11.4. Motor Node
The movement of the motor can either be controlled in position or in velocity mode. If used in position mode, the positon can be set as absolute value or as relative change of the current position target.
Attention
The relative position target changes the previous position target and is not based on the current motor position. Thus, a rapid succession of relative position setpoints might move the position setpoint quickly outside the safe range.
11.4.1. Publishers
~/position
- Type
- Description
Current motor position in increments of the motion controller’s position encoder. The position is also converted to physical units [m] based on the conversion factor in the configuration.
~/velocity
- Type
- Description
Current motor velocity in RPM of the motor. The translational velocity of the respective gantry axis depends on the gear ratio. The conversion is performed based on the factor specified in the configuration file.
Note
The velocity is computed as difference quotient of the motor position.
~/motor_status
- Type
- Description
Contains several motor status values, such as if the motor is currently homing, if the target position is reached, or the status of the limit switches. See the message definition for details.
11.4.2. Subscriptions
~/setpoint/absolute_position
- Type
- Description
Absolute position target. Can be set either in motor increments or in physical units [m].
~/setpoint/relative_position
- Type
- Description
Relative position change. Can be set either in motor increments or in physical units [m].
~/setpoint/velocity
- Type
- Description
Velocity target for velocity control.