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doi: 10.1177/0020294018819543pmid: N/A
Shear thickening fluid is a smart material with rheological properties that can be rapidly varied by excitation changes. To fully explore the advantages of using shear thickening fluid in various devices, a phenomenological model for simulating complex viscosity characteristics of the shear thickening fluid has been developed, and an analytical model has been presented to predict the mechanical characteristics and performance of a damper filled with shear thickening fluid. Based on the analytical model, the force displacement curves are first analyzed for different excitation amplitudes and frequencies. Second, an investigation of the time history of the damping force at various excitation amplitudes is conducted. Finally, the effects of key design parameters on the force displacement and force velocity curves are discussed. The results show that the shear thickening fluid damper exhibits significant velocity correlation, and the damping force increased as the shear rate of shear thickening fluid increased until the threshold value. For the vibration with high frequency, or fast velocity, or large amplitude, the shear thickening fluid is easy to have high shear rate, which results in a great vibration control capability for the shear thickening fluid damper.
doi: 10.1177/0020294018819548pmid: N/A
Modeling of aeroelastic system of wind turbine blade section based on chordwise rigid trailing-edge flap has been investigated. The flutter suppression of blade section exhibiting flap-wise bending and twist deformation is performed by equivalent sliding mode control. Aerodynamic expressions are based on the modified quasi-steady model which is attached to the influences of trailing-edge flap. The continuous equivalent sliding mode control algorithm based on quadratic feedback parameter is applied to realize flutter suppression, with displacements and velocities, control input of angle of trailing-edge flap and sliding mode function demonstrated. To facilitate the process of computer implementation, the discrete equivalent sliding mode control algorithm is discussed in detail, with better control effects and angle control of trailing-edge flap demonstrated. The quadratic feedback–based equivalent sliding mode control algorithm, including continuous equivalent sliding mode control and discrete equivalent sliding mode control, realizes the analysis of control effects based on feedback parameter with empirical adjustment coefficient. This provides schemes of not only theoretical simulation but also real-time implementation for the application of equivalent sliding mode control in different engineering projects.
doi: 10.1177/0020294018819549pmid: N/A
Leader-following consensus of multi-agent systems with general linear models is investigated via event-based impulsive control approach. Event-based impulsive controller and state-dependent triggering function are designed. Impulsive instants are determined by certain triggering events, that is, impulsive effect performs only at the instants when events occur, and so as controller update. Sufficient conditions on leader-following consensus are proposed by using stability theory of impulsive differential equations, matrix theory, and inequality technique. Zeno-behavior is also excluded for the concerned closed-loop system. Besides, a technique that used the state information of agents only at event instants is proposed to avoid continuous communication among agents. Finally, an example is presented to illustrate the effectiveness of the obtained theoretical results.
Lin, Yunhan; Zhou, Haotian; Chen, Mingyu; Min, Huasong
doi: 10.1177/0020294018819552pmid: N/A
With the development of the technologies such as computer vision, natural language interaction, process control technology, and sensor technology, the discussion of automatic sorting system of robot hits a hotspot in the robot community. This paper presents an automatic sorting system for industrial robot with the technologies of 3D visual perception, natural language interaction and automatic programming. Therein, a ‘rule-scene’ matching and interaction algorithm is proposed to combine all these modules together. By utilising our algorithm, robot can interact with human beings according to the real-time actual three-dimensional scene information and can guide users to give correct rules through speech when the rule is invalid. After getting the correct rules, robot can sort the object automatically using the automatic programming and execution algorithm designed in this study. In the experimental section, the designed system is applied to a fruit-sorting scene, which proves the effectiveness and practicability of the system.
Huang, Jian; Li, Yuanyuan; Jiang, Bei; Cao, Le
doi: 10.1177/0020294018819554pmid: N/A
As an important support for test and control projects, sensor’s performance is directly related to the accuracy of the measurement. To fully analyze the sources of measurement uncertainty for a surface acoustic wave micro-pressure sensor, in this study the Monte Carlo method and Guide to the Expression of Uncertainty in Measurement to evaluate measurement uncertainty of sensors are used, the sensing experiment was conducted and the measurement addition model was established. We determined the source of measurement uncertainty for a surface acoustic wave micro-pressure sensor. The results show that the Monte Carlo method can obtain a more reliable and accurate inclusion interval in the measurement uncertainty evaluation of a surface acoustic wave micro-pressure sensor.
doi: 10.1177/0020294018823026pmid: N/A
This paper formulates a coupling dynamic model for a flexible manipulator system with harmonic drive using experimental identification method. Parameters of the driven model of the harmonic joint and parameters of coupling vibration model of the flexible manipulator are identified. Accordingly, coupling dynamic models of the proposed system are obtained. Coulomb friction of the joint is identified by step current excitation and uniform rotation experiments at a low speed. Then, the transfer function model of the harmonic joint is established and identified by a pseudorandom binary sequence excitation. And predicted outputs of the obtained model are in good agreement with the experimental setup. Relationships between strain of the flexible manipulator and coupling torque are presented by theoretical derivation. Based on the theoretical model, transfer function from the angular displacement of the servo motor to the coupling torque is identified. Experimental results show this identified model match well with the proposed structure, both in the time and frequency domain. As a result, coupling dynamic modelling of the flexible manipulator system with harmonic drive is accomplished.
Yang, Bo; Liu, Fuhuang; Zhang, Meng
doi: 10.1177/0020294018823028pmid: N/A
To improve surplus torque suppression and loading performance of electric load simulators, this paper presents a loading control strategy based on the new mapping approach and fuzzy inference scheme in the fuzzy Cerebellar Model Articulation Controller. The proposed mapping approach and fuzzy inference scheme in the fuzzy Cerebellar Model Articulation Controller, designed free from the mathematical model of system, comprises a mapping fuzzy Cerebellar Model Articulation Controller and a fuzzy inference controller, in which the former is the main controller. By introducing the new mapping approach in mapping fuzzy Cerebellar Model Articulation Controller, the proposed control strategy is actually a global network with local weight updating and its continuity has been enhanced. The fuzzy inference controller is used as a fuzzy compensator. As a torque controlled system, electric load simulator takes the loading error as the performance index. The results of dynamic simulation and experiments indicate that the proposed loading control strategy can achieve favorable control performance.
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