For my Electromechanical Systems and Robotics class, we were tasked with building a two link serial manipulator. The goal was to be able draw in two dimensions by attaching a pen to the end of the manipulator.
To begin, we designed and fabricated hardware that enabled smooth and consistent movement of the pen. Next, we connected encoders to the motors and wired the motor controllers to both the motors and an Arduino. For implementing the control algorithm, we connected the Arduino to a laptop, using Matlab to execute the code.
To prevent the manipulator from crashing into itself, we defined a range of motion that constrained the angles at which the motors could rotate. We then employed inverse kinematics to develop a function that determined the necessary motor angles to position the pen at a desired location. This function allowed us to define a trajectory of points for creating the intended shape to be drawn.
Lastly, we implemented a PD (Proportional-Derivative) controller to ensure accurate motor movement to the required angles. The adjacent plot illustrates the controller's performance, demonstrating that the manipulator achieves acceptable accuracy in reaching the set points when using the PD controller.
