Neck pitch and head rotation (q1 and q2)

Neck pitch movement is actuated by two synchronized Dynamixel MX-106R servomotors bolted to the mounting bracket (part no. 40009488). Servo horns are connected to to two neck supports (parts no. 40009489/90). These supports serve as limiters for neck pitch and are the mounting place for casing of the head rotation servo. Head rotation is based on a Dynamixel MX-64R servomotor. Its active horn is connected to the neck mounting (part no. 40009486) which is supported by a modified igus bearing (part no. 40009514). The mechanism and limits for neck pitch are shown in Fig. 1

neck driveneck pitch
Fig. 1 Neck drive and neck pitch limits.


Head pitch and bottom disc (q3 and q4)

The head pitch is actuated by a Dynamixel MX-28R. Its horns are fixed to the support tube using two mountings (part no. 40009492) connected to the bottom disc servo mounting (part no. 40009504). The casing of the head pitch servo is fixed to the neck mounting (part 40009486). The bottom disc (part no. 40009505) is also actuated by a Dynamixel MX-28R servomotor. There are two mountings (part no. 40009491) connecting both the active and passive servo horns to the bottom disc plate. The mechanism is shown in Fig. 2.

bottom disc drive
Fig. 2 Bottom disc drive.

Top disc (q5)

The top disc (part no. 40009510) can move up and down owing to a Dynamixel MX-28R servomotor. There are two mountings (part no. 40009491) connecting both the active and passive servo horns to the top disc plate. The servo casing is fixed to the main support tube (part no. 40009497) of the robot with a mounting (part no. 40009509). The mechanism is shown in Fig. 3.

top disc drive
Fig. 3 Top disc drive.

Eye drive (q6-q11)

The complete eye drive allows to rotate and protrude the eyeball as well as close/open the eyelid. Eye protrusion is achieved via a modified linear drive (SLN-27 produced by igus) driven by a Maxon DCX 22S motor. The motor drives a screw (part no. 40009515) which in turn drives a carriage (part no. 40009512) with a custom 3d printed mounting (part no. 40009499 Rev. A) that holds the eye rotation servo and also contacts the limit switches on the controller in order to determine carriage starting position. The screw actuating the carriage has a 5 mm thread pitch which allows very rapid eye protrusion. Eye rotation is achieved with a MKS DS75K-N servo coupled with a long eye support tube (part no. 40009484) mounted in a bearing (part no. 40009494) which allows simultaneous eye rotation and protrusion. The eyeball (part no. 40009500) is mounted at the end of this tube. It is hollow inside to accomodate the eyelid servo. The mechanism for the right eye is shown in Fig. 4.

eye driveFig. 4 Eye drive.

Drive system summary

Joint Drive Manufacturer Documentation
q1 2x Dynamixel MX-106R Robotis LINK
q2 Dynamixel MX-64R Robotis LINK
q3 Dynamixel MX-28R Robotis LINK
q4 Dynamixel MX-28R Robotis LINK
q5 Dynamixel MX-28R Robotis LINK
q8 maxon DCX22S maxon motors LINK
q11 maxon DCX22S maxon motors LINK



EMYS and FLASH are Open Source and distributed according to the GPL v2.0 © Rev. 0.9.2, 23.11.2017

FLASH Documentation