{"id":1771,"date":"2024-06-28T03:49:38","date_gmt":"2024-06-28T03:49:38","guid":{"rendered":"https:\/\/iotthinghub.com\/?p=1771"},"modified":"2024-08-11T17:03:40","modified_gmt":"2024-08-11T17:03:40","slug":"servo-motor-control","status":"publish","type":"post","link":"https:\/\/iotthinghub.com\/?p=1771","title":{"rendered":"Servo Motor Control"},"content":{"rendered":"\n

A servomotor is a rotary actuator that allows for precise control of angular position, velocity and acceleration. Most modern servomotor are designed and supplied around a dedicated control module. So that servomotor doesn\u2019t require a driver. A microcontroller PWM pin can be used directly to control the servomotor.<\/p>\n\n\n\n

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From picture it is seen that the servomotor works at 50Hz frequency. Let\u2019s make a 50Hz frequency using Timer1 with Fast PWM.<\/p>\n\n\n\n

            We know the frequency using Fast PWM<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Let\u2019s look at the Waveform Generation Mode Bit<\/p>\n\n\n\n

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Let use Fast PWM with TOP value ICR1 with parameter F_CPU=8MHz and prescaler=64, than<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

The full program as follow-<\/p>\n\n\n

\n\/************************************************************************************************\n*************************************************************************************************\n*********************************** Servo Motor Control****************************************\n*************************************************************************************************\n\t\tSubeer Kumar Sarkar\n\t\tElectrical & Electronic Engineer\n************************************************************************************************\n************************************************************************************************\n***********************************************************************************************\/\n#include<avr\/io.h>\n#include<util\/delay.h>\nint main(void)\n{\nDDRB|=(1<<DDB1)|(1<<DDB2);\t\t\t\t\t\t\t\t\t\/\/OC1B & OC1A connected\n\/***********************Fast PWM TOP=ICR1 non-inverting mode************************************\/\nTCCR1A|=(1<<WGM11)|(1<<COM1B1)|(1<<COM1A1);\nTCCR1B|=(1<<WGM13)|(1<<WGM12)|(1<<CS11)|(1<<CS10);\t\t    \/\/prescalling 64\nICR1=2499;\t\t\t\t\t\t\t\t\t\t\t\t\t\/\/time preiod 50Hz\n\/***********************************************************************************************\/\nwhile(1)\n{\n\tfor(int i=125;i<=249;i++)\n\t{\n\t\tOCR1B=i;\n\t\t_delay_ms(80);\n\t}\n\n}\nreturn 0;\n}\n<\/pre><\/div>\n\n\n
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download<\/a><\/div>\n<\/div>\n<\/div>\n\n\n\n
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Servo control using ATmega8.rar<\/a><\/p>\n<\/div>\n<\/div>\n\n\n\n
Sometime you need to control multiple servomotors at the same time. In this case we need to set I\/O port and clear I\/O port in such meaner that a 50Hz pulse is generated. To generate a 50Hz pulse we use Fast PWM with TOP value ICR1, F_CPU=8MHz and prescaler=64. The coding is same for 50Hz frequency above. The next thing is to set I\/O port at beginning and clear I\/O port when we wanted. The trick is to set I\/O port at interrupt and clear it in main program. In that procedure we can get our desire pulse. Let use Timer1 Compare A vector to set I\/O port<\/p>\n\n\n
\n\/*************** Interrupt Enable ****************************\/\n#include<avr\/interrupt.h>\nsei();\t\/\/Global Interrupt Enable\nTIMSK|=(1<<OCIE1A);  \/\/Timer1, Output Compare A Match Interrupt Enable\n\/*********************   Set logic  ****************************\/\nISR(TIMER1_COMPA_vect)\n{\n   \/\/set I\/O port\n}\n<\/pre><\/div>\n\n\n
Now the clear logic is to check the TCNT1 value and define a TCNT1 condition to clear each I\/O ports. A simple C code as follow-<\/p>\n\n\n
\nif(TCNT1>=140 && TCNT1<=249)\n  {\n   if(TCNT1>=140) PORTx &=~(1<<PINx);\n   if(TCNT1>=180) PORTx &=~(1<<PINx);\n-------------------------------------------------------------\n  }\n<\/pre><\/div>\n\n\n
The complete program as follow-<\/p>\n\n\n
