jros wrote: > Yesterday we did our first trial with the new kinematics. > > It was really exciting!! :) > > But there was a shuden movement at the start of the homing sequence. > > We have programed the homing sequence so that all the joints goes > upwards at the same time. > > > We first tested with trivkins, and no problem. > > But wen using our kins (the only change is the kinematics loaded), and > pressing home, a sudden movement (it sounds like and impact: PUM!) of > the axis happens and the machine stops. > > If we manually move one machine axis, and press home again, > the homing sequence is performed without problem. > > We have to dig a little more to diagnose this (what are the exact > conditions that give rise to the PUM), but we would prefer to avoid the > quick movement when debbuging (to avoid machine fatige). > > I can put the motors appart, but I presume somebody out there would have > a better solution, like some changes in the configuration so that the > strongest signal sended to the motors being weak (we are using current > to control the motors -at least that is what we think-). >
The HAL PID block has the ability to limit the output range. Check the parameter "pid.N.max-output" on the PID man page, or at http://www.linuxcnc.org/docs/devel/html/man/man9/pid.9.html > Can you drive us in that or similar direction?. > > Can anybody figure the reason of the PUM? -may be too little information > right now-. The PUM is not mechanical not related with a particular > initial fisical position of the machine, because there is no singular > configuration, and every degree of fredom is free to move. Our > kinematiks exhibits coherent values for XYZRPW (0,0,0,0,0,0) and 012345 > (0,0,0,0,0,0) -in emc interface-, that are consistent with the > kinematics (they are a solution of the forward and of the reverse > kinematics). Homing of a parallel kinematics machine is untested, because none of the current developers has (or has access to) such a machine. If you provide details of what you see (including for example halscope screen captures and complete HAL and INI file listings), we will try to help. The motion controller provides many HAL pins and signals that can be observed with halscope. For a list refer to "man motion", or http://www.linuxcnc.org/docs/devel/html/man/man9/motion.9.html For example, you can trigger halscope on the rising edge of "axis.N.homing", and observe "axis.N.motor-pos-cmd" to see if there is some discontinuity in the commanded position. Likewise, you can (and probably should) add temporary add HAL parameters to your kinematics module, to make the Cartesian coordinates available for scoping. Regards, John Kasunich ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
