Moment of Inertia and the Inertia Setting

The moment of inertia is defined as “the ratio of the torque applied to a rigid body and its resistance to motion”. This value is typically referred to as “the moment of inertia”, “inertia”, or “GD2”. When the Manipulator operates with additional objects (such as an end effector) attached to the shaft, the moment of inertia of load must be considered.

CAUTION

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The moment of inertia of the load (weight of the hand and workpiece) must be 0.05 kg·m² or less for LA3-A and 0.12 kg m² for LA6-A. The LA-A series Manipulators are not designed to work with a moment of inertia exceeding 0.05 kg·m² for LA3-A and 0.12 kg m ² for LA6-A. Always set the value corresponding to the moment of inertia. Setting a value that is smaller than the actual moment of inertia may cause errors, shock and insufficient function of the Manipulator. Also, the life cycle of parts may be shortened and positional gap due to belt tooth bumping may occur.

The acceptable moment of inertia of load

• LA3-A

  • Rated weight: 0.005 kg·m²
  • Max.: 0.05 kg·m²

• LA6-A

  • Rated weight: 0.01 kg·m²
  • Max.: 0.12 kg·m²

If the moment of inertia of the load exceeds the rated weight, change the setting of the moment of inertia parameter of the Inertia command. After the setting is changed, the maximum acceleration/deceleration of Joint #4 during PTP motion that corresponds to the "Inertia" value is corrected automatically.