I am working on robotics project. The drive chassis is powered by a 3-cell 12V 8 Amps battery (I might also go for connecting two batteries to attain speed as my drive motors work at 24V full power). The battery can get charged up to 12.8V.
As I start driving the chassis, the voltage goes on dropping which is obvious! But that's where the problem arises. All my calculations of Arduino are based on a constant value of voltage. So when the voltage drops the calculations go wrong. I tried taking feedback from the voltage and changing the code, but it gets too complicated. I need a stable voltage of at least 11V (or 22V in the future). What can I do?
Best Answer
First, fix the code to take the measured voltage into account. No, it's not "too complicated". Get someone that knows what they are doing.
Second, regulating the voltage to motors to get specific speed or accumulated distance is futile. Measure speed or distance directly, then vary the motor drive to whatever it needs to be to produce the desired result. Due to the closed loop feedback, this will automatically compensate for the power voltage. For a little faster and more linear response (which allows the control algorithm to work more simply), I'd add a little feed-forward based on the measured power voltage. The control loop puts out a normalized drive level, and the code that sets the PWM duty cycle takes the power voltage into account so that the desired drive level is achieved independent of power voltage and transparently to the control loop. This is all well within the capability of a modern microcontroller.