Energy storage systems (ESSs) play a very important role in recent years. Flywheel is one of the oldest storage energy devices and it has several benefits. Flywheel Energy Storage System (FESS) can be applied from very small micro-satellites to huge power networks. A comprehensive review of FESS for hybrid vehicle, railway, wind power system, hybrid power generation system, power network, marine, space and other applications are presented in this paper. There are three main devices in FESS, including machine, bearing, and Power Electronic Interface (PEI). Furthermore, advantages and disadvantages all of them have been presented. In addition a brief review of new and conventional power electronic converters used in FESS, have been discussed. Finally, practical ways to develop this technology in the future are presented.

A comprehensive review of Flywheel Energy Storage System technology

https://vbn.aau.dk/ws/files/337950041/robotics_09_00016.pdf

A review on design of upper limb exoskeletons

We present an upper-body exoskeleton for rehabilitation, called Harmony, that provides natural coordinated motions on the shoulder with a wide range of motion, and force and impedance controllability. The exoskeleton consists of an anatomical shoulder mechanism with five active degrees of freedom, and one degree of freedom elbow and wrist mechanisms powered by series elastic actuators. The dynamic model of the exoskeleton is formulated using a recursive Newton-Euler algorithm with spatial dynamics representation. A baseline control algorithm is developed to achieve dynamic transparency and scapulohumeral rhythm assistance, and the coupled stability of the robot-human system at the baseline control is investigated. Experiments were conducted to evaluate the kinematic and dynamic characteristics of the exoskeleton. The results show that the exoskeleton exhibits good kinematic compatibility to the human body with a wide range of motion and performs task-space force and impedance control behaviors reliably.

An upper-body rehabilitation exoskeleton Harmony with an anatomical shoulder mechanism

In this paper, we present a soft wearable robot for the shoulder which has the potential to assist individuals suffering from a range of neuromuscular conditions affecting the shoulder to perform activities of daily living. This wearable robot combines two types of soft textile pneumatic actuators which were custom developed for this particular application to support the upper arm through shoulder abduction and horizontal flexion/extension. The advantage of a textile-based approach is that the robot can be lightweight, low-profile, comfortable and non-restrictive to the wearer, and easy to don like an item of clothing. The actuator's ability to fold flat when not in use allows the robot to be almost invisible under clothing, potentially allowing the user to avoid any stigma associated with using assistive devices in public. To abduct the arm, a textilebased pneumatic actuator was developed to fit within the axilla to push the arm upwards, while a pair of smaller actuators pivot the abduction actuator to allow for horizontal extension and flexion. The individual textile actuators were experimentally evaluated before being integrated into a wearable garment. Human subject testing was performed to evaluate the ability of the robot to assist the arm by monitoring changes in biological muscle activity when comparing the robot powered on and off. Preliminary results show large reductions in muscular effort in targeted muscles, demonstrating the feasibility and promise of such a soft wearable robot for the shoulder.

A soft wearable robot for the shoulder: Design, characterization, and preliminary testing

This paper presents a state-of-the-art review of axial-flux permanent-magnet (AFPM) machines in the aspects of construction, features, electromagnetic and thermal modeling, simulation, analysis, design, materials, and manufacturing. Some key references on the above-mentioned aspects pertaining to the machine are discussed briefly. Particular emphasis is given on the design and performance analysis of AFPM machines. A comparison among different permanent magnet machines is also provided. Thus, this paper makes a bridge between the currently used permanent magnet machines in industry and the recent developments of AFPM machines.

A Comprehensive Review of Axial-Flux Permanent-Magnet Machines

We present a control strategy for the shoulder mechanism of an upper-body exoskeleton, called HARMONY, to assist in achieving coordinated motion at the shoulder complex. HARMONY is equipped with a novel mechanism that supports the natural mobility of the human shoulder, including the scapulohumeral rhythm, which is the coordinated motion between the upper arm (humerus) and shoulder blade (scapula). The key idea of the control strategy is to introduce a coupling torque based on impedance corresponding to a reference trajectory of the rhythmic motion after compensating for gravity force from the robot. This control scheme allows for the variability in the rhythmic motion, while gently providing a force to facilitate the scapulohumeral rhythm when the shoulder is out of the normal coordinated motion. Experimental results show that the coupling torque safely induces the rhythmic motion of the shoulder girdle in the presence of abnormal coordinated motion.

Controls for the shoulder mechanism of an upper-body exoskeleton for promoting scapulohumeral rhythm

Design of Nonlinear Rotational Stiffness Using a Noncircular Pulley-Spring Mechanism

The present disclosure includes a robotic exoskeleton comprising a back portion providing at least two degrees of freedom, two shoulder portions, each shoulder portion providing at least five degrees of freedom, two elbow portions, each elbow portion providing at least one degree of freedom, and two forearm portions, each forearm portion providing at least one degree of freedom. The present disclosure may also relate to associated robotic forearm joints and robotic shoulder joints.

Upper-body robotic exoskeleton

A small-sized flywheel energy storage system has been developed using a high-temperature superconductor bearing. In our previous paper, a small-sized flywheel was fabricated and successfully rotated at 38 000 rpm under a vacuum condition. However, a large drag torque was present because of the non-axisymmetric magnetic flux of the motor/bearing magnet and the eddy current loss in the planar stator, resulting in a short spin-down time of 20–30 s and a coefficient of friction of 0.15. This paper presents the design, fabrication and electromagnetic analysis of the flywheel in order to reduce the large drag torque. The advanced flywheel designed for solving the non-axisymmetric magnetic flux problem comprises eight motor magnets and a single bearing magnet, a magnetic screening disc, and an aluminium disc which is 50 mm in diameter and 5 mm in thickness. The eddy current loss in the planar stator is minimized by reducing the contact area between the planar stator and the motor magnets. The maximum rotational speed increases 1.3 times to 51 000 rpm and the spin-down time increases 600 times to 3 h 20 min. On the basis of these results, the coefficient of friction decreases 100 times to 0.001–0.002.

http://iopscience.iop.org/article/10.1088/0953-2048/20/7/009/pdf

Bongsu Kim

Papers

An upper-body rehabilitation exoskeleton Harmony with an anatomical shoulder mechanism

Controls for the shoulder mechanism of an upper-body exoskeleton for promoting scapulohumeral rhythm

Design of Nonlinear Rotational Stiffness Using a Noncircular Pulley-Spring Mechanism

Upper-body robotic exoskeleton

Advanced design and experiment of a small-sized flywheel energy storage system using a high-temperature superconductor bearing