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"Mariam and the Daniels'" NORMAN robot is an autonomous line-following robot whose only desire is to collect and dispense coal (foam balls) into buckets. Starting in a random orientation, NORMAN's objective is to determine which arena it is in (Blue/Green) and travel to the coal dispenser. It then collects the coal, finds a nearby bucket, dispenses the coal, and repeats.
Game Design
Game Design
The game, "Tilt-A-World: Tip the Seesaw," is a head-to-head autonomous robotics competition in which robots navigate an arena, collect coal from dispensers, and deposit it into buckets attached to mechanical seesaws. The objective of each robot is to tilt as many seesaws as possible toward its side of the field, thereby earning points and outperforming its opponent.
Overall Objective
Each team places their autonomous robot in one half of the arena. During a 2 minute and 18 second match, the robot must:
Navigate through the arena autonomously
Acquire coal from designated dispensers
Transport that coal to seesaws positioned along the center divider
Deposit the coal pieces into the buckets at the ends of the seesaw
A team receives points when enough coal has been deposited into a bucket to cause the seesaw to tip toward that team's side. Each successfully tilted seesaw counts as one point.
At the end of the match, the team with the greater number of tilted seesaws is declared the winner.
Arena Layout
The playing field is a square arena approximately 2.4 m × 2.4 m, divided into two equal halves by a central wall that supports the seesaws. Each team operates exclusively within its own half of the arena and may not cross into the opponent’s region.
The key elements of the arena include:
Coal Dispensers – Located at the back of each team’s field. These structures contain the coal pieces that robots must collect during gameplay.
Seesaw Mechanisms – Positioned along the center wall separating the two teams. Each seesaw has two buckets, one facing each team.
Navigation Tape – Black tape lines run across the arena floor to assist robots with navigation and alignment toward objectives.
IR Beacons – Multiple modulated infrared beacons are placed throughout the arena to provide navigational references for the robots.
These features collectively create a structured environment where robots must combine navigation, sensing, and manipulation capabilities.
Coal and Dispensing System
Coal pieces are represented by small foam spheres approximately 45 mm in diameter. These lightweight objects are stored inside the dispensers prior to the start of the match.
Robots must interact with the dispenser to acquire coal before transporting it to the scoring area. Because the coal pieces are small and loosely packed, the mechanism used to acquire and transport coal becomes an important design challenge for each team.
The Gameplay
The Gameplay
Localization
Localization
At the beginning of the match, the robot must determine whether it is placed in the Blue Arena or the Green Arena.
To do this, the robot rotates clockwise while monitoring beacon signals using a custom beacon detection circuit. During testing, we observed that the beacon sensor could not reliably detect the beacon on the far side of the arena because the buckets and bucket stands blocked the line of sight. However, the robot could reliably detect the nearest beacon (either the left or right beacon). NORMAN determines which side of the arena it is in by looking for the two central beacons (Beacon R and L).
NORMAN has two microcontrollers (PIC32s)—one that acts as a leader, and the other as a follower. The follower PIC32 sends a 16-bit code to the leader PIC32, indicating which sensors are active. If the bit corresponding to either the left or right beacon is detected, the Beacon Service interprets the signal and generates one of two events:
ES_IN_ARENA_GREEN – left beacon detected
ES_IN_ARENA_BLUE – right beacon detected
This event is sent to the GamePlay Hierarchical State Machine (GamePlayHSM).
IMG_1042.movNavigation
Navigation
NORMAN's navigation system relies entirely on tape sensing and does not use beacon signals during normal movement.
The robot uses five tape sensors arranged in two groups. The three front sensors are used for continuous line following, while two additional sensors located below the wheel axle are used to detect junctions in the tape path.
The front sensors provide information about the robot’s alignment with the tape. The leader PIC interprets these signals and sends tape detection events for "Left," "Middle," and "Right" to the Tape Service. The Tape Service then applies PD control to adjust the relative speeds of the left and right drive motors in order to keep the robot centered on the tape. Each sensor combination is converted into a control error value (for example, left only = −2, left + middle = −1, middle only = 0, etc.), which determines how each motor should correct its rotation.
The two rear sensors are spaced such that they can detect tape branches and junctions. If the right rear sensor detects tape while the left does not, the robot identifies a right junction. If the left rear sensor detects tape while the right does not, it identifies a left junction. If both sensors detect tape simultaneously, the robot identifies a T-junction.
These junction detections are sent as events to the gameplay state machine, which determines whether the robot should continue forward, turn, or transition to another behavior.
IMG_1039.mov
Collection
Collection
Once NORMAN navigates to the dispenser, it positions itself to collect the balls. The collection mechanism includes a micro servo connected to a 3D-printed paddle designed to fit within the small opening of the dispenser.
The paddle repeatedly swings into the dispenser to push balls out of the chute and into the robot. The servo performs this motion seven times.
After completing intake, NORMAN begins navigating towards a new bucket.
IMG_1043.movDeposition
Deposition
After collecting balls from the dispenser, NORMAN navigates to the buckets by following the tape lines. Our strategy was to target only the three buckets which can be reached by following the tape lines.
Each of these tape buckets is marked by a T-junction, as shown in the arena layout. When the navigation system detects this T-junction using the rear tape sensors, the robot stops and begins the dispensing sequence.
To release the balls, a servo-driven arm rotates approximately 180 degrees, lifting the storage container and allowing the balls to fall into the bucket. The arm remains in this raised position for 6 seconds to ensure the balls have sufficient time to exit the robot.
After this delay, the arm returns to its original position so the robot can continue the gameplay sequence.
IMG_1041.movEnd of Game
End of Game
Each game round lasts 2 minutes and 18 seconds, after which the robot must stop all activity. To enforce this requirement, the system maintains an internal timer that begins when gameplay is initiated. Once the timer reaches the round limit, the robot transitions into an End Game state.
In this state, all locomotion and manipulation actions are immediately disabled to ensure the robot no longer interacts with the arena. At the same time, the system updates the visual indicator on the robot: all LEDs switch to solid red. The robot remains in this inactive state until power is reset or the next match begins.
Full Game Demonstration
Full Game Demonstration
IMG_1041.MOVPage updated
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