scholarly journals Dynamic Behavior Analysis and Stability Control of Tethered Satellite Formation Deployment

Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 62
Author(s):  
Kangyu Zhang ◽  
Kuan Lu ◽  
Xiaohui Gu ◽  
Chao Fu ◽  
Shibo Zhao
Keyword(s):  
Dynamic Behavior ◽  
Release Rate ◽  
Stability Control ◽  
Life Cycles ◽  
Space Environment ◽  
Length Variation ◽  
Tethered Satellite ◽  
Control Laws ◽  
Satellite Formation ◽  
Rigid Rod

In recent years, Tethered Space Systems (TSSs) have received significant attention in aerospace research as a result of their significant advantages: dexterousness, long life cycles and fuel-less engines. However, configurational conversion processes of tethered satellite formation systems in a complex space environment are essentially unstable. Due to their structural peculiarities and the special environment in outer space, TSS vibrations are easily produced. These types of vibrations are extremely harmful to spacecraft. Hence, the nonlinear dynamic behavior of systems based on a simplified rigid-rod tether model is analyzed in this paper. Two stability control laws for tether release rate and tether tension are proposed in order to control tether length variation. In addition, periodic stability of time-varying control systems after deployment is analyzed by using Floquet theory, and small parameter domains of systems in asymptotically stable states are obtained. Numerical simulations show that proposed tether tension controls can suppress in-plane and out-of-plane librations of rigid tethered satellites, while spacecraft and tether stability control goals can be achieved. Most importantly, this paper provides tether release rate and tether tension control laws for suppressing wide-ranging TSS vibrations that are valuable for improving TSS attitude control accuracy and performance, specifically for TSSs that are operating in low-eccentricity orbits.

Robust Sliding Mode Tracking Control for Linear Tethered Satellite Formation Deployment

2021 ◽  
pp. 3435-3447
Author(s):  
Wang Ben ◽  
Wang Changqing ◽  
Li Aijun ◽  
Yu. M. Zabolotnov
Keyword(s):  
Tracking Control ◽  
Sliding Mode ◽  
Tethered Satellite ◽  
Satellite Formation ◽  
Mode Tracking

Modeling and Experimental Testing of Hoverboard Dynamic Behavior

2017 ◽  
Author(s):  
Arnoldo Castro ◽  
William Singhose ◽  
Xiaoshu Liu ◽  
Khalid Sorensen ◽  
Eun Chan Kwak
Keyword(s):  
Dynamic Model ◽  
Dynamic Behavior ◽  
Motion Capture ◽  
Environmental Conditions ◽  
Experimental Testing ◽  
Motion Capture Data ◽  
Control Laws ◽  
Operator Action ◽  
The Stability ◽  
Unexpected Behavior

Self-balancing human transporters are naturally unstable. However, when coupled with sophisticated control laws, these machines can provide mobility within a finite stability envelope. Challenging environmental conditions, or unanticipated operator action, can cause these machines to exhibit unexpected behavior. In an effort to better understand the behavior of these systems inside and outside the stability envelope, a dynamic model of a hoverboard is presented. Motion-capture data is also presented in which an operator’s interactions with the hoverboard were recorded.

scholarly journals Phyla-specific Correlated Dynamics in Tropomyosin

2018 ◽  
Author(s):  
J.K. James ◽  
V. Nanda
Keyword(s):  
Muscle Contraction ◽  
Dynamic Behavior ◽  
Long Range ◽  
Coiled Coil ◽  
Molecular Simulations ◽  
Actin Binding ◽  
Extensive Sequence ◽  
Dynamic Correlations ◽  
Rigid Rod ◽  
Structural Fluctuations

ABSTRACTTropomyosin (Tpm) is a continuous α-helical coiled-coil homodimer that regulates actinomyosin interactions in muscle. We examined extended molecular simulations of four Tpms, two from the vertebrate phylum Chordata (rat and pig), and two from the invertebrate Arthropoda (shrimp and lobster), and found that despite extensive sequence and structural homologyacross metazoans, dynamic behavior – particularly long range structural fluctuations – were clearly distinct between phyla. Vertebrate Tpms were flexible and sampled complex, multi-state conformational landscapes. Invertebrate Tpms were rigid, sampling highly constrained harmonic landscapes. Filtering of trajectories by PCA into essential subspaces showed significant overlap within but not between phyla. In vertebrate Tpms, hinge-regions decoupled long-range inter-helical motions and suggested distinct domains. In contrast, crustacean Tpms lacked significant long range dynamic correlations – behaving more like a single rigid rod. Although Tpm sequence and structure has highly conserved over the last 0.6-billion years since the split of ancestral bilateria into protostomes and deuterostomes, divergence seems to have occurred at the level of long-range correlated dynamics, reflecting adaptations to phyla-specific requirements of actin binding and muscle contraction.

Managing driving disturbances in lateral vehicle dynamics via adaptive integrated chassis control

2020 ◽  
pp. 146441932097737
Author(s):  
Narjes Ahmadian ◽  
Alireza Khosravi ◽  
Pouria Sarhadi
Keyword(s):  
Adaptive Control ◽  
Control Method ◽  
Linear Time ◽  
Hierarchical Control ◽  
Control Level ◽  
Adaptive Controller ◽  
Stability Control ◽  
Control Laws ◽  
Mimo Model ◽  
Yaw Moment

This paper presents a vehicle stability control method based on a multi-input multi-output (MIMO) model reference adaptive control (MRAC) strategy as an advanced driver assistance system (ADAS) to enhance the handling and yaw stability of the vehicle lateral dynamics. The corrective yaw moment and additive steering angle are generated using direct yaw moment control (DYC) and active front steering (AFS) at the upper control level in the hierarchical control algorithm. A nonlinear term is added to the conventional adaptive control laws to handle parametric uncertainties and disturbances. The desired yaw moment generated by the upper-level controller is converted to the brake forces and is distributed to the rear wheels by an optimal procedure at the lower-level. The major contribution of this study is the introduction of a nonlinear integrated adaptive control method based on a constraint optimization algorithm. To verify the effectiveness of the proposed control strategy, the nonlinear integrated adaptive controller, and linear time-varying MRAC are designed and used for comparison. Simulation results are performed for the J-turn and double lane change (DLC) manoeuvres at high speeds and low tyre-road friction coefficients. The desired performance of the proposed controller exhibited significant improvement compared to the conventional MRAC in terms of yaw rate tracking and handling of sideslip limitation.

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