s which is more than five times the speed provided by the drives alone. The Awiwi Hand is, to the author’s knowledge, the first robot hand able to perform all grasps of M. Cutkoskys grasp taxonomy [Cutkosky 1989]. The robustness, fast dynamics and grasping performance of the Awiwi Hand is thought to enable future humanoid robots to operate in "field robotics" rather than in laboratories built for the robots. It will speed up the development of robotic applications since developers will no longer have to bother to avoid possibly costly collisions of the robot. Methods such as reinforcement learning, which need failed task execution attempts to succeed, can be used without fears of severely damaging the robot. The method underlying this development is not limited to robot hands. The proposed methodology will help realize a new generation of humanoid robots that can assist the human being even in harsh environments without damage and for example might fall over without damage. They will hopefully accommodate the demand of the human society for robot assistants that is well documented by the public interest in humanoid robotics