scholarly journals Active Loading Control Design for a Wearable Exoskeleton with a Bowden Cable for Transmission

Actuators ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 108
Author(s):  
Zhipeng Wang ◽  
Seungmin Rho ◽  
Chifu Yang ◽  
Feng Jiang ◽  
Zhen Ding ◽  
...  
Keyword(s):  
Disturbance Observer ◽  
Power Transmission ◽  
Dynamic Performance ◽  
Concentrated Mass ◽  
Force Loading ◽  
Nominal Model ◽  
Modeling Errors ◽  
Wearable Exoskeleton ◽  
The Stability ◽  
Pole Configuration

Exoskeletons with a Bowden cable for power transmission have the advantages of a concentrated mass and flexible movement. However, their integrated motor is disturbed by the Bowden cable’s friction, which limits the performance of the force loading response. In this paper, we solve this problem by designing an outer-loop feedforward-feedback proportion-differentiation controller based on an inner loop disturbance observer. Firstly, the inner loop’s dynamic performance is equivalent to the designed nominal model using the proposed disturbance observer, which effectively compensates for the parameter perturbation and friction disturbance. Secondly, based on an analysis of the stability of the inner loop controller, we obtain the stability condition and discuss the influence of modeling errors on the inner loop’s dynamic performance. Thirdly, to avoid excessive noise from the force sensors being introduced into the designed disturbance observer, we propose the feedforward-feedback proportion-differentiation controller based on the nominal model and pole configuration, which improves the outer loop’s force loading performance. Experiments are conducted, which verify the effectiveness of the proposed methods.

Dynamic Performance of High-Speed Electric Multiple Unit within Multi-Body System Simulation

2019 ◽  
Vol 12 (4) ◽  
pp. 339-349
Author(s):  
Junguo Wang ◽  
Daoping Gong ◽  
Rui Sun ◽  
Yongxiang Zhao
Keyword(s):  
High Speed ◽  
Rapid Development ◽  
Dynamic Performance ◽  
Body System ◽  
High Speed Railway ◽  
Evaluation Indexes ◽  
Actual Operation ◽  
Multiple Unit ◽  
The Stability ◽  
Multi Body

Background: With the rapid development of the high-speed railway, the dynamic performance such as running stability and safety of the high-speed train is increasingly important. This paper focuses on the dynamic performance of high-speed Electric Multiple Unit (EMU), especially the dynamic characteristics of the bogie frame and car body. Various patents have been discussed in this article. Objective: To develop the Multi-Body System (MBS) model of EMU, verify whether the dynamic performance meets the actual operation requirements, and provide some useful information for dynamics and structural design of the proposed EMU. Methods: According to the technical characteristics of a typical EMU, a MBS model is established via SIMPACK, and the measured data of China high-speed railway is taken as the excitation of track random irregularity. To test the dynamic performance of the EMU, including the stability and safety, some evaluation indexes such as wheel-axle lateral forces, wheel-axle lateral vertical forces, derailment coefficients and wheel unloading rates are also calculated and analyzed in detail. Results: The MBS model of EMU has better dynamic performance especially curving performance, and some evaluation indexes of the stability and safety have also reached China’s high-speed railway standards. Conclusion: The effectiveness of the proposed MBS model is verified, and the dynamic performance of the MBS model can meet the design requirements of high-speed EMU.

Novel transient stability analysis of grid connected hybrid wind/PV system using UPFC

2021 ◽  
pp. 002072092110032
Author(s):  
S Arockiaraj ◽  
BV Manikandan
Keyword(s):  
Fuzzy Logic ◽  
Transient Stability ◽  
Fuzzy Logic Controller ◽  
Power Transmission ◽  
Dynamic Performance ◽  
Wind Farms ◽  
Pv System ◽  
Turbine Generator ◽  
Series Compensation ◽  
Wind Turbine System

