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Electric spring (ES) is a demand response method that can stabilize the voltage of critical loads and improve power quality, especially in a weak power grid with a high proportion of renewable energy sources. Most of existing ESs are implemented by voltage-source inverter (VSI), which has some shortcomings. For example, the DC-link capacitor limits the service life of ES, and the battery is costly and hard to recycle. Besides, conventional VSI cannot boost the voltage, which limits the application of ES in high-voltage occasions. This study aims to propose a novel scheme of ES to solve the above problems.

In this work, an ES topology based on current-source inverter (CSI) without a battery is presented, and a direct current control strategy is proposed. The operating principles, voltage regulation range and parameter design of the proposed ES are discussed in detail.

The proposed ES is applicable to various voltage levels, and the harmonics are effectively suppressed, which have been validated via the experimental results in both ideal and distorted grid conditions.

An ES topology based on battery-less CSI is proposed for the first time, which reduces the cost and prolongs the service time of ES. A novel control strategy is proposed to realize the functions of voltage regulation and harmonic suppression.

The purpose of this paper is to make a more precise prediction of the life of servo motors used in aircraft. The variation of the axial load created by the wave washer for bearing, which is one of the factors affecting the bearing life of the electric motors and servo motors used in aircraft, was analyzed.

In electric motors and servo motors that body as stator, the height of the stator stack affects the compression amount of the wave washer spring. Working with electric motor and servo manufacturers, production-related variations in stator height were determined by making multiple measurements. The reaction forces resulting from these compression amounts were simulated by mathematical modeling with the finite element method, and also experimentally measured on real parts.

Results obtained with finite element method and real experiments were compared. By adding the force differences to the general operating conditions, the effect on the bearing life was theoretically determined. In a servo motor with this type of construction, the difference in stator height created different axial loads on the motor shaft. The difference of these loads affected the motor bearing life.

The results implicated in terms of flight safety, maintenance operation and resource efficiency.

The results of this study are effective in determining the maintenance intervals more clearly. This study can be used for the design criteria of aircraft servo motors. These servos, which are especially used to move the flight control surfaces, contribute to flight safety as the life expectancy will be clearer.

This study may be effective in preventing aviation accidents caused by servo motors. It can make maintenance management more efficient.

This study investigated the effect of aircraft servo motor design inputs on servo motor life, considering the production.

This paper deals with the collaborative design of electromagnetic devices over the internet network. The design is made by both mechanical and electrical engineers. So, the paper tries to show the importance but also constraints to size such a system using a collaborative optimisation process.

The paper compares two approaches in order to size an electromechanical actuator between mechanical and electrical engineers. In the first one, each profession designs its part, and only common constrained are negotiated. This can result in a design process with many iterations. In the second one, electrical and mechanical engineers built together a common model of the structure and a common list of specifications: this allows a global optimisation that is more efficient.

The main result of the paper is that the second approach in which a global model is built between electrical and mechanical engineers is more efficient.

The originality of the paper is to explore the problems and difficulties of an optimisation of an electromechanical device between engineers of different culture working together over the internet network.

GYROSCOPES are widely used in flight test instrumentation for measurement of angular rate of rotation.

A SPRING is defined as a device for storing and retaining energy. This definition is very much a simplification and every designer should have some idea of what is involved in selection of springs and the design of them where necessary. This article only covers springs made from metallic materials, although mention must be made of the fact that springs may be devised from such materials as glass fibre reinforced plastics, rubber, air and other fluids.

The purpose of this paper is to propose a novel actuator with adaptable compliance for robotic applications.

In order to achieve limb actuation similar to that of human muscles, a novel actuator with adaptable compliance is proposed. Three principal design paradigms currently exist in the development of artificial muscles that have been adopted at several research centres, universities and commercial organizations around the world. The first approach consists of using compliant actuator systems such as pneumatic actuators. The second approach undertakes the development of electroactive polymers that deform when a voltage is applied. The third approach involves electromechanical devices typically comprising an electrical actuator and an elastic element in combination. The proposed actuator extends on the third approach. It comprises an electrical DC motor in serial configuration and a novel elastic device exhibiting variable stiffness.

The novel elastic device complements the mechanical structure of the device, enabling adaptation to the dynamic effects of external forces.

Several applications for the actuator with adaptable compliance have been identified in the field of human‐like robotics.

Prototypic experimentation has successfully demonstrated the variable stiffness of the device.

This chapter tests theoretically and empirically the existence of a stable relationship between energy consumption and CO2 emissions. Based on microeconomics and physics, a model has been specified and applied to annual data for twenty countries, which representing 61 percent of the world’s population in 2018, over the period 1995–2015. The data are from the International Energy Agency (2019) and econometric techniques including panel data and causality tests have been used. The results indicate that there is a causal relationship between energy consumption and CO2 emissions. In general, consumers cannot directly change emissions caused by production processes, but they can act on emissions caused by their own domestic energy consumption. Approximately three quarters of domestic energy consumption is due to heating and domestic hot water consumption. Taking into account the lower emissions and the lower economic cost of the initial investment, four potential energy systems have been selected for use in heating and domestic hot water. Their social returns have been assessed across nine of the twenty countries in the sample over a lifecycle of 25 years from 2018: France, Portugal, Ireland, Spain, Iceland, Germany, United Kingdom, Morocco and the United States. Cost-benefit analysis techniques have been used for this purpose and the results indicate that the use of thermal water, where applicable, is the most socially profitable system among the proposed systems, followed by natural gas. The least socially profitable systems are those using electricity.

TRENDS in modern aeroplane design toward multi‐engined types super‐charged for high altitude operation have imposed new demands upon variable‐pitch airscrew equipment. To secure the best operating conditions with a minimum of attention from the pilot, constant speed control is essential. To meet the requirements of increased speed range, a wide operating range of blade angles is necessary. To prevent possible further damage to the engine and aeroplane due to “windmilling,” in the event of failure of one of the power plants, and to secure a maximum of performance from the remaining power, it is highly desirable that the airscrew be capable of attaining blade angles of 85 to 90 deg. or of being “feathered.” For maximum flexibility, the airscrew control should be independent of the engine. At all times, it is essential that the pilot should have ready means of selecting and controlling the type of operation desired.

The purpose of this paper is to describe designing Pobot V2, a robot capable to climb poles with a cylindrical or conical shape.

This paper describes the design of the pole‐climbing robot Pobot V2, based on the innovative principle of rolling self‐locking that uses no energy to maintain itself at a given altitude.

The robot is also capable of avoiding tangential obstacles, crossing small collars and regulating passively its normal contact force on conical poles with a diameter that evolves from 300 to 100 mm. The work is validated by experiments. The robot can also perform axial rotation, can cross‐tangential obstacles and climb poles with a strong conical shape, due to passive normal force regulation with springs and a force amplifying linkage. The first experiments showed excellent stability during vertical climbing.

More work will be required to make the robot more rigid, more compact, and lighter. The robot is jointly patented by Thales and IFMA.

It is original because of its rolling self‐locking concept: rolling allows continuous ascension whereas self‐locking guarantees a null energy consumption while staying still on the pole.

Japan puts the emphasis on assembly, while growth is not what it used to be. John Hartley reports.