Build Duke Humanoid v1

Steps

18

Subassemblies

6

Hands-on time (sum)

—

Critical path

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Your progress · this device

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18 steps have no time estimate; times above are lower bounds.

1. Fabrication
   01

   Order the CNC parts

   Download the CNC and DIY STEP zip from the BOM page and order every 'machined' part in Al 6061 (the lab used JLCCNC: ISO 2768 medium, Ra 3.2). Order mirror parts as separate left and right files; symmetric parts use one file for both legs. Holes are tapped by the shop or by you.

   CHECKYou have 15 body parts, 14 upper-leg plates, 26 lower-leg parts and 10 load shafts, and an M4 screw threads by hand into every tapped hole.

   Parts in

   • Body plates: 2x B_Shelf_Plate, 1x B_Base_Plate, 12x B_Corner_Connectorcnc.body
   • Upper leg (hip) plates, 7 per leg: Hip_0 Top/Front/Back/Inner/Outer, Hip_1 Inner/Outer (all symmetric)cnc.upper-leg
   • Lower leg parts, 13 per leg: Hip_to_Lower_Connector, Shank_Plate Outer/Inner, Knee_Joint_Holder, Knee_Rocker, Ankle_Rocker, 2x Shank_Ankle_Link, 2x Knee_Link, Shank_Link_Main, Shank_Link_Back, Foot_Main (mirror parts have L and R files)cnc.lower-leg
   • Bearing_Load_Shaftcnc.load-shaft

   Tools

   —

   Torque

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   Time

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   After

   Start

   Source

   notion.so

2. 02

   Print the DIY parts and grip the soles

   Print with the per-part settings in the manufacturing table. Apply 2 in grip tape to each foot sole and fuse it with a heat gun at about 300 °F, moving quickly so the printed foot does not deform.

   CHECKA FX29 load cell drops into each enclosure with its button proud of the surface, and the grip tape does not lift at the edges when flexed.

   Parts in

   • B_Teensy_Mount and B_IMU_Mountprinted.electronics-mounts
   • Knee_Stopper (mirror)printed.knee-stopper
   • Foot_Sole: hard (PLA/PLA-CF, 100% rectilinear) or soft (TPU 95A, 60% adaptive cubic, 0 walls, flow 0.9, ~60-70A)printed.foot-sole
   • Load_Cell_Enclosureprinted.load-cell-enclosure
   • Motor protection guards L/R_P_0..P_4printed.motor-protection
   • Joint zeroing jigs: A_hip_0_2_5_7, A_knee_ankle_3_4_L, A_knee_ankle_8_9_R, A_hip_1_L, A_hip_6_R (one of each design)printed.alignment-jigs
   • Filament: PLA (Creality), PLA-CF (Bambu Lab), TPU 95A HF (Polymaker)other.filament
   • CATTONGUE non-abrasive grip tape, 2 in (foot soles)other.grip-tape

   Tools

   FDM printer (lab used Bambu Lab X1C and Prusa MK4), Smooth PEI (PLA) and textured PEI (TPU) sheets, Heat gun

   Torque

   —

   Time

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   After

   Start

   Source

   notion.so

3. Test rig
   03

   Build the 80/20 test gantry

   Build the frame from the 80/20 extrusions (mitred 4080 members per the provided drawing) and plates. The robot hangs from it for dynamics matching and first walking.

   CHECKThe frame stands without rocking and a hanging robot's feet clear the floor with room for a full leg swing.

   Parts in

   • 80/20 gantry extrusion: 1x 40-8016 @ 1828.8 mm, 2x 40-8080 @ 1828.8 mm, 2x 40-8080 @ 1524 mm, 4x 40-4080 @ 1219.2 mm (mitred), 2x 40-4080 @ 609.6 mm (mitred)structure.gantry-extrusion
   • 80/20 gantry plates and brackets: 6x 14105 corner bracket, 4x 40-4325, 4x 40-4328, 4x 40-4365, 12x 40-4362, 4x 40-4330, 8x 40-4331structure.gantry-plates
   • Gantry fasteners: M8 sliding T-nuts (18 packs of 20) and M8x1.25x16 SHCS (9 packs of 40)fastener.gantry

   Tools

   Hex keys

   Torque

   —

   Time

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   After

   Start

   Source

   notion.so

4. Legs
   04

   Upper legs: hip yaw, roll and pitch

   Follow the upper-leg assembly video for each leg. Motor_1 rotor takes M5x25, Motor_0 rotor M4x25, everything else M4x12. Use a sesame-seed amount of Loctite 222; excess threadlocker can damage the motors.

