[jmace]

Before my injury in 1994, I was an avid outdoorsman and was planning on going to college on a shooting scholarship. In 2004, my uncle made me a shooting rig that used my electric wheelchair's 12 V DC batteries to power 2 gear motors that adjusts the rig's elevation and windage by turning a threaded rod through a nut. Over the past four years I have noticed a steady decline in precision mostly due to just old age as some of the threaded holes are starting to egg out and the overall slop of the system has grown exponentially.

This year, we made some changes: 1.) Using a linear actuator for elevation control, 2.) Moved the windage motor location 6" further forward than it was prior. This has introduced a couple of issues: 1.) There is a noticeable "jerkiness" when the elevation and/or windage adjustments are engaged (the motor will spin for about 15 seconds as it moves In the opposite direction and when it does pickup all the "slack" it will "jerk"), 3.) I need more resolution at lower speeds than that of which the gear-motor and linear actuator gives me. My current gear motor and linear actuator, under load (~20 pounds), engage at about 1.3 V DC. I would like this to be at an even lower voltage and in turn speed.

We are running a closed loop circuit using Post Width Modulation. For adjustments to elevation and windage (y-axis and x-axis respectively) we are using a 12 V DC Joystick. The further the joystick moves off center the faster the corresponding motor goes, and letting it spring back to center stopping the corresponding motor immediately.The servomotor controllers that we are using are (BARDAC ).

What do we have to do to obtain the resolution I desire. I'm thinking about reducing friction between the two pieces using ball bearings or the like, or, setting up some gearing like somewhere along these lines (20:1 = 3 RPM from a 60 RPM gear-motor)?

Thank you in advance,
Jim

[dmsgdt112]

The supplied user friendly Control Panel software allows the user to set-up the module quickly. The operator is able to move the mechanism to different positions by pressing the corresponding buttons of the Control Panel or by using the joystick and/or trackball.