All of Spring Flamingo's motors are located in its upper body, with power being transmitted to the joints via cable drives. Series Elastic Actuation is employed at each degree of freedom, allowing for accurate application of torques and a high degree of shock tolerance. The force control bandwidth we achieve is approximately 20 Hz. Rotary potentiometers at the hips, knees, ankles, and boom measure joint angles and body pitch. Linear compression springs are located in the actuators to implement Series Elastic Actuation.
Linear potentiometers measure the spring compression.
In all there are six actuators and thirteen sensors on Spring Flamingo. We have implemented simple walking algorithms for walking on flat terrain. With these algorithms, we have successfully compelled the robot to reliably take consecutive un-aided laps as shown in the MPEG video below. As of Summer 1999 we have developed walking algorithms for fast walking up to 1.2 meters per second. Some of these algorithms exploit the natural dynamics of the robot to allow for simpler control with a more graceful result.