Hi Dejan, Assuming that you're running with a fairly standard PR2 configuration, the laser controller that you're running is documented here: http://www.ros.org/wiki/pr2_mechanism_controllers/LaserScannerTrajController The* set_periodic_cmd *service call can execute only a subset of the profiles that are possible with *set_traj_cmd*. *set_periodic_cmd *can only do triangle wave profiles where the laser moves the same speed on both the up and down sweep. The *set_traj_cmd* lets you specify all the timepoints of the trajectory, giving much more flexibility. Suppose you have a periodic command with period=4, amplitude=2, and offset=1. The equivalent trajectory command would have the following timepoints: time_from_start=0, pos=3 time_from_start=2, pos=-1 time_from_start=4, pos=3 Hopefully this helps! Vijay On Sat, Sep 11, 2010 at 3:31 PM, Dejan Pangercic wrote: > Hi there, > I noticed that there are 2 ways to configure laser_tilt_controller, > one with pr2_msgs/LaserTrajCmd (as in e.g. pr2_move_base, > pr2_move_base.py) message and > second with a pr2_msgs/PeriodicCmd (as in e.g. send_periodic_cmd.py). > What is the actual difference? Can one somehow find the mapping > between > their values? > > I have a case where I drive(using pr2_2dnav) around with the PR2, halt > at the certain locations and map the environment. The tilting rate at > mapping has to of course be significantly slower that the one needed > by the "pr2_2dnav" application which requires constant back-and-forth > reconfiguration. So far my preferred method of configuring the > laser_tilt_controller was by using the send_periodic_cmd.py program > but then I do not seem to be able to hit the same configuration as > done by the "pr2_2dnav" which consequentially results in sloppy > performance by the latter. > So if the mapping between both messages is possible I'd be > tremendously glad to learn about. > > thx and cheers, D. > > -- > MSc. Dejan Pangercic > PhD Student/Researcher > Intelligent Autonomous Systems Group > Technische Universität München > Telephone: +49 (89) 289-26908 > E-Mail: dejan.pangercic@cs.tum.edu > WWW: http://ias.cs.tum.edu/people/pangercic > _______________________________________________ > ros-users mailing list > ros-users@code.ros.org > https://code.ros.org/mailman/listinfo/ros-users > -- Vijay Pradeep Systems Engineer Willow Garage, Inc. vpradeep@willowgarage.com