GEAR Rescue Robots - 2025 National Robotics Challenge
Logan and Robert's robot features a vacuum-type ball handler. A 3D printed fan enclosed in a 3D printed blower housing provides the vacuum. Connected to the air input of the blower is a long tube. At the end of the tube there is a servo that opens and closes a door. When a ball is to be sucked up, the door is opened. At other times the door is closed to prevent retrieved balls from escaping. To deposit the balls in the receiver, the tube is tilted down and the door opened. Tilting of the blower is done with a worm drive attached to the blower housing. The bottom of the worm drive connects to a geared servo drive that provides horizontal rotation of the blower assembly.
Collette and Ginny's robot also features a vacuum-type ball handler but differs in the details of construction. The blower assembly is attached to a worm drive to provide a tilting action. However, there is not additional mechanism to rotate the blower horizontally as in Logan and Robert's robot. Collette and Ginny's robot has a feature not included on Logan and Robert's. The tube connecting to the blower can extend. A linear actuator mounted to the tube assembly provides the force to extend and retract the tube. The range of movement of the actuator is limited by two electrical switches wired with diodes. One switch opens at each end of the range of motion. When the switch opens, current flow is allowed only through the diode wired with the switch. This permits the actuator motor to only spin in the opposite direction from the direction that caused the switch to open.
This photo shows the tube assembly in the fully extended position, which causes the tube assembly to be 7 inches longer than the fully closed position. The tube assembly is comprised of three parts. The center section nests inside the outer section and the inner section nests inside the center section.
Sam, Charlie and CJ's robot has a completely different type of ball handler, not involving a blower. There is a pair of half-spherical cups at the end of an arm that capture the ball. The arm can be raised and lowered by a worm drive (seen at the front of the robot). Similar to Logan and Robert's robot, the worm drive sits above another drive that provides circular motion in the horizontal direction (the large gear seen below the worm drive is rotated by a servo). Sam, Charlie and CJ were nominated for the Honda Innovation Award for their ball handling design.
In this photo we see the robot with its arm extended forward and the cups open ready to capture a ball.
Here we see the underside of the robot. All three of our robots have the frame arrangement seen in this photo. There are two frames connected by a hinge which allows articulation of the frame. This provides better performance in climbing the stairs. The articulation is limited by two limit bars. Here you can see that the robot is equipped with four motors, one for each track. The blue box contains the battery. Also seen in the photo are the snap circuit breakers (5 amp) that protect the motors during a stall condition.
In this photo you can see a clutch mechanism (red 3D printed part) that protects the robot from damage should a moving part crash into another part of the robot. The part is 3D printed with a hole just smaller than needed to accommodate the shaft that it grips. Then the hole is drilled to a diameter that matches the diameter of the shaft. Then a slot is cut on one side of the clutch body. A screw and nut are used to adjust the grip on the shaft so that it holds the shaft until a limiting torque is achieved. Then the drive shaft slips inside the clutch body. These clutches were applied on all three robots.
