An Analytical and Modular Software Workbench for Solving Kinematics and Dynamics of Series-Parallel Hybrid Robots

2020 ◽  
Vol 12 (2) ◽  
Author(s):  
Shivesh Kumar ◽  
Kai Alexander von Szadkowski ◽  
Andreas Mueller ◽  
Frank Kirchner
Keyword(s):  
Dynamic Modeling ◽  
Dynamic Properties ◽  
Weight Ratio ◽  
Robot Dynamics ◽  
Parallel Mechanisms ◽  
Modeling Tools ◽  
Closed Loops ◽  
Modular Software ◽  
Parallel Hybrid ◽  
And Control

Abstract Parallel mechanisms are increasingly being used as modular subsystem units in various robots and man-machine interfaces for their superior stiffness, payload-to-weight ratio, and dynamic properties. This leads to series-parallel hybrid robotic systems that are challenging to model and control due to the presence of various closed loops. Most model-based kinematic and dynamic modeling tools resolve loop closure constraints numerically and hence suffer from inefficiency and accuracy issues. Additionally, they do not exploit the modularity in robot design. In this paper, we present a modular and analytical approach toward kinematic and dynamic modeling of series-parallel hybrid robots. This approach has been implemented in a software framework called hybrid robot dynamics (hyrodyn) and its application is demonstrated with the help of a series-parallel hybrid humanoid robot recently developed at DFKI-RIC.

An Analytical and Modular Software Workbench for Solving Kinematics and Dynamics of Series-Parallel Hybrid Robots

2019 ◽  
Author(s):  
Shivesh Kumar ◽  
Andreas Mueller
Keyword(s):  
Dynamic Modeling ◽  
Dynamic Properties ◽  
Weight Ratio ◽  
Robot Dynamics ◽  
Parallel Mechanisms ◽  
Modeling Tools ◽  
Closed Loops ◽  
Modular Software ◽  
Parallel Hybrid ◽  
And Control

Abstract Parallel mechanisms are increasingly being used as modular subsystem units in various robots and man-machine interfaces for their superior stiffness, payload-to-weight ratio and dynamic properties. This leads to series-parallel hybrid robotic systems which are difficult to model and control due to the presence of various closed loops. Most model based kinematic and dynamic modeling tools resolve loop closure constraints numerically and hence suffer from inefficiency and accuracy issues. Also, they do not exploit the modularity in robot design. In this paper, we present a modular and analytical approach towards kinematic and dynamic modeling of series-parallel hybrid robots. This approach has been implemented in a software framework called Hybrid Robot Dynamics (HyRoDyn) and its application is demonstrated with the help of a series-parallel hybrid humanoid robot recently developed at DFKI-RIC.

scholarly journals Oscillations and control of spherical parallel manipulator

2019 ◽  
Vol 16 (3) ◽  
pp. 172988141984639
Author(s):  
Nguyen Huu Khanh Nhan ◽  
Vo Dinh Tung ◽  
Sergey Kheylo ◽  
Glazunov Victor
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Properties ◽  
Nonlinear Phenomena ◽  
Parallel Mechanisms ◽  
Inverse Dynamic ◽  
Work Area ◽  
Dynamics Of Mechanism ◽  
And Control ◽  
Spherical Parallel Manipulator

In recent years, there has been a growing number of studies in spherical parallel mechanisms, particularly synthesis, kinematics, and work area singularities. The interaction of degrees of freedom and geometry leads to the nonlinear phenomena, in the dynamics of mechanism. There are few studies into the dynamic properties of such mechanisms. This article deals with the dynamic property of the parallel spherical manipulators, with three degrees of freedom, and presents determination of acceleration input links, oscillations, and the problem of control. Algorithm of control is based on the concept of minimized coordinates, velocities, and acceleration using inverse dynamic problems. This allows synthesis of this algorithm, which can realize a motion in accordance with prescribed trajectories. Finally, the results of calculations are defined.

Infused salbutamol accentuates acid-induced lung injury in the rat

1986 ◽  
Vol 71 (2) ◽  
pp. 205-209 ◽  
Author(s):  
Stanley Braude ◽  
David Royston
Keyword(s):  
Lung Injury ◽  
Intravenous Infusion ◽  
Time Course ◽  
Weight Ratio ◽  
Dry Weight ◽  
Adrenergic Agonist ◽  
Lung Water ◽  
Significant Difference ◽  
And Control ◽  
Control Infusion

1. The effect in the rat of salbutamol infusion (1 μg min−1 kg−1) on acid-induced lung injury has been determined. Severity of lung injury was assessed by two techniques: the pulmonary clearance of 99mTc-diethylenetriaminepenta-acetate (99mTc-DTPA) and the lung wet/dry weight ratio, giving indices of alveolar epithelial permeability and transendothelial water filtration respectively. 2. Mean half-time of clearance of 99mTc-DTPA was increased significantly in rats who had intratracheal acid-induced injury and control (saline) intravenous infusion (19.4 ± 2.6 min) compared with non-acid-treated rats (98.1 ± 7.2) (P < 0.0001). However, those animals who had intratracheal acid injury and subsequent salbutamol intravenous infusion had significantly faster clearance (11.5 ± 1.9) than the acid and control infusion group (P < 0.05). 3. Gravimetric lung water in the acid-only rats (expressed as wet/dry weight ratio) was increased significantly (6.4 ± 0.3) compared with the non-acid-treated controls (5.4 ± 0.2) (P < 0.01). Acid-treated rats who had salbutamol infused had dramatically increased lung water (10.0 ± 0.6) (P < 0.001 vs acid and control infusion). 4. Intravenous salbutamol infusion itself produced no significant difference in the results for both techniques, compared with the non-acid-treated time-course controls. 5. Infused salbutamol accentuates acid-induced lung injury in the rat. Possible factors responsible for these findings include β2-adrenergic agonist mediated inhibition of hypoxic pulmonary vasoconstriction (HPV) and a predominant β1-adrenergic agonist inotropic effect of salbutamol with resultant rise in pulmonary artery pressure.

Riccati Discrete Time Transfer Matrix Method for Dynamic Modeling and Simulation of an Underwater Towed System

2012 ◽  
Vol 79 (4) ◽  
Author(s):  
Guoping Wang ◽  
Bao Rong ◽  
Ling Tao ◽  
Xiaoting Rui
Keyword(s):  
Modeling And Simulation ◽  
Dynamic Modeling ◽  
Computational Efficiency ◽  
Finite Segment ◽  
Modeling And Control ◽  
Global Dynamic ◽  
Transfer Equations ◽  
High Matrix ◽  
Towed Cable ◽  
And Control

Efficient, precise dynamic modeling and control of complex underwater towed systems has become a research focus in the field of multibody dynamics. In this paper, based on finite segment model of cable, by defining the new state vectors and deducing the new transfer equations of underwater towed systems, a new highly efficient method for dynamic modeling and simulation of underwater towed systems is presented and the pay-out/reel-in process of towed cable is studied. The computational efficiency and numerical stability of the proposed method are discussed. When using the method to study the dynamics of underwater towed systems, it avoids the global dynamic equations of system, and simplifies solving procedure. Irrespective of the degree of freedom of underwater towed system, the matrices involved in the proposed method are always very small, which greatly improve the computational efficiency and avoids the computing difficulties caused by too high matrix orders for complex underwater towed systems. Formulations of the method as well as numerical simulations are given to validate the proposed method.

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