Active Vibration Control Using Centrifugal Forces Created by Eccentrically Rotating Masses

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Richard Bäumer ◽  
Uwe Starossek
Keyword(s):  
Feedback Control ◽  
Low Power ◽  
Energy Demand ◽  
Control Algorithm ◽  
State Variables ◽  
Active Mass ◽  
Rotation Mode ◽  
Continuous Rotation ◽  
Mode Of Operation ◽  
Power And Energy

The twin rotor damper (TRD) is a newly developed active mass damper. It is presented here along with respective closed-loop control algorithms. The greatest advantage of the device is its low power demand when operated in a preferred mode of operation, the continuous rotation mode. In this mode, two eccentric masses rotate in opposite directions about two parallel axes with a mostly constant angular velocity. The resultant force is harmonic and can be used for the control of structural vibrations. To study the effect of the TRD on a single degree-of-freedom (SDOF) oscillator, various state variables are introduced and a feedback control algorithm is developed for the continuous rotation mode of operation. For reaching and leaving the continuous rotation mode, ramp-up and ramp-down trajectories are developed. These trajectories are designed such that the power and energy demand as well as the mechanical wear on the device are minimized. The feedback control algorithm is validated on a test setup. The damping effectiveness and the low power and energy demands encourage further investigation of the device under stochastic loading and comparisons with other active mass dampers.

scholarly journals Low Power and Energy Efficient Street Light System Using IoT

2021 ◽  
Vol 1084 (1) ◽  
pp. 012120
Author(s):  
M Srinivasan ◽  
P Manojkumar ◽  
A Dheepancharavarthy
Keyword(s):  
Low Power ◽  
Energy Efficient ◽  
Light System ◽  
Power And Energy

scholarly journals Influence of CFRC Insulating Plates on Spark Plasma Sintering Process

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 393
Author(s):  
Alexander M. Laptev ◽  
Jürgen Hennicke ◽  
Robert Ihl
Keyword(s):  
Temperature Distribution ◽  
Spark Plasma Sintering ◽  
Energy Demand ◽  
Composite Powders ◽  
Fem Method ◽  
Plasma Sintering ◽  
Axial Temperature ◽  
Spark Plasma ◽  
Power And Energy ◽  
The Impact

Spark Plasma Sintering (SPS) is a technology used for fast consolidation of metallic, ceramic, and composite powders. The upscaling of this technology requires a reduction in energy consumption and homogenization of temperature in compacts. The application of Carbon Fiber-Reinforced Carbon (CFRC) insulating plates between the sintering setup and the electrodes is frequently considered as a measure to attain these goals. However, the efficiency of such a practice remains largely unexplored so far. In the present paper, the impact of CFRC plates on required power, total sintering energy, and temperature distribution was investigated by experiments and by Finite Element Modeling (FEM). The study was performed at a temperature of 1000 °C with a graphite dummy mimicking an SPS setup. A rather moderate influence of CFRC plates on power and energy demand was found. Furthermore, the cooling stage becomes considerably longer. However, the application of CFRC plates leads to a significant reduction in the axial temperature gradient. The comparative analysis of experimental and modeling results showed the good capability of the FEM method for prediction of temperature distribution and required electric current. However, a discrepancy between measured and calculated voltage and power was found. This issue must be further investigated, considering the influence of AC harmonics in the DC field.

Robust active disturbance attenuation control of an uncertain quadrotor

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nigar Ahmed ◽  
Ajeet kumar Bhatia ◽  
Syed Awais Ali Shah
Keyword(s):  
Control Algorithm ◽  
Sliding Mode ◽  
The State ◽  
Disturbance Attenuation ◽  
State Variables ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Content Type ◽  
Highly Nonlinear ◽  
The Stability

PurposeThe aim of this research is to design a robust active disturbance attenuation control (RADAC) technique combined with an extended high gain observer (EHGO) and low pass filter (LPF).Design/methodology/approachFor designing a RADAC technique, the sliding mode control (SMC) method is used. Since the standard method of SMC exhibits a chattering phenomenon in the controller, a multilayer sliding mode surface is designed for avoiding the chattering. In addition, to attenuate the unwanted uncertainties and disturbances (UUDs), the techniques of EHGO and LPF are deployed. Besides acting as a patch for disturbance attenuation, the EHGO design estimates the state variables. To investigate the stability and effectiveness of the designed control algorithm, the stability analysis followed by the simulation study is presented.FindingsThe major findings include the design of a chattering-free RADAC controller based on the multilayer sliding mode surface. Furthermore, a criterion of integrating the LPF scheme within the EHGO scheme is also developed to attenuate matched and mismatched UUDs.Practical implicationsIn practice, the quadrotor flight is opposed by different kinds of the UUDs. And, the model of the quadrotor is a highly nonlinear underactuated model. Thus, the dynamics of the quadrotor model become more complex and uncertain due to the additional UUDs. Hence, it is necessary to design a robust disturbance attenuation technique with the ability to estimate the state variables and attenuate the UUDs and also achieve the desired control objectives.Originality/valueDesigning control methods to attenuate the disturbances while assuming that the state variables are known is a common practice. However, investigating the uncertain plants with unknown states along with the disturbances is rarely taken in consideration for the control design. Hence, this paper presents a control algorithm to address the issues of the UUDs as well as investigate a criterion to reduce the chattering incurred in the controller due to the standard SMC algorithm.

scholarly journals Robust H ∞ state-feedback control for linear systems

2017 ◽  
Vol 473 (2200) ◽  
pp. 20160934 ◽  
Author(s):  
Hao Chen ◽  
Zhenzhen Zhang ◽  
Huazhang Wang
Keyword(s):  
Feedback Control ◽  
Linear Systems ◽  
Control Algorithm ◽  
State Feedback ◽  
Convex Combination ◽  
State Feedback Control ◽  
Parameter Uncertainties ◽  
Globally Asymptotically Stable ◽  
Loop Control ◽  
Control Approach

This paper investigates the problem of robust H ∞ control for linear systems. First, the state-feedback closed-loop control algorithm is designed. Second, by employing the geometric progression theory, a modified augmented Lyapunov–Krasovskii functional (LKF) with the geometric integral interval is established. Then, parameter uncertainties and the derivative of the delay are flexibly described by introducing the convex combination skill. This technique can eliminate the unnecessary enlargement of the LKF derivative estimation, which gives less conservatism. In addition, the designed controller can ensure that the linear systems are globally asymptotically stable with a guaranteed H ∞ performance in the presence of a disturbance input and parameter uncertainties. A liquid monopropellant rocket motor with a pressure feeding system is evaluated in a simulation example. It shows that this proposed state-feedback control approach achieves the expected results for linear systems in the sense of the prescribed H ∞ performance.

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