A self-commissioning controller 7 for a field-oriented elevator
motor controller 14 includes calculating an integral gain K I , a
proportional gain Kp, and an overall gain (Gc) for the motor controller;
obtaining initial values of a rotor time constant τ R , magnetizing current
Id, and motor torque constant K T for the motor controller 14, and
obtaining a value of a motor transient inductance Lσ; calculating final
values for said rotor time constant τ R and magnetizing current Id, using
said transient inductance Lσ; and calculating a system inertia J*
parameter for speed loop compensation 16 within the motor controller
14. The controller 7 may also include calculating the initial values for
τ R , Id, and K T *, and performing self-commissioning automatically upon
receiving a command from a service tool 80.

Self-commissioning controller for a field-oriented elevator motor/drive system

A method and apparatus for tuning control loop parameters in a motion control system, is provided. In one embodiment, tuning of the proportional and integral gains of a servocontroller's velocity loop compensator is provided, as well as tuning of the cutoff frequencies of the servocontroller's low pass filters. In this embodiment, random noise excitation is added to the velocity command during a plurality of movement types for a machine tool axis. During each movement type, frequency response measurements are taken. Then, a composite frequency response can be selected by concatenating portions of the various frequency response measurements, so as to simulate a worst case scenario for the machine tool axis. From this composite response, an open loop response can be calculated and displayed, as well as bandwidth, phase margin, and gain margin values. The user can then enter the compensator parameters which were used when this data was taken, as well as proposed parameters. The system can automatically predict, or simulate, the effects of the proposed parameters on bandwidth, gain margin, and phase margin, based upon the composite data. Accordingly, the user need not actually try out the proposed parameters on the machine. Moreover, the simulated responses for the proposed parameters are based upon actual frequency response data taken during actual operating conditions of the system, and, accordingly, the inaccuracies of using mathematical assumptions are avoided.

Method and apparatus for tuning control system parameters

A control apparatus is disclosed that comprises a primary proportional, integral, differential (APID@) controller capable of receiving a first setpoint and a first process variable and generating therefrom a second setpoint; and a secondary controller capable of receiving the second setpoint and a second process variable and generating therefrom an output control signal, wherein the primary PID controller is capable of receiving from the secondary controller a feedback signal 1) that indicates that a previous value of the second setpoint exceeds a limit associated with an output control signal of the secondary controller, and 2) that transfers a value of a signal from the secondary controller. The primary PID controller is then capable of limiting the contribution of the integral calculation component in a PID calculation that generates a new current value of the second setpoint. The integral calculation component may be excluded, included, or partially included in the PID calculation in order to efficiently minimize the effect of undesirable erratic output signals.

Systems and methods for limiting integral calculation components in pid controllers

In tuning a controller for a process in a feedback control system, a method is provided for bringing the system into asymmetric self-excited oscillations for measuring the frequency of the oscillations, average over the period value of the process output signal and average over the period control signal and tuning the controller in dependence of the measurements obtained. An element having a non-linear characteristic is introduced into the system in series with the process and set point signal is applied to excite asymmetric self-excited oscillations in the system. An algorithm and formulas are given for identification of the process model having the form of first order plus dead time transfer function. PI controller settings are given as a function of the dead time/time constant ratio. An apparatus for performing the method is disclosed.

Method and apparatus for tuning a PID controller

A PID filter employed in a timing recovery phase-locked loop (PLL) for synchronizing the sampling of a read signal from a magnetic read head in a sampled amplitude read channel for magnetic recording. In addition to a proportional and integral term, the PID filter comprises a derivative term to decrease the settling time of the PLL by increasing the phase margin and damping. Consequently, the PLL locks onto the acquisition preamble in a shorter period thereby reducing the necessary preamble length and maximizing storage area for user data. The derivative term of the loop filter is disabled during tracking mode in order to attenuate noise in the phase error and to reduce gain variance associated with tracking arbitrary user data. The structure of the PID loop filter is transformed into an alternative structure in order to minimize the computation path latency between delay registers to avoid limiting the speed of the read channel. To defeat possible harmonic lock conditions caused by non-linearities in the phase-locked loop, a frequency error is added to the accumulation path (integrating path) of the PID filter. A further transformation provides better range and resolution for the PID filter coefficients.

PID loop filter for timing recovery in a sampled amplitude read channel

An autotuning procedure for a PID-type controller employs a low frequency sine wave as an exciting input and models the controlled system as a second order linear system. The system is tuned to a desired damping ratio by following an overdamped trajectory, in closed loop gain and phase lag space, to the target closed loop gain and phase lag values on a locus of a desired damping ratio as based on that modeling system.

Chia P. Day

Papers

Automatic tuning apparatus for PID controllers