Updated 2/17/20
Key Search Words: ROBOT, ROBOTICS, ROBOTIC VISION, ARTIFICIAL INTELLIGENCE, AI, GEOBOT

 

      


            
The Geobot must be able
            to secure specimens during its travels and store them for the
            return trip. All the mechanical design, shop work with drill
            press, band saw, and 3D printer are now finished. The arm is
            motorized with expensive Hitec high torque all metal servos,
            and each motor can draw over an ampere of current. 

            
Shown above is the robot
            revealing the arm in the folded travel position. It will stay
            in this mode even if power is not applied due to spring pressure.
            The arm has four degrees of freedom: Rotation at the base, tilt
            at the base, elbow, and gripper. The gripper is not articulated
            to pivot because of the mode of sample collection does not warrant
            this as you will see.

            
The Hardware

            

 Lets
            start with the collection gripper. Samples will be taken at ground
            level of both rock and soil, and a scraping cup like gripper
            was created. The cups are geared together so that they open simultaneously
            by pulling only on one side with a servo. The servo shaft is
            seen here on the left cup. Most importantly, the gripper cups
            are replaceable with 4 screws so other designs can be tested.


            


            
 Since all robot
            arms are based on cantilevered beams, a opposing force must be
            applied to balance the mechanics such that the motors do not
            have to lift a heavy lever arm. Small extension springs in the
            base are able to perfectly balance the entire weight of the arm,
            even when fully extended horizontally.

            
The azimuthal rotation
            base here is quite a bit of design work. More will be detailed
            later, but for now I can tell you the weight is carried by dozens
            of standard marbles...

            

 Elbow
            details. A strong motor rotates the fore arm vertically. The
            return spring is an extension spring that equalized the loading
            on the motor. It allows for a horizontal position on the arm
            without stressing the motors too much. The lower servo here is
            the lever for the push rod to open and close the gripper cups.
            

            
You Tube Video of Arm in Action
 This
            short video clip shows each motor element being excercised one
            at at time.

Previous Uploads on this robot:

1.  Basic concepts and prototype, Base design
2.  Construction of the tower assembly
3.  Connection of base to tower
4.  Base Tower integration
5.  Magnetometer, Sounds, Head Lights and rotation
6.  Code and implementation of the Magnetometer for Navigation

 

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