Patent ID: 8222853
Filing Date: 2012-07-17
Classification: H02P

Abstract:
1. A servo motor control apparatus, having a feedback loop which obtains an amount of deviations from command information notified from outside and information on a rotational operation detected by a detection section, performs arithmetic operation processing on the deviation amount by use of a predetermined control parameter group including a control gain, and controls a rotational operation of a servo motor by a rotation control signal generated by the arithmetic operation processing, to perform feedback control such that the rotational operation of the servo motor tracks the command information, the apparatus comprising: an oscillation detecting section, which detects oscillation of the feedback loop, to output an oscillation detection signal indicating a result of the detection; a parameter operating section, which gives an operational instruction to set a control parameter in the control parameter group of the feedback loop based upon the oscillation detection signal; and an updating section, which is supplied with a set value for setting a control parameter, and sets the control parameter in the feedback loop while making an update thereon in accordance with the operational instruction given by the parameter operating section, wherein the updating section includes: a stiffness value updating section, which is supplied with a stiffness value in accordance with stiffness of a load of the servo motor as the set value, and outputs the stiffness value while making an update thereon in accordance with an operational instruction of the parameter operating section; and a parameter setting section, which converts the stiffness value of the stiffness value updating section into a plurality of control parameter values, and supplies each of the converted control parameter values to the feedback loop, to set the values therein, and when the oscillation detection signal indicates detection of oscillation, in accordance with an operational instruction of the parameter operating section, the stiffness value updating section returns a most recently updated and set stiffness value back to a previous stiffness value, and supplies this turned-back stiffness value to the parameter setting section; when the oscillation detection signal indicates no detection of oscillation, the parameter operating section gives the updating section an operational instruction to set a control parameter in accordance with the supplied set value, and when the oscillation detection signal indicates detection of oscillation, the parameter operating section gives the updating section an operational instruction to set such a control parameter as to narrow a frequency band width of the feedback loop.