Surrounding Object Material Detection and Identification Method for Robots Based on Ultrasonic Echo Signals

Table 1

The calculation equations of feature parameters.

Feature parameters	Calculation equations
Peak
Arithmetic mean
Absolute mean
Root mean square
Variance
Mean square
Kurtosis
Skewness
Kurtosis indicator
Skewness indicator
Clearance indicator
Crest indicator
Waveform indicator
Impulse indicator
Peak energy
The peak energy’s frequency