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Design of the robot : the Robotic Arm

The   prehension unit is fitted with three servomotors for the rotation and a fourth one for the tigthening of the gripper.
The connection with the base is carried out by the fixing of the first servomotor with the help of two M3 screws.

Design of the arm
Draft of the robotic arm (Pdf, 246 Ko)

Mass properties and center of gravity determination are very important for selection of the servomotors (model, torque), especially  the lowering arm servomotor (servo 2).


Note : a calculation page permits to recapitulate each part influence and to adjust if necessary properties of the elements.
1°) we attribute a specific material to the servomotor to have a mass of 17 g.
Note : select the context Attributes , the fonction Material and choose : Manager materials. Then create a specific material (Mat_comp_Servo) in the category Miscellaneous, with density 1.72 kg/dm3.
2°) we open the ROBOT ASSEMBLY file and we apply the fonction Analyse element with physical informations display to the Arm Tiny-S compact D.

Note : informations display concern the arm alone. To take into account the object to deplace (8 g in our calculation page), we have to modelize it in the sub assembly document and apply an appropriate material to it.

The design of the arm includes angular drivers to parameter its position. We just have to select the tool Modify élément , click on the arm to accede to the menu list of the four angular position parameters.

Rotation angle arm (servo 1)

C = -28° C = +42°
Rotation C-28°

Lowering angle arm (servo 2)

B = +45° B = -90°

Rotation angle wrist (servo 3)

A = -90° A = +90°

Gripper opening angle (servo 4)

Angle +90° Angle -10°