Current Issue : April - June Volume : 2021 Issue Number : 2 Articles : 5 Articles
Dual-slider positioning in a miniaturized system is crucial in many industrial applications. This paper presents a miniaturized dual-slider linear actuator by employing one piezoelectric element (PZT) and integrating the methods of electrostatic adhesion and inertia drive. Two inertia drive methods can be converted by clamping and releasing one of the sliders on a base. Two thin-film electrodes are mounted on the base for clamping and releasing the slider by electrostatic adhesion. The actuator can thus drive dual sliders independently by converting the two inertia drive methods. A prototype is developed with a compact size of 30 mm (L) × 11 mm (W) × 11 mm (H) to evaluate the basic performance of the actuator. The maximum driving speeds of the two sliders are 31.7 mm/s and 16 mm/s, respectively, while the resolution of them is 60 nm and 13 nm, respectively. Additionally, the actuator can drive both the two sliders for long motion ranges of 14 mm. With a compact size and excellent physical performance, the proposed device has the potential for multi-slider positioning in miniaturized equipment....
This article focuses on controlling single-input-single-output (SISO) nonlinear systems with actuator failures via sliding mode control (SMC) and composite learning SMC (CLSMC). In the design of the SMC, an integer-order sliding surface is proposed, and an adaptive law is constructed to update the parameter evaluation in the actuator failure. The SMC method can achieve the tracking error approaching zero if a strict permanent excitation (PE) condition is satisfied. To mitigate this requirement, by using all data recorded while the controller works, we construct prediction errors that are utilized to produce a composite learning adaptive law. Then, the proposed CLSMC method not only drives the tracking error to zero but also realizes the accurate evaluation of the unmatched unknown parameter in the actuator failure. In addition, in the proposed CLSMC method, we only need to satisfy an interval excitation (IE) condition. Simulation results are presented to indicate the validity of our methods....
The technological advantages that biosensors have over conventional technical sensors for odor detection have not yet been comprehensively analyzed. However, this is necessary for assessing their suitability for specific fields of application as well as their improvement and development goals. In this paper specific market potentials of biosensors for odor detection are identified by applying a tailored methodology that enables the derivation and systematic comparison of both the performance profiles of biosensors as well as the requirement profiles for various application fields. Therefore, the fulfillment of defined requirements is evaluated for biosensors by means of 16 selected technical criteria in order to determine a specific performance profile. Further, a selection of application fields for odor detection sensors is derived to compare the importance of the criteria for each of the fields, leading to market-specific requirement profiles. The analysis reveals that the requirement criteria considered to be the most important ones across all application fields are high specificity, high selectivity, high repeat accuracy, high resolution, high accuracy, and high sensitivity. All these criteria, except for the repeat accuracy, can potentially be better met by biosensors than by technical sensors, according to the results obtained. Therefore, biosensor technology in general has a high application potential for all the areas of application under consideration. Health and safety applications especially are considered to have high potential for biosensors due to their correspondence between requirement and performance profiles....
A compact and flexible hydraulic double-cylinder actuation scheme is proposed for use in applications, especially where power density is extremely demanding. In view of flexible amounting requirements, long and thin hoses were utilized to connect two cylinders. Affecting the actuation preciseness, volume variation of the hoses caused by pressurized oil and bubbles was the main problem the system encountered. In this study, an active disturbance rejection control (ADRC) strategy was adopted for the improvement of displacement control performance under uncertain external load. After the experimental verification of the necessity of a hose model for the system, a centralized-parameter hose model was constructed where the coefficients are determined on the basis of the experimental data. Additionally, the system and the controller proposed were mathematically modeled. Simulation results shows that the system using ADRC exhibited higher displacement accuracy and better dynamic performance than that using PID (Proportion-Integral-Derivative) or fuzzy PID. ADRC has a stronger disturbance rejection ability. ADRC is an effective solution to nonlinear control of systems with uncertain parameters or various loads....
We studied the chaotic peculiarities of magnetic-mechanical coupled system of GMA. Based on the working principle of GMA and according to Newton’s second law of motion, first piezomagnetic equation, disk spring design theory, and structural dynamics principle of GMA, the present study established a GMA magnetic-mechanical coupled system model. By carrying out data modeling of this coupled system model, the bifurcation chart of the system with the variation of damping factor, excitation force, and exciting frequency parameters as well as the homologous offset oscillogram, phase plane trace chart, and Poincar´e diagram was obtained, and the chaotic peculiarities of the system were analyzed. The influence of parametric errors on the coupled system was studied. The analytical results showed that the oscillation equation of the GMA magnetic-mechanical coupled system had nonlinearity and the movement morphology was complicated and diversified. By adjusting the damping factor, exciting frequency, and excitation force parameters of the system, the system could work under the stable interval, which provided theoretical support for the stability design of GMA....
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