New lower price for Axon II ($78) and Axon Mote ($58).
0 Members and 1 Guest are viewing this topic.
If I did hire someone, I would want to try to get advice on the whole system.
So, if I wanted to, I could step the poles one step and get a specific movement distance. (Of course, it all depends on the amount of poles, tire diameter, etc. I understand all of that.) My problem is every controller I've found lets me say "Go forward/Go Backwards" at some 2.5-5v mapped range of speeds. I can't say, jump forward one step.As I mentioned, I want to build a self balancing robot. With a motor this big, simply saying "forward/backwards" would make it jerk around. However, if I can control the steps, I can simply say "When the gyro/accelerometer that is mounted on the top of the robot shows a certain angle. [ tangent = (opposite/adjacent) or tan(robot height/distance the robot can move in one step) ] Then jump forward one step. (Maybe a little less so it slow starts falling backwards and you have a little dance forward/backwards that is mostly controlled instead of some random result.
It's this motor here: Hub Motor 48V3KW (High Torque)(disc-brake)
So I'm wrong in thinking you can just power one phase and have it 'lock' or break there, and then power phase 2 to have it step forward one step?
check gyro.. check gyro.. gyro balanced stop.
You are right, however due to internal assembly of Your motor (3 coils set at 120° from one another), the smallest step You can take is 120° when full-stepping and 60° when half-stepping (alternately powering 2 and 1 coil at given time).
Gyro does not show angle (balance/imbalance), what it does show is angular velocity (degrees per second) at which something is rotating.
Quote from: stridera on November 28, 2012, 06:11:15 AMSo I'm wrong in thinking you can just power one phase and have it 'lock' or break there, and then power phase 2 to have it step forward one step?You are right, however due to internal assembly of Your motor (3 coils set at 120° from one another), the smallest step You can take is 120° when full-stepping and 60° when half-stepping (alternately powering 2 and 1 coil at given time). So the smallest distance You can achieve when half-stepping is wheel circumference / 6, which is well below precision needed to smoothly balance the robot.
Apart from this, a BLDC motor is not a stepper and is not made to "lock" (which it shouldn't in a balancing vehicle anyway).
A good balancing robot is constantly correcting.
I'll change my question. Can you guys suggest a good controller that could handle the 3 phase sensored 48v 3kw peak power handling that accepts either serial communication or some non-analog input so I can have some precise control over how the movement? If not, do you know a place where I can get schematics for such a system or hire someone to build it?
I told you that this motor is way overkill and a smaller one will be easier to control, as it won't have that much inertia to overcome.
What's wrong with analog?!Any digitial representation will, due to its quantization, have a limited amount of voltage steps, while an analog signal is continous.
I am not available for such a project, as I believe the motor is wrong for your project and so will be impossible to get good results from - and the contractor is always blamed for the customers bad decisions Further, you want your very own "personal trainer" to tag along on your project, which you'll not be happy to pay for, as you probably will need say 50 hours of guidance added to the development costs, so the bottom line will quickly reach, or even surpass, the $10k mark.
The company that sold you the motor does have a controller for the 3kW motor. I don't know how fast it can reverse the motor (as fast reversing isn't a priority on a regular bike), but shoot them an email - $200 will buy you a 3kW controller (or two hours of my time on X-mas sale )