The jitter comes from closing the command loop around a delayed TCP position. Do not calculate each Cartesian target from the latest returned pose. Maintain the outgoing reference as independent command state, update that state from the 3D mouse, and transmit a reference every robot update cycle.
Identify the delayed-feedback failure
The robot reports TCP position every 10–20 ms, while communication delay is around 100 ms. If the reported position is approximately 100 ms old, it trails the command stream by about 5–10 update intervals. Recalculating new destination = returned position + mouse delta can therefore place a new target behind the robot's present position, producing reversal or stop-start motion.
| Signal | Observed timing | Control consequence |
|---|---|---|
| TCP position report | Every 10–20 ms | Frequent reports do not eliminate transport delay. |
| Communication delay | Around 100 ms | The received pose may represent an earlier robot state. |
| Cartesian target | Required every 10–20 ms | Suppressing updates or repeatedly holding a completed target can stop motion. |
Maintain an independent Cartesian command state
Initialize the command state from a known TCP position, then integrate mouse increments into the previous commanded target instead of re-anchoring every command to delayed feedback. Continue transmitting the command state every 10–20 ms. Use returned TCP data for monitoring and reconciliation, but not as the direct base of every incremental command.
At initialization:
target = known TCP position
Every command cycle:
read available mouse delta
target = target + mouse delta
send target to robot
Independently:
receive reported TCP position
use it for monitoring and verification
This separates command generation from asynchronous feedback. Any correction that reconciles target state with reported position requires a defined delay model and robot-interface behavior; the evidence does not provide enough information to specify such a predictor safely.
Use velocity references for continuous teleoperation
If the robot interface supports velocity references, map the 3D mouse direction and amplitude to commanded TCP velocity and refresh that reference every cycle. This avoids constructing a moving position target from a stale position report and directly expresses the operator's intent to continue moving.
A hybrid design can use position control for low mouse amplitude and velocity control for high amplitude, combining fine positioning with larger continuous moves. The switching threshold, scaling, and transition handling are not specified by the evidence and must be selected and validated for the actual robot interface.
Verify the correction
- Log the returned TCP pose, outgoing target or velocity reference, mouse input, and timestamps on the same time base.
- Confirm that every 10–20 ms command cycle transmits a reference, regardless of whether a new pose report or mouse update arrived.
- For position control, verify that the target derives from the prior command state rather than directly from the delayed TCP report.
- During a steady forward input, check that the outgoing reference does not reverse because an older TCP sample arrived.
- If using velocity control, verify that mouse direction and amplitude produce the intended velocity direction and magnitude, and that the reference continues to refresh each cycle.
FAQ
Why does my robotic arm move backward with a Cartesian target?
Around 100 ms of communication delay can make the returned TCP position approximately 5–10 update intervals old when updates occur every 10–20 ms. Adding a mouse delta to that stale pose can generate a target behind the robot's present position.
How should I update a robot Cartesian target with communication delay?
Maintain an independent target state, add each mouse delta to the previous commanded target, and transmit that state every 10–20 ms. Do not rebuild every target directly from the delayed returned TCP position.
Should a 3D mouse command robot position or velocity?
Velocity references better represent continuous direction and amplitude input when the robot interface supports them. A hybrid approach can retain position control for low-amplitude fine motion and use velocity control for higher-amplitude motion, but its switching threshold requires system-specific validation.
