design robotic arm using stepper motor and gears

[anasfuad33eng]

hi, all i designed a two degree of freedom robotic arm by using 2 stepper motors: unipolar, 1.8 degree for elbow joint i used worm gear, and a timing belt
i test my stepper motors with out loads work good if i want rotate my stepper motor at angle of 90 deg, i need 50 pulses (i use 4 sequence, full step mode) but when i use the worm gears in design of my robotic arm i found if i want to make the robotic arm move at an angle of 90 need more than 500 pulses in other word the number of required pulses increased more than ten times is this because of using worm gears? are the worm gears reduce the rotation angles? please help with details

 

[jsherman]

My guess would be that your motors don't supply a lot of torque. How heavy are your gears? Stepper motors, if I recall, have different torques for different speeds, as well, so that could also factor into your perceived effect.