This subassembly is designed to swing out and grab a wobble goal so that it can be transported and lifted over the back wall into the drop zone.
The mechanism consists of a geared down sail winch servo to swing the arm out and a normal servo to actuate the gripper. The robot moves to place the neck of the wobble goal in the vee notch and then the driver actuates the gripper servo. The arm can then be moved to a vertical position which allows the wobble goal to be dropped over the wall.
The arm is fabricated from a stock aluminum extrusion from the hardware store. Three 3D printed parts provide the notch and the gripper. The notch was split into two separate parts to make printing easier.
As we used this subsystem in the robot, it became clear that too much precision of position was required to capture the goal. This resulted in a loss of precious time and prevented us from trying to place two wobble goals in the autonomous period. So we designed a different gripper:
Now, the grabber will capture the goal if the neck is anywhere within the “vee.”