Hi, you are correct it's not right in this case. (I didn't follow the exact calls, but if it's like you did, then you're right). It should probably be defined in the ini, at least as sane velocities for TRAJ.
I am not sure how to limit the velocities based on joints - that depends on kinematics _and_ on the position/move of the joint(s). If you have a suggestion how to do this, I'm all ears. Regards, Alex From: Yi-Shin Li Sent: Tuesday, November 10, 2009 5:55 PM To: EMC developers Subject: Re: [Emc-developers] the trajectory planner might not besuitableforany machines with non-trivial kinematics Hi Alex, Take configs/sim/sim_xyzbc.ini as an example: it has JOINT_* sections for joint parameters its AXIS_* sections are basically empty it take gantrykins emccanon.cc::getStraightAcceleration() was called for trajectory planning. It calls emcAxisGetMaxAcceleration() for AxisConfig[axis].MaxAccel, the MaxAccel of corresponding axis. MaxAccel is set by emcAxisSetMaxAcceleration() at iniaxis.cc::loadAxis(). In this configuration, it doesn't define MAX_ACCELERATION for AXIS_* sections. Therefore, the MaxAccel is set as the 1.0, the DEFAULT_AXIS_MAX_ACCELERATION. As a result the velocity/acceleration is way too small while running G-code. IMHO, we can calculate the MaxAccel of each AXIS(x,y,z,a,...) based on kinematics and corresponding JOINT settings. What's your opinion? Yishin On Mon, Nov 9, 2009 at 4:29 PM, Alex Joni <[email protected]> wrote: Hi Yishin, actually in this case (emccanon.cc) it is correct. The calculations you are looking at are for the X axis. The X axis is the same no matter what machine you have. It is further down (in the motion controller, trajectory planner) that this X move would have to be scaled further based on _joints_ limits. Regards, Alex ----- Original Message ----- From: Yi-Shin Li To: EMC developers Sent: Sunday, November 08, 2009 2:01 PM Subject: Re: [Emc-developers] the trajectory planner might not be suitableforany machines with non-trivial kinematics Hi Alex, I've pulled the joints_axes3 branch, built and tried it. In this branch, the getStraightVelocity() and getStraightAcceleration() on emccanon.cc are not suitable for non-trivial kinematics yet. I will file a feature request on SourceForge later. Regards, Yishin On Thu, Nov 5, 2009 at 2:22 AM, Alex Joni <[email protected]> wrote: Hi Yi-Shin, unfortunately you are correct. There are some problems in the current version of emc2, that joints (motors) and axes (carthesian directions) are mixed in a couple of places. There is ongoing work (on the joints-axes3 branch) to fix this. But it's a lot of work (in a lot of layers and places), so there is no fixed timeline when it will be useable. Regards, Alex From: Yi-Shin Li Sent: Wednesday, November 04, 2009 6:13 PM To: emc-developers Subject: [Emc-developers] the trajectory planner might not be suitable forany machines with non-trivial kinematics Hello emc-developers, I was digging into an issue for SCARA Robot controlled by EMC2. That is, the angular acceleration for the first 2 joints is way too larger than the one set by its configuration file. After carefully analyzing the dumped trace, I found it might be caused by misleading trajectory planning results. I then found an interesting issue for the trajectory planner, i.e. it might not be suitable for any machines with non-trivial kinematics. Please take a look for the following code at getStraightAcceleration() on emccanon.cc: tx = dx? (dx / FROM_EXT_LEN(AXIS_MAX_ACCELERATION[0])): 0.0; For non-trivial kinematic machines, such as SCARA, the dx is contributed by several joints other than AXIS_0. However, the above code assume that it only depends on AXIS_0, which is not true for those machines. Therefore, the calculated accel/velocity for trajectory planner may be incorrect. Is my understanding for above statement correct? 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