scholarly journals Discussion: “Analog Simulation of Rigid Link Mechanisms” (Timm, R. F., 1967, ASME J. Eng. Ind., 89, pp. 199–204)

1967 ◽  
Vol 89 (2) ◽  
pp. 204-205
Author(s):  
J. E. Shigley
Keyword(s):  
Analog Simulation ◽  
Rigid Link

Analog Simulation of Rigid Link Mechanisms

1967 ◽  
Vol 89 (2) ◽  
pp. 199-204 ◽  
Author(s):  
R. F. Timm
Keyword(s):  
Analog Circuit ◽  
Analog Computer ◽  
Analog Simulation ◽  
Rigid Link ◽  
Four Bar Linkage

This paper describes a procedure for simulating rigid link mechanisms on an analog computer. The computer circuit enables one to record all kinematic variables, i.e., displacements, velocities, and accelerations, for any point on the mechanism using conventional, commercially available computing elements. Also included in the paper is a scaled analog circuit for simulating velocities and displacements for the four-bar linkage, along with records of these parameters from the author’s simulation.

scholarly journals Task-space regulation of rigid-link electrically-driven robots with uncertain kinematics using neural networks

2021 ◽  
Vol 54 (1-2) ◽  
pp. 102-115
Author(s):  
Wenhui Si ◽  
Lingyan Zhao ◽  
Jianping Wei ◽  
Zhiguang Guan
Keyword(s):  
Neural Networks ◽  
Asymptotic Stability ◽  
Control Method ◽  
Joint Space ◽  
Robot Kinematics ◽  
Rbf Neural Networks ◽  
Task Space ◽  
Actuator Dynamics ◽  
Rigid Link ◽  
On Line

Extensive research efforts have been made to address the motion control of rigid-link electrically-driven (RLED) robots in literature. However, most existing results were designed in joint space and need to be converted to task space as more and more control tasks are defined in their operational space. In this work, the direct task-space regulation of RLED robots with uncertain kinematics is studied by using neural networks (NN) technique. Radial basis function (RBF) neural networks are used to estimate complicated and calibration heavy robot kinematics and dynamics. The NN weights are updated on-line through two adaptation laws without the necessity of off-line training. Compared with most existing NN-based robot control results, the novelty of the proposed method lies in that asymptotic stability of the overall system can be achieved instead of just uniformly ultimately bounded (UUB) stability. Moreover, the proposed control method can tolerate not only the actuator dynamics uncertainty but also the uncertainty in robot kinematics by adopting an adaptive Jacobian matrix. The asymptotic stability of the overall system is proven rigorously through Lyapunov analysis. Numerical studies have been carried out to verify efficiency of the proposed method.

scholarly journals Noncontact restoration of missing parts of stone Buddha statue based on three-dimensional virtual modeling and assembly simulation

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Young Hoon Jo ◽  
Seonghyuk Hong ◽  
Seong Yeon Jo ◽  
Yoon Mi Kwon
Keyword(s):  
3D Printing ◽  
Reference Model ◽  
Three Dimensional ◽  
Contact Method ◽  
Cultural Artifacts ◽  
Analog Simulation ◽  
Remarkable Case ◽  
Interface Surface ◽  
Restoration Technique ◽  
Assembly Simulation

Abstract Three-dimensional (3D) digital technology is an essential conservation method that complements the traditional restoration technique of cultural artifacts. In this study, 3D scanning, virtual restoration modeling, and 3D printing were used as a noncontact approach for restoring a damaged stone-seated Bodhisattva (stone Buddha statue). First, a 3D model with an average point density of 0.2 mm was created by integrating the fixed high-precision scanning of the exterior and the handheld mid-precision scanning of the interior excavated hole. Using a 3D deterioration map of the stone Buddha statue, the area of the missing parts was measured to be 400.1 cm2 (5.5% of the total area). Moreover, 257.1 cm2 (64.2% of the missing part area) of four parts, including the head, surrounding area of the Baekho, right ear, and right eye, for which symmetry was applicable for modeling or there could be ascertainable historical evidence for the total missing parts, was selected for restoration. The virtual restoration of the missing parts of the stone Buddha statue was performed using a haptic modeling system in the following order. First, the location of the three fragments detached from the head was determined. Next, a reference model was selected, and its symmetrization and modification with respect to the original model were conducted. Further, estimation modeling and outer shape description were achieved through historical research and consultation with experts. The heuristic-based assembly suitability of the created virtual restoration model (461 cm3) was verified by design mockup printing and digital–analog simulation. In particular, to address assembly interference, the interface surface was modified and reprocessed several times. Accordingly, the volume of the final design mockup decreased by 5.2% (437 cm3). Photopolymerization 3D printing technology was used for the actual restoration of the stone Buddha statue, and considering the surface roughness, the layer thickness of the material used for restoration was set at 0.10 mm. Finally, the surface of the printed output was colored to prevent yellowing and joined to the missing parts of the stone Buddha statue. This study presents a remarkable case of shifting from the traditional manual-contact method to the contactless digital method for restoring artifacts and is expected to largely contribute to increasing the usability of digital technologies in the restoration of cultural artifacts.

Analog Simulation of the Magnetic Hysteresis

1983 ◽  
Vol PAS-102 (5) ◽  
pp. 1235-1239 ◽  
Author(s):  
Farouk A.A. Zaher ◽  
Ahmed Shobeir
Keyword(s):  
Magnetic Hysteresis ◽  
Analog Simulation

Dynamic Response of Surface-Moored Vertical Barrier to Wave Action by Analog and Digital Simulation

1974 ◽  
Vol 96 (1) ◽  
pp. 335-342
Author(s):  
J. R. Fowler ◽  
E. I. Bailey
Keyword(s):  
Theoretical Model ◽  
Digital Simulation ◽  
Nonlinear Problems ◽  
Analog Computer ◽  
Two Dimensional ◽  
Test Program ◽  
Analog Simulation ◽  
Vertical Barrier ◽  
Amplitude Data ◽  
Lab Test

The two-dimensional dynamics of an oil containment barrier, which was designed to have very low tensile loads due to current and waves, were simulated with a theoretical model. The model was solved on both analog and digital computers, and a lab test program conducted to verify the model. For nonlinear problems such as this, for which “exact” solutions do not exist, the analog computer has many advantages, principally rapid parameter studies and convenient plotting output, plus giving the engineer a real time “feel” for the problem. The problem treated here was especially well-suited to analog simulation. Charts and graphs present maximum force and amplitude data, and experimental verification of the solution was obtained from wave tank studies.

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