The Design of Robotic Arm Adaptive Fuzzy Controller Based on Oscillator and Differentiator

State variables are acquired when tracking the trace of the robotic arm with adaptive fuzzy controller. Since some variables are difficult to or cannot be measured directly, we introduced the second order oscillator and the second order differentiator that converges in finite time to obtain the value of each state variable. In this paper, a model based on the dynamics analysis of robotic arm was build to design the second order oscillator and the second order differentiator that converges in finite time to obtain the value of each state variable. The designed adaptive fuzzy controller for robotic arm achieved high accuracy in trace tracking. Simulation results of two-link robotic arm show the adaptive fuzzy controller for robotic arm based on differentiators is adaptable, flexible. This controller is simple to design, easy to implement, and has a good value for the application of robotic arm system.</p

The Design of Robotic Arm Adaptive Fuzzy Controller Based on Oscillator and Differentiator

State variables are acquired when tracking the trace of the robotic arm with adaptive fuzzy controller. Since some variables are difficult to or cannot be measured directly, we introduced the second order oscillator and the second order differentiator that converges in finite time to obtain the value of each state variable. In this paper, a model based on the dynamics analysis of robotic arm was build to design the second order oscillator and the second order differentiator that converges in finite time to obtain the value of each state variable. The designed adaptive fuzzy controller for robotic arm achieved high accuracy in trace tracking. Simulation results of two-link robotic arm show the adaptive fuzzy controller for robotic arm based on differentiators is adaptable, flexible. This controller is simple to design, easy to implement, and has a good value for the application of robotic arm system

Fluvial sediment source to sink transfer at the Yellow River Delta: Quantifications, causes, and environmental impacts

Intensified human interventions in river basins and deltas lead to more complexities of environmental changes during the Anthropocene. Changes in river regime especially a dramatic reduction in sediment delivery increase challenges of the morphological and ecological sustainability of river deltas. In evaluating deltaic risks and sustainable solutions, researches are often limited to single geomorphic units of the deltaic system, and investigations of sediment source to sink transfer at river deltas under recent river regimes are often missing. The Yellow River Delta (YRD) presents as a typical megadelta under stressors induced by changing environments. This study utilizes a period of 20-yr high-resolution topography data of the deltaic channel and its subaqueous delta to investigate sediment transport and source to sink process by integrated methods of field measurements and numerical simulations. The results indicate that the deltaic channel has transitioned from net accretion to erosion after the implementation of the Water-Sediment Regulation Scheme (WSRS) in 2002. The active river mouth experienced a slow accretion phase since the river channel diverted to Qing 8 channel, with a reduced vertical deposition rate of 0.15 m/yr, whilst its adjacent Gudong littoral zone had a −0.11 m/yr erosion rate. Under the new fluvial regime, the river-borne suspended sediment tends to transport southwards to the Laizhou Bay, followed by the river-derived sediment transport eastward and northward to the offshore delta. It is clear that with the continued human activities in the region, the YRD is at the potential state of deltaic transition both in the deltaic channel and its subaqueous delta. This transition is believed to be beneficial to the deltaic channel stability, but it could significantly impact on the geomorphic and ecologic sustainability of the entire deltaic system

Big World in the Small Space: Constructing Hollow Zeolite Microspheres Using a Sustainable Template

Hollow zeolite microspheres have attracted considerable interest due to their unique properties and great potential applications. In this work, we report a simple and cost-effective approach for constructing hollow zeolite microspheres based on a biomass-derived template, i.e., carboxymethylcellulose sodium (CMC). As an example, a hollow ZSM-5 microsphere with a hollow core smaller than 1 μm in diameter and a complete crystal shell is synthesized. This approach overcomes most of the limitations associated with the existing methods, such as complex operations and costly spherical templates. By studying the growth process in detail, a possible formation mechanism is proposed. The crystallization of the hollow zeolite microsphere is through a “surface to core” process, in which the interaction between the CMC and the zeolite gel and the decomposition of the polymer network play the critical roles

A Minor Diterpenoid with a New 6/5/7/3 Fused-Ring Skeleton from <i>Euphorbia micractina</i>

A novel diterpenoid with an unprecedented 6/5/7/3 fused-ring skeleton, euphorbactin (<b>1</b>), was isolated from an ethanol extract of the roots of <i>Euphorbia micractina.</i> The structure was determined by extensive spectroscopic studies, especially by 2D NMR and CD data analysis. A proposed biosynthetic pathway and preliminary investigations of the biological activity of compound <b>1</b> are also discussed