Sharif Digital Repository

In this paper, the three-dimensional large deformation frictional contact of powder forming process is modeled using a simple computational algorithm based on the augmented-Lagrange approach. The technique is applied by imposing the contact constraints and modifying the contact properties of frictional slip through the node-to-surface (NTS) contact algorithm. The Coulomb friction law is employed to simulate the friction between the rigid punch and the work-piece by the use of penalty and augmented-Lagrange approaches. It is shown that the augmented-Lagrange technique significantly improves imposing of the constraints on contact surfaces. The nonlinear contact friction algorithm is employed... 

Amphibious single wheel robot consists of a sharp-edged wheel actuated by a spinning flywheel for steering and a drive motor for propulsion. The spinning flywheel acts as a gyroscope to stabilize the robot and also can be tilted to achieve steering. In this paper, the kinematics of a single wheel robot in water, Gyrover, is analyzed and then a simple mechanism for driving it is proposed. In previous studies, Lagrange approach is used for hydrodynamic modeling of the robot. A nonlinear position controller is designed to bring the robot to any desired position. Based on the designed controller, a tracking controller is augmented to the robot. For simplicity the added mass effect has been...