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Design of the robot : Standart Components

The base of the robot  contains two DC gear-motors. Each of them drives a wheel. Each motor is run  seperately by the microcontroller through a control unit.


The chosen componant is a Micromotors DC gear-motor, model : L149.6.21.
Advantages : cheap, small, it can bear a  10 N radial weight .
The chosen solution of assembly is to fix the wheel directly on the rotor arm with a screw on the flat side of the shaft. The motor is mounted on the plate with two front-face holes.

Data sheet :
Micromotors série L149 (Pdf, 40 Ko)
Modeling :
Draft of the DC gear-motor (Pdf, 69 Ko)

The arm of the robot is fitted with  four servomotors. They allow the three rotations of te arm as well as the tightening of the gripper.

The chosen model is a very compact Multiplex model (Tiny-S).
The advantages of this reference is its small size
(30 x 12 x 30 mm) together with an good torque (26 Ncm).
Its lightness
(17 g) also makes it possible to limit the couple coming from the weight of the arm.

Data sheet :
Extract of Multiplex documentation : servomotors (Pdf, 41 Ko). Page presenting each model principal caracteristics of constructer's analogic servomotors. Example applications are given for each reference.
Notes regarding the installation and operation of servos :
Extract of Multiplex documentation : important terms (Pdf, 34 Ko). Page explaining caracteristics, selection criterias and utilisation advices to optimize period of use and reduce consumption.
Modeling :
Draft of the servomotor (Pdf, 83 Ko)