Il 13/09/2010 12:27, Andy Pugh ha scritto: > On 13 September 2010 10:51, Spiderdab<77...@tiscali.it> wrote: > > >> than, as Brian suggest is interesting, but i really cannot know the >> formulas of the arcs i'm drawing. >> also writing by hand the acceleration like g1 f100, g1 f150, g1 f220, g1 >> f400.... you know, the show is like 5 minutes of a volleyball doing >> maybe 80 arcs in the air!! cannot write all by hand!! >> > It's fairly simple mathematics. > yes i know, but i can't write them.. > Excel can probably do it, (using the goal-seek algotithms). In flight > the path of the ball is governed by well-known ballistic equations. > Given a start-point, velocity and launch angle and an end-point the > rest is a simple piecewise calculation. > I think it is worth getting it right, as I suspect that we have a much > better idea of what objects in flight behave like (or we could never > catch them, or hit them) and if the trajectories are unrealistic I > think it will detract from the effect. > > I was about to start on a spreadsheet to generate ballistic > trajectories as G-code, then remembered that I am at work and paid to > do other stuff. When do you need this project working? > you're a gentleman.. maybe i just need a little example to start, than i can improve that so i'm not going to take away time from your work. (but tell me truth, which is more interesting? :-)
my stuff must work for the end of this week, now i'm improving the hardware, drums, changing cables with different dyneemas, and looking for the best way to rig the ball, and the right amount of water to put in it!!! >> 1) immagine the ball flyng at 30mt/min in one direction, and then >> suddenly the direction become opposite. the ball bounces for the >> 'impact' (sorry for my poor english..) and the stepper motors loose some >> step. >> > This is the reason that EMC defines a max accelleration in the INI > file. You should be able to set this such that you never lose steps. > > >> 2) tryed to use in the .ini file a slow acceleration, but using that it >> return me error when i jog in world mode. i realized that the slower is >> acceleration, the slower is the jog speed that i can reach without >> errors in world mode. >> > This happens when the STEPGEN_MAXACCELL is lower than the > MAX_ACCELERATION in the INI file. Generally the stepgen should have a > higher number than the max_accel. > I think you need to set these values to the actual physical maximum of > the axes (with a bit of overhead) and the control the trajectory with > feedrate. > yes, i'm following the rule of STEPGEN_MAXACCEL greater than the MAX_ACCEL, but the only way not to have errors is to set them at very high number, right now:375000 and 300000. i would like to use for base acc 10000.. anyway this is my .ini, if can be helpful: [EMC] MACHINE = Volley DEBUG = 0x7FFFFFFF [DISPLAY] DISPLAY = axis EDITOR = gedit POSITION_OFFSET = RELATIVE POSITION_FEEDBACK = ACTUAL MAX_FEED_OVERRIDE = 1.2 INTRO_GRAPHIC = emc2.gif INTRO_TIME = 2 PROGRAM_PREFIX = /home/dab-cnc/emc2/nc_files/tetrapod INCREMENTS = 50mm 10mm 5mm 1mm .5mm .1mm .05mm .001mm .0001mm [TASK] TASK = milltask CYCLE_TIME = 0.010 [RS274NGC] PARAMETER_FILE = emc.var [EMCMOT] EMCMOT = motmod COMM_TIMEOUT = 1.0 COMM_WAIT = 0.010 BASE_PERIOD = 55555 SERVO_PERIOD = 1000000 [HAL] HALFILE = Volley.hal HALFILE = custom.hal POSTGUI_HALFILE = custom_postgui.hal [TRAJ] AXES = 4 COORDINATES = X Y Z A LINEAR_UNITS = mm ANGULAR_UNITS = degree CYCLE_TIME = 0.010 DEFAULT_VELOCITY = 300.00 MAX_LINEAR_VELOCITY = 3000.00 [EMCIO] EMCIO = io CYCLE_TIME = 0.100 TOOL_TABLE = tool.tbl [AXIS_0] to [AXIS_3] **they are equal** TYPE = LINEAR HOME = 2900.0 MAX_VELOCITY = 3000.0 MAX_ACCELERATION = 300000.0 STEPGEN_MAXACCEL = 375000.0 SCALE = 5.26142716212 FERROR = 2.0 MIN_FERROR = 1.0 MIN_LIMIT = -3000.0 MAX_LIMIT = 4000.0 HOME_OFFSET = 2900.0 thanks, davide. ------------------------------------------------------------------------------ Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing http://p.sf.net/sfu/novell-sfdev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
