STM32霍尔编码器电机测速原理详解

        本次选用的编码器电机为13线的霍尔编码器电机，电机减速比为30：1，转动一圈输出13*30=390个脉冲。轮胎直径为75mm，轮胎周长为pi*d=3*75=225mm.定时器采用四倍频计数，则一圈输出390*4=1560个脉冲。具体编码器知识这里就不多说了。

         根据测速原理：假设编码器输出的脉冲数为N，而电机转动一圈输出1569个脉冲，转动一圈轮子将前进225mm。那输出脉冲数为N时前进的距离就应该为225*（N/1560）mm，再除以时间及可得速度。

下面为具体代码：

encoder.c文件

#include "encoder.h"

void Encoder_TIM2_Init(void)
{
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);		//开时钟
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
	
	GPIO_InitTypeDef GPIO_InitStruct;							//配置IO口
	GPIO_InitStruct.GPIO_Mode = GPIO_Mode_IN_FLOATING;
	GPIO_InitStruct.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1;
	GPIO_Init(GPIOA, &GPIO_InitStruct);
	
	TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStruct;				//定时器初始化
	TIM_TimeBaseInitStruct.TIM_ClockDivision = TIM_CKD_DIV1;
	TIM_TimeBaseInitStruct.TIM_CounterMode = TIM_CounterMode_Up;
	TIM_TimeBaseInitStruct.TIM_Period = 65535;
	TIM_TimeBaseInitStruct.TIM_Prescaler = 0;
	TIM_TimeBaseInit(TIM2, &TIM_TimeBaseInitStruct);
	
	//定时器编码器模式初始化
	TIM_EncoderInterfaceConfig(TIM2, TIM_EncoderMode_TI12, TIM_ICPolarity_Rising, TIM_ICPolarity_Rising);
	
	TIM_ICInitTypeDef TIM_ICInitStruct; 						//输入捕获单元配置
	TIM_ICStructInit(&TIM_ICInitStruct);
	TIM_ICInitStruct.TIM_ICFilter = 10;
	TIM_ICInit(TIM2, &TIM_ICInitStruct);
	
	TIM_ClearFlag(TIM2, TIM_FLAG_Update);
	
	TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);
	
	TIM_SetCounter(TIM2, 0);
	
	TIM_Cmd(TIM2, ENABLE);
}

void Encoder_TIM4_Init(void)
{
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);
	
	GPIO_InitTypeDef GPIO_InitStruct;
	GPIO_InitStruct.GPIO_Mode = GPIO_Mode_IN_FLOATING;
	GPIO_InitStruct.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
	GPIO_Init(GPIOB, &GPIO_InitStruct);
	
	TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStruct;
	TIM_TimeBaseInitStruct.TIM_ClockDivision = TIM_CKD_DIV1;
	TIM_TimeBaseInitStruct.TIM_CounterMode = TIM_CounterMode_Up;
	TIM_TimeBaseInitStruct.TIM_Period = 65535;
	TIM_TimeBaseInitStruct.TIM_Prescaler = 0;
	TIM_TimeBaseInit(TIM4, &TIM_TimeBaseInitStruct);
	
	TIM_EncoderInterfaceConfig(TIM4, TIM_EncoderMode_TI12, TIM_ICPolarity_Rising, TIM_ICPolarity_Rising);
	
	
	TIM_ICInitTypeDef TIM_ICInitStruct; 
	TIM_ICStructInit(&TIM_ICInitStruct);
	TIM_ICInitStruct.TIM_ICFilter = 10;
	TIM_ICInit(TIM4, &TIM_ICInitStruct);
	
	TIM_ClearFlag(TIM4, TIM_FLAG_Update);
	
	TIM_ITConfig(TIM4, TIM_IT_Update, ENABLE);
	
	TIM_SetCounter(TIM4, 0);
	
	TIM_Cmd(TIM4, ENABLE);
}

int Read_Spead(int TIMx)			//读取编码器输出脉冲数
{
	int value_1;
	switch(TIMx)
	{
		case 2:value_1 = (short)TIM_GetCounter(TIM2);TIM_SetCounter(TIM2, 0);break;
		case 4:value_1 = (short)TIM_GetCounter(TIM4);TIM_SetCounter(TIM4, 0);break;
		default:value_1 = 0;
	}
	return value_1;
}

void TIM2_IRQHander(void)
{
	if(TIM_GetITStatus(TIM2, TIM_IT_Update) == 1)
	{
		TIM_ClearITPendingBit(TIM2, TIM_IT_Update);
	}
}

void TIM4_IRQHander(void)
{
	if(TIM_GetITStatus(TIM4, TIM_IT_Update) == 1)
	{
		TIM_ClearITPendingBit(TIM4, TIM_IT_Update);
	}
}

        我使用的是简单的delay一下来采集定时器捕获的编码器脉冲数，不过我建议使用定时器中断来处理编码器采集。此函数只采集右轮脉冲进行计算

主函数循环体内函数：

while(1)
	{
		delay_s(1);
		{
			uint16_t right = Read_Spead(2);//采集右轮脉冲数
			displacement = 0.225 * (right / 1560);//计算位移
			speed = displacement;//由于我设置的为延时一秒就不用除时间
			OLED_Float(0, 0, speed, 4);//通过OLED显示速度
			set_PWM(999);//设置电机PWM
			TIM_SetCounter(TIM2, 0);//下一次一秒计数前再一次将计数清零
		}
	}