Method of feedforward control for servomotor
AssigneeFanuc Corporation
InventorYasusuke Iwashita
Life of this patent
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Abstract
A control method of a servomotor, such that a moving command for position-velocity processing, which is executed in every sampling period obtained by dividing a distribution period of moving commands into N units of equal parts, is determined from the above described moving commands of the distribution period. A velocity compensatory component is obtained on the basis of a moving command in a distribution period preceding by one period the present distribution period and is added to a velocity command, and an acceleration compensatory component obtained on the basis of a moving command preceding the time of the present position-velocity loop processing is added to a torque command, so that the phase of acceleration compensatory data is advanced from that of velocity compensatory data in feedforward operations.
Claims11
A method of feedforward control for a servomotor, to control the servomotor through position-velocity loop control to be executed by a moving command in each sampling period obtained by dividing a present distribution period of the moving command into N equal parts, said method comprising the steps of:
- reading a moving command in a distribution period preceding by one period the present distribution period to determine a moving command for each position-velocity loop processing, multiplying the determined moving command by a positional feedforward coefficient to produce a positional feedforward amount, performing positional loop processing to obtain a velocity command, and adding the position feedforward amount to the velocity command obtained by positional loop processing to determine the velocity command with respect to velocity loop processing;
- and
- determining a moving command preceding the time of the present position-velocity loop processing, multiplying a differentiated value of the obtained moving command by a velocity feedforward coefficient so produce a velocity feedforward amount, performing velocity loop processing to produce a torque command, and adding the velocity feedforward amount to the torque command obtained by velocity loop processing to determine a torque command to the servomotor.
A method of feedforward control for a servomotor, to control the servomotor through position-velocity loop control to be executed by a moving command obtained in each sampling period obtained by dividing a moving command obtained in each sampling period obtained by dividing a present distribution period of the moving command into N equal parts, said method comprising the steps of:
- reading a moving command in a distribution period preceding by one period the present distribution period to determine a moving mean value of moving commands corresponding to N units of position-velocity loop processing periods centering around the period of each position-velocity loop processing, multiplying the determined moving mean value by a positional feedforward coefficient to produce a positional feedforward amount, performing positional loop processing to determine a velocity command, and adding the positional feedforward amount to the velocity command obtained by positional loop processing to determine the velocity command with respect to velocity loop processing;
- and
- determining a moving mean value of moving commands corresponding to N units of position-velocity loop processing periods centering around the time preceding the period of the present position-velocity loop processing, multiplying a differentiated value of the obtained moving mean value by a velocity feedforward coefficient to produce a velocity feedforward amount, performing velocity loop processing to produce a torque command, and adding the velocity feedforward amount to the torque command obtained by velocity loop processing to determine a torque command to the servomotor.
A method of feedforward control for a servomotor, to control the servomotor through position-velocity loop control to be executed by a moving command in each sampling period obtained by dividing a present distribution period of the moving command into N equal parts, said method comprising the steps of:
- reading a moving command in a distribution period preceding by one period the present distribution period to determine a moving command for each position-velocity loop processing, to produce a velocity compensatory component;
- determining a moving average value of moving commands corresponding to N units of position of moving commands, corresponding to N units of position-velocity loop processing periods centering around the period preceding the period of the position-velocity loop processing used to obtain the velocity compensatory component, differentiating the moving average value and multiplying the differentiated value by a velocity feedforward coefficient, to produce an acceleration compensatory component;
- performing velocity loop processing using the velocity compensatory component to produce a torque command;
- advancing a phase of the acceleration compensatory component from that of the velocity compensatory component;
- and
- adding the phase advanced acceleration compensatory component to the torque command, to produce a new torque command to the servomotor.
Dependencies are inferred from the claim text.