In transmission line, the series compensation is used to improve stability and increases the power transmission capacity. It generates sub synchronous resonance (SSR) at turbine-generator shaft due to the interaction between the series compensation and wind turbine system. To solve this, several methods have been presented. However, these provide less performance during contingency period. Therefore, to mitigate the SSR and also to improve the dynamic performance of hybrid wind and PV system connected with series compensated wind farms, the adaptive technique of the Black Widow Optimization algorithm based Fuzzy Logic Controller (BWO-FLC) with UPFC is proposed in this paper. Here, the objective function is solved optimally using BWO technique. Based on this, the Fuzzy Logic Controller is designed. The results proved that the proposed controller performs the mitigation of SSR. The damping ratios of proposed controller to mitigation of SSR are 0.0098, 0.0139, and 0.0195 for wind speed of 6, 8 and 10 m/s respectively.

Power transmission system modelling

1998 ◽  
Vol 212 (6) ◽  
pp. 497-505 ◽  
Author(s):  
H Bartlett ◽  
R Whalley
Keyword(s):  
Power Transmission ◽  
Dynamic Performance ◽  
Torsional Oscillation ◽  
Transmission System ◽  
System Modelling ◽  
Hybrid Modelling ◽  
Response Characteristics ◽  
Power Transmission System ◽  
Discrete Modelling ◽  
Modelling Techniques

This paper employs hybrid modelling techniques in the investigation of the dynamic performance of ‘long’ driveshafts, which include a clutch and load, for power transmission purposes. The power transmission system considered is suitable for a wide variety of applications in which the load is coupled directly to the clutch and hence to the ‘long’ driveshaft. Owing to the length of the shaft and relatively pointwise location of the clutch and load, a distributed—lumped (D—L) description of the arrangement is investigated. This enables the behaviour of the dispersed driveline shaft to be ‘adequately’ replicated along with the connecting elements. A discrete modelling approach is adopted and analysis and simulated response characteristics are presented, thereby validating the technique. Existing results on clutch judder are referred to and the interaction between judder and the driveshaft torsional oscillation is commented upon.

The Correlation between Time and Frequency Dynamic Performance of Control System

2014 ◽  
Vol 628 ◽  
pp. 186-189
Author(s):  
Meng Xiong Zeng ◽  
Jin Feng Zhao ◽  
Wen Ouyang
Keyword(s):  
Control System ◽  
Performance Index ◽  
Dynamic Performance ◽  
Frequency Domain Analysis ◽  
Practical Significance ◽  
Order System ◽  
Time Frequency ◽  
Performance Indexes ◽  
Quantitative Performance ◽  
The Stability

The control system performance requirement was divided into three parts. They were the stability, rapidity and accuracy. The time-frequency domain analysis in the requirements of three performance were measured through quantitative performance index. The mutual restriction of time-frequency performance and system characteristic parameters of normal second order was discussed. The correlation of system time-frequency performance index was established. The relationship between time-frequency performance indexes in standard two order system was extended to higher order system. The mutually constraining and time-frequency correlation between each performance index was obtained by analysis and calculation. The work had been done above had practical significance to reflect the system dynamic performance in different analytical domains.

Coordinated Control for Novel Full Hybrid Vehicles

2013 ◽  
Vol 860-863 ◽  
pp. 1073-1077 ◽  
Author(s):  
Zhi Guo Kong ◽  
Hong Wei Zhang ◽  
Zi Ning Tang
Keyword(s):  
Control Method ◽  
Dynamic Performance ◽  
Coordinated Control ◽  
Rate Of Change ◽  
Adjustment Process ◽  
Accelerator Pedal ◽  
Dynamic Constraints ◽  
Electric Bus ◽  
The Stability ◽  
Working Point

In order to improve the performance of a new type of full hybrid electric bus, this paper puts forward a set of coordinated control method to adjust the operation of the engine and two motors. In the engine start-stop logic control, comprehensive consideration of SOC, the speed of the bus and the accelerator pedal stroke are performed, while hysteresis control is introduced to improve the stability of the control; In the engine working point adjusting control, not only the engine speed command rate of change was optimized, but also the output torque rate was optimized to match the air injection and exhaust, etc. Further, the method based on dynamic constraints was used to optimize the working point adjustment process. At present, there are hundreds of busses operates in route. Results verify the feasibility and effectiveness of the control method. The vehicle has good fuel economy, and the dynamic performance and driving comfort are also greatly improved.

