摘要 |
A torque command value and an acceleration detection value are accumulated when a driven portion is subjected to acceleration/deceleration driving, and, from a ratio between the two, inertia of a movable portion is calculated. By executing the acceleration/deceleration driving about a position where influence of gravity torque is zero, the influence of the gravity torque included in the torque command value before and after the center position is offset, whereby inertia can be estimated correctly even with a machine structure in which the influence of gravity differs depending on the position of the motor. |