This project implements a linear speed controller for three stepper motors. The motors runs independently and can have different or similar speed profile/angular acceleration. The firmware was implemented on Keil RTX RTOS, and it was run and tested on LCP2378 controller. The speed controller algorithm is based on this paper : “Generate stepper-motor speed profiles in real time” posted by David Austin [1].
Firmware
Main loop
/*----------------------------------------------------------------- * Main: Initialize and start RTX Kernel *---------------------------------------------------------------*/ int main (void) { U32 volatile start; /* Wait for debugger connection 0.3s*/ for (start = 0; start < 1000000; start++) {;} os_sys_init (init); /* Initialize RTX and start init */ }
Init task initializes three tasks. Each task handles the speed control of a stepper motor
/*-------------------------------------------
* Task 1 'init': Initialize
*------------------------------------------*/
__task void init (void) {
FIO2DIR = 0x000000FF; /* P2.0..7 defined as Outputs */
FIO2MASK = 0x00000000;
FIO2PIN = 0x00000000;
PINSEL10 = 0;
serial_init ();
motors_parameters_init();
motors_calculations();
t_SMotor1= os_tsk_create(SMotor1,0); /* start task */
t_SMotor2= os_tsk_create(SMotor2,0); /* start task */
t_SMotor3= os_tsk_create(SMotor3,0); /* start task */
os_tsk_delete_self ();
}
Firmware Download
The complete firmware can be downloaded from the link below:
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References
[1] David Austin, “Generate stepper-motor speed profiles in real time.” Retrieved from: https://www.embedded.com/design/mcus-processors-and-socs/4006438/Generate-stepper-motor-speed-profiles-in-real-time
[2] “Linear speed control of stepper motor.” Retrieved from: http://ww1.microchip.com/downloads/en/appnotes/doc8017.pdf
Embedded Design 