Experimental validation and simulation of a U-Shaped elastic beam robot for stable running locomotion

This paper presents an innovative terrestrial robot employing a vibration-based locomotion system powered by a single DC motor with an eccentric rotating mass. The robot, composed of a U-shaped aluminum elastic beam and lightweight wooden feet, attains steady mobility by synchronizing torsional vibrations with centrifugal forces. Experimental and simulated analyses were performed at three angular velocities (ω₁ = 125.66 rad/s, ω₂ = 251.33 rad/s, ω₃ = 376.99 rad/s) to assess stability, deviation, velocity, and hopping performance. The results indicated that a rise in angular velocity significantly improved locomotion efficiency. At ω₁, the robot attained an average body velocity of 85.46 mm/s and a hopping distance of 405.88 mm. At ω₂, the velocity rose to 221.24 mm/s with a hopping distance of 418.24 mm, but ω₃ achieved optimal performance with a velocity of 265.49 mm/s and a hopping distance of 424.08 mm. Deviation responses settled within ± 2 mm after 2.5 s at ω₃, in contrast to more pronounced oscillations at ω₁. Simulation results largely aligned with experimental outcomes in hopping distance (error < 3 mm at ω₃) but routinely underestimated body velocity by 50-60%. The findings corroborate the suggested model for predicting vertical displacement, while underscoring the necessity for refinement to accurately capture horizontal velocity dynamics.