the dragonbot
The Dragonbot is a mechatronic mythical beast that is equipped with the capability and intelligence to launch standard nerf balls at a target within a 6 foot range. It is specifically designed to play the game of battleship as part of Stanford's ME 218b Smart Product Design course.
The Dragonbot's shooting mechanism consists of two horizontally mounted counter-rotating wheels similar to a pitch machine. Nerf balls are fed one at a time by a servo controlled loader, and the entire shooting and loader mechanism sits on a servo controlled turret.
The Dragonbot has a 20" tail that allows balls to be received from the re-supply depot while still remaining in view of the camera system, a precondition for shooting. At the end of the tail an IR LED is mounted that queries the re-load station for a new ball. There is also an IR beam break sensor at the end of the tail that can report when a nerf ball is received, however this capability was not utilized in our final implementation. Newly loaded nerf balls travel down the tail into the loading mechanism which is mounted in the center of the turret.
At the front of the turret there is an IR beacon sensor that can detect the location of the enemy power station.
The majority of the electronic circuits are mounted on the walls of the tail, including the microprocessor unit, the "E128", which is mounted as close to the wireless communicator, or "FAC", as possible. The remainder of the circuits are mounted on the head or the sides of the front of the bot. No circuits are mounted on the turret in order to simplify wiring and keep the turret as light as possible.
The Dragonbot sits on 2 motor controlled rear wheels and 1 wide front wheel. The driving chassis is optimized for straight forward and reverse driving, but turning can also be achieved. The motors can be run under PI control based on the orientation and location of the bot on the field.
Sitting atop the Dragonbot is a fiducial marker that can be read by the game camera system. Below that is the FAC which wirelessly communicates with the camera system and can be queried by the E128 about the locations of all the ships and bots on the field as well as power station status and game start/ game end transitions.
The Dragonbot achieves accurate and precise shooting through its robust mechanical design and software controls. Encoders were created for the shooting motors by placing a black plate with one white tape strip on top of each shooting wheel and mounting a tape sensor about 1/8" above the shooting wheel. The speed of each shooting motor is under PI control and maintains the desired RPM even as a nerf ball is propelled between the wheels. The Dragonbot can reliably shoot a nerf ball into a coffee mug sitting 6 feet away as evidenced in the video below.
The Dragonbot's shooting mechanism consists of two horizontally mounted counter-rotating wheels similar to a pitch machine. Nerf balls are fed one at a time by a servo controlled loader, and the entire shooting and loader mechanism sits on a servo controlled turret.
The Dragonbot has a 20" tail that allows balls to be received from the re-supply depot while still remaining in view of the camera system, a precondition for shooting. At the end of the tail an IR LED is mounted that queries the re-load station for a new ball. There is also an IR beam break sensor at the end of the tail that can report when a nerf ball is received, however this capability was not utilized in our final implementation. Newly loaded nerf balls travel down the tail into the loading mechanism which is mounted in the center of the turret.
At the front of the turret there is an IR beacon sensor that can detect the location of the enemy power station.
The majority of the electronic circuits are mounted on the walls of the tail, including the microprocessor unit, the "E128", which is mounted as close to the wireless communicator, or "FAC", as possible. The remainder of the circuits are mounted on the head or the sides of the front of the bot. No circuits are mounted on the turret in order to simplify wiring and keep the turret as light as possible.
The Dragonbot sits on 2 motor controlled rear wheels and 1 wide front wheel. The driving chassis is optimized for straight forward and reverse driving, but turning can also be achieved. The motors can be run under PI control based on the orientation and location of the bot on the field.
Sitting atop the Dragonbot is a fiducial marker that can be read by the game camera system. Below that is the FAC which wirelessly communicates with the camera system and can be queried by the E128 about the locations of all the ships and bots on the field as well as power station status and game start/ game end transitions.
The Dragonbot achieves accurate and precise shooting through its robust mechanical design and software controls. Encoders were created for the shooting motors by placing a black plate with one white tape strip on top of each shooting wheel and mounting a tape sensor about 1/8" above the shooting wheel. The speed of each shooting motor is under PI control and maintains the desired RPM even as a nerf ball is propelled between the wheels. The Dragonbot can reliably shoot a nerf ball into a coffee mug sitting 6 feet away as evidenced in the video below.
During the game, the Dragonbot stores the locations of all enemy ships as well as the last known location of the enemy bot. It fires once on each enemy ship, and then once on the enemy bot. If it had ever missed the bot, it would have gone through the enemy ships that were missed and fired on them followed by the bot. This would have repeated until the game ended.