Search Results (9)

Brakes are essential parts of any system that involves motion. A few seconds are spent applying the brake, accumulating enough force to retard a system. In case of emergency stops, we need an efficient braking system that acts quickly and safely to avoid any mishaps. This work aims to develop a prototype of an instantaneous braking system, which can stop the motion of a rotating member. The operating principle of the device is the electromagnetic actuation of a solenoid. The actuation of a solenoid is simple and instantaneous. As a result, we could achieve immediate braking of a rotating member. Full article

The mobility of today and tomorrow is characterized by technological change and new challenges in drive concepts such as electric or hydrogen vehicles. Abolishing conventional combustion engines creates even more need for switching or valve technology in mobility systems. For switching and controlling purposes, solenoids are used in large numbers and in a wide variety of applications, thus making a significant contribution to the overall success of the energy transition, and not only in the automotive sector. Despite their long existence, continued research is being carried out on solenoids involving new materials and actuator concepts. Great interest is focused on providing an adjustable force–displacement characteristic while simultaneously reducing the noise during switching. At IKFF, research is being conducted on hybrid electromagnets in the border area of switching and holding solenoids. This paper aims to present the major advantages of this hybrid drive concept based on an electromagnetic FEA simulation study of two drive concepts and specially developed and characterized prototypes with magnetic shape memory (MSM) alloys. The concepts differ in the spatial orientation of the MSM sticks to generate an active stroke of the plunger, which contributes to a beneficial force–displacement characteristic and lower power consumption while minimizing switching noise. Full article

This paper proposes a design for a one-coil long-stroke permanent magnet actuator (PMA) applied to a load breaker switch with a novel mechanism applicable to railways. As a new load breaker switch applicable to railway overhead lines has a double-insulation structure of the vacuum interrupter (VI) and a disconnect switch (DS) for higher insulation, the actuator to control the switch requires a very long stroke. While the traditional mechanism of the PMA implements a stroke of 10 to 30 mm, the load breaker switch with a double-insulation structure requires a stroke of 120 mm. To do so, we used the finite element method (FEM) and designed a novel one-coil long-stroke PMA. Then, values from FEM analysis were compared with measured holding force data, and a simplified prototype test-jig was used to confirm the actuator’s operating characteristics. In addition, the electromagnetic force, plunger rotation, and part weight ratio, which affect operating performance, were adapted in its design. By doing so, we confirmed the operating performance required for the one-coil long-stroke PMA for a new load breaker switch with a double-insulation structure with a VI average opening speed of 1.4 m/s and an average closing speed of 0.9 m/s at 1/2 of full stroke. Full article

Thermal switches contribute to efficient and safe thermal management of components and overall systems in various technical applications by actively controlling heat transfer in response to varying thermal loads and ambient conditions. Heat pipes are passive heat transfer devices constituting an integral part of various thermal management systems such as in spacecraft or consumer electronics thermal control. Heat pipes also form a promising approach for thermal switches due to their high effective thermal conductivity. In this paper, a wickless copper-water heat pipe based thermal switch with an electromagnetic linear actuator is presented. The magnetically actuated motion of a plunger integrated into the heat pipe affects the latent heat transport cycle leading to a switchable heat transfer. Thermal measurements conducted to determine the total thermal resistance of the heat pipe demonstrate the efficacy of the thermal switch. It was found that the thermal resistance of the heat pipe was increased by up to 53% in off state while the heat pipe performance in on state was not significantly affected by the integrated mechanism. Full article

Existing transmission line full-scale tests rely on natural winds and have low test efficiency. In this paper, taking a reduced-scale test line with a 35.4 m span as an example, an electromagnetism-based transmission line galloping test system is designed. The plunger electromagnet periodically provides mechanical energy which vibrates the wire system in place of complex pneumatic loads. The finite element model of the electromagnet device is established and the influence of related parameters is analyzed. The power supply and control circuit of the excitation device are designed. The vibration of the transmission line is monitored by accelerometers and the displacement calculation method based on discrete wavelet transform (DWT) is proposed. Considering the geometric nonlinearity of the wire system, an adaptive excitation method based on wavelet decomposition and reconstruction of the acceleration signal is proposed. The vibration response of the wire under different coil currents and excitation modes is monitored and analyzed. The results show that the actual line galloping can be simulated by the designed electromagnetic system, the vibration frequency is close to the second natural frequency and the vibration amplitude can be controlled by changing the coil current. Full article

A model-based study is carried out based on a combination of mathematical and Maxwell models to develop a high-performance electric pressure regulator utilized for compressed-natural-gas-fueled vehicles. To reduce computational cost, a symmetric two-direction model of the electric pressure regulator is established in Maxwell software, in which its material properties and dimension parameters are obtained on the base of specifications of a real electric pressure regulator. The output of simulating in Maxwell is the electromagnetic force, which is significantly improved when changing core shape in the various dimensions ∆1, ∆2, and ∆3. The optimal electromagnetic force is utilized for the mathematical models as an input variable to simulate the operational characteristics of the electric pressure regulator such as displacement and response time of plunger. The operational characteristics of the electric pressure regulator are examined under the influences of key parameters, including inlet gas pressure, diameter of orifice, and spring stiffness. By optimizing these key parameters, the simulated results in this study show that an electric pressure regulator with high performance can be obtained. Full article

Techniques for estimating the plunger position have successfully proven to support operation and monitoring of electromagnetic actuators without the necessity of additional sensors. Sophisticated techniques in this field make use of an oversampled measurement of the rippled driving current in order to reconstruct the position. However, oversampling algorithms place high demands on AD converters and require significant computational effort which are not desirable in low-cost actuation systems. Moreover, such low-cost actuators are affected by eddy currents and parasitic capacitances, which influence the current ripple significantly. Therefore, in this work, those current ripples are modeled and analyzed extensively taking into account those effects. The Integrator-Based Direct Inductance Measurement (IDIM) technique, used for processing the current ripples, is presented and compared experimentally to an oversampling technique in terms of noise robustness and implementation effort. A practical use case scenario in terms of a sensorless end-position detection for a switching solenoid is discussed and evaluated. The obtained results prove that the IDIM technique outperforms oversampling algorithms under certain conditions in terms of noise robustness, thereby requiring less sampling and calculation effort. The IDIM technique is shown to provide a robust position estimation in low-cost applications as in the presented example involving a end-position detection. Full article

This article focuses on indirect coil guns used for launching non-magnetic objects. A mechatronic model, coupling electrical, mechanical, and electromagnetic models, is proposed. This model is applied to the optimization of a kicking system used on limited size robots for propelling real soccer balls at the RoboCup. Working with an existing coil gun, we show that fine tuning its setup, especially the initial position and the length of the non-magnetic plunger extension, leads to an increase in the ball speed of $30\%$ compared to previous results. Full article

We develop a solenoid actuator with a ferromagnetic plunger to generate both rectilinear and turning motions of a multi-segmented robot. Each segment of the miniaturized robot is actuated by a pair of solenoids, and in-phase and out-of-phase actuations of the solenoid pair cause the linear and turning motions. The theoretical analysis on the actuation force by the solenoid with the magnetic plunger is implemented based on the Biot-Savart law. The optimal design parameters of the solenoid are determined to actuate a segmented body. We manufacture the miniaturized robot consisting of two segments and a pair of solenoids. Experiments are performed to measure the linear and angular displacements of the two-segmented robot for various frictional conditions. Full article