Ok guys I have a question for you. I am currently building a tracked rover and I am in the process of wiring up the motors to a speed control. Assuming the motors aren’t too hot for the controller to handle, how would I connect three motors to the same controller? I don’t know whether to wire them in series or parallel.
Also, a while back we were discussing motor encoders and how they don’t work too well with four wheeled or tracked rovers. What if you mounted one encoder on a free spinning wheel in front of the robot and another perpendicular to the treads/wheels in the same configuration? I was just wondering because a colleague of mine was thinking of doing so and I wasn’t sure if it would work or not.
Thanks
Zack
first off id like to ask the reason for three motors to one controller?
ill assume they all drive the same track so the motor question depends on the kind of current and voltage, if your motors are low volt and your controller can handle three times the required motor voltage i would do series. if your motor controller cant hand the volts but can handle the triple the current draw of your motor stalled, then do parallel.
the encoder setup i had always invisioned on a tracked bot would look much like the one found on the back of johny 5 from the movie short circut. one encoder for the rotation of the draging wheel and perhaps a pot to determine the direction relative to the body the dragging wheel is facing.
not many speed controllers will handle three motors. it greatly depends on the number of turns(windings) the motors have and voltage applied. the greater the number of turns the less current required. its the curent draw that’ll pop your controller. i’m curious as to why 3 motors.
I’ll have to look it up but I have the formulas somewhere to calculate motor turns, voltage applied, current draw, etc.
If I could find my damn digital camera I would show you why I am using 3 motors on one controller. But, since I can’t locate it currently, I am building a tracked rover with three gearwheels on each track, each attached to a motor. The rover itself is designed to be a testbed to help me learn how to program in PBasic along with my Basic Stamp2.
I soldered it up today in parallel and it worked fine when I tested each string of motors and controller individually. When I wired them together though, I think I mixed up a few wires because when I plugged in the battery the left track began to spin. This was when the motor controller’s switch was positioned off. I’m going to fix it whenever I get the chance and hopefully I’ll find my camera to show you.
Wired in series, the motors will run with half the power they would if they were wired alone. This is good if you want low end torq while having good runtime.
Wired in parallel, the motors will see full power and if they were ran alone. Make sure you ESC can handle it.
I remember a long time ago I wired a 4WD sumo with the motors on each side in series. It has the same effect as a rear differential. If one of the motors has less of a load it will receive all of the voltage and leave very little for the motor that still has traction. Wiring motors in series is a bad idea unless their outputs are physically connected via some external hardware.
I would show you why I am using 3 motors on one controller. But, since I can’t locate it currently, I am building a tracked rover with three gearwheels on each track, each attached to a motor. The rover itself is designed to be a testbed to help me learn how to program in PBasic along with my Basic Stamp2.