Linear Slide Joystick

[moosetracks555]

I am trying to give an operator a control for moving a 25’ slide. In a past application I used an analog joystick with a frequency drive. It works ok, and once the operator gets used to the deceleration and response they can usually get close. For another application with a 36” stroke I built a 12” linear joystick out of a linear slide and a linear transducer. It is a 3 to 1 ratio (move the slider 1” get 3” of stroke) and it enables the operator to move the slide to different positions very quickly and still make the small moves accurately. I am afraid if I use a 12” linear joystick on a 25’ slide the small moves will be difficult. I was considering a device like a trackball that would allow them to make small moves easily, and large moves very quickly. I don’t know if it would be any better than the joystick. Does anyone have any suggestions?


In case you want to know there is a linear slide positioned above a log (tree) and they are going to mark the beginning, end and defects with a laser line mounted on the slide.

 

[Anton1988]

Could you use 2 linear joysticks 1 for large movements and the other for "fine" movements i would have linked these thru a plc to the frequency drive. BUT i would have thought if you have the fine linear joystick as a high resistance in series with the large movement joystick which would be a low resistance (i may have these the wrong way round).

Please note this is not tried and tested.
Hope this helps
Let me know what you come up with.
Regards
Anton

 

[ScottyUK]

Can you implement a non-linear gain function within software (or hardware if you're feeling creative) so that a small joystick movement from the neutral point produces a slow speed response and a large movement produces a high speed response? A piecewise approximation with maybe seven or nine points would be adequate to give a reasonable 'curve'.


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If we learn from our mistakes I'm getting a great education!

 

[lifeguard1]

You can put a timer in so that the longer they hold the joy stick in one direction the higher the mulitpler adds to the analog output to the freq drive.