Would you be able to provide a picture (or sketch) of the machine to clearly show the relative motions of xyza? On Nov 16, 2012 6:13 PM, "Martin Lederhilger" <martin.lederhil...@gmx.at> wrote:
> Hello, > > I have upgraded my 3-axis cartesian machine with a 4th rotatory axis, > which looks along the X-axis. In my g-code programs I want to use X, Y > and Z for the position of the tool's tip on the workpiece and A for the > angle between the z-axis and the axis of the tool - which is always in > the yz-plane. > > Therefore I have written a kinematics module, but it seems that I have > problems with the tool length compensation. Now I have the following > questions: > > In kinematicsForward and kinematicsInverse: What is the point EmcPose > 'world' exactly? Is it the absolute pose of the tool tip (like specified > in the g-code program) or is the tool length compensation already > applied by the interpreter? - In principle this could be possible since > A, (B and C) are known. Tool offsets could be specified in the tool's > coordinate system then. Then pose 'world' would be the mount point of > the tool in my case. This second option would be beneficial, because > then no kinematics module has to deal with tool length compensation. > > Or do I have to handle the tool length compensation by myself in the > kinematics via a HAL input pin which gets the tool length information > from motion.tool_offset_z or w? > > Before I had the 4th axis, I used trivkins, and it does not contain any > tool length compensation related code, but tool length compensation > already worked out of the box. So probably it is already applied by the > interpreter. But in the source code I have only found that the > tool_offset is added / subtracted to / from other poses. With a trivial > kinematic this is sufficient, but my tool's axis is not along x-, y- or > the z-axis - it is [0, -sin(A), cos(A)]. > > Does it matter which entry of the tool table (Z or W) I use for tool > length compensation? > > Maybe I have simply overlooked something. The rest of my kinematics > module works in principle (qualitative movement is OK, it seems to be > just off by the tool's length). > > One other thing: Does the AXIS user interface support displaying the > orientation of the tool. It seems that it always looks along the z-axis, > regardless of A. > > I am using LinuxCNC 2.5.1. By the way thanks for this great software. > > > Thank you in advance for your answers, > > Martin > > > > ------------------------------------------------------------------------------ > Monitor your physical, virtual and cloud infrastructure from a single > web console. Get in-depth insight into apps, servers, databases, vmware, > SAP, cloud infrastructure, etc. Download 30-day Free Trial. > Pricing starts from $795 for 25 servers or applications! > http://p.sf.net/sfu/zoho_dev2dev_nov > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ Monitor your physical, virtual and cloud infrastructure from a single web console. Get in-depth insight into apps, servers, databases, vmware, SAP, cloud infrastructure, etc. Download 30-day Free Trial. Pricing starts from $795 for 25 servers or applications! http://p.sf.net/sfu/zoho_dev2dev_nov _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