   CHECKEach hip axis turns by hand through its range with no binding and no axial play at the 65x85x10 bearings.

   Parts in

   • Upper leg (hip) plates, 7 per leg: Hip_0 Top/Front/Back/Inner/Outer, Hip_1 Inner/Outer (all symmetric)cnc.upper-leg
   • Motorevo PA-100-2018 geared motor, 18:1 (rated 40 Nm / 20 A), hip yaw, hip roll, kneeactuator.pa100-18
   • Motorevo PA-100-2020 geared motor, 20:1 (rated 44.8 Nm / 20 A), hip pitchactuator.pa100-20
   • Bearing 65x85x10 mm (hip and knee motor axes)structure.bearing-65x85x10
   • Flanged bearing 25x37x7 mmstructure.bearing-25x37x7f
   • M5x25 socket head cap screw (Motor_1 rotor)fastener.m5x25-shcs
   • M4x25 socket head cap screw (Motor_0 and Motor_2 rotors)fastener.m4x25-shcs
   • M4x12 button head screw (everything else)fastener.m4x12-bhcs
   • Loctite 222 low-strength threadlockerother.loctite-222
   • PTFE lubricant (bearings)other.ptfe-grease

   Tools

   Hex keys (wiki recommends Bondhus)

   Torque

   —

   Time

   —

   After

   01

   Source

   notion.so

5. 05

   Lower legs: knee and ankle parallel linkage

   Follow the lower-leg video: mount Motor_3 (knee) and Motor_4 (ankle) with M4x12, Motor_2 rotor with M4x25, and build the knee and shank-ankle linkages on M4x20 screws and nuts with needle bearings and spacers.

   CHECKKnee and ankle move through their range by hand with no play in the linkage, and the knee stopper stops hyperextension.

   Parts in

   • Lower leg parts, 13 per leg: Hip_to_Lower_Connector, Shank_Plate Outer/Inner, Knee_Joint_Holder, Knee_Rocker, Ankle_Rocker, 2x Shank_Ankle_Link, 2x Knee_Link, Shank_Link_Main, Shank_Link_Back, Foot_Main (mirror parts have L and R files)cnc.lower-leg
   • Bearing_Load_Shaftcnc.load-shaft
   • Motorevo PA-100-2018 geared motor, 18:1 (rated 40 Nm / 20 A), hip yaw, hip roll, kneeactuator.pa100-18
   • Motorevo PA-100-2010 geared motor, 10:1 (rated 22.4 Nm / 20 A), ankleactuator.pa100-10
   • Bearing 65x85x10 mm (hip and knee motor axes)structure.bearing-65x85x10
   • Flanged bearing 25x37x7 mmstructure.bearing-25x37x7f
   • Needle bearing 10x14x10 mm (knee/ankle linkage)structure.needle-10x14x10
   • Spacer / thrust washer 18x10x2 mmstructure.spacer-18x10x2
   • 10 mm external retaining ring (lower leg shafts)structure.retaining-ring-10
   • M4x25 socket head cap screw (Motor_0 and Motor_2 rotors)fastener.m4x25-shcs
   • M4x20 screw (parallel linkage)fastener.m4x20
   • M4 nut (parallel linkage)fastener.m4-nut
   • M4x12 button head screw (everything else)fastener.m4x12-bhcs
   • Knee_Stopper (mirror)printed.knee-stopper
   • Loctite 222 low-strength threadlockerother.loctite-222

   Tools

   —

   Torque

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   Time

   —

   After

   04, 02

   Source

   notion.so

6. Body
   06

   Base plate: hip motors, IMU, sensor-board mount

   Screw the hip 0/5 motors (20:1 and 18:1) to the top side of the base plate with M4x12, using very little Loctite. Seat the IMU on its mount with the cable in the channel, centre it with the wired side facing forward, and push it onto the plate pegs. Tap and fit the PCB mount, then stand an extrusion in each corner with corner brackets, M5 screws and sliders.

   CHECKThe IMU is on the robot centreline with its cable side forward, and the four corner extrusions are square to the plate.

