STM32 直流減速電機(jī)控制
在直流減速電機(jī)控制中，最常用的方法就是通過PWM來控制直流電機(jī)的轉(zhuǎn)速。在控制小車走直線的過程中，需要兩者的轉(zhuǎn)速一置（如果要走得很直，還需要在短時(shí)間內(nèi)保證兩者的行程大致相當(dāng)，這可以用PID算法來控制）。因此，在檢測(cè)到兩者轉(zhuǎn)速不一樣時(shí)，需要?jiǎng)討B(tài)調(diào)整其中一個(gè)或兩個(gè)輪子的PWM的點(diǎn)空比（簡(jiǎn)單點(diǎn)的就以一個(gè)輪為基準(zhǔn)，調(diào)整另外一個(gè)輪子即可；如果以一個(gè)固定的標(biāo)準(zhǔn)的話，需要調(diào)整兩個(gè)輪子的PWM占空比）。
1 程序第一步：設(shè)置GPIO，略（輸出PWM的管腳用Mode_AF_PP即可）
2
3 程序第二步：設(shè)置定時(shí)器，（保證產(chǎn)生兩路PWM即可，我用的是TIM4）
4
5 void TIM4_Configuration(void)
6 {
7 TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;
8 TIM_OCInitTypeDef TIM_OCInitStructure;
9
10 //時(shí)間基初始化
11 TIM_TimeBaseInitStructure.TIM_Period=144; //18K/144=125Hz,這個(gè)是電機(jī)PWM的頻率
12 TIM_TimeBaseInitStructure.TIM_Prescaler=4000; //72000000/4000=18K
13 TIM_TimeBaseInitStructure.TIM_ClockDivision=TIM_CKD_DIV1;
14 TIM_TimeBaseInitStructure.TIM_CounterMode=TIM_CounterMode_Up;
15 TIM_TimeBaseInitStructure.TIM_RepetitionCounter=0x0000;
16
17 TIM_TimeBaseInit(TIM4,&TIM_TimeBaseInitStructure);
18
19 //輸出比較模式設(shè)置,用于4路PWM輸出
20 TIM_OCInitStructure.TIM_OCMode=TIM_OCMode_PWM2; //輸出PWM
21 TIM_OCInitStructure.TIM_OutputState=TIM_OutputState_Enable; //使能正向通道
22 TIM_OCInitStructure.TIM_OutputNState=TIM_OutputState_Disable; //失能反向通道
23 TIM_OCInitStructure.TIM_Pulse=PWM_L; //左輪DIR的占空比
24 TIM_OCInitStructure.TIM_OCPolarity=TIM_OCPolarity_Low; //輸出極性為低電平
25 TIM_OCInitStructure.TIM_OCNPolarity=TIM_OCPolarity_High;//互補(bǔ)輸出極性為高電平
26 TIM_OCInitStructure.TIM_OCIdleState=TIM_OCIdleState_Set;
27 TIM_OCInitStructure.TIM_OCNIdleState=TIM_OCNIdleState_Reset;
28
29 TIM_OC1Init(TIM4,&TIM_OCInitStructure); //PWM_L初始化
30 TIM_OC1PreloadConfig(TIM4,TIM_OCPreload_Disable); //改變點(diǎn)空比后,立即產(chǎn)生效應(yīng)
31
32 TIM_OCInitStructure.TIM_Pulse=PWM_R; //左輪PWM的占空比
33 TIM_OC2Init(TIM4,&TIM_OCInitStructure); //PWM_R初始化
34 TIM_OC2PreloadConfig(TIM4,TIM_OCPreload_Disable); //改變點(diǎn)空比后,立即產(chǎn)生效應(yīng)
35
36 //使能定時(shí)器4
37 TIM_Cmd(TIM4,ENABLE);
38 TIM_CtrlPWMOutputs(TIM4,ENABLE);
程序第一步：設(shè)置GPIO，略（輸出PWM的管腳用Mode_AF_PP即可）
程序第二步：設(shè)置定時(shí)器，（保證產(chǎn)生兩路PWM即可，我用的是TIM4）
void TIM4_Configuration(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;
//時(shí)間基初始化
TIM_TimeBaseInitStructure.TIM_Period=144; //18K/144=125Hz,這個(gè)是電機(jī)PWM的頻率
TIM_TimeBaseInitStructure.TIM_Prescaler=4000; //72000000/4000=18K
TIM_TimeBaseInitStructure.TIM_ClockDivision=TIM_CKD_DIV1;
TIM_TimeBaseInitStructure.TIM_CounterMode=TIM_CounterMode_Up;
TIM_TimeBaseInitStructure.TIM_RepetitionCounter=0x0000;
TIM_TimeBaseInit(TIM4,&TIM_TimeBaseInitStructure);
//輸出比較模式設(shè)置,用于4路PWM輸出
TIM_OCInitStructure.TIM_OCMode=TIM_OCMode_PWM2; //輸出PWM
TIM_OCInitStructure.TIM_OutputState=TIM_OutputState_Enable; //使能正向通道
TIM_OCInitStructure.TIM_OutputNState=TIM_OutputState_Disable; //失能反向通道
