A new versatile hydraulically powered quadruped robot (HyQ) has been developed to serve as a platform to study not only highly dynamic motions, such as running and jumping, but also careful navigation over very rough terrain. HyQ stands 1 m tall, weighs roughly 90 kg, and features 12 torque-controlled joints powered by a combination of hydraulic and electric actuators. The hydraulic actuation permits the robot to perform powerful and dynamic motions that are hard to achieve with more traditional electrically actuated robots. This paper describes design and specifications of the robot and presents details on the hardware of the quadruped platform, such as the mechanical design of the four articulated legs and of the torso frame, and the configuration of the hydraulic power system. Results from the first walking experiments are presented, along with test studies using a previously built prototype leg.

In human and robot collaborative hybrid assembly cell as we proposed, it is important to develop automatic subtask allocation strategy for human and robot in usage of their advantages. We introduce a folk-joint task model that describes the sequential and parallel features and logic restriction of human and robot collaboration appropriately. To preserve a cost-effectiveness level of task allocation, we develop a logic mathematic method to quantitatively describe this discrete-event system by considering the system tradeoff between the assembly time cost and payment cost. A genetic based revolutionary algorithm is developed for real-time and reliable subtask allocation to meet the required cost-effectiveness. This task allocation strategy is built for a human worker and collaborates with various robot co-workers to meet the small production situation in future. The performance of proposed algorithm is experimentally studied, and the cost-effectiveness is analyzed comparatively on an electronic assembly case.Note to Practitioners-This paper was motivated by the critical demand within the manufacturing industry to meet the High-Mix, Low-Volume requirements for the changing consumer market demands. A fully robotic manufacturing process cannot obtain sufficient flexibility with a highly variable product line. Therefore, it must aim towards a complimentary cost-effectiveness to improve productivity from other ways. By taking advantage of a human's adaptability and flexibility, we can exploit the concept of a hybrid assembly system for medium sized manufacturing processes. Hybrid assembly creates a modern assembly mode where the robot works as co-worker to collaborate with the human and share the same working space and time. Hybrid assembly cell emphasizes two challenging issues to somehow improve the manufacturing productivity: (1) the way of describing and modeling human and robot collaboration and coordination, and (2) the effective task scheduling and allocation strategy for human and robot. This research is focused on the subtask allocation method while considering the features of human and robot collaboration. The original contribution of this work is the design of an offline and online resource constraint project scheduling problem (RCPSP) algorithm for hybrid assembly systems. The resource is not only limited to the recycle resource, but also extend to the features of human and robot, such as human fatigue issues, and robot assembly failure issues. This RCPSP for hybrid assembly is to realize both sequential and parallel task scheduling between human and several robots while minimizing the assembly time and payment Manuscript cost. This algorithm is fast in reaching the semi-optimal solution, therefore it can be used for both offline and online situations. The simulation results demonstrates the effectiveness of this task scheduling algorithms. We believe this study is helpful to improve the productivity for hybrid assembly system. Index Terms-Genetic algorithm, human and robot collaboration, hybrid assembly sys...

During recent decades, strain gauge-based joint torque sensors have been commonly used to provide high-fidelity torque measurements in robotics. Although measurement of joint torque/force is often required in engineering research and development, the gluing and wiring of strain gauges used as torque sensors pose difficulties during integration within the restricted space available in small joints. The problem is compounded by the need for a scalable geometric design to measure joint torque. In this communication, we describe a novel design of a strain gauge-based mono-axial torque sensor referred to as square-cut torque sensor (SCTS), the significant features of which are high degree of linearity, symmetry, and high scalability in terms of both size and measuring range. Most importantly, SCTS provides easy access for gluing and wiring of the strain gauges on sensor surface despite the limited available space. We demonstrated that the SCTS was better in terms of symmetry (clockwise and counterclockwise rotation) and more linear. These capabilities have been shown through finite element modeling (ANSYS) confirmed by observed data obtained by load testing experiments. The high performance of SCTS was confirmed by studies involving changes in size, material and/or wings width and thickness. Finally, we demonstrated that the SCTS can be successfully implementation inside the hip joints of miniaturized hydraulically actuated quadruped robot-MiniHyQ. This communication is based on work presented at the 18th International Conference on Climbing and Walking Robots (CLAWAR).

Recent studies for packaging using cartons have modeled carton folds as equivalent mechanisms by considering creases as revolute joints and panels as links. This raises the interest in the study of stiffness characteristics of creases, which have a variable stiffness in contrast to a constant stiffness of a revolute joint and subsequently that of a whole carton fold. This paper investigates the stiffness characteristics of creases and reveals for the first time the folding motion and moment diagram in carton manipulation. Three characteristic stages were provided to characterize the crease stiffness, which has a variable value during carton manipulation. The paper further investigates the integrated stiffness of a combination joint and develops the integrated stiffness of a complete carton fold. The study is then extended to the integrated stiffness of a type of carton folds.

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Gesture recognition is essential for human and robot collaboration. Within an industrial hybrid assembly cell, the performance of such a system significantly affects the safety of human workers. This work presents an approach to recognizing hand gestures accurately during an assembly task while in collaboration with a robot co-worker. We have designed and developed a sensor system for measuring natural human-robot interactions. The position and rotation information of a human worker's hands and fingertips are tracked in 3D space while completing a task. A modified chain-code method is proposed to describe the motion trajectory of the measured hands and fingertips. The Hidden Markov Model (HMM) method is adopted to recognize patterns via data streams and identify workers' gesture patterns and assembly intentions. The effectiveness of the proposed system is verified by experimental results. The outcome demonstrates that the proposed system is able to automatically segment the data streams and recognize the gesture patterns thus represented with a reasonable accuracy ratio.

Although timing belt drives have recently been increasingly used in mechanical design, their behaviour is still considered to a large extent to be unpredictable, especially under varying operative conditions. The acoustic emission of the transmissions, above all, has been thoroughly investigated in past years, but noise still represents an unresolved problem for many applications and a concern for belt designers; therefore, the availability of good predictive models would be very useful for both design and application phases. The present work describes a multi-body numerical model that has been developed for the characterization of the dynamic behaviour of timing belt transmissions, with the nal goal of assessing the acoustic radiation of a given design. Modelling and simulation have been performed by means of commercial software packages, but more additional programming was required to obtain dynamic models capable of simulating the complex behaviour of toothed belt transmissions. Several experimental tests have been performed to identify the many parameters that in uence system dynamics and to validate the resulting computer aided engineering (CAE) model.

The computation of skin forces and deformations for tactile rendering requires an accurate model of the extremely nonlinear behavior of the skin. In this work, we investigate the characterization of finger mechanics with the goal of designing accurate nonlinear models for tactile rendering. First, we describe a measurement setup that enables the acquisition of contact force and contact area in the context of controlled finger indentation experiments. Second, we describe an optimization procedure that estimates the parameters of strain-limiting deformation models that match best the acquired data. We show that the acquisition setup allows the measurement of force and area information with high repeatability, and the estimation method reaches nonlinear models that match the measured data with high accuracy.