Declination Axis Stepper Motor Drive Test
Today we tested the newly developed mechanism for the Alan Young telescope’s declination axis drive. It is powered by a stepper motor, controlled by an Arduino microprocessor and EasyDriver board.
We have fabricated a system of three belts and pulleys to give a reduction ratio of 398:1. This means the stepper motor running at a practical maximum speed of 30 rpm, produces a slew rate of around 0.5 degrees per second.
The motor is controlled by software running on the Arduino and so its rotation speed can be easily slowed to give a lower slew rate, as we did today.
When testing it today for the first time, it worked well and easily moved the telescope tube smoothly up and down. It also locked the tube in position once stopped, because of course, the stepper motor remains powered up, even when not moving.
It was a fun and promising test. We now need to complete the fly-off, main belt tensioning mechanism and refine the software-based control system.
