Print ISBN 978-3-030-70315-8, Online ISBN 978-3-030-70316-5
Abstract
The simple kinematics of commercial prosthetic wrists limits the individuals in performing a wide range of tasks and restore natural motor functions. We propose a functional prosthesis that improves grasping capabilities through the addition of a simple yet useful 3 DoF myoelectric wrist joint with compliant and rigid properties. Its locking capability enables the adjustment of hand configuration in pre-grasping phases and separates the hand motion from the wrist motion. The proposed wrist, combined with a prosthetic hand, was tested with 8 able-bodied subjects and 1 subject with limb loss. It was compared to a common commercial rotational wrist and to subjects’ natural wrist. Results evidence the feasibility of the prototype, improved performance capabilities, and the subjects’ first impression about the proposed system. Finally, a prosthesis user tested and compared systems during Activities of Daily Living (ADL).
Based on previous experience with prosthesis users and literature, this paper introduces three important aspects to further develop functional transradial myoelectric prostheses: stiffness modulation, grasp reliability and limb dexterity. In particular, we propose three possible solutions and discuss on the insights observed about the exploration of impedance control in prosthetic hands during Activities of Daily Living and social interaction, the introduction of an articulated palm to increase all hand parts contribution in grasping, and a compact 3 DoF myoelectric wrist capable to switch from compliant to rigid properties during pre-grasping phase to decrease compensatory movements and favour more natural body postures in prosthesis users.
Analytics for the Sharing Economy: Mathematics, Engineering and Business Perspectives
Pagination
25–37
Publisher
Springer International Publishing
City
Cham
ISBN Number
978-3-030-35032-1
Abstract
Interconnection of a large number of systems has become a reality from a technological point of view although intelligent connection among smart systems still presents a challenge in several application scenarios. More specifically, when many smart devices must accomplish an overall goal based on information exchanges with other devices, several factors render this task a real challenge, such as, knowing what specific information to exchange, with whom, how to go about it, and when this exchange will occur. Moreover, interconnected devices may require access to or the use of common resources, making the management of the overall system even more complex. The management of shared resources usually sets the goal of optimizing usage while guaranteeing achievement of the overall goals. Algorithms or protocols that grant the device a correct, safe and optimized access to resources play a fundamental role. In this chapter we will provide those algorithms that are fundamental in several different application scenarios that allow for the development of more complex algorithms in order to manage interconnected systems in the management of shared resources.
To physically interact with a rich variety of environments and situation-oriented requirements, humans continuously adapt both the stiffness and the force of their limbs through antagonistic muscle coactivation. Reflecting this behaviour in prostheses may promote control naturalness and intuitiveness and, consequently, their acceptance in everyday life. We propose a method capable of a simultaneous and proportional decoding of position and stiffness intentions from two surface electro-myographic sensors placed over a pair of antagonistic muscles. First, the algorithm is validated and compared to existing control modalities. Then, the algorithm is implemented in a soft under-actuated prosthetic hand (SoftHand Pro). We investigated the feasibility of our approach in a preliminary study involving one prosthetic user. Our future goal is to evaluate the usability of the proposed approach executing a variety of tasks including physical social interaction with other subjects (see Figure 1). Our hypothesis is that variable stiffness could be a compromise between firm control and safe interaction.
Robotic hand engineers usually focus on finger capabilities, often disregarding the palm contribution. Inspired by human anatomy, this paper explores the advantages of including a flexible concave palm into the design of a robotic hand actuated by soft synergies. We analyse how the inclusion of an articulated palm improves finger workspace and manipulability. We propose a mechanical design of a modular palm with two elastic rolling-contact palmar joints, that can be integrated on the Pisa/IIT SoftHand, without introducing additional motors. With this prototype, we evaluate experimentally the grasping capabilities of a robotic palm. We compare its performance to that of the same robotic hand with the palm fixed, and to that of a human hand. To assess the effective grasp quality achieved by the three systems, we measure the contact area using paint-transfer patterns in different grasping actions. Preliminary grasping experiments show a closer resemblance of the soft-palm robotic hand to the human hand. Results evidence a higher adaptive capability and a larger involvement of all fingers in grasping.
To physically interact with a rich variety of environments and to match situation-dependent requirements, humans adapt both the force and stiffness of their limbs. Reflecting this behavior in prostheses may promote a more natural and intuitive control and, consequently, improve prostheses acceptance in everyday life. This pilot study proposes a method to control a prosthetic robot hand and its impedance, and explores the utility of variable stiffness when performing activities of daily living and physical social interactions. The proposed method is capable of a simultaneous and proportional decoding of position and stiffness intentions from two surface electro-myographic sensors placed over a pair of antagonistic muscles. The feasibility of our approach is validated and compared to existing control modalities in a preliminary study involving one prosthesis user. The algorithm is implemented in a soft under-actuated prosthetic hand (SoftHand Pro). Then, we evaluate the usability of the proposed approach while executing a variety of tasks. Among these tasks, the user interacts with other 12 able-bodied subjects, whose experiences were also assessed. Several statistically significant aspects from the System Usability Scale indicate user's preference of variable stiffness control over low or high constant stiffness due to its reactivity and adaptability. Feedback reported by able-bodied subjects reveal a general tendency to favor soft interaction, i.e., low stiffness, which is perceived more human-like and comfortable. These combined results suggest the use of variable stiffness as a viable compromise between firm control and safe interaction which is worth investigating further.
Summary This paper deals with the application of model predictive control (MPC) to optimize power flows in a network of interconnected microgrids (MGs). More specifically, a distributed MPC (DMPC) approach is used to compute for each MG how much active power should be exchanged with other MGs and with the outer power grid. Due to the presence of coupled variables, the DMPC approach must be used in a suitable way to guarantee the feasibility of the consensus procedure among the MGs. For this purpose, we adopt a tailored dual decomposition method that allows us to reach a feasible solution while guaranteeing the privacy of single MGs (ie, without having to share private information like the amount of generated energy or locally consumed energy). Simulation results demonstrate the features of the proposed cooperative control strategy and the obtained benefits with respect to other classical centralized control methods.