   Parts in

   • Body plates: 2x B_Shelf_Plate, 1x B_Base_Plate, 12x B_Corner_Connectorcnc.body
   • B_Teensy_Mount and B_IMU_Mountprinted.electronics-mounts
   • MicroStrain 3DM-CV7-AHRS IMUsensor.imu
   • 2020 aluminium extrusion, cut: 4x 353 mm, 2x 260 mm (b), 2x 260 mm (c)structure.extrusion-2020
   • M4x12 button head screw (everything else)fastener.m4x12-bhcs
   • M5x10 button head screw (corner connectors)fastener.m5x10-bhcs
   • M5 sliding T-nut for 2020 extrusionfastener.m5-tnut
   • M4 and M5 external-tooth lock washers (as needed)fastener.lock-washers

   Tools

   —

   Torque

   —

   Time

   —

   After

   04, 02

   Source

   notion.so

7. Legs
   07

   Feet with toe and heel load cells

   Seat the sensor holders in the empty foot, line the foot holes up with the aluminium, insert each load cell with the ridge aligned, then screw the foot on with Loctite. Do not overtighten; it can damage the force sensors.

   CHECKThe foot sits flat on a table, and pressing each corner deflects only the load-cell button, not the sole.

   Parts in

   • Foot_Sole: hard (PLA/PLA-CF, 100% rectilinear) or soft (TPU 95A, 60% adaptive cubic, 0 walls, flow 0.9, ~60-70A)printed.foot-sole
   • Load_Cell_Enclosureprinted.load-cell-enclosure
   • TE FX29 compression load cell, 100 lbf, I2C (toe and heel of each foot)sensor.load-cell
   • Lower leg parts, 13 per leg: Hip_to_Lower_Connector, Shank_Plate Outer/Inner, Knee_Joint_Holder, Knee_Rocker, Ankle_Rocker, 2x Shank_Ankle_Link, 2x Knee_Link, Shank_Link_Main, Shank_Link_Back, Foot_Main (mirror parts have L and R files)cnc.lower-leg

   Tools

   —

   Torque

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   Time

   —

   After

   05

   Source

   notion.so

8. 08

   Fit the TPU motor guards

   Fit the ten TPU motor protection pieces (P_0 to P_4 per leg) over the actuators.

   CHECKNo guard touches a moving link anywhere in the range of motion.

   Parts in

   • Motor protection guards L/R_P_0..P_4printed.motor-protection

   Tools

   —

   Torque

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   Time

   —

   After

   05

   Source

   notion.so

9. Body
   09

   Middle plate: motor controllers

   Mount two motor controllers per controller plate with heat conduction to the plate, fit the power and ground splitters in the middle, tap the middle plate and fix the controller plates without overtightening. Slide the plate onto the extrusions with the controllers facing down, leaving room for the top plate.

   CHECKAll ten controllers are fixed, cable-tied, and their EtherCAT and power ports are reachable.

   Parts in

   • Body plates: 2x B_Shelf_Plate, 1x B_Base_Plate, 12x B_Corner_Connectorcnc.body
   • Motor controller assembly (Elmo-based EtherCAT drive, CiA 402), one per motorelectronics.motor-controller
   • M5x10 button head screw (corner connectors)fastener.m5x10-bhcs
   • M5 sliding T-nut for 2020 extrusionfastener.m5-tnut

   Tools

   —

   Torque

   —

   Time

   —

   After

   06

   Source

   notion.so

10. 10

    Top plate and top frame

    Fit the top plate on corner brackets and sliders (an onboard Jetson is optional and goes between the plates). Build the rectangular top frame from 3-way connectors and slide it onto the body.

    CHECKThe body is rigid when twisted by hand and the top frame can take the gantry hook.

    Parts in

    • Body plates: 2x B_Shelf_Plate, 1x B_Base_Plate, 12x B_Corner_Connectorcnc.body
    • 3-way corner connector assembly for 2020 extrusion (top frame)structure.3way-connector
    • 2020 aluminium extrusion, cut: 4x 353 mm, 2x 260 mm (b), 2x 260 mm (c)structure.extrusion-2020
    • M5x10 button head screw (corner connectors)fastener.m5x10-bhcs
    • M5 sliding T-nut for 2020 extrusionfastener.m5-tnut

    Tools

    —

    Torque

    —

    Time

    —

    After

    09

    Source

    notion.so

11. Electrical
    11

    Sensor board: Teensy, I2C mux, IMU and load-cell leads

    Hand-solder the IMU ribbon (wire 1 is red) to USB and UART. Make one Ethernet extender per leg carrying two load cells on MX1.25 connectors using the wiki's colour map. Keep every load-cell I2C line separate into its own TCA9548A channel, give every device its own decoupling capacitor, and connect the mux to the Teensy I2C pins.

