Hello Everyone,
I'm currently trying to implement a PID control on a fatigue loading machine. What I'm trying is creating a cyclic (sinusodial) load input as a pressure value, which is my SP, and try to track this by controlling a proportional hydraulic valve with PID.
I'm now pretty on the way of controlling the system for f=0.01Hz (load frequency). I have tuned the system with Ziegler-Nichols method (although I do not have much experience, I tried to implement the basics) However, I need a higher frequency to complete my loadings in a reasonable time (i.e 1 Hz), but when I start to increase the frequency, all I obtain is a chattering system with big deviations in the pressure and sometimes impact loading.
The question is; how can I modify a PID controller to track faster inputs? Does the maximum trackable frequency depend on the natural frequency of the overall system? If so, what can I do the increase the natural frequency ? (i.e will stiffening the frame help? etc.)
Thanks for your patience in reading this.
I'm currently trying to implement a PID control on a fatigue loading machine. What I'm trying is creating a cyclic (sinusodial) load input as a pressure value, which is my SP, and try to track this by controlling a proportional hydraulic valve with PID.
I'm now pretty on the way of controlling the system for f=0.01Hz (load frequency). I have tuned the system with Ziegler-Nichols method (although I do not have much experience, I tried to implement the basics) However, I need a higher frequency to complete my loadings in a reasonable time (i.e 1 Hz), but when I start to increase the frequency, all I obtain is a chattering system with big deviations in the pressure and sometimes impact loading.
The question is; how can I modify a PID controller to track faster inputs? Does the maximum trackable frequency depend on the natural frequency of the overall system? If so, what can I do the increase the natural frequency ? (i.e will stiffening the frame help? etc.)
Thanks for your patience in reading this.