Page 582 - Mechatronics with Experiments

JWST499-Cetinkunt
JWST499-c07
568 MECHATRONICS Printer: Yet to Come October 9, 2014 8:41 254mm×178mm
The initial conditions are
y (0) = 0.0 (7.668)
1
y (0) = 0.0 (7.669)
2
y (0) = 0.0 (7.670)
3
̇ y (0) = 0.0 (7.671)
1
̇ y (0) = 0.0 (7.672)
2
̇ y (0) = 0.0 (7.673)
3
2
p (0) = (m + m ) ⋅ 9.81∕A he = (9.81) ⋅ 110 000 N∕m (7.674)
he
2
3
p (0) = 0.0 (7.675)
re
3
V (0) = 0.01 m (7.676)
he
V (0) = 0.01 m 3 (7.677)
re
The input conditions are
y (t) = 0.0 (7.678)
0
F load (t) = 0.0; 0 ≤ t ≤ 2.0 s (7.679)
= 10 000 N; 2.0 < t ≤ 6.0 s (7.680)
= 0.0; 6.0 < t ≤ 10.0 s (7.681)
x (t) = 0.0 (7.682)
s
6
2
p (t) = 20 ⋅ 10 N∕m constant (7.683)
P
which simulates a case of response of all three inertias and pressures on both sides of the
cylinder when the valve is in neutral position and a sudden change occurs on the load
(Figure 7.106). Other conditions of valve control and the resulting behavior of the system
can be easily simulated by specifying the valve spool motion as a function of time or as a
control signal from a closed loop control logic. Here, we assumed that we used a valve with
symmetric orifice geometry between all ports (pump to head-end, rod-end to tank, head-end
to tank, pump to rod-end). In this particular simulation, the flow coefficients do not affect
the simulation results because the valve is in neutral position and leakage through the valve
at neutral position is neglected. However, the valve orifice geometry between ports has an
important effect on the system transient response when the valve spool is in flow regulating
mode of operation, that is when the valve spool is positioned outside the deadband region
and allows flow between ports.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%Filename: Sim381.m
% Sim381.m

t_0 =0.0;
t_f =10.0 ;
t_sample = 0.001 ;
z=zeros(8,1);
z(1) = 0.0 ;
z(2) = 0.0 ;
z(3) = 0.0 ;
z(5) = 0.0 ;
z(5) = 0.0 ;
z(6) = 0.0 ;
z(7) = 1100∗9.81/0.01 ;
z(8) = 0.0 ;