| 26 | | Closed-loop motor control (including the Talons) typically uses PID control loops to achieve the mechanism's control objectives: balancing responsiveness with stability. PID control considers 3 factors (P, I, D) when deciding how to adjust motor power to balance responsiveness (how fast the motor responds to changes) with stability (not over/under shooting the target). Because motors drive different mechanisms with different loads, inertia, speeds, and responsiveness requirements, you must tune the PID factors properly for each Talon when you configure it for close-loop control; this email discusses in plain language what that means. |
| | 26 | Closed-loop motor control (including the Talons) typically uses PID control loops to achieve the mechanism's control objectives: balancing responsiveness with stability. PID control considers 3 factors (P, I, D) when deciding how to adjust motor power to balance responsiveness (how fast the motor responds to changes) with stability (not over/under shooting the target). Because motors drive different mechanisms with different loads, inertia, speeds, and responsiveness requirements, you must tune the PID factors properly for each Talon when you configure it for close-loop control; this page discusses in plain language what that means. |
| 36 | | PID is used to balance responsiveness and stability using 3 factors (P, I, D) that you can tune. When you configure your talon for closed loop control, you will need to set those 3 factors. There is no perfect setting, it's always going to be a trade off between responsiveness and stability, but you should experiment with different values to tune your mechanism properly (there are also mathematical approaches to tuning that I will not address here). |
| | 36 | PID is used to balance responsiveness and stability using factors P, I, D, and sometimes F that you can tune. When you configure your talon for closed loop control, you will need to set those 3 factors. There is no perfect setting, it's always going to be a trade off between responsiveness and stability, but you should experiment with different values to tune your mechanism properly (there are also mathematical approaches to tuning that I will not address here). |
| 37 | 37 | |
| 38 | 38 | * Proportion (P): Power is increased/decreased in proportion to how far the last measurement was from its goal (i.e. the instantaneous error): if far from goal, add a lot of power, if close to goal, add a little power). Adjusting P determines how responsive the system is. |
| 39 | 39 | * Integral (I): Power is increased/decreased in proportion to the average size and duration of the error: this accelerates movement towards the goal, increasing responsiveness, but increasing the tendency to overshoot goals (instability). |
| 40 | 40 | * Derivative (D): Power is increased/decreased in proportion to the rate at which the motor is approaching its goal (i.e. if the motor is not closing in fast enough, increase power, if it is closing in fast, decrease power); D increases stability by slowing the motor as it approaches its goal; this lets you increase P and I (responsiveness) without making the system unstable. |
