Hello, me and my partners have been working on a project recently where we implement an arduino based metal sensor on a ground robot. Our main issue was attaching the sensor to the robot.
We settled on a plastic arm and we want it to move 60 degrees in both directions continuously. So we chose the Tower Pro MG996R servo due to its 13kg torque, and to not over load it, we will attach the main arm to a smaller arm and connect the servo to that arm. The main arm will also be on a bearing to help.
Attached below is a picture of the process that we are thinking of.
My questions are:
Will the servo be able to handle the weight, even with the bearing and smaller arm.
and for the smaller arm, can it be a rod or a stick like in the picture, or should we go with a joint?
Thank you.
Pic, posted properly:
Will the servo be able to handle the weight
That would depend on the value of the weight, the dimensions of the arms, and the direction of "down", which you forgot to state.
Please look up the units of torque. "kg" is not a unit of torque.
the weight will be around 1.5 kg, and the arm will have a length of 50 cm and width of 2 cm.
As for the torque, I only stated what was written on the servo that we chose
and what do you mean by direction of down?
omaryehya:
the weight will be around 1.5 kg, and the arm will have a length of 50 cm and width of 2 cm.
There are three arms in that image. Two combine to look like a single purple one; the third is the red one. You need all dimensions to calculate the torque the servo has to deliver.
"down" is that the object going down or the servo arm going down?
ohh ok, I see
no no the purple part is the whole arm, it will be 50 cm with the bearing in the middle, we will probably adjust the length later so that we have more on the inner side.
the smaller arm which will help the servo should be around 10 cm long since we need some space on the robot.
I am sorry that I don't have a very definitive answer. This is a group project and all of this is still in the schematics part so we are trying to get this correct.
Last part about the down direction, I don't think that anything will be moving down, since the arm will be moving 60 degrees in both directions (left and right) and the sensor connected to the end of it.
As for the torque, I only stated what was written on the servo that we chose
"kg" is not a unit of torque, however kgf-cm is.
If a 1.5 kg weight is to be moved up and down at the end of a 50 cm arm, then you need at least 50*1.5 = 75 kgf-cm of torque.
If the weight is moving from side to side, less torque will suffice. The more torque that the servo can supply, the more quickly you can move the arm.
Length of green bar unimportant.
Distances which will need to be known are from bearing center to payload, from bearing centre to where green servo link attaches, distance from centre of servo arm attaching screw to where green arm attaches.