"Crab Walk" to Your Next Destination...It's energy efficient

Science researchers are studying the way fiddler crabs migrate from nest to sea. Researchers replaced the sandy terrain with a slippery material and found that the fiddler crab was coming up short from the nest. It was found that the fiddler crabs move from one location to the next not by seeing or sensing their surroundings, but by calculating how much energy their muscles and body were used for locomotion. This would be an excellent method for small UAVs to navigate rocky and uneven terrain for two reasons: tire slippage and energy conservation.


UAVs are often used in sandy or rocky terrain where it is easy for tires to slip. This is especially problematic because most wheeled robots use high tech odometers to collect distance information from the number of wheel revolutions. A slipping wheel distorts the distance that the robot has traveled. Like the crab, UAVs that have slipping tires will not arrive at their destination. Using the Fiddler crab’s navigation method, travel distance can be better predicted and therefore make for a better performing UAV.

The crab scientists found that crabs optimize for energy because the speed of the crab can vary. The crabs are capable of moving quickly or slowly, and therefore adjusting their stride lengths. This means the do not simply count steps. Researchers believe crabs monitor the amount of energy they expel over the duration of the journey.

Knowing a UAV’s energy usage on long endurance trip is very important because many UAVs use batteries. UAV’s must constantly conserve energy. Energy level can be important to decide what tasks can be completed or what speed to complete them.

Currently it’s not ground robots that are monitoring power levels, it’s air vehicles. High altitude solar powered aircraft such as Helios and Centurion move to different configurations to collect more sun rays. Because their main power source is the sun, they must constantly monitor usage. If an aircraft looses power, it doesn’t simply get stuck in the sand. It falls out of the sky. Using this type of method in ground robots may be beneficial for long trips.

In order to navigate using energy usage, more sensors and computers are required to be on the robot. This can add more complexity to the robot rather than simply counting wheel revolutions. However, for trips over varied terrain where precise locations are required, this may be the best method. So the best way for your UAV to travel may be the crab walk.