Table 2 Simulation model parameters and initial value

Servo valve gain \(K_{{\text{axv}}}\) (mm/v)

0.45

Natural frequency of servo valve \(\omega\) (rad/s)

628

Damping ratio of servo valve \(\zeta\)

0.77

Effective piston area of servo cylinder \(A_{\text{P}}\) (mm²)

336.8

Volume of input oil pipe \(V_{{\text{g1}}}\) (mm³)

620

Volume of output oil pipe \(V_{{\text{g2}}}\) (mm³)

860

Total piston stroke of servo cylinder \(L\)(mm)

50

Initial piston position of servo cylinder \(L_{0}\) (mm)

20

System return oil pressure \(p_{\text{0}}\) (MPa)

0.5

Proportional gain \(K_{\text{P}}\)

8

Force sensor gain\(K_{\text{f}} \;(\text{V}/\text{kN})\)

0.0769

External leakage coefficient \(C_{{\text{ep}}}\) (mm³·(s·MPa)^{− 1})

0

Internal leakage coefficient \(C_{{\text{ip}}}\) (mm³·(s·MPa)^{− 1})

238

Conversion mass \(m_{\text{t}} \;\text{(kg)}\)

1.1315

Effective bulk modulus \(\beta_{\text{e}}\) MPa

800

Load stiffness \(K\;(\text{kN}/\text{m})\)

450

Viscous damping coefficient \(B_{\text{p}} \;(\text{k}N/(\text{m} \cdot \text{s}^{ - 1} \text{)})\)

2

Conversion coefficient \(K_{\text{d}} \;(\text{m}{\text{m}}^{2} /\text{s)}\)

124.8