STM32步进电机驱动的算法

在脉冲模式下，步进电机启动器的脉冲频率与速度成正比，函数void CalculateSModelLine(float fre[], unsigned short period[], float len, float fre_max, float fre_min, float flexible)主要目的就是生成每一个细分步加速的速度。芯片用的是stm32f103c8t6，驱动器用的是2DM420。

程序流程如下：

• STM32硬件基本初始化，主要是针对定时器

• 调用函数CalculateSModelLine（）生 成每一个细分步定时器的自动重装载值（实际就是改变脉冲的周期）

• 打开定时器

• 更新中断发生，将数组中的数据赋值给定时器的自动重装载寄存器

• 跳出中断后脉冲频频率就变化了

• 下一次更新中断产生

对应的计算接口code:

/* calculate the Period and Freq array value, fill the Period value into the Period register during the timer interrupt.

*calculate the acceleration procedure , a totally 1000 elements array.

* parameter fre[]: point to the array that keeps the freq value.

* period[]: point to the array that keeps the timer period value.

* len: the procedure of acceleration length.it is best thing to set the float number, some compile software maybe transfer error if set it as a int

* fre_max: maximum speed, frequency vale.

* fre_min: start minimum speed, frequency vale. mind : 10000000/65535 = 152, so fre_min can't less than 152.

* flexible: flexible value. adjust the S curves

*/

void CalculateSModelLine(float fre[], unsigned short period[], float len, float fre_max, float fre_min, float flexible)

{

int i=0;

float deno ;

float melo ;

float delt = fre_max-fre_min;

for(; i;>

{

melo = flexible * (i-len/2) / (len/2);

deno = 1.0 / (1 + expf(-melo)); //expf is a library function of exponential(e)

fre[i] = delt * deno + fre_min;

period[i] = (unsigned short)(10000000.0 / fre[i]); // 10000000 is the timer driver frequency

}

return ;

}