STM32中使用PWM对舵机控制

1、硬件JIE

2、PWM口配置

3、角度转换

4、main函数中应用

5、工程下载连接

1、硬件介绍

单片机：STM32F1

舵机：MG995

2、PWM口配置

20毫秒的PWM脉冲占空比，对舵机控制效果较好

计算的公式：

PSC、ARR值的选取：SG90要求的频率是20ms，则72MHz / (PSC+1) / (ARR+1) = 1/0.02；这里PSC和ARR的参数是不固定的。经过多次尝试最终确定PSC=72-1，ARR=20k-1时，舵机旋转效果最好。

PWM配置程序

void pwm_init(void)
{GPIO_InitTypeDef GPIO_InitStructure_For_Servo;TIM_TimeBaseInitTypeDef TIM_TimeBaseImitStructure;TIM_OCInitTypeDef TIM_OCInitStructure;/*µÚÒ»²½¿ªÆôRCCÊ±ÖÓ*/RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);/*µÚ¶þ²½ÅäÖÃGPIO¶Ë¿---PA1Ú*/GPIO_InitStructure_For_Servo.GPIO_Mode = GPIO_Mode_AF_PP;GPIO_InitStructure_For_Servo.GPIO_Pin = GPIO_Pin_1;GPIO_InitStructure_For_Servo.GPIO_Speed = GPIO_Speed_50MHz;GPIO_Init(GPIOA,&GPIO_InitStructure_For_Servo);TIM_InternalClockConfig(TIM2);/*??????*//*µÚÈý²½ÅäÖÃÊ±»ùµ¥Ôª*/   //20msÆµÂÊ(¶æ»úÒªÇóµÄÕâ¸öÆµÂÊÐ§¹û×îºÃ)TIM_TimeBaseImitStructure.TIM_ClockDivision = TIM_CKD_DIV1;TIM_TimeBaseImitStructure.TIM_CounterMode = TIM_CounterMode_Up;TIM_TimeBaseImitStructure.TIM_Period = 20000 - 1;TIM_TimeBaseImitStructure.TIM_Prescaler = 72 - 1;TIM_TimeBaseImitStructure.TIM_RepetitionCounter = 0;TIM_TimeBaseInit(TIM2,&TIM_TimeBaseImitStructure);/*µÚËÄ²½ÅäÖÃÊä³ö±È½Ïµ¥Ôª*/TIM_OCStructInit(&TIM_OCInitStructure);TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;TIM_OCInitStructure.TIM_Pulse = 0; /*CCR*/TIM_OC2Init(TIM2,&TIM_OCInitStructure);/*µÚÎå²½Ê¹ÄÜÊ±ÖÓ*/TIM_Cmd(TIM2,ENABLE);
}

设置脉冲

void pwm_setcompare2(uint16_t compare)
{TIM_SetCompare2(TIM2,compare);
}

完整代码


#include "pwm.h"void pwm_init(void)
{GPIO_InitTypeDef GPIO_InitStructure_For_Servo;TIM_TimeBaseInitTypeDef TIM_TimeBaseImitStructure;TIM_OCInitTypeDef TIM_OCInitStructure;/*µÚÒ»²½¿ªÆôRCCÊ±ÖÓ*/RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);/*µÚ¶þ²½ÅäÖÃGPIO¶Ë¿---PA1Ú*/GPIO_InitStructure_For_Servo.GPIO_Mode = GPIO_Mode_AF_PP;GPIO_InitStructure_For_Servo.GPIO_Pin = GPIO_Pin_1;GPIO_InitStructure_For_Servo.GPIO_Speed = GPIO_Speed_50MHz;GPIO_Init(GPIOA,&GPIO_InitStructure_For_Servo);TIM_InternalClockConfig(TIM2);/*??????*//*µÚÈý²½ÅäÖÃÊ±»ùµ¥Ôª*/   //20msÆµÂÊ(¶æ»úÒªÇóµÄÕâ¸öÆµÂÊÐ§¹û×îºÃ)TIM_TimeBaseImitStructure.TIM_ClockDivision = TIM_CKD_DIV1;TIM_TimeBaseImitStructure.TIM_CounterMode = TIM_CounterMode_Up;TIM_TimeBaseImitStructure.TIM_Period = 20000 - 1;TIM_TimeBaseImitStructure.TIM_Prescaler = 72 - 1;TIM_TimeBaseImitStructure.TIM_RepetitionCounter = 0;TIM_TimeBaseInit(TIM2,&TIM_TimeBaseImitStructure);/*µÚËÄ²½ÅäÖÃÊä³ö±È½Ïµ¥Ôª*/TIM_OCStructInit(&TIM_OCInitStructure);TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;TIM_OCInitStructure.TIM_Pulse = 0; /*CCR*/TIM_OC2Init(TIM2,&TIM_OCInitStructure);/*µÚÎå²½Ê¹ÄÜÊ±ÖÓ*/TIM_Cmd(TIM2,ENABLE);
}void pwm_setcompare2(uint16_t compare)
{TIM_SetCompare2(TIM2,compare);
}

