S
Hi,
I am trying to control a motor using PID control using the Texas Instruments DSP board, tms320c31. I would just like someone to tell me if I used the right PID control equation. I used the bilinear transformation 2/T(z-1)/(z+1) to
transfer the time equation y(t) = kpe(t) + ki*(integral of e(t)) + kd de(t)/dt
and obtained the difference equation
y)n) = y(n-2) + k1e + k2e(n-1) +k3e(n-2)where K1 = Kp + 2Kd/T + K1T/2
K2 = KiT - 4Kd/T
k3 = KiT/2 + 2Kd/T - Kp
but it is not working..instead of converging to the setpoint it is diverging. What I did was just use arbitrary values for the gains (i.e without modelling) so I don't kn ow if that is the problem. I know that varying the gains will
affect the system but I didn't think to such extent. Any advice?
Thanks,
Shelly
I am trying to control a motor using PID control using the Texas Instruments DSP board, tms320c31. I would just like someone to tell me if I used the right PID control equation. I used the bilinear transformation 2/T(z-1)/(z+1) to
transfer the time equation y(t) = kpe(t) + ki*(integral of e(t)) + kd de(t)/dt
and obtained the difference equation
y)n) = y(n-2) + k1e + k2e(n-1) +k3e(n-2)where K1 = Kp + 2Kd/T + K1T/2
K2 = KiT - 4Kd/T
k3 = KiT/2 + 2Kd/T - Kp
but it is not working..instead of converging to the setpoint it is diverging. What I did was just use arbitrary values for the gains (i.e without modelling) so I don't kn ow if that is the problem. I know that varying the gains will
affect the system but I didn't think to such extent. Any advice?
Thanks,
Shelly