Fig. 2: Tethered locomotion tests and parameters optimization.
From: A wireless controlled robotic insect with ultrafast untethered running speeds
a Measurements of the relative running speeds of four prototypes with different body lengths (prototype #2.1−2.4, 10, 15, 20 and 25 mm) versus the current frequency, with the current amplitude remaining 0.15 A. b Measurements of the relative running speeds of the four prototypes versus current amplitude, with the frequency remaining constant. c Measurements of the maximum relative running speeds of the four prototypes versus the payload mass near the resonant state, with the current amplitude remaining 0.15 A. All error bars represent the standard deviation of four measurements. d Diagram illustrating the simplified structure of the BHMbot. e Simplified planar dynamical model of the BHMbot to analyze the motion characteristics of the BHMbot. f Dimensions of the planar dynamical model, including four generalized coordinates used to establish the dynamic equations of the model. g Simulation results of normalized relative linear running speed on the paper substrate versus cantilever width wc and the relative distance z between the hollow coil and the magnet. h Simulation results of normalized relative linear running speed on the paper substrate versus body tilt angle θ0 and the distance lr between the rear feet and the COM of the body in the vertical body direction. The color bar represents the magnitude of the normalized running speed, with the red color area indicating the fastest running speed. i Optical photo of the tethered BHMbot (prototype #3) using optimized structural parameters moving forward at a maximum speed of 50 cm s−1 (33.3 BL s−1). j Optical photo of the tethered BHMbot (prototype #4) moving forward with a relative speed of 25 BL s−1 when carrying a hexagonal nut (2000 mg), which is more than five times its body mass (370 mg). k Experimental and simulation results of the relative running speed of the optimized BHMbot (prototype #3) versus the slope angle (from 0° to 7.2°). The error bars represent the standard deviation of four measurements. l Optical photo showing prototype #3 moving on a slope of 6° with a maximum speed of 6.5 BL s−1.
