@article {3638, title = {Dynamic Morphological Computation Through Damping Design of Soft Continuum Robots}, journal = {Frontiers in Robotics and AI}, year = {2019}, author = {A. Di Lallo and M. G. Catalano and M. Garabini and G. Grioli and M Gabiccini and A. Bicchi} } @article {3326, title = {Decentralized Trajectory Tracking Control for Soft Robots Interacting with the Environment}, journal = {IEEE Transactions on Robotics (T-RO).}, volume = {Early Access}, year = {2018}, month = {06/2018}, abstract = {

Despite the classic nature of the problem, trajectory

tracking for soft robots, i.e. robots with compliant elements

deliberately introduced in their design, still presents several

challenges. One of these is to design controllers which can

obtain sufficiently high performance while preserving the physical

characteristics intrinsic to soft robots. Indeed, classic control

schemes using high gain feedback actions fundamentally alter the

natural compliance of soft robots effectively stiffening them, thus

de facto defeating their main design purpose. As an alternative

approach, we consider here to use a low-gain feedback, while

exploiting feedforward components. In order to cope with the

complexity and uncertainty of the dynamics, we adopt a decentralized,

iteratively learned feedforward action, combined with

a locally optimal feedback control. The relative authority of the

feedback and feedforward control actions adapts with the degree

of uncertainty of the learned component. The effectiveness of the

method is experimentally verified on several robotic structures

and working conditions, including unexpected interactions with

the environment, where preservation of softness is critical for

safety and robustness.

}, keywords = {Robotics}, author = {F. Angelini and C. Della Santina and M. Garabini and M. Bianchi and G M Gasparri and G. Grioli and M. G. Catalano and A. Bicchi} } @conference {3218, title = {Design and characterization of a novel high-compliance spring for robots with soft joints}, booktitle = {IEEE International Conference on Advanced Intelligent Mechatronics (AIM)}, year = {2017}, publisher = {IEEE}, organization = {IEEE}, address = {Munich, Germany, 3-7 July 2017}, abstract = {

Low stiffness elements have a number of applications in Soft Robotics, from Series Elastic Actuators (SEA) to torque sensors for compliant systems. In its general formulation, the design problem of elastic components is complex and depends on several variables: material properties, load range, shape factor and size constraints. Consequently, most of the spring designs presented in literature are based on heuristics or are optimized for specific working conditions. This work presents the design study and characterization of a scalable spoked elastic element with hinge tip constraints. We compared the proposed design with three existing spring principles, showing that the spoked solution is the convenient option for low-stiffness and low shape factor elastic elements. Therefore, a design analysis on the main scaling parameters of the spoked spring, namely number of spokes and type of constraints, is presented. Finally, an experimental characterization has been conducted on physical prototypes. The agreement among simulations and experimental results demonstrates the effectiveness of the proposed concept.

}, keywords = {Robotics}, doi = {10.1109/AIM.2017.8014029}, url = {http://ieeexplore.ieee.org/document/8014029/}, author = {F. Negrello and M. G. Catalano and M. Garabini and M. Poggiani and D. G. Caldwell and N. G. Tsagarakis and A. Bicchi} } @conference {3219, title = {Design, control and validation of the variable stiffness exoskeleton FLExo}, booktitle = {International Conference on Rehabilitation Robotics (ICORR)}, year = {2017}, pages = {539 - 546}, publisher = {IEEE}, organization = {IEEE}, address = {London, UK, 17-20 July 2017}, abstract = {

In this paper we present the design of a one degree of freedom assistive platform to augment the strength of upper limbs. The core element is a variable stiffness actuator, closely reproducing the behavior of a pair of antagonistic muscles. The novelty introduced by this device is the analogy of its control parameters with those of the human muscle system, the threshold lengths. The analogy can be obtained from a proper tuning of the mechanical system parameters. Based on this, the idea is to control inputs by directly mapping the estimation of the muscle activations, e.g. via ElectroMyoGraphic(EMG) sensors, on the exoskeleton. The control policy resulting from this mapping acts in feedforward in a way to exploit the muscle-like dynamics of the mechanical device. Thanks to the particular structure of the actuator, the exoskeleton joint stiffness naturally results from that mapping. The platform as well as the novel control idea have been experimentally validated and the results show a substantial reduction of the subject muscle effort.

}, keywords = {Robotics}, doi = {10.1109/ICORR.2017.8009304}, url = {http://ieeexplore.ieee.org/document/8009304/}, author = {S. Mghames and M. Laghi and C. Della Santina and M. Garabini and M. G. Catalano and G. Grioli and A. Bicchi} } @conference {2113, title = {Drum Stroke Variation Using Variable Stiffness Actuators}, booktitle = {IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2014)}, year = {2014}, pages = {3892 - 3897 }, publisher = {IEEE}, organization = {IEEE}, address = {Chicago, IL, USA}, abstract = {

One interesting field of robotics technology is related to the entertainment industry. Performing a musical piece using a robot is a difficult task because music presents many features like melody, rhythm, tone, harmony and so on. Addressing these tasks with a robot is not trivial to implement. Most of approaches which related to this specific field lacks of quality to perform in front of human audience. Implementation of human-like motions can not be properly achieved with a conventional robot actuator. Consequently, we exploit a new type of actuator which simplifies the drawbacks of a conventional one. We used Variable Stiffness Actuator(VSA) instead of using conventional actuator. We can control position, force, and stiffness, simultaneously by using VSA. The most important novel feature is its controllable stiffness. When the stiffness of the actuator is changed, the characteristics of the actuator{\textquoteright}s response also changes. We implemented the specific stroke which is called {\textquotedblleft}double stroke{\textquotedblright} using one of variable stiffness actuator. Although the double stroke is known as a special stroke which could be performed by human only, double stroke is successfully implemented by stiffness variation.

}, keywords = {Robotics}, doi = {10.1109/IROS.2014.6943109}, author = {Y. Kim and M. Garabini and J. Park and A. Bicchi} }