Hi Brenda, the code above contains everything you need to get the PID controller running. You will only need to replace the getAngle() function with you sensor reading code and moveMotors() with the code controlling your motors. I’ve updated the code above to make this clearer. Yes, you can use a single PID controller to make a robot with encoders to drive straight.

Hi Ramius,
The code shown is not complete; I’ve only written it to show how the PID controller can be used. A full version of my self-balancing code can be found in the final part of my tutorial here. Yes, encoders would definitely improve the robot’s balancing performance. There are some other tutorials online where they describe how to integrate encoders into the PID code.
Simon

Regards

However on the serial, I just obtain a single value and the motors begin to rotate continuously in one direction, without stopping. I guess the sensor stops transmitting values to the controller once the motor begins to move (Values not updated, hence motor rotates continuously?)

Any help for this? Also please do check out the comment I sent via the About page.

I assume you’re using the balancing program I posted a while back? If it doesn’t say “Initializing” after you see “Ready to Balance!”, and you are holding the robot vertical and still, then there is something wrong with the sensor. Here are a number of pointers that might help:

• Have you updated the Gyro & Accel offsets in the setup function with your own values?
• Is the sensor module facing the right direction? Check this by putting the line Serial.println(ypr[1] * 180/M_PI); just before the PID function is called in the main loop.
• My code does not use interrupts, as I used a Galileo Gen2 board instead of an Arduino Mega. All the same, this code should still work for you.
• To send a new P-value for the PID controller over serial, type: “P” and then a new number between 1-50. The same can be done for the “I” and the “D” values.

The sensor is working alright and the loop looks fine too. My motors don’t respond according to the balance; they don’t switch on at all even after I get the ‘Ready to Balance’ on the monitor. How do I debug with the monitor? I am unable to set values via the serial monitor.

What changes should I be making to the code?

PS I am using the MPU6050 along with an interrupt on an Arduino Mega.

Hi Vivek! Calibrating the PID values definitely is the hardest part of the project. If you really are having no luck with the system, I would suggest checking that the sensor is working properly, and that the time between each loop is short (less than 10ms) and is relatively regular.