Used in the Antweight robot Gyrobot, as well as the Battlebots competitor Wrecks, this system uses a gyroscope and stationary feet that lift as the entire robot rotates due to gyroscopic precession when the gyroscope is tilted by a servo motor. This design can use the gyroscope as a spinning weapon (horizontal or vertical) which allows for efficient double-usage of the gyroscope mass. Although Gyrobot and Wrecks appear to be walking as it translates across the arena, they're not classified as walking robots under current rules. This unusual drive train produces strange and often unpredictable movements, though has shown to be successful in combat.Suction fan – Several competitors experimented with the use of fans to evacuate air from a low-clearance shell to suck the robot down onto the arena surface and add traction. Robotica competitor Armorgeddon used a suction fan to increase traction and pushing power, and Robot Wars and Battlebots competitor Killerhurtz experimented with use of a suction fan to counter the forces from its hammer/axe weapon, a system that was demonstrated as giving the robot the ability to climb walls but was never utilised in combat. Similar designs have appeared in robot-sumo competitions where traction is a key factor.Magnetic Wheels – Another approach to gaining traction and stability involves the use of rare-earth magnets, either ring-shaped as wheels or simply attached to the robot's base. This is, naturally, only effective in arenas which have magnetic metal surfaces. Due to the expense of large ring magnets, this trick has been used almost exclusively in three-pound and under "insect class" robots, although a lightweight battlebot General Gau tried implementing them. A multibot named Hammer and Anvil would later use magnets in the lightweight category, with some success. Heavyweight Robotica competitor Hot Wheels attempted to use a large chassis-mounted magnet to gain traction and apparent weight, and Beta unsuccessfully attempted to use an electromagnet to counter the reaction forces of its massive hammer weapon at the BattleBots competition. This however was removed for future competitions as the power of the magnets rendered the robot unable to move.Mecanum wheels – Together with a specialized motor control system, mecanum wheels allow controlled motion in any direction without turning, as demonstrated by Alcoholic Stepfather in a 2004 match, and by the hammer-wielding Battlebots competitor Shatter! in 2019.Translational drift – Also known as Melty Brain or Tornado Drive, this sophisticated system supplements the thwackbot drivetrain