ME446 PROJECT WEBSITE
FINAL PROJECT
FINAL PROJECT TASK
The final project task was to use position/impedance control to make the robot arm do a desired sequence of tasks which is highlighted in the figure below. Task 1 was making the end effector move vertically down into the hole and then move it out. The second task was to move the robot arm around the obstacle without hitting it. The third task was to move the end effector along a zigzag path and finally, the last task, was to move the egg vertically down without breaking it. The task was marked as complete when the robot arm came back to it's home position.
SUCCESSFUL TRIAL - 2.80SEC
Fastest run of the class! The video says it all. We use the force control for task 1, task 3 and task 4 since we need to make the end effector move along a particular trajectory without having too much force being exerted perpendicular to it. If the forces perpendicular to the trajectory are high, then either the end effector will twist or the entire setup clamped to the table will move considerably.
CRACK THE EGG!!
Crack! Crack! Unsuccessful attempt. The gains were not tuned correctly for the last task. The gains in the vertical direction, when pressing down on egg, were low. Hence, under gravity, the gravitational torque on the arm was high relative to the motor torques and end effector "fell" vertically down on the egg, breaking it.