Effect of Intermolecular Forces on the Static and Dynamic Performance of Air Bearing Sliders: Part II—Dependence of the Stability on Hamaker Constant, Suspension Preload and Pitch Angle

2005 ◽  
Vol 128 (1) ◽  
pp. 203-208 ◽  
Author(s):  
Vineet Gupta ◽  
David B. Bogy
Keyword(s):  
Pitch Angle ◽  
Dynamic Performance ◽  
Hard Disk Drives ◽  
Intermolecular Forces ◽  
Flying Height ◽  
Total Force ◽  
Air Bearing ◽  
Force Increase ◽  
The Stability ◽  
Fly Height

Intermolecular and surface forces contribute significantly to the total forces acting on air bearing sliders for flying heights below 5 nm. Their contributions to the total force increase sharply with the reduction in flying height, and hence their existence can no longer be ignored in air bearing simulation for hard disk drives. Various experimentally observed dynamic instabilities can be explained by the inclusion of these forces in the model for low flying sliders. In this paper parametric studies are presented using a 3-DOF model to better understand the effect of the Hamaker constants, suspension pre load and pitch angle on the dynamic stability/instability of the sliders. A stiffness matrix is used to characterize the stability in the vertical, pitch, and roll directions. The fly height diagrams are used to examine the multiple equilibriums that exist for low flying heights. It has been found that the system instability increases as the magnitude of the van der Waals force increases. It has also been found that higher suspension pre load and higher pitch angles tend to stabilize the system.

scholarly journals Failure Mechanism and Mitigation Measures of the G1002 Electricity Pylon Landslide at the Jinping I Hydropower Station

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Gang Luo ◽  
Yutian Zhong ◽  
Yuanxiang Yang
Keyword(s):  
Failure Mechanism ◽  
Power Transmission ◽  
Heavy Precipitation ◽  
Mitigation Strategies ◽  
Mitigation Measures ◽  
Hydropower Station ◽  
Residual Soil ◽  
Valley Slope ◽  
Jinping I Hydropower Station ◽  
The Stability

On August 29 and 30, 2012, local extreme rainfalls struck the construction area of the Jinping I Hydropower Station, Xichang, China, and triggered many geohazards. The upper region of the left valley slope 200 m downstream of the dam failed and slid, exposing the D-pile of the G1002 electricity pylon and threatening the entire power transmission line. Therefore, guaranteeing the stability of the residual soil masses in the rear area of the main scarp and the safety of the G1002 electricity pylon became a primary emergency task. Geological field surveys, topographical mapping, study of the failure mechanisms, and stability evaluations were carried out from October 12, 2012, to November 7, 2013. It is revealed that the failure mechanism of the G1002 electricity pylon landslide is flood-induced tractive sliding along the interlayer between the colluvium and the bedrock, significantly influenced by heavy precipitation and frequent blasting activities during the dam construction. The residual soil masses around the G1002 electricity pylon foundation are unstable under rainfall conditions. In order to ensure the stability of the residual soil masses and pylon foundation, a mitigation measure of the anchor cables combined with lattice frame beams was proposed and applied in practice. This paper provides insights into the problems associated with the selection of the locations of electricity pylons in ravine regions as well as mitigation strategies for similar landslides.

scholarly journals The Energy Compensation of the HRG Based on the Double-Frequency Parametric Excitation of the Discrete Electrode

