Search Results (184)

This paper proposes an energy-efficient current control strategy for drive modules of permanent magnetic actuators (PMAs) to reduce the cost and volume of DC-link capacitors. The drive module of the PMA does not receive the input power from an external power source during operation. Instead, the externally charged DC-link capacitors are used as internal backup power sources to guarantee the reliable operation even in the case of an emergency. Therefore, it is important to use the charged energy efficiently within the limited DC-link capacitors. However, conventional control strategies using a voltage open loop have trouble reducing the energy waste. This is because the drive module with the voltage open loop uses unnecessary energy even after the PMA mover has finished its movement. To figure it out, the proposed control strategy adopts a current control loop to save energy even if the displacement of the PMA mover is unknown. In addition, the proposed strategy can ensure the successful operation of the PMA by using the driving force analysis. The efficacy of the proposed strategy is verified through the experimental test. It would be expected that the proposed strategy can reduce the cost and volume of the PMA drive system. Full article

The increasing adoption of industrial robots has significantly advanced manufacturing efficiency and flexibility. However, this expansion introduces new energy consumption challenges, especially as electricity has become the dominant energy source in automated systems. As the industrial sector faces rising energy costs and ambitious sustainability goals, understanding and minimizing the energy consumption of robotic systems is imperative. This review presents a structured analysis of energy consumption in industrial robots, linking mechanical design, actuation systems, and control strategies to their energetic effects. We first discuss different industrial robot types and their kinematic configurations, identifying how structural characteristics influence energy use. The article then categorizes energy consumption optimization strategies into software-based and hardware-based approaches. A comparative SWOT analysis highlights the strengths and limitations of each approach. The review also explores emerging trends such as DC microgrid integration. The future directions underline the need for standardized energy assessment frameworks and the development of hybrid optimization strategies that combine the reviewed approaches, suitable for being applied in real-world industrial robot applications. This work provides a comprehensive foundation for establishing best practices in energy consumption optimization for industrial robots. Full article

Chaotic behavior and memory-dependent dynamics in fractional-order brushless DC motors (FOBLDCMs) pose significant challenges for robust and stable control design, particularly when physical constraints such as actuator saturation and rate limitations are present. Existing control frameworks often neglect these nonlinear limitations, resulting in performance degradation and potential instability in practical applications. Motivated by these challenges, this paper presents a comprehensive Lyapunov-based stability and control synthesis framework for FOBLDCMs within the fractional-order (FO) range $0<v<1$. The proposed methodology employs indirect, direct, and composite Lyapunov functions to derive sufficient stability conditions under four scenarios: unconstrained input, saturation-only, rate-limited-only, and combined constraints. For each case, a family of stabilizing controllers is designed to explicitly handle the respective limitations. To the best of our knowledge, this is the first study to rigorously address both saturation and rate limitations in the control design of FO chaotic systems. Numerical simulations confirm that the proposed controllers significantly improve performance over existing methods. Specifically, the unconstrained controller achieves a notable reduction in control energy (from $2.72\times {10}^5$ to $1.83\times {10}^5$), a 26.3% decrease in maximum control effort, and enhanced or comparable tracking accuracy, as indicated by lower ISE and RMSE values. These results highlight the robustness and practical applicability of the proposed control framework for real-world FO electromechanical systems. Full article

To address the challenges of small aperture size, limited scanning angles, and high fabrication costs in existing scanning micromirrors, this paper proposes a large-aperture biaxial electromagnetically driven scanning micromirror. The scanning micromirror utilizes a stainless-steel mirror structure and an actuation structure composed of arc-shaped permanent magnets (NdFeB 52), iron cores, and copper coils. By optimizing the magnet layout and coil design, it achieves large optical scanning angles in biaxial non-resonant scanning mode. Experimental results demonstrate that the optical scanning angles reach 61.4° (x-axis) under a DC driving current of ±18.1 mA and 61.1° (y-axis) under a DC driving current of ±25.2 mA with an effective mirror aperture of 9.54 mm × 10 mm. The resonant frequencies are 89 Hz (x-axis) and 63 Hz (y-axis). Experimental results verify the feasibility of biaxial independent control in non-resonant scanning mode. The design is fabricated using a low-cost computer numerical control (CNC) milling process and exhibits application potential in fields such as LiDAR, projection display, and optical communication, providing a novel approach for performance optimization of large-aperture scanning micromirrors. Full article

This paper presents the design of a four omni-wheeled mobile robot consisting of four omni wheels, with each wheel connecting to a separate DC motor. Additionally, the presence of a telescopic leg with a linear RC servo actuator enables the robot to adapt to various landscape changes, including obstacle overcoming. We have designed and manufactured the physical prototype of the robot based on the simulation results. The proposed robot can traverse in both vertical and horizontal directions without altering its orientation, thereby enhancing its stability during operation. The experimental results confirm the robot’s effectiveness in autonomously adapting its position in response to sudden changes in the landscape, enabling it to navigate and climb steps successfully. Full article

