An Energy Efficient Quadruped with Two-Stage Equilibrator

A first consideration of the applications of mechanical equilibrators to legged locomotion is presented. Equilibrators are shown to eliminate “geometric work” while allowing simultaneous dual actuation of each leg joint of a quadruped. Gravitational forces on both the vehicle body and legs are decoupled from actuator force/torque requirements. In addition, for slow speeds and when leg kinetic energy is ignored, both joint actuator torques and joint actuator work approach zero. Dynamic simulation demonstrates that proper equilibrator design can reduce peak torque of leg actuators by more than 90 percent and offer a vehicle specific resistance 70 percent smaller than that of tracked vehicles.