Our main goals for our design were to make sure that our build would be very rigid and stable. We knew that we wanted to make sure that all of our joints would be held with screws and bearings that were pressure fit into the parts. This would help us achieve a very smooth and sturdy joint for our Arm and Gripper. We wanted to make sure that the gripper would be able to grip a water bottle tight enough so that it would not slip out when we raised the arm. We also wanted the arm and gripper to be independent systems, so we had to plan how we were going to implement our servos with our links. We found that simple flat links with joints would be an effective method to accomplish our gripper mechanism. For our Arm, we wanted to be able to have the necessary range of motion that would be able to grab the water bottle from the base plane and be able to lift the water bottle to a reasonable height. (Around 8 in.)
We planned for the gripper to have a mirrored parallel 4-bar mechanism to be able to perform the gripper motion. For the arm, we planned for a parallel 4 bar mechanism to be able to lift the gripper up and down while keeping it parallel to the floor.
We were mainly able to plan out our design using Solidowrk Sketches to be able to see how everything would fit together and the spacing of all of our components.
Initially, it was planned that we would have a servo for the gripper and a DC motor for our Arm, as we were concerned about the torque required by the arm to lift a water bottle. However, the arm's range of motion was so limited that having a DC motor with an encoder attached would not be able to perform as accurate motions as a High Powered Servo.
Initial Gripper Design
Initial Arm Design