To simulate the robotic arm , we used Matlab with Corke's robotic toolbox.
The first step was the modeling of the robot in the simulated environment and the definition of the necessary parameters ( links between motors, masses , inertias etc.)
After modeling the robot, we solved the forward kinematics by calculating the Denavit-Hartenberg paremeters
| Link | θi | di | ai | αi |
|---|---|---|---|---|
| 1 | θ1 | 0 | 0 | -90° |
| 2 | θ2 | 0 | 0 | 90° |
| 3 | θ3 | 0 | 0 | 0 |
| 4 | 0 | d4 | 0 | 0 |
By expressing the parameters of the robot as a function of the Cartesian coordinates we get the following equations:
To make the end-effector move in a circular path during a specific amount of time , we have to define at least 9 points to form the path and then direct the arm into them with a specified order.
Of course before we actualy move the robot, we have to solve the robot's Dynamics.
The formation of the Euler-Lagrange equation will enable us to find the actual forces we need to apply in the motors, to force the arm move in a certain way.
Finally to optimize the movement of the robot into the specified path, it is essential to add a control mechanism. We choosed ato do that using feedforward-torque control.
After applying the control, we tried to move the robot in a circular path and measured the difference between the desired path and the actual movement.