SLIN motion velocity Profile

Hello everyone,

I am working on a project that requires to discover the equations of motion for the SLIN motion, however i cannot find information about the velocity profile of this motion anywhere. Furthermore since it is only possible to define the maximum velocity in cartesian coordinates but not the acceleration, I cannot understand how the motion planner is able to create the trajectory with only the initial and final points and the maximum velocity.

Thank you in advance.

I am doing my master thesis on mechanical engineering which involves using SLIN motions to perform a trajectory with any given velocity profile

Quote from Fubini

Similar trajectory planning but third order for slin can be activated by setting $spl_vel_mode to #CART.

I have tested both the $spl_vel_mode #cart and $spl_vel_restr in simulation (KUKA SIM PRO with officelite) and they seem to give the same results to each other so it left me wondering what their pratical difference is since in the system variables manual I could not get a clear explanation.

Also when using SLIN with #CART the time it takes to get to the programmed acceleration is much bigger compared to LIN, I have increased $JERK.CP which resulted in a slight improvement but I was wondering if there is some way to further reduce this time?

Thank you in advance,

Quote from Fubini

What values are assigned to acceleration? What acc/jerk do you use for orientation?

In case of #opt axis specific values are used $acc_axis[], $gear_jerk[]. In case of #cart cartesian ones $acc and $jerk are used. This includes ori component.

Do you use inline forms or expert programs?

Also lookup system integrators manual. This stuff is explained in there and not the system variables documentation.

Fubini

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I use the INI folder to start the program and the rest is all written by me.

I am using 100 for jerk.cp and 0.2 for acc.cp, I did not change the values of acc/jerk for orientation because i was testing for a linear path with no change in the orientation.

In the tests I have done the jerk is always bigger near the programmed velocity than when the speed is closed to zero which I dont understand.

DEF slinvel()
INI
$BWDSTART = FALSE
PFAT_ACT = PDEFAULT
FDAT_ACT = FHOME
$H_POS = XHOME
PTP XHOME

$SPL_VEL_MODE = #CART
$JERK.CP = 100
$ACC.CP = 0.2
$VEL.CP = 0.4
SLIN {X 100}

WAIT SEC 0.1
$TRACE.NAME[]="slinvel"
$TRACE.MODE = #T_START
SLIN {X 1300}
WAIT SEC 0.1
$TRACE.MODE = #STOP

END

The trace channel used was KRCIpo CartVEL_CmdIpo and the acceleration was obtained by calculating the difference quotient.

The test was performed with a KUKA KR22 R1610-2 using SIM PRO and Officelite with KSS V8.3.38.

Thank you for the help.