State-of-the-art teleoperation systems are installed in various specialized robots, such as disaster, underwater, and surgical robots. However, the sensitive nature of their tasks causes psychological stress in operators. To reduce this stress, bilateral controllers are used to achieve a force feedback function that can support operational skills with gravity/friction compensation and haptic perception. Therefore, we developed several types of haptic devices with magnetorheological (MR) fluids as the core technology for fine haptics. MR fluids are composite materials comprising ferromagnetic particles, medium oils, and several types of additives. Their rheological properties change rapidly, stably, and repeatedly with the application of an external magnetic field. In our previous study, we developed desktop and standalone MR fluid (MRF)-based haptic devices for surgical simulations. However, handheld devices have not yet been developed. Therefore, we designed and developed a compact MR fluid device with a total mass and maximum torque of approximately 100 g and 0.3 Nm, respectively. Static, step, hysteresis, and repeat tests were conducted for the 0.3 Nm-class MRF device. According to the results of the repeat tests, the variation coefficient was 0.5% for a current input of 0.5 A, demonstrating the suitability of the developed device as a fine haptic generator.

Structural batteries refer to multifunctional composite materials capable of storing and delivering electrical energy while carrying mechanical loads. One of the most promising structural battery concepts demonstrated to date utilises carbon fibres in both electrodes, providing combined high electrochemical capacity, electric conductivity and elastic modulus and strength. This paper reports on the state-of-the-art for all-carbon fibre based structural batteries.

The current paper discusses the use of magnetorheological fluids (MRFs) for the lubrication of journal bearings as an effective solution for controlling performance-wise a variety of rotor bearing systems applying an external magnetic field. To account for the magnetic flux production in the lubricating layer, a 2D axisymmetric magnetostatic model is developed while the static performance metrics of the journal bearing are assessed via a 3D CFD analysis modeling the MR fluid as a Bingham plastic, the rheological parameters of which depend on magnetic field intensity. Moreover, is concluded that MRFs have a wear compensatory feature, increasing the minimum lubricant thickness to a degree that completely compensates possible wear, filling the worn region with high viscosity lubricant.

In order to solve the high-frequency vibration problem of industrial pipeline in petrochemical enterprises, a tuned mass damper (TMD) based on magnetorheological (MR) technology was proposed. The magnetorheological-tuned mass damper (MR-TMD) can reduce the vibration response of the structure by tuning resonance with the pipeline system, it can also have the semi-active control characteristics of MR devices. By analyzing the vibration signals collected on the pipeline site, the relevant design requirements and parameters of the damper were determined. The optimal frequency ratio, passive damping, and mass ratio of the damper were determined using the optimal design theory. Meanwhile, the high-performance MR composite was prepared for the working conditions of MR-TMD and a modified Herschle-Bulkley model was derived to characterize the behavior of the material. Furthermore, the mechanical performance of the proposed MR-TMD was tested, the output damping force is about 890.5 N when the applied current is 2 A, which can meet the working requirements of pipeline vibration attenuation. Then, according to the established vibration control model of pipeline system, the vibration system was simulated and analyzed combined with LQR algorithm, and the vibration attenuation performance in different conditions were predicted and compared. The research shows that the TMD combined with MR technology can effectively reduce the vibration of industrial pipeline system.

Vibration control remains a pivotal challenge in engineering, demanding solutions that offer wideband and low-frequency effectiveness with minimal energy. This paper introduces a hybrid vibration control method, combining semi-active piezoelectric (Piezo), and passive acoustic black hole (ABH) techniques. The semi-active approach, similar to Bang-Bang control, efficiently curtails low-frequency vibrations without precise control modes, using scant external energy. Concurrently, passive strategies exploit the ABH effect to absorb medium-high frequency waves through focused damping. The integration of Piezoelectric integrated ABH (Piezo-ABH) structures showcases the feasibility of broad-spectrum vibration dampening, with experimental outcomes revealing significant vibration reduction across 20 ∼ 2000 Hz, averaging an 8.0 dB decrease.