Biomimetic Legged Robots Operating in Rough Environments

Gravity and Inclination Effects on the Design of Quadruped Robots
Dynamic Running Quadruped for Crater Exploration

Leg uncompressed length and compliance have significant impact on the performance of quadruped robots. Also, gravity has a direct effect on robot motion characteristics. We used a planar lumped parameter model of a quadruped robot and an extensive research scheme to determine the optimum design parameters for quadrupeds moving in various gravity environments. An optimum region of leg spring constant and uncompressed length emerges for level terrain traversal. The maximum values for negative and positive slopes according to forward velocity in three gravity environments are also determined. Experiments with the NTUA Quadruped are conducted to validate the simulation environment. Experimental results obtained using internal sensors show that the quadruped robot performs gaits with the desired characteristics and in accordance to simulations.

Image 1: A lumped parameter planar quadruped model					Image 2: Motion Phases and Events that trigger them

 

Image 3: Quadruped motion during crater exploration

 

Image 4: Achievable forward velocity vs. ground inclination for different gravity environments (Earth, Mars, Moon).					Image 5: Uncompressed leg length vs. fwd velocity. Level terrain.

 

Image 6: Body pitch. Simulation and IMU data. Level terrain.					Image 7: Forward velocity. Simulation and IMU data. Level terrain.

 

Image 8: Spring constant vs. fwd velocity. Level terrain.