The following table describes how to setup a robot that includes pairs of motors that operate in unison to drive individual axes of the robot. Typically, this special control technique is employed for the X-axis of a gantry robot where an X motor is placed on each side of the cross beam.
Refer to the details on your Kinematic Module to determine if this feature is available for your robot model.
For a detailed description of this setup, please see the Split-Axis Control documentation.
| Setup 3-Split: Split-Axis control mode | ||
|---|---|---|
| Function | Action / DataID's | See Also |
| Split-axis mask |
Perform Setup 2A to define the number of robots and axes. During this process, set bits in the "Split-axis mask" (2001) to enable split-axis control of individual axes. |
(Web) ... > Joint/Cartesian control > Basic parameters |
| Basic servo configuration | Perform Setup 2B. As you do this, ensure that you select a configuration that includes an extra servoed motor for the split-axis. For example, if you have an XYZ robot, select four servoed motors. |
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| Current loop |
Perform Setup 2C to setup the encoder and current loop for all motors including both motors of each split-axis. |
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| Commutation reference determination |
If the split-axes are not subject to gravity loading or excessive friction, perform Setup 2D for finding the commutation reference in the normal fashion. Otherwise, see the Split-Axis Control documentation for additional information. |
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| Position loop | Perform Setup 2E to configure the position loop for all motors. Normally, split axes motors should have very similar tuning constants. In some cases, it may be helpful to turn on the "Split axis cross-coupling gain" (10339) and "Cross-coupling error SPR filter pole, Hz" (10341). This adds another term to the PID computations that assists in keeping the split axes aligned. |
(Web) ... > Servo parameters > Compensation |
| Joint and Cartesian control | Execute Setup 2F in the standard fashion to initialize the Joint and Cartesian control parameters. Define one extra parameter in the "Joint to motor scale factors" (2300) for each extra motor added for a split axis. |
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| Homing sequence | Perform Setup 2G to set the zero position and limit stops. To ensure that split-axis motors are not driven independently, set the "Homing sequence" (2802) and the "Homing order" (2810) to either home all motors simultaneously or home split-axis motors simultaneously. |
(Web) ... > Joint/Cartesian control > Homing/jogging |
| Power on alignment speed | Set the "Homing speed 1, ecnts/sec" (2804) to a slow speed value so that split-axis motors will move slowly into alignment each time that motor power is enabled. |
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