A simple dynamic model and stability analysis of a steam boiler drum

Abstract A model is developed for analyzing mechanical systems with a pair of bodies with topological changes in their kinematic constraints. It is built upon the concept of Poincaré map rather than following the traditional methods of differential equations. The model provides a set of well-defined and naturally-discrete equations of motion and is capable of giving physical insights of dynamic characteristics of deadbeat convergence of multiple collisions and periodic or chaotic responses. The development of dynamic model and a local stability analysis are presented in Part 1, and the global analysis and numerical simulation are discussed in Part 2.

Download Full-text

Modeling and Grasp Stability Analysis for Object Manipulation by Soft Rolling Fingertips

International Journal of Humanoid Robotics ◽

10.1142/s0219843614500200 ◽

2014 ◽

Vol 11 (03) ◽

pp. 1450020 ◽

Cited By ~ 2

Author(s):

John Fasoulas ◽

Michael Sfakiotakis

Keyword(s):

Stability Analysis ◽

Dynamic Model ◽

Object Manipulation ◽

Kinematics And Dynamics ◽

Control Law ◽

Two Dimensional ◽

Orientation Control ◽

Grasp Stability ◽

Different Types ◽

General Dynamic

This paper presents a general dynamic model that describes the two-dimensional grasp by two robotic fingers with soft fingertips. We derive the system's kinematics and dynamics by incorporating rolling constraints that depend on the deformation and on the rolling distance characteristics of the fingertips' material. We analyze the grasp stability at equilibrium, and conclude that the rolling properties of the fingertips can play an important role in grasp stability, especially when the width of the grasped object is small compared to the radius of the tips. Subsequently, a controller, which is based on the fingertips' rolling properties, is proposed for stable grasping concurrent with object orientation control. We evaluate the dynamic model under the proposed control law by simulations and experiments that make use of two different types of soft fingertip materials, through which it is confirmed that the dynamic model can successfully capture the effect of the fingertips' deformation and their rolling distance characteristics. Finally, we use the dynamic model to demonstrate by simulations the significance of the fingertips' rolling properties in grasping thin objects.

Download Full-text

Omnidirectional Mobile Robot Dynamic Model Identification by NARX Neural Network and Stability Analysis Using the APLF Method

Symmetry ◽

10.3390/sym12091430 ◽

2020 ◽

Vol 12 (9) ◽

pp. 1430

Author(s):

Liang Xin ◽

Yuchao Wang ◽

Huixuan Fu

Keyword(s):

Neural Network ◽

Stability Analysis ◽

Mobile Robot ◽

Dynamic Model ◽

Complex Dynamics ◽

Model Identification ◽

Theoretical Method ◽

Omnidirectional Mobile Robot ◽

Path Dependent ◽

Narx Neural Network

In this paper, the NARX neural network system is used to identify the complex dynamics model of omnidirectional mobile robot while rotating with moving, and analyze its stability. When the mobile robot model rotates and moves at the same time, the dynamic model of the mobile robot is complex and there is motion coupling. The change of the model in different states is a kind of symmetry. In order to solve the problem that there is a big difference between the mechanism modeling motion simulation and the actual data, the dynamic model identification of mobile robot in special state based on NARX neural network is proposed, and the stability analysis method is given. To verify that the dynamic model of NARX identification is consistent with that of the mobile robot, the Activation Path-Dependent Lyapunov Function (APLF) algorithm is used to distinguish the NARX neural network model expressed by LDI. However, the APLF method needs to calculate a large number of LMIs in practice and takes a lot of time, and, to solve this problem, an optimized APLF method is proposed. The experimental results verify the effectiveness of the theoretical method.

Download Full-text