Chassis Design
Base Panel:
The foundation of the entire robot relied on the Base Panel of the chassis. The base panel was manufactured by laser cutting various mounting holes in 1/4" thick duron. This allowed us to be able to mount as many components to a solid base as possible, including the motor drive, vertical walls, TIVA micro-controller, and bumper system.
The foundation of the entire robot relied on the Base Panel of the chassis. The base panel was manufactured by laser cutting various mounting holes in 1/4" thick duron. This allowed us to be able to mount as many components to a solid base as possible, including the motor drive, vertical walls, TIVA micro-controller, and bumper system.
Vertical Walls & Top Panel:
To protect the electrical components of the robot, we surrounded them with 1/8" duron. We used a living hinge design to allow the duron be flexible enough wrap around the corners of the chassis. The sections of the vertical walls not dedicated the living hinge also double as mounting spots for some of our breadboards.
The top panel of the chassis made of a 1/4" duron that houses the phototransistor for sensing the MINERs and the easy-to-access TIVA and motor switches.
To protect the electrical components of the robot, we surrounded them with 1/8" duron. We used a living hinge design to allow the duron be flexible enough wrap around the corners of the chassis. The sections of the vertical walls not dedicated the living hinge also double as mounting spots for some of our breadboards.
The top panel of the chassis made of a 1/4" duron that houses the phototransistor for sensing the MINERs and the easy-to-access TIVA and motor switches.
Drive-train
For our drive-train we implemented a simple 3-point back-wheel drive design, including 2 motor-driven wheels powered by a 7.2V battery for each motor and an TLE-5206 motor driver for the H-bridge, and 1 passive caster wheel to maintain balance. The shaft of the motors were protected by using a coupler and shaft attached directly to the wheels. This assembly was then mounted to the chassis using 3D printed pillow blocks. We also mounted the motor encoder using custom 3D printed mounts.
Electromagnet Holder
In order to retrieve and transport the MINER, we opted to use a 250N electromagnet and beam break circuit using an NPN photo-transistor and IR LED. The electromagnet allowed us to use minimal components in order to manipulate the MINER and the beam break allowed us to communicate with the software whether or not we have retrieved the MINER.
We 3D printed a custom holder to hold the electromagnet and beam break in an appropriate position such that having the MINER touch the electromagnet triggers a beam break. The holder also featured a curvature that was approximately the diameter of the ferrous strip surrounding the MINER. We adjusted the height of this assembly by placing it on a duron platform that could be raised/lowered by adjusting the height of the nuts on the threaded rods. This allowed for maximum contact with the MINER during retrieval and navigation.
We 3D printed a custom holder to hold the electromagnet and beam break in an appropriate position such that having the MINER touch the electromagnet triggers a beam break. The holder also featured a curvature that was approximately the diameter of the ferrous strip surrounding the MINER. We adjusted the height of this assembly by placing it on a duron platform that could be raised/lowered by adjusting the height of the nuts on the threaded rods. This allowed for maximum contact with the MINER during retrieval and navigation.
Bumpers
The bumpers consist of 6 laser cut 1/8" thick duron panels, 4 of which are capable of collision detection. We biased the placement of collision-detecting bumpers to the 3 front-most panels of the robot since the competition rules specify that if our robot causes the collision (by hitting from the front sides), we are responsible for reacting. The 4th collision detecting panel is the back-most panel so we can react to bumping into the walls from the back.
The collision detection of bumpers work by triggering a single limit switch placed just behind a duron panel. The limit switch is placed in the center of the panel lengthwise spring-loaded shafts (made using should screws) are paced on either side of the limit switch symmetrically. The spring-loaded shafts and limit switches are mounted to the chassis' base panel using custom 3D-printed parts. When the panel is pressed at any point along the panel ,the panel pushes against the limit switch causing it to click and communicate to the software that there has been a collision. The spring loaded shaft then pushes the panel back to its original position.
The collision detection of bumpers work by triggering a single limit switch placed just behind a duron panel. The limit switch is placed in the center of the panel lengthwise spring-loaded shafts (made using should screws) are paced on either side of the limit switch symmetrically. The spring-loaded shafts and limit switches are mounted to the chassis' base panel using custom 3D-printed parts. When the panel is pressed at any point along the panel ,the panel pushes against the limit switch causing it to click and communicate to the software that there has been a collision. The spring loaded shaft then pushes the panel back to its original position.