Coordinate Conversion

Coordinate conversion of the Force Sensor refers to converting the output values of the Force Sensor to the force and torque in the force coordinate system.
All of the force functions are performed in the force coordinate system. Coordinate conversion is always performed automatically.
The force coordinate system can be set by the force coordinate object. The force functions are performed while dynamically switching between the coordinate systems.
Even if the coordinate conversion is used, the output value of Force Sensor does not change. When the output value of Force Sensor has exceeded the rated value, even if the displayed value is within the rated value of Force Sensor, a 5548 error occurs.

CAUTION

If the flange offset or force coordinate object is set incorrectly, the output values of the Force Sensor are converted to the force and torque in a wrong coordinate system. If the force control function is performed in this state, the force control function may perform an unintended operation. Configure the settings carefully, and first verify the operation and then perform the force control function.

Correspondence between the Force Sensor Coordinate System and Tool Coordinate System
To perform coordinate conversion of the output values of the Force Sensor, you need to set the flange offset which means a relative relation between the Force Sensor and the robot.
The physical meaning of the flange offset is the amount of offset by the sensor flange. For the flange offset, use the bottom center position of the Force Sensor viewed from the tool 0 coordinate system of the robot as the origin and set the position and posture of the coordinate system so its direction aligns with the Force Sensor coordinate system.
The offset depending on the robot mounting method using the Epson sensor flange is as follows.

Manipulator model
Sensor model
Mounting type

Flange Offsets

(X, Y, Z, U, V, W)
C4 series S250N Table top mounting (0, 0, 5, 0, 0, 0)
Ceiling mounting (0, 0, 5, 180, 0, 0)
C8 series S250L, S250P Table top mounting (0, 0, 5, 0, 0, 0)
Ceiling mounting (0, 0, 5, 180, 0, 0)
Wall mounting (0, 0, 5, 0, 0, 0)
C12 series S250L Table top mounting (0, 0, 5, 0, 0, 0)
N2 series S250H Table top mounting (0, 0, 5, 0, 0, 0)
Ceiling mounting (0, 0, 5, 180, 0, 0)
N6 series SH250LH Table top mounting (0, 0, 0, 0, 0, 0)
Ceiling mounting (0, 0, 0, 180, 0, 0)
G3, G6, GX4, GX8 series S2503, S2506 All (0, 0, -22, 180, 0, 180)
G10, G20, GX10, GX20 series S25010 (0, 0, -24, 180, 0, 180)
RS series S2503 (0, 0, -22, 180, 0, 180)

When you make a sensor flange yourself, measure the offset and set the flange offset.
The flange offset can be set in the flange offset can be set in [System Configuration]-[Controller]- [Force Sensor]-[Sensor*] or by the F_FlangeOffset statement. For details on the setting procedure, refer to the following section and manual.

Correspondence between the Tool Coordinate System and Force Coordinate System
The force coordinate system is a coordinate system with an offset from the tool coordinate system. Therefore, when the tool tip of the robot moves or the offset of the selected tool coordinate system is changed, the force coordinate system also moves following the movement or change.
The offset of the force coordinate system is set in the force coordinate object.
The origin of the force coordinate system is defined by the offset from the currently selected tool coordinate system using the Position property.
The orientation of the force coordinate system can be selected from the following coordinate systems. The Orientation property is used.

  • Base coodinate system
    The orientation of the coordinate system is always aligned with the base coordinate system. It does not change even though the posture of the robot or the tool setting is changed.
  • Local Coordinate System
    At the same time, select the number of the local coordinate system to be used. The orientation of the coordinate system is always aligned with the local coordinate system with the selected number. It does not change even though the posture of the robot or the tool setting is changed.
  • Tool Coordinate System
    The orientation of the coordinate system is always aligned with the tool coordinate system. It changes according to the posture of the robot or the tool setting.
  • Custom coodinate system
    The values of the rotating movement from the tool coordinate system are set in U, V, and W simultaneously. The orientation of the coordinate system is the orientation with an offset from the tool coordinate system. It changes according to the posture of the robot or the tool setting.
    The force coordinate object can be set in [Force Editor] or by the FSet statement. For details on the setting procedure, refer to the following section and manual.

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