Polydimethylsiloxane (PDMS) and poly(3,4-ethylene dioxythiophene):poly(4-styrene-sulfonate) (PEDOT:PSS) composites were tested to determine their suitability for charging small-scale batteries in conjunction with a piezoelectric actuator as an energy harvester. Two different PEDOT:PSS patterns (zigzag and serpentine) were tested, and the maximum DC voltage of a system incorporating PEDOT:PSS was determined. The aim of this work is to study the effect of soft corners in the electrical routing of aircraft and IoT sensors. The zigzag and serpentine patterns were considered for this study because of their simplicity in design. Without the polymer, 2.3 V was produced by the actuator, while adding PEDOT:PSS resulted in the voltage being reduced to 1.7 V. The piezoelectric actuator was connected to a 3.6 V rechargeable Li-ion battery, and the battery’s voltage was recorded over 1 h. The voltage from the piezoelectric actuator was 3.8 V. Without PEDOT:PSS, the battery was charged to a maximum of 3 V. Adding the PEDOT:PSS to the circuit reduced the maximum charge to a voltage of 2 V. The results indicate that while PEDOT:PSS composites can be used in conjunction with piezoelectric energy harvesters, more work is still needed to optimize the system to increase efficiency and charging rates. Full article

Faults in the DC drive circuit of UAV electro-hydrostatic actuators directly affect the flight safety of a UAV. An integrated learning and Bayesian network-based fault diagnosis strategy is proposed to address the problems of early fault diagnosis, poor unbalanced data processing performance, and lack of interpretability in intelligent fault diagnosis in engineering practice. In the data preprocessing stage, Pearson coefficients are used for feature correlation analysis, and XGBoost performs feature screening to extract key features from the collected DC drive circuit data. This process effectively saves computational resources while significantly reducing the risk of overfitting. The optimal weak learner selection for the high-performance boosting integrated learner is identified through comparative validation. The performance of the proposed diagnostic strategy is fully verified by setting up different comparison algorithms in two experimental circuits. The experimental results show that the strategy outperforms the comparison algorithms in various scenarios such as data balancing, data imbalance, early-stage faults, and high noise; in particular, it shows a significant advantage in diagnosing data imbalance and early-stage faults. The interpretable fault diagnosis of UAV DC drive circuits is realized by the interpretation strategy of Bayesian networks, which provides the necessary theoretical and methodological support for practical engineering operations. Full article

Different locations and types of faults affect the safe and reliable operation of DC microgrids. Therefore, this paper proposes a secondary multiple fault-tolerant control scheme for a DC microgrid based on a sliding mode observer to ensure the voltage is restored to the rated value and realize the proportional current sharing of all sources. Firstly, the secondary control model of the DC microgrid is established, considering the multiple faults of actuators and sensors simultaneously. Secondly, the system model is transformed into two subsystems by bilinear coordinate transformation, and multiple faults decoupling between the sensor and actuator is realized. Then, two sliding mode observers are designed for the two transformed subsystems. The sliding mode variable structure equivalent principle is used to reconstruct the faults at different positions without knowing the fault models in advance, which is convenient for subsequent processing. Then, the fault-tolerant controller based on the sliding mode observer is designed, which uses the reconstructed value to offset the influence of sensor and actuator faults on the DC microgrid and realizes the fault-tolerant control of the DC microgrid. Finally, the effectiveness of the proposed control strategy is verified by experiments. Full article

Direct current (DC) motors are widely used in various applications because of their operational advantages and ease of control compared to those of other rotating machines. This study focuses on regulating the operation of a bidirectional conveyor powered by a permanent magnet DC motor driven by a full H-bridge power converter. The mechatronic system, comprising a conveyor, a DC motor, and a power converter, is modeled using first-order differential equations. For control design purposes, a simplified actuator model is derived, treating the conveyor load as an external disturbance. A linear control scheme, based on classical control theory, is proposed to ensure that the actuator velocity tracks the reference input. To improve the disturbance rejection, particularly against variations in mechanical loads, an extended state observer is incorporated. Simulation tests validated the proposed control scheme, highlighting the functionality and tradeoffs of its internal components. Full article

In this study, we investigated the influence of an epoxy end-capped polypropylene oxide crosslinker (epoxy-PPO) on the formation of the crosslinked network structure, the stress–strain response, and the electro-mechanical actuation performance of a maleic anhydride functionalized liquid isoprene rubber (LIR). The crosslinker amount varied from 10 (C-LIR-10) to 50 (C-LIR-50) weight parts per hundred parts (phr) of LIR. The swelling test of the cured rubbers revealed that C-LIR-20 formed the densest crosslinked network with the lowest chloroform uptake value within this series. The crosslinked rubber became stiffer in tensile response upon increasing the epoxy-PPO amount from C-LIR-10 to C-LIR-20 and then softened at higher amounts. The SEM measurements were used to relate this composition-induced softening of the rubbers to the phase morphology evolution from nanoscale homogeneity in C-LIR-10 to microscale segregations of excess crosslinkers in C-LIR-50. The use of epoxy-PPO improved the dielectric constant value of LIR; however, the leakage current through the films also increased from 25 µA DC to 320 µA DC for LIR-30 and LIR-50, respectively, during DEA operation. The electro-mechanical actuation tests with circular actuators showed that the C-LIR-10 elastomer film demonstrated a radial strain of 1.7% on activation at an electric field strength of 17.5 V/µm. At higher crosslinker amounts, the close proximity of excess epoxy-PPO molecules caused leakage current across elastomer films thus diminishing the actuation strain of otherwise relatively softer elastomers with higher dielectric constant values. Full article

