TABLE 2.

Comparison between the conventional tactile sensing technologies for MIS.

	Piezoresistive sensors	Piezoelectric sensors	Capacitive sensors	Optical sensors
Hysteresis	High	Low	High	Low
Temperature dependence	Yes	Yes	No	No
Humidity dependence	No	No	Yes	No
Power consumption	High	Very low	Low	High
Linearity	Good	Good	Fair	Good
Cost	Very low	Low	Medium	High
Electronics	Simple	Simple	Intermediate	Complex
Static pressure capability	Yes	No	Yes	Yes
Advantages	- Small size	- Small size	- Better stability and higher sensitivity than the two other electrical sensors	- High spatial resolution
	- Easy multi-axial force measurement	- No moving parts	—	- Compatible with MRI scanners
	- Simple readout circuits	- Self-powered	—	—
	- Low noise	- High bandwidth	—	—
Limitations	- Sensitive to EM noise	- Suitable for the measurement of dynamic loads only	- Sensitive to EM noise	- Sensitive changes in light intensity due to cables bending
	- Trade-off between the sensitivity and the stiffness of the structure	- Requires a charge amplifier	- Signal processing complexity	- Requires precise alignment and packaging of fibers to maintain the calibration
	- Trade-off between scaling down and power consumption	—	- Requires careful circuit design to reduce the effects of parasitic capacitance	—