TIM_OCInitStructure.TIM_Pulse=PWM_L; //左輪DIR的占空比
TIM_OCInitStructure.TIM_OCPolarity=TIM_OCPolarity_Low; //輸出極性為低電平
TIM_OCInitStructure.TIM_OCNPolarity=TIM_OCPolarity_High;//互補(bǔ)輸出極性為高電平
TIM_OCInitStructure.TIM_OCIdleState=TIM_OCIdleState_Set;
TIM_OCInitStructure.TIM_OCNIdleState=TIM_OCNIdleState_Reset;
TIM_OC1Init(TIM4,&TIM_OCInitStructure); //PWM_L初始化
TIM_OC1PreloadConfig(TIM4,TIM_OCPreload_Disable); //改變點(diǎn)空比后,立即產(chǎn)生效應(yīng)
TIM_OCInitStructure.TIM_Pulse=PWM_R; //左輪PWM的占空比
TIM_OC2Init(TIM4,&TIM_OCInitStructure); //PWM_R初始化
TIM_OC2PreloadConfig(TIM4,TIM_OCPreload_Disable); //改變點(diǎn)空比后,立即產(chǎn)生效應(yīng)
//使能定時(shí)器4
TIM_Cmd(TIM4,ENABLE);
TIM_CtrlPWMOutputs(TIM4,ENABLE);
1 程序第三步：
2
3 在SysTick中斷中，讀取兩個(gè)輪子的速度（具體的方法是：每0.1秒讀一次，并以此人作為速度的依據(jù)），并比較，如果以右輪為基準(zhǔn)，則調(diào)整左輪的PWM占空比。涉及到關(guān)鍵語句是：TIM_SetCompare1（）；
4
5 u16 COUN1=0;
6 u16 COUN2=0;
7
8 volatile u16 Dist_L=0; //左輪行程脈沖數(shù)
9 volatile u16 Dist_R=0; //右輪行程脈沖數(shù)
10 void SysTick_Handler(void)
11 {
12
13 COUN1=TIM1->CNT; //左輪在0.1秒里脈沖數(shù)
14 COUN2=TIM2->CNT; //右輪在0.1秒里脈沖數(shù)
15 Dist_L=Dist_L+COUN1; //左輪行程脈沖數(shù)
16 Dist_R=Dist_R+COUN2; //右輪行程脈沖數(shù)
17 if( (COUN1-COUN2)>2)
18 {
19 PWM_L= TIM_GetCapture1(TIM4);
20 TIM_SetCompare1(TIM4, PWM_L - 4);
21 }
22 else if ( (COUN2-COUN1)>2)
23 {
24 PWM_L= TIM_GetCapture1(TIM4);
25 TIM_SetCompare1(TIM4, PWM_L + 4);
26 }
27
28 TIM_SetCounter(TIM1, 0);
29 TIM_SetCounter(TIM2, 0);
30
31 }
32
33 關(guān)于TIM_SetCompareX（；）這個(gè)函數(shù)，還是有很多用途的，其中另外一個(gè)用途，就是用于產(chǎn)生不同頻率的PWM，具體程序如下：
34
35 u16 capture = 0;
36
37 extern vu16 CCR1_Val;
38 extern vu16 CCR2_Val;
39 extern vu16 CCR3_Val;
40 extern vu16 CCR4_Val;
41
42 void TIM2_IRQHandler(void)
43 {
44
45 /* TIM2_CH1 toggling with frequency = 183.1 Hz */
46 if (TIM_GetITStatus(TIM2, TIM_IT_CC1) != RESET)
47 {
48 TIM_ClearITPendingBit(TIM2, TIM_IT_CC1 );
49 capture = TIM_GetCapture1(TIM2);
50 TIM_SetCompare1(TIM2, capture + CCR1_Val );
51 }
52
53 /* TIM2_CH2 toggling with frequency = 366.2 Hz */
54 if (TIM_GetITStatus(TIM2, TIM_IT_CC2) != RESET)
55 {
56 TIM_ClearITPendingBit(TIM2, TIM_IT_CC2);
57 capture = TIM_GetCapture2(TIM2);
58 TIM_SetCompare2(TIM2, capture + CCR2_Val);
59 }
60
61 /* TIM2_CH3 toggling with frequency = 732.4 Hz */
62 if (TIM_GetITStatus(TIM2, TIM_IT_CC3) != RESET)
63 {
64 TIM_ClearITPendingBit(TIM2, TIM_IT_CC3);
65 capture = TIM_GetCapture3(TIM2);
66 TIM_SetCompare3(TIM2, capture + CCR3_Val);
67 }
68
69 /* TIM2_CH4 toggling with frequency = 1464.8 Hz */
70 if (TIM_GetITStatus(TIM2, TIM_IT_CC4) != RESET)
71 {
72 TIM_ClearITPendingBit(TIM2, TIM_IT_CC4);
73 capture = TIM_GetCapture4(TIM2);
74 TIM_SetCompare4(TIM2, capture + CCR4_Val);
75 }
76
77 }
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