Table 1. Structural parameters and material properties.

Parameter	Description	Value
E	PDMS Young’s Modulus	550 kPa
l	Length of PDMS spring leg	7.07 mm
w	Width of PDMS spring leg	3 mm
h	Height of PDMS spring leg	3 mm
As	PDMS stage area	2 cm × 2 cm
R	Radius of NdFeB magnet	6 mm
t	Thickness of NdFeB magnet	4.5 mm
N	Turns of EMG coil	120
L × B × H	Dimension of whole device	4 cm × 4 cm × 2.5 cm
d1, d2	Gap between two triboelectric layer	1 cm