ATHLETE Robot Revisited

[Photo of ATHLETE with Brian Wilcox, source: JPL]

Some time ago, I referred you to a video on the JPL robot, ATHLETE. Last week, I learned more about this platform at the ASME conference where Curtis L. Collins granted us an overview.

They’re targeting the Moon. They want ATHLETE to cover 99% of the lunar landscape. The prototype is 2.2 m high, 4 m wide and weighs 850 kg. Its size is limited by the fact that they have to put it on a trailer to carry it to test sites. The real ATHLETE should be two or three times larger. Its maximum speed is 10 km/hr.

Since the project’s inception in 2005, ATHLETE was envisaged to be more than a mobile robot. The four functions it will have to fulfil are:

1. Mobility – ability to ambulate on wheels and/or on foot. The wheels are actually “tweels”, a hybrid between a tire and a wheel. This consists of a rim made with a responsive material, a little like on a Segway.
2. Manipulation – ability to use its limbs to handle items. Each limb is a manipulator with six degrees of freedom. With the right tools, they can drill into the ground, grab objects, etc.
3. Transportation –ability to move resources on the ground that the astronauts may need.
4. Landing system – cushion the landing of the lunar module.

Seven processors are needed to control this beast. Only one is used for direct control. The other six are used to analyze the images of the six cameras, one on each leg. Absolute and incremental encoders are used on the joints. Their positioning laid out makes it possible to determine the torque at each joint. The robot also has a GPS and an IMU. It is not designed to be totally autonomous. A human will always be involved in the process.

Future work will consist in developing metal tweels and testing landings. Unfortunately, we can’t have access to the videos that showed ATHLETE raising two legs to allow a trailer to be placed under it. It then alit on the trailer, folded its legs, and rode to the JPL.