This paper proposes a variable mechanism structure based on a ball screw design for precise displacement control in axial piston pumps, with the objective of improving actuator position and velocity control within the displacement-controlled (DC) systems. Traditional valve-controlled cylinder variable mechanisms (VCCVM) often suffer from limited control precision over the swash plate due to numerous uncertain parameters within the hydraulic system. To address this issue, a ball screw is utilized to replace the original valve-controlled cylinder for swash plate control, enhancing accuracy and responsiveness. In addition, an in-depth analysis of the Ball Screw Variable Mechanism (BSVM) is conducted, leading to the development of a coupled mechanical–hydraulic dynamic model. Based on this model, a controller is designed to improve system performance. Finally, the effectiveness and high performance of the proposed new structure and control strategy were validated through comparative experiments and simulations. The experimental results confirm the advantages of the proposed design, demonstrating satisfactory improvements in control precision. Full article

Control delay phenomena, such as time delays and actuator lags, can compromise the control performance of autonomous mobility systems, leading to increased control errors. Therefore, it is essential to develop a control delay compensation algorithm. This paper proposes a Lyapunov-based backstepping steering control algorithm to compensate for control delays in autonomous mobility systems. To estimate the control delay in the steering system, the Recursive Least Squares (RLS) algorithm was employed to calculate the time constant in real time. The control delay was estimated using an RLS designed based on a first-order differential equation. A backstepping steering controller was developed to calculate the desired steering angle using simplified error dynamics for reference path tracking. The control errors, specifically the lateral preview and yaw angle errors, were derived by calculating the path error between the current position and the waypoint. The performance of the proposed control algorithm was evaluated using the DC motor and CarMaker software 8.1.1(IPG Automotive, Karlsruhe, Germany) under scenarios involving sinusoidal input and four-curved loop and S-curved paths respectively. Full article

Quasi-direct current (Q-DC) filamentary electrical discharges are used to control the shock train in a back-pressured Mach 2 duct flow. The coupled interaction between the plasma filaments and the shock train leading edge (STLE) is studied for a variety of boundary conditions. Electrical parameters associated with the discharge are recorded during actuation, demonstrating a close correlation between the STLE position and dynamics. High-speed self-aligned focusing schlieren (SAFS) and high frame-rate color camera imaging are the primary optical diagnostics used to study the flowfield and plasma morphology. Shock tracking and plasma characterization algorithms are employed to extract time-resolved quantitative data during shock–plasma interactions. Four distinct shock–plasma interaction types are identified and outlined, revealing a strong dependence on the spacing between the uncontrolled STLE and discharge electrodes and a moderate dependence on flow parameters. Full article

The use of vacuum-hybrid DC circuit breaking methods allows the short-circuit current to be switched off in a shorter time, resulting in a reduction in the arc burning time. This requires the use of a drive, such as the Thomson Coil Actuator TCA, capable of providing a short response time for opening the vacuum interrupter VI, regardless of its rated current. The IDD is powered by a pre-charged capacitor, which, together with the drive coil, forms an LC oscillating circuit that, when switched on by a thyristor, generates a current pulse of several kA with a frequency above 1 kHz. The paper investigates the effect of modifying the basic IDD power supply circuit by adding semiconductor diodes to shape the current pulse and improve its performance. The authors also focused on exploring the impact of the connection quality and their length and the associated loss in drive force while proving that a circuit with a reverse diode on the IDD coil is most beneficial and that the effect of the circuit on the front of the current pulse can significantly slow down the drive. Full article

In order to solve the problem of the slow initial speed caused by the large mass of the bistable permanent magnetic actuator (PMA) in the traditional bistable permanent magnetic–electromagnetic repulsion mechanism (PM-ERM), a novel fast contact operating mechanism is proposed by using the flexible spring system (SS) between the PMA and the ERM. The novel structure can separate the mass of the PMA and the ERM at the initial phase of the interrupting process, improve the initial speed of the contact and increase the initial opening distance of the contact. Firstly, the paper conducts an extensive investigation and analysis of the principle of the existing fast operating mechanism and points out the advantages and disadvantages of the existing mechanism. In order to meet the requirement of fast interrupting and improve the service life of the mechanism, a novel mechanism is proposed. And then, the working principle of the novel mechanism is introduced. The cooperative relationship between the ERM and the PMA and the working principle and performance parameter requirements of the ERM, SS and PMA are analyzed and designed. Finally, the feasibility of the novel mechanism is verified by the experiment. The results show that the opening distance of the novel operating mechanism can reach 2.25 mm in 1 ms. Compared with 1.24 mm of the traditional operating mechanism, it improves the initial opening distance of the contact by 81.5% and is conducive to the rapid interruption of the Hybrid DC current-limiting circuit breaker (HDCCLCB). Full article