US 7,030,585 B2 · Controller

Abstract

A controller capable of preventing response delay and generation of vibrations attributable thereto during position control of a movable part of a machine having low rigidity. A motor for driving a machine having low rigidity is subjected to position and velocity loop control. Compensation amount Q1 proportional to command velocity obtained by differentiating a position command and compensation amount Q2 proportional to second-order differentiated command acceleration are obtained. Compensation amounts Q1 and Q2 are added together, thus obtaining a velocity offset amount Vof corresponding to a estimated torsion amount. A differentiated value of the velocity offset amount is multiplied by coefficient β to obtain a torque offset amount Tof. The velocity offset amount Vof is added to a velocity command Vcs obtained by position loop control 1. The torque offset amount Tof is added to a torque command Tc outputted in velocity loop control 2, and the result is used as a drive command to the motor. Based on the velocity and the torque offset amount Vof and Tof, a torsion amount between motor 3 and the machine is controlled. The machine position and velocity are controlled with accuracy by regular position and velocity loop control.

Claims20

Dependent claims

A controller for controlling a servomotor for driving a movable part of a machine such that a position of the movable part is controlled by performing a position loop control based on a position command and a detected motor position to obtain a velocity command and by performing a velocity loop control based on the velocity command and a detected motor velocity to obtain a torque command for the servomotor, said controller comprising:

velocity command determining means for obtaining a compensated velocity command for the velocity loop control by adding a velocity offset amount, proportional to a command acceleration and corresponding to a torsion amount, to the velocity command outputted by the position loop control;
torque offset calculation means for calculating a torque offset amount based on a differentiated value of the velocity offset amount;
and
torque command determining means for obtaining a compensated torque command for the servomotor by adding the torque offset amount to a torque command outputted by the velocity loop control performed based on the compensated velocity command.

1 more element

A controller for controlling a servomotor for driving a movable part of a machine such that a position of the movable part is controlled by performing a position loop control based on a command position and a detected motor position to obtain a velocity command and by performing a velocity loop control based on the velocity command and a detected motor velocity to obtain a torque command for the servomotor, said controller comprising:

velocity offset calculation means for obtaining a velocity offset amount by adding a first offset amount proportional to a command velocity and a second offset amount proportional to a command acceleration;
velocity command determining means for obtaining a compensated velocity command for the velocity loop control by adding the velocity offset amount to the velocity command outputted by the position loop control;
torque offset calculation means for calculating a torque offset amount based on a differentiated value of the velocity offset amount;
and
torque command determining means for obtaining a compensated torque command for the servomotor by adding the torque offset amount to the torque command outputted by the velocity loop control performed based on the compensated velocity command.

2 more elements

A controller for controlling a servomotor for driving a movable part of a machine so as to control a position of the movable part, comprising:

first position control means for obtaining a first velocity command based on a position deviation between a command position and a detected rotational position of the servomotor;
second position control means for obtaining a second velocity command based on a position deviation between the command position and a detected position of the movable part of the machine;
calculation means for calculating a velocity command difference obtained by subtracting the first velocity command from the second velocity command;
velocity control means for performing a velocity loop control based on a velocity command and a detected rotational velocity of the servomotor to obtain a torque command for the servomotor;
velocity offset calculation means for obtaining a velocity offset amount as a high frequency component of a difference obtained by subtracting the velocity command difference from an offset amount proportional to a command acceleration;
torque offset calculation means for calculating a torque offset amount based on a differentiated value of the velocity offset amount;
velocity command determining means for obtaining the velocity command to said velocity control means by summing a low frequency component of the velocity command difference, the first velocity command and the velocity offset amount;
and
torque command determining means for to obtaining a compensated torque command for the servomotor by adding the torque offset amount to a torque command outputted from said velocity control means.

6 more elements

Dependencies are inferred from the claim text.

Controller

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Controller

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Abstract

Claims20