Driving force analysis for the secondary adjustable system in FAST

Robotica ◽  
2011 ◽  
Vol 29 (6) ◽  
pp. 903-915 ◽  
Author(s):  
Zhu-Feng Shao ◽  
Xiaoqiang Tang ◽  
Xu Chen ◽  
Li-Ping Wang
Keyword(s):  
Trajectory Optimization ◽  
Driving Force ◽  
Dynamic Models ◽  
Inverse Dynamics ◽  
Driving Forces ◽  
Euler Method ◽  
Central Component ◽  
Force Analysis ◽  
Inverse Dynamic ◽  
Driving Force Analysis

SUMMARYThe Secondary Adjustable System (SAS) addressed here is a central component of the Five-hundred-meter Aperture Spherical radio Telescope (FAST). It is a 6-degree-of-freedom rigid Stewart manipulator, in which one platform (the end-effector) should be controlled to track-desired trajectory when another platform (denoted as the base) is moving. Driving force analysis of the SAS is the basis for selecting rational servomotors and guaranteeing the dynamic performance, which will affect the terminal pose accuracy of the FAST. In order to determine the driving forces of the SAS, using the Newton–Euler method, the inverse dynamics of the Stewart manipulator is modeled by considering the motion of the base. Compared with the traditional dynamic models, the inverse dynamic model introduced here possesses an inherent wider application range. By adopting the kinematic and dynamic parameters of the FAST prototype, the driving force analysis of the SAS is carried out, and the driving force optimization strategies are proposed. Calculation and analysis presented in the paper reveal that there are three main factors affecting the driving forces of the SAS. In addition, the driving force analysis of this paper lays out guidelines for the design and control of the FAST prototype, as well as the structure and trajectory optimization.

scholarly journals An Integrated Investigation of Spatiotemporal Habitat Quality Dynamics and Driving Forces in the Upper Basin of Miyun Reservoir, North China

2018 ◽  
Vol 10 (12) ◽  
pp. 4625 ◽  
Author(s):  
Shengjun Yan ◽  
Xuan Wang ◽  
Yanpeng Cai ◽  
Chunhui Li ◽  
Rui Yan ◽  
...  
Keyword(s):  
Logistic Regression ◽  
Habitat Quality ◽  
Driving Force ◽  
North China ◽  
Population Change ◽  
Driving Forces ◽  
Policy Formulation ◽  
Force Analysis ◽  
Miyun Reservoir ◽  
Driving Force Analysis

Understanding changes in habitat quality and the driving forces of these changes at landscape scales is a critical part of effective ecosystem management. The present study investigated spatiotemporal habitat quality dynamics and related driving forces from 2005 to 2015 in the upper basin of Miyun Reservoir in North China by constructing an effective framework integrated InVEST and binary logistic regression models. This framework expanded the driving force analysis into an assessment of changes in habitat quality and intuitively verified the effectiveness of relevant environmental policies. The proposed method of combining the equidistant random sampling method and the method of introducing spatial lag variables in logistic regression equation can effectively solve spatial autocorrelation with a large enough number of sampling points. Overall, habitat quality improved during the study period. Spatially, a concentrated loss of habitat occurred in the southeastern part of the basin between the reservoir and mountainous areas, while other areas gradually recovered. Driving force analysis showed that lower elevation mountain land, gentle slopes, locations near rural land or roads, larger areas of grain cultivation, and areas with little population change had a higher likelihood of having changed in habitat quality in the upper basin of Miyun Reservoir. These results suggested that the present policy of protecting the ecosystem had a positive effect on improving habitat quality. In the future, the human activity management related to habitat quality needs to be strengthened. The present study would provide a reference for land use policy formulation and biodiversity conservation.

Revisiting the inverse dynamics of the Gough–Stewart platform manipulator with special emphasis on universal–prismatic–spherical leg and internal singularity

2012 ◽  
Vol 226 (10) ◽  
pp. 2422-2439 ◽  
Author(s):  
Mohamed Afroun ◽  
Antoine Dequidt ◽  
Laurent Vermeiren
Keyword(s):  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Dynamic Models ◽  
Inverse Dynamics ◽  
Driving Forces ◽  
Stewart Platform ◽  
Inverse Dynamic ◽  
Computational Burden ◽  
Six Degrees Of Freedom ◽  
Leg Kinematics

This article discusses the dynamic modeling for control of Gough–Stewart platform manipulator with special emphasis on universal–prismatic–spherical leg kinematics. Inverse dynamic model of these six degrees of freedom parallel manipulator robots is reviewed, while complete dynamics with true kinematics of universal–prismatic–spherical legs is compared with several models found in the literature. Most existing models have not taken into account some of the legs kinematical effects, namely the legs angular velocity around their axes and the internal singularities due to passive joints; some other used a simplified parameterization to describe the leg kinematics. Furthermore, some kinetic assumption can be used to reduce the computational burden. This article shows the effect of all these simplifications on the driving forces by simulating the different dynamic models for a commercial manipulator and for different sets of geometric and dynamic parameters of manipulator.

On the Dynamic Modeling of a Bevel-Geared Surgical Robotic Mechanism

2010 ◽  
Vol 4 (4) ◽  
Author(s):  
Xiaoli Zhang ◽  
Carl A. Nelson
Keyword(s):  
Sensitivity Analysis ◽  
Dynamic Modeling ◽  
Dynamic Models ◽  
Driving Forces ◽  
Dynamic Control ◽  
Design Stage ◽  
Inverse Dynamic ◽  
Surgical Tool ◽  
Tissue Manipulation ◽  
Clinical Experiments

The use of robotics to enhance visualization and tissue manipulation capabilities contributes to the advancement of minimally invasive surgery. For the development of surgical robot manipulators, the use of advanced dynamic control is an important aspect at the design stage to determine the driving forces and/or torques, which must be exerted by the actuators in order to produce a desirable trajectory of the end effector. Therefore, this study focuses on the generation of inverse dynamic models for a spherical bevel-geared mechanism called Compact Bevel-geared Robot for Advanced Surgery (CoBRASurge), which is used as a surgical tool manipulator. For given typical trajectories of end effectors in clinical experiments, the motion of each element in the mechanism can be derived using the inverse kinematic equations. The driving torques exerted by actuators can be determined according to the presented inverse dynamic formulations. The simulation results of CoBRASurge reveal the nature of the driving torques in spherical bevel-geared mechanisms. In addition, sensitivity analysis of mass contribution has been performed to evaluate the effect of individual elements on the peak driving torques. Dynamic models, such as the one presented, can be used for the design of advanced dynamic control systems, including gravity compensation and haptic interfaces for enhanced surgical functionality. The accompanying sensitivity analysis also provides a solid guideline for the design of the next generation CoBRASurge prototype. The present dynamic modeling methodology also gives a general dynamic analysis approach for other spherical articulated linkage mechanisms.

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