RoboBall III is a spherical mobile robot developed at the Robotics and Automation Design Lab (RAD Lab) at Texas A&M University. The entire unit is enclosed in a flexible, spherical shell about 1.8 m (6 ft) in diameter and weighing roughly 150 kg. It moves using a pendulum drive: shifting an internal pendulum changes the sphere's center of mass and makes it roll. Only two actuators, both located entirely inside the shell, power the robot.
The concept was designed by Dr. Robert Ambrose at NASA in 2003; an initial prototype was built and shelved, and work resumed in 2021 after Ambrose joined Texas A&M. The earlier RoboBall II, about 0.5 m in diameter, reached 20 mph. RoboBall III delivers roughly 2.5 times more torque, climbs 20-degree slopes, and its shell withstands temperatures down to -184°C and rolls over steel shards. Building one unit costs about US$250,000.
The robot is being considered for rough-terrain exploration — from beaches and water-to-land transitions (planned trials at Galveston beach), through post-disaster mapping, to lunar surface exploration (including Shackleton Crater). The work is led by Ph.D. students Rishi Jangale and Derek Pravecek. RoboBall III remains a research prototype.
Dimensions, weight and structural proportions
