International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

This research proposes a simulation of a Stäubli TX90 robot based on Simulink Toolbox of Matlab. The goal is to predict the position and trajectory of its end-effector, with high reliability. The simulator takes into consideration loading, deformations, calibrated kinematic parameters, and all eventual sources of disturbance. A comparison between real and simulated data reveals the reliability and the accuracy of the simulator.

Parameters of the robots are always changed due to the load being carried. Robust control is a method that considers the changes of control system performance related to the modification of system parameters. Stability and performance of the system can be well protected in case the change of system parameters does not affect the system. Even if there is several modified parameters, robust control system still provides the ability of control in a desired manner.

In this work, parameters are made changeable and the upper limit of the uncertainty parameter is kept constant unlike other robust control studies. Control parameter is updated over time depending on the trigonometric functions. The values of the constant control parameters in trigonometric functions affect the performance of the system and it is quite difficult to find appropriate control parameter values. Logical fuzzy compensator is designed to find this parameter and investigated the effects on the tracking error of two-link robot.

Fuzzy Logic associated robust control methods developed using robust control has been compared through a computer simulation using the same trajectory and same model. Thanks to the designed fuzzy logic associated robust controller, robust control is improved and two-link robot’s trajectory tracking error has been reduced to a very small value.

The linear theory including the effects of bending-torsion coupling and rotatory inertia is used to derive the equations of motion for a space beam with variable curvature. The governing differential equations of motion are derived based on Euler-Bernoulli beam theory via Hamilton’s principle. The full, coupled system of governing partial differential equations has a total order of 12.

The natural frequencies and mode shapes of an Euler-Bernoulli beam with a rectangular cross- section, which has a surface crack, is investigated. The crack is modeled as a change (sudden or gradual) in the cross-section of the beam, and the perturbation approach is used assuming that the crack is much smaller than the beam cross section. Computations of natural frequencies and mode shapes were carried out for four different crack shapes with rectangular, triangular and parabolic profiles when viewed through the side of the beam. The results are listed in non-dimensional form for various values of the parameters characterizing the crack.