Emanuele Guglielmino

Design of HyQ – a hydraulically and electrically actuated quadruped robot

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.

Semi-active suspension control : improved vehicle ride and road friendliness

Dampers and Vehicle Modelling.- Human Body Analysis.- Semi-active Control Algorithms.- Friction Dampers.- Magnetorheological Dampers.- Case Studies.

Shape function-based kinematics and dynamics for variable length continuum robotic arms

This paper presents a new three dimensional kinematic and dynamic model for variable length continuum arm robotic structures using a novel shape function-based approach. The model incorporates geometrically constrained structure of the arm to derive its deformation shape function. It is able to simulate spatial bending, pure elongation, and incorporates a new stiffness control feature. The model is validated through numerical simulations, based on a prototype continuum arm, that yields physically accurate results.

Design, modeling and control of a pneumatically actuated manipulator inspired by biological continuum structures

Biological tentacles, such as octopus arms, have entirely flexible structures and virtually infinite degrees of freedom (DOF) that allow for elongation, shortening and bending at any point along the arm length. The amazing dexterity of biological tentacles has driven the growing implementation of continuum manipulators in robotic systems. This paper presents a pneumatic manipulator inspired by biological continuum structures in some of their key features and functions, such as continuum morphology, intrinsic compliance and stereotyped motions with hyper redundant DOF. The kinematics and dynamics of the manipulator are formulated and identified, and a hierarchical controller taking inspiration from the structure of an octopus nervous system is used to relate desired stereotyped motions to individual actuator inputs. Simulations and experiments are carried out to validate the model and prototype where good agreement was found between the two.

Novel modal approach for kinematics of multisection continuum arms

This paper presents a new three dimensional (3D) kinematic model based on mode shape functions (MSF) for multisection continuum arms. It solves the singularity problems associated with previous models and introduces a novel approach for intuitively deriving exact, singularity-free MSFs, thus avoiding mode switching schemes and simplifying error models. The model is able to simulate spatial bending, pure elongation/contraction, and introduces inverse orientation kinematics for the first time to multisection continuum arms. Also, it carefully accounts for physical constraints in the joint space to provide enhanced insight into practical mechanics, and produces correct results for both forward and inverse kinematics. The model is validated through simulations, based on a prototype continuum robotic arm. Proposed approach is applicable to a broad spectrum of continuum robotic arm designs.

Dynamic model of a hyper-redundant, octopus-like manipulator for underwater applications

The octopus arm is a unique tool that combines strength and flexibility. It can shorten, elongate and bend at any point along its length. To model this behavior, a hyper-redundant manipulator composed of multiple segments is proposed. Each segment is a parallel robotic mechanism with redundant actuation. The kinematics and dynamics of this manipulator are analyzed and simulated utilizing a modular computational modeling method. Simulation results for some primitive movements are presented, and the effect of hydrodynamic forces is included.

A soft body as a reservoir: case studies in a dynamic model of octopus-inspired soft robotic arm

The behaviors of the animals or embodied agents are characterized by the dynamic coupling between the brain, the body, and the environment. This implies that control, which is conventionally thought to be handled by the brain or a controller, can partially be outsourced to the physical body and the interaction with the environment. This idea has been demonstrated in a number of recently constructed robots, in particular from the field of “soft robotics”. Soft robots are made of a soft material introducing high-dimensionality, non-linearity, and elasticity, which often makes the robots difficult to control. Biological systems such as the octopus are mastering their complex bodies in highly sophisticated manners by capitalizing on their body dynamics. We will demonstrate that the structure of the octopus arm cannot only be exploited for generating behavior but also, in a sense, as a computational resource. By using a soft robotic arm inspired by the octopus we show in a number of experiments how control is partially incorporated into the physical arms dynamics and how the arms dynamics can be exploited to approximate non-linear dynamical systems and embed non-linear limit cycles. Future application scenarios as well as the implications of the results for the octopus biology are also discussed.

A controlled friction damper for vehicle applications

This paper examines the performance of a servo-driven dry-friction damper in a car suspension application; this device is a potential alternative to a traditional viscous damper. The friction damper is semi-active: damping is controlled without energy introduction into the system and hence the power required is much smaller than fully active systems. Models for the friction damper hydraulic drive and vehicle ride are developed. It is shown through simulation and experimental studies that a VSC-controlled friction damper has potentially superior performance to a conventional damper. Limitations of the current design are identified and suggestions for improvements are outlined.

Dynamic modeling and control of an octopus inspired multiple continuum arm robot

This paper proposes a dynamic model for a multiple continuum arm robot inspired by live octopuses. The kinematics and dynamics for a single arm are analyzed and formulated including the longitudinal muscles, radial muscles, isovolumetric constraints, and interaction between suckers and an object. The single arm model is then expanded to a multiple arm system that is capable of generating archetypal locomotion patterns such as crawling and swimming. A hierarchical controller based on octopus neurophysiology is used to achieve simple and reliable control of the multiple continuum arm system. Simulations for single arm movements and multiple arm locomotions are presented. The results of this work can be used in the study of control schemes for multiple continuum arm robots and live octopuses.

Dynamic continuum arm model for use with underwater robotic manipulators inspired by octopus vulgaris

Continuum structures with a very high or infinite number of degrees of freedom (DOF) are very interesting structures in nature. Mimicking this kind of structures artificially is challenging due to the high number of required DOF. This paper presents a kinematic and dynamic model for an underwater robotic manipulator inspired by Octopus vulgaris. Then, a prototype arm inspired by live octopus is presented and the model validated experimentally. Initial comparisons of simulated and experimental results show good agreement.