    CHECKContinuity on every extender wire; with one load cell on a Linux I2C bus, `i2cdetect -y <bus>` shows 0x28.

    Parts in

    • PJRC Teensy 4.0 with pins (sensor hub: IMU over UART, load cells over I2C)electronics.teensy40
    • TCA9548A 8-channel I2C multiplexer breakout (FX29 address 0x28 is fixed)electronics.i2c-mux
    • 4.7 kΩ resistor (I2C pull-ups)electronics.r-4k7
    • 220 Ω resistorelectronics.r-220
    • 100 nF capacitor (per-device decoupling on the sensor board)electronics.c-100n
    • Samtec FFSD-05-S-05.00-01-N ribbon cable (IMU has no premade leads; solder USB + UART by hand)cable.imu-connector
    • Monoprice SlimRun Ethernet patch cable, ~2 m per leg, re-terminated as load-cell extenderscable.load-cell-extender
    • Pre-crimped MX1.25 male/female connector set (detachable load cells)cable.mx125
    • MicroStrain 3DM-CV7-AHRS IMUsensor.imu
    • TE FX29 compression load cell, 100 lbf, I2C (toe and heel of each foot)sensor.load-cell

    Tools

    Soldering iron, Multimeter

    Torque

    —

    Time

    —

    After

    07, 06

    Source

    notion.so

12. 12

    48 V supply bank, e-stop and bus capacitor

    Safety · human-verified required

    Wire four RSP-2000-48 supplies in parallel per the Mean Well datasheet: 12 AWG AC input (check your cable's colours), 24 AWG current-share signals, 8 AWG outputs to the distribution block, the e-stop on each supply's remote on/off, and the 0.33 F capacitor on the block with 4 AWG. Keep the motor controllers disconnected.

    CHECKWith controllers unplugged: the block reads about 48 V with correct polarity, and pressing the e-stop drops it to 0 V on all four supplies.

    This step can hurt a person or ruin parts. Its instructions need sign-off by a human who has done it before relying on them. Stop and ask if anything differs from what you see.

    Parts in

    • Mean Well RSP-2000-48 48 V 2000 W supply, 4 in parallel (active current sharing)power.psu
    • Latching emergency stop switch on the supplies' remote on/offpower.estop
    • KEMET ALS70A334QS063 0.33 F capacitor on the distribution blockpower.capacitor
    • Power distribution block (uxcell terminal block)power.distribution-block
    • 12 AWG 3-prong AC power cable, one per supplycable.ac-12awg
    • Power wire: 8 AWG (supply outputs), 4 AWG (capacitor), 24 AWG (current-share signals)cable.wire-power

    Tools

    Crimp tool, Multimeter

    Torque

    —

    Time

    —

    After

    09

    Source

    notion.so

13. 13

    EtherCAT chain and host

    Safety · human-verified required

    Daisy-chain the ten controllers in the wiki's topology order to the host's Ethernet port, then power the bus from the supply bank with the robot hanging on the gantry.

    CHECK`sudo ./ext/SOEM/test/linux/slaveinfo/slaveinfo enp3s0 -sdo` lists 10 slaves.

    This step can hurt a person or ruin parts. Its instructions need sign-off by a human who has done it before relying on them. Stop and ask if anything differs from what you see.

    Parts in

    • Motor controller assembly (Elmo-based EtherCAT drive, CiA 402), one per motorelectronics.motor-controller
    • Linux PC, Ubuntu 22.04 + CUDA 12.3, Ethernet port used as EtherCAT master (e.g. enp3s0)compute.host

    Tools

    SOEM slaveinfo

    Torque

    —

    Time

    —

    After

    12, 10

    Source

    notion.so

14. Bring-up
    14

    Load and match the drive configurations

    Safety · human-verified required

    For each joint pair, import the published .gprm file (motor0 to motor4 pages) under Expert Tuning > Axis Configuration > Import Page Parameters, