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Tangent connector
yvan_krähenbühl
Member Posts: 5 ✭
Hello everyone,
I'm a "beginner" who uses Onshape in my hobbies. In “Assembly”, I want to “roll” a ball in a ‘rail’ made up of two 90° strips forming a sort of “V” groove or dihedron.
I use the “tangent” connector, but I can only select the ball and one plane, not two as I would “intuitively” tend to do.
I've spent a lot of time testing and searching on the Internet, but unfortunately without success.
Can anyone help me? Thank you in advance for your answers.
Yvan
Best Answer
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yvan_krähenbühl
Member Posts: 5 ✭
Hi,
Thanks for tip… ;)
I finally did it!
https://cad.onshape.com/documents/98d0f9b674e3365a7227ea2b/w/25454ae53d9b621dd1e74906/e/f8e4992ad130941989b7baef?renderMode=0&uiState=67faeba7be295367673035cd
I created the ball and a “plate” (centered on the ball) directly in the parts workshop. First I created the ball's sketch circle directly tangent to the rails, then a plate (which will serve as a “slide” aligned with the ball's center... . In this way, the center of the ball and the center of the plate are “identical” (in the same place). In the assembly process, when the ball and plate are imported, these 2 elements remain in place in relation to each other. Knowing, in the parts workshop, where the plate is in relation to the rails, I can place everything precisely. First I create a slide connector between the ball and the plate, then I place the plate connector (fixed link) correctly in relation to the rails.
This way, I can move the ball along the rail, and the rail can also move (pivot connection).
This doesn't replace my lack of knowledge, as I still don't understand how to place the ball (in the assembly) tangent to two planes (surface)...
Best regards.
YvanPS. This model will be 3d printed (laser cut rails) in order to connect the rail to a servo motor connected to an Arduino board (with an ultrasonic distance sensor) in order to stabilize the ball in the middle of the rail (PID algorithms).
1
Answers
@yvan_krähenbühl
You'll need to use a slider mate (to have the ball slide along the rail) plus a rotate mate (to make it rotate while sliding), then apply a rack-and-pinion condition (to get the right amount of rotations). You'll probably need to create an invisible dummy part, to have something to base the rolling action on, so the ball rotates the right way.
https://cad.onshape.com/documents/71fc008d9243a885635708b5/w/0cf8076d68a685a48318f84d/e/d594d6ffb37f162ea7ea0e58?renderMode=0&uiState=67fa704e2973460eab614018
Thank you for your answer... it will help me in a second time... For the moment, I don't know how to place the ball so that it rests on the walls of the rails...
I don't know if I'm approaching the problem from the right angle, but it seemed to me that I should start by positioning the ball correctly “on” the rails.
Am I wrong?
A peak behind the magician's curtain.
Hi,
Thanks for tip… ;)
I finally did it!
https://cad.onshape.com/documents/98d0f9b674e3365a7227ea2b/w/25454ae53d9b621dd1e74906/e/f8e4992ad130941989b7baef?renderMode=0&uiState=67faeba7be295367673035cd
I created the ball and a “plate” (centered on the ball) directly in the parts workshop. First I created the ball's sketch circle directly tangent to the rails, then a plate (which will serve as a “slide” aligned with the ball's center... . In this way, the center of the ball and the center of the plate are “identical” (in the same place). In the assembly process, when the ball and plate are imported, these 2 elements remain in place in relation to each other. Knowing, in the parts workshop, where the plate is in relation to the rails, I can place everything precisely. First I create a slide connector between the ball and the plate, then I place the plate connector (fixed link) correctly in relation to the rails.
This way, I can move the ball along the rail, and the rail can also move (pivot connection).
This doesn't replace my lack of knowledge, as I still don't understand how to place the ball (in the assembly) tangent to two planes (surface)...
Best regards.
Yvan
PS. This model will be 3d printed (laser cut rails) in order to connect the rail to a servo motor connected to an Arduino board (with an ultrasonic distance sensor) in order to stabilize the ball in the middle of the rail (PID algorithms).
And the latest version (with tip from @MDesign 😉 thanks !)
https://cad.onshape.com/documents/98d0f9b674e3365a7227ea2b/w/25454ae53d9b621dd1e74906/e/6a5a00938cd4a1595aa96afe
That's all @martin_kopplow credit. I just removed the curtain. 😉