From: Estimation of the friction force during the needle insertion using the disturbance observer and the recursive least square
Needle diameter d [m]
1.60 × 10-3
Needle mass m [kg]
2.18 × 10-3
Dynamic friction coefficient μ
0.663
6.63
The Pressure of tissue to the needle P [N/m2]
63.7 × 102
The coefficient of velocity s
197