Linear cartesian path planning

[joao-pm-santos96]

Hi developers!
This package really seams to achieve wonderful results! Congratulations!

I have one question: is it possible to build a plan where the TCP/end-effector follows a linear trajectory?

Thank you!

[marip8]

Nominally yes. Trajopt can accept joint waypoints or Cartesian waypoints, and it represents movement between these waypoints in joint space (i.e. a joint-interpolated arc, rather than a straight linear line). However, if your waypoints are spaced closely enough together and are on your linear trajectory, the joint-interpolated arc between waypoints approximates a line.

If you're using trajopt through tesseract, you can denote the MoveInstructions of your motion planning input as LINEAR moves; then the SimplePlanner (which generates a seed trajectory for Trajopt) will do linear interpolation between those waypoints at some specifiable density to approximate a line. Then Trajopt will optimize the trajectory per the other constraints that were added to the optimization

trajopt_ifopt also has a Cartesian line constraint that you could check out. I'm not entirely sure how it works or if it has been thoroughly tested though

[joao-pm-santos96]

Thank you for the detailed explanation! That is beautiful!

[joao-pm-santos96]

Also, if you may help, where can I find the list the possible constraints and/or costs that we can add to the request?

[marip8]

The headers in trajopt_ifopt provide a conceptual overview of what constraints are available. I think the only one that hasn't been ported from trajopt is the singularity avoidance constraint.

The tesseract default trajopt composite profile and plan profile also set up some default constraints that you can enable/disable and set different cost values for