3、角度转换

void servo_set_angle(double angle)
{pwm_setcompare2(angle / 180 * 2000 + 500);
}

完整代码

#include "stepmotor.h"
#include "pwm.h"void servo_init(void)
{pwm_init();}void servo_set_angle(double angle)
{pwm_setcompare2(angle / 180 * 2000 + 500);
}

4、main函数中应用

2秒运动执行一次，分别从0度->180度->270度。(若180度舵机，运动到180度就不再往后转270度了，等到0度的时候转到0度)

        //2秒运行一次if(i%2000==0){count++;//printf("count:%d \r\n",count);//printf("Pitch: %.2f ,Roll: %.2f,Yaw: %.2f \r\n",Pitch,Roll,Yaw);			//Pitch,Roll,YawÊý¾Ý´«µ½´®¿Ú	count2++;if(count2==1){angle=0;servo_set_angle(angle);printf("angle:%.2f \r\n",angle);}if(count2==2){angle=180;servo_set_angle(angle);printf("angle:%.2f \r\n",angle);}if(count2==3){angle=270;servo_set_angle(angle);count2=0;printf("angle:%.2f \r\n",angle);}}

完整代码

#include "system.h"
#include "SysTick.h"
#include "SysDelay.h"
#include "led.h"
#include "usart.h"
#include "mpu6050.h"
#include "stepmotor.h"double angle;int main()
{u8 count=0;u16 i=0;	u16 count2=0;SystemInit();                   		//ÏµÍ³³õÊ¼»¯	SysDelay_Init(72);									//×Ô¶¨ÒåÑÓÊ±º¯Êý³õÊ¼»¯LED_Init();USART1_Config();										//´®¿Ú1³õÊ¼»¯ ÉÏÎ»»úUSART3_Config();										//´®¿Ú3³õÊ¼»¯ À¶ÑÀÓëUSART3¹«ÓÃÏàÍ¬IO¿ÚSysDelay_ms(10);										//10ºÁÃëÑÓÊ±MPU6050_Init();						   				//MPU6050 DMPÍÓÂÝÒÇ³õÊ¼»¯delay_ms(1000);servo_init();while(1){/* 1¡¢LEDµÆÉÁË¸ */	if(i%500==0){led1=!led1;}//2ÃëÖ´ÐÐÒ»´Îif(i%2000==0){count++;//printf("count:%d \r\n",count);//printf("Pitch: %.2f ,Roll: %.2f,Yaw: %.2f \r\n",Pitch,Roll,Yaw);			//Pitch,Roll,YawÊý¾Ý´«µ½´®¿Ú	count2++;if(count2==1){angle=0;servo_set_angle(angle);printf("angle:%.2f \r\n",angle);}if(count2==2){angle=180;servo_set_angle(angle);printf("angle:%.2f \r\n",angle);}if(count2==3){angle=270;servo_set_angle(angle);count2=0;printf("angle:%.2f \r\n",angle);}}//20ºÁÃëÖ´ÐÐÒ»´Îif(i%20==0){}/*»ñÈ¡MPU6050½Ç¶È×´Ì¬*///ÔÚ´®¿ÚÊý¾Ý·¢ËÍÖ®ºó MPU6050_Pose();										//Pitch·¹ö£¬Roll¸©Ñö£¬YawÆ«º½SysDelay_ms(1);									//1ºÁÃëÑÓÊ±i++;}
}