TMS320F280049C: Acceleration Control in MotorControl Lab is05

Hey TI - i found a work around.

I am not sure about the get and setAccel_rps2 functions.  The set seems to work on deceleration but not on acceleration. I assume these functions are not implemented?

I was able to get full control by changing the following line

float32_t  speed_maxDelta_Hz = (motorVars.speedRef_Hz/userParams.trajFreq_Hz);

to 

float32_t  speed_maxDelta_Hz = (motorVars.accelerationMax_Hzps/userParams.trajFreq_Hz);

Brett

Brett Nourrcier said:

motorVars.accelerationMax_Hzps does not work (i.e., it does not control motor acceleration/deceleration)

You have to set speed via motorVars.speedRef.Hz up or down to control PI speed. One problem is the PI speed control oscillates up/down 80Hz-97Hz unless speed is input >97Hz. The integral seems ridiculously low.

Brett Nourrcier said:

I was able to get full control by changing the following line

Yet this value was set very low in user.h was suggested trouble shooting guide to make 20Hzps.

//! \brief Defines maximum acceleration for the estimation speed profiles, Hz/sec
//!
#define USER_MAX_ACCEL_Hzps ((float32_t)(20.0))//2.0

Thanks GI.  I can control speed down to ~ 0 without issue.  One of the issues I found with out of the box TI speed control (with MotorControl) is the controller definitely relies on the USER_MOTOR_INERTIA_Kpgm2 setting (which was/is not the case on the MotorWare implementation).  The default value for inertia did not work well with my motor. 

Brett

Brett Nourrcier said:

Thanks GI.  I can control speed down to ~ 0 without issue

That user.h parameter was a restriction in real time is05.js acceleration Hz/s. If you tried to enter real time value greater than 2Hz/sec it would be ignored. Where did you make the acceleration change you show above 1st post, mainISR calls?

Brett Nourrcier said:

The default value for inertia did not work well with my motor.

The formula below with Wb/ seems to struggle with user.h entry of inertia. We bypass it via // (user.c) code to check for user.h motor inertia entry, let it fall through to default inertia formula. It seems the division (Wb/Math2Pi) is not exactly correct for VLI motors, PI oscillates badly disrupts inverter drive DC bus voltage. Formula below is not default, rather the one for known manufactures motor type inertia. 

pUserParams->Kctrl_Wb_p_kgm2 = (float32_t)3.0 *
pUserParams->motor_numPolePairs *

pUserParams->motor_ratedFlux_Wb /
(float32_t) (2.0 * USER_MOTOR_INERTIA_Kgm2);

Hey GI - I made the change in the is05_motor_id.c program.  In the background loop where the trajectory generator is updated, the EST_setMaxDelta_spd_Hz function is called.  The original call was made with

speed_maxDelta_Hz = motorVars.speedRef_Hz /userParams.trajFreq_Hz. 

I changed it to 

speed_maxDelta_Hz = (motorVars.accelerationMax_Hzps/userParams.trajFreq_Hz)

and I get accel control.

As to your inertia comment, the default setting for Kctrl_Wb_p_kgm2 had the flux set too low for my motor;  I could not get high end speeds .  Once I figured that out, I changed user.c to eliminate the USER_MOTOR if statements (they were all defined the same) and went to the following:

and then started tweaking the inertia value in user.h.  The tweaking was all trial and error but I could watch Idq_ref_A.value[1] and it seemed to be a good indicator that the controller was working correctly.  It would oscillate bad when it went out of control.

Brett