stepper vs servo
What is the motor driving? Is it linkages , pulley and timing belt, or other?
It seems you want the position of something to be determined by the position of the joystick. And you say a servo motor could do it but you are concerned about the torque. And with stepper you are not sure about the speed?
So I think to start we need to know some specifications: what you are driving with the motor, how far (angle) are the two extreme positions, how much time (secs) to get from one extreme to the other, and what is maximum torque expected? Note if you are trying to move a mass from one position to another relatively fast the motor must provide that extra torque but that can be accounted for if we know what is expected of this system.
Ok, ok I see, more detail is needed, so here is the whole story:
I'm sitting in a wheelchair - for the moment I'm driving a power wheelchair controlled by a joystick - but ordered a seated segway and will get it next week but I want to be prepared.
My goal is to replace the steering, which is normally done by the handle bar pushed left or right, by a motor.
In seated segways the handle bar can be removed for better access.
This reduces my questions to one simple task.
I would add a drawing but don't know how. So I try to describe it as good as possible.
The result should be to turn the shaft of the segway around its pivot point. So I need either a lever of a certain length or a belt driven disk of a certain radius. Both are the main key element in the force needed. This force acts perpenticular to the radius or the end of the lever.
Assuming the neutral position of the shaft equals 0° and is identical with the zero point / home position of the motor I will need to turn it around its pivot to -45° and +45° maybe its -50° and +50°. If these are the both extremes they must be reached with 1 sec or less. So the angle span of lets say 100° in 1 sec is the speed that is required. The longer the lever or the radius the less force is required, but I'm limited in space.
I was searching several segway pages to get an info about how much torque is required to turn the shaft but no success. If anyone knows please let me know.
Also, if at all possible, a way to attach drawings.