\n\/****************************************************************************************************\n*****************************************************************************************************\n***************************** Multiple Servo Motor Control ****************************************** \n*****************************************************************************************************\n\t\tSubeer Kumar Sarkar\n\t\tElectrical & Electronic Engineer\n******************************************************************************************************\n******************************************************************************************************\n*****************************************************************************************************\/\n#include<avr\/io.h>\n#include<util\/delay.h>\n#include<avr\/interrupt.h>\nint main(void)\n{\nDDRD|=0x0f;\n\/********************************Fast PWM  prescalling 64*********************************************\/\nTCCR1A|=(1<<WGM11);            \t\t\t\t\t\t   \/\/Normal port operation, OC1A\/OC1B disconnected\nTCCR1B|=(1<<WGM13)|(1<<WGM12)|(1<<CS10)|(1<<CS11);\nTIMSK|=(1<<OCIE1A);\t\t\t\t\t\t\t\t\t   \/\/Timer1, Output Compare A Match Interrupt Enable\t\t\t\t\t\t\nsei();\t\t\t\t\t\t\t\t\t\t\t\t\t   \/\/Globel Interrupt Enable\nICR1=2499;\t\t\t\t\t\t\t\t\t\t           \/\/Time preiod 50Hz\n\/******************************************************************************************************\/\nwhile(1)\n{\n\/**************************************** Clear Logic *************************************************\/\nif(TCNT1>=140 && TCNT1<=249)\n{\tif(TCNT1>=140) PORTD &=~(1<<PIND0);\n\tif(TCNT1>=180) PORTD &=~(1<<PIND1);\n\tif(TCNT1>=200) PORTD &=~(1<<PIND2);\n\tif(TCNT1>=240) PORTD &=~(1<<PIND3);\n}\n\/*******************************************************************************************************\/\n}\nreturn 0;\n}\n\/*************************************** Set Logic *****************************************************\/\nISR(TIMER1_COMPA_vect)\n{\nPORTD=0x0f;\n}\n\/*******************************************************************************************************\/\n<\/pre><\/div>\n\n\n
For crystal setting The FUSE bit as follow-<\/p>\n\n\n\n
                        HFUSE=0xc9<\/strong> &  LFUSE=0xEF<\/strong><\/p>\n\n\n\n
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download<\/a><\/div>\n<\/div>\n<\/div>\n\n\n\n
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Multiple Servo control using ATmega8.rar<\/a><\/p>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"
A servomotor is a rotary actuator that allows for precise control of angular position, velocity and acceleration. Most modern servomotor are designed and supplied around a dedicated control module. So that servomotor doesn\u2019t require a driver. A microcontroller PWM pin can be used directly to control the servomotor. From picture it is seen that the […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[15],"tags":[],"class_list":["post-1771","post","type-post","status-publish","format-standard","hentry","category-pwm"],"_links":{"self":[{"href":"https:\/\/iotthinghub.com\/index.php?rest_route=\/wp\/v2\/posts\/1771","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/iotthinghub.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/iotthinghub.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/iotthinghub.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/iotthinghub.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1771"}],"version-history":[{"count":14,"href":"https:\/\/iotthinghub.com\/index.php?rest_route=\/wp\/v2\/posts\/1771\/revisions"}],"predecessor-version":[{"id":2615,"href":"https:\/\/iotthinghub.com\/index.php?rest_route=\/wp\/v2\/posts\/1771\/revisions\/2615"}],"wp:attachment":[{"href":"https:\/\/iotthinghub.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1771"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/iotthinghub.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1771"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/iotthinghub.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1771"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}