Overview and Specifications

Overview and specification of the hardware used by NUbots.
Updated 13 May 2022

The NUbots team uses the NUgus hardware platform, a modification of the igus® Humanoid Open Platform. The NUgus robots are 3D printed using fused deposition modelling.

Coronal and saggital images of the NUgus robot
Coronal and saggital images of the NUgus robot

igus® Modifications

The following modifications were made to fit our specific requirements:

  • The components of the robot were split to to fit the size of the printer bed and volume.
  • The torso was modified to have open shoulder covers for shoulder servo cable access.

Servos

The arms and head of the NUgus robot use Dynamixel MX64AR servos, with two in each shoulder, one in each elbow, and two in the neck. The legs use Dynamixel MX106 servos, with two in each ankle, three in each hip, and one in each knee.

There are custom made mounting brackets milled from aluminium for the flywheels, and servo-to-servo mounting brackets in the neck, hip, and ankle. There are also 3D printed cable clamps on the back of the knees, ankle and hip blocks.

The servos have been modified to include a 1.5KE18CA TranZorb, formerly 1N6385 TranZorb, connected in parallel to the servo motor. This is done to prevent induced EMF from overloading the electronics in the servo. EMF can be induced when the servos are manually moved without power being applied (i.e. grabbing the robot's leg and forcing the knee to bend).

Top view of the mounted TranZorb. The two arms of the TranZorb are soldered to the motor terminals. Hot glue is added to stabilise the TranZorb against shocks and vibrations.
Top view of the mounted TranZorb. The two arms of the TranZorb are soldered to the motor terminals. Hot glue is added to stabilise the TranZorb against shocks and vibrations.
Side view of the mounted TranZorb. TranZorb arm is soldered on to the motor terminal along with the already existing motor connection, which is a black cable
Side view of the mounted TranZorb. TranZorb arm is soldered on to the motor terminal along with the already existing motor connection (black cable)

The TranZorb is soldered directly on to the terminals of the servo motor. Hot glue is applied to stabilise the TranZorb against shocks and vibrations.

Cameras

The NUgus robot uses two FLIR Blackfly S USB3 cameras with a C-Mount lens positioned in their head, producing images at up to 170FPS. Two custom-built S-Mount to C-Mount lens adaptors are used to attach two Lensation 180° fisheye S-Mount lenses. Two 20" USB3 micro USB to up angle USB A cables are used to connect the cameras to the robot's computer.

Computing

The NUgus robot uses the Intel NUC7i7bnh with a Silverstone NT07-115X cooling fan. The cooling fan's supporting arms were removed and extra screw holes drilled to line up with the mounting points on the NUC. A copper spacing plate was milled to bridge the gap between the NUC processor and the fan.

The USB and fan sense connectors are Molex 51021-0400 and the power connectors on the NUC and fan are Molex 50-37-5043. The CM740 to NUC power connector is a Yeonho SMH250-02.

It has 8GB of RAM, a 256GB SSD, and a Robotis CM740 Sub Controller.

Networking

The NUgus robot has an Ethernet port as well as WiFi capability. It has two custom-ordered 15cm MHF.4 to RP-SMA wireless antenna cables from the RFShop, with two RP-SMA antennas which are around 1" long.

Power

The NUgus robot has a Cosel AC/DC Power Supply. It uses a 3850mAh 4S LiPo Battery when not plugged into power. It uses a rebuilt Darwin power board and a custom 16A cylindrical fuse holder. The NUC power board which distributes power to the cooling fan and the NUC is also custom. The NUgus robot uses custom cables to provide power to the fan, the NUC, and sense and speed control to the fan.

Foot Studs

The studs attached to the feet have been purchased from RS Online. Phil Dombkins can shave the sides of these cylindrical rubber studs into a more conical shape (and has done so in the past). An M5 nut is needed for attaching the studs to the feet.

Tools
NUgan
Main Codebase
Getting Started
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