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3549
Author(s):  
Wanliang Zhao ◽  
Hao Yang ◽  
Fucheng Liu ◽  
Yan Su ◽  
Lijun Song
Keyword(s):  
Parametric Excitation ◽  
Dynamical Equation ◽  
Dynamic Performance ◽  
Free Precession ◽  
Double Frequency ◽  
Energy Compensation ◽  
Hemispherical Resonator ◽  
The Stability ◽  
Resonator Vibration ◽  
Excitation Parameters

In this study, for energy compensation in the whole-angle control of Hemispherical Resonator Gyro (HRG), the dynamical equation of the resonator, which is excited by parametric excitation of the discrete electrode, is established, the stability conditions are analyzed, and the method of the double-frequency parametric excitation by the discrete electrode is derived. To obtain the optimal parametric excitation of the resonator, the total energy stability of the resonator is simulated for the evolution of the resonator vibration with different excitation parameters and the free precession of the standing wave by the parametric excitation. In addition, the whole-angle control of the HRG is designed, and the energy compensation of parametric excitation is proven by the experiments. The results of the experiments show that the energy compensation of the HRG in the whole-angle control can be realized using discrete electrodes with double-frequency parametric excitation, which significantly improves the dynamic performance of the whole-angle control compared to the force-to-rebalance.

Novel robust controller design for load sway reduction in double-pendulum overhead cranes

2018 ◽  
Vol 233 (12) ◽  
pp. 4359-4371 ◽  
Author(s):  
Huimin Ouyang ◽  
Xin Deng ◽  
Huan Xi ◽  
Jinxin Hu ◽  
Guangming Zhang ◽  
...  
Keyword(s):  
Controller Design ◽  
Dynamic Performance ◽  
Optimization Method ◽  
Linear Matrix ◽  
Double Pendulum ◽  
Control Performance ◽  
Mass Property ◽  
Length Changes ◽  
The Stability ◽  
Dynamic Performance Analysis

It is seen that when the hook mass is larger than the load mass or the load has distributed mass property, the load sway of the crane system presents as double-pendulum effect. In this situation, crane system has two different natural frequencies so that the sway characteristic becomes more complex and greatly increases the difficulty of the dynamic performance analysis and controller design. Moreover, the rope length changes significantly affect the stability and control performance of the crane system. In order to solve the aforementioned problems, the linear dynamics of a two-dimensional overhead crane with double-pendulum effect is derived based on a disturbance observer, and is decoupled for controller design by modal analysis. Next, a state feedback controller is presented to achieve robust control performance for a given range of rope length changes. The controller gains are obtained via linear matrix inequality optimization method. Finally, numerical simulations and experimental results validate that the proposed method has superior control performance.

Dynamic Performance and Stability Research of VMI-APIOBPCS in Apparel Industry Based on Control Theory

2018 ◽  
Vol 14 (2) ◽  
pp. 56-76 ◽  
Author(s):  
Xueli Zhan ◽  
Qin Zhang ◽  
Wenfeng Xie
Keyword(s):  
Supply Chain ◽  
Control Theory ◽  
System Integration ◽  
Production Control ◽  
Dynamic Performance ◽  
Apparel Industry ◽  
Supply Chain System ◽  
Hurwitz Stability ◽  
New Ideas ◽  
The Stability

In this article, the authors mainly investigate the dynamic performance of VMI-APIOBPCS (Vendor Manage Inventory-Automatic Pipeline Inventory and Order Based Production Control System) in the apparel industry. With the increasing importance of supply chain system integration, VMI-APIOBPCS can integrate various kinds of elements in the real operation, which is proved to be very effective in solving complex problems. Apparel supply chains have relatively more complicated dynamic behaviors because of the factors like volatile demand, the strong seasonality of sales and the large number of items with short life cycle or lacking historical data. In order to clear these behaviors, and come up with new ideas to solve present difficulties, the authors apply classic control theory to build up the model of VMI-APIOBPCS in apparel supply chain. They then analyze the dynamic performance of apparel supply chain and use Routh-Hurwitz Stability Criterion to analyze the stability on the expectation that the outcomes of our research can be useful in the practical occasions.

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