motors

[sg_karthick]

hello. i am new to world of robotics.
i wanna know which are all the motor controls used in robots which is controlled by a mocrocontroller.
pls give a brief idea of servo and steppar motor.

 

[Triode]

well, you have servos which typically have 3 wires, 2 for + and - dc, generally black and red, 5 volts and a signal wire, most often white, to which you supply a timed pulse. The width of the pulse controls the position of the servo, typically 0.9 or 1 millisecond is all the way to one side and 2 milliseconds is the other with other positions linearly vary with the signal in between. Obviously I can't and don't need to tell you everything here, if you need more search for "servo PWM control"

Steppers come in a few types, the main distinction Bypolar and Unipolar, they also come in different phases but 2 phase is most common for hobbyists. With these you send current (how much depends on the ratings of the motor) to the coils in different patterns for different speed, direction, and precisions of movement. The shaft of the motor turns to the nearest orientation that aligns it with the set(s) of coils that are active. To control this you will need to amplify the signal from your microcontroller, search "transistor as switch" and "h bridge" for this. For more specifics on the motors themselves search "stepper motor types" then do some searches and read some articles on sequencing. There's so much of it out there that there is really no point in anyone going into massive detail but the people here are really helpful if you get confused on something specific once you've done your homework.

 

[dknguyen]

There are also brushed and brushless motors. The difference between them is that the brushless motors has no brushes to automatically switch the current betweeh the windings/electromagnets to automatically to keep the motor spinning- the electronics must switch the current themselves (you know how a brushed motor works right?)

 

[sg_karthick]

so if i am using a motor for sterring wheel control of a robotic car which can i use steppar of servo?

 

[Leftyretro]

so if i am using a motor for sterring wheel control of a robotic car which can i use steppar of servo?

Your choice. A lot depends on the speed, weight of the vechile, voltage source available. Standard R/C servos are the simplest, cheapest and probably the best choice for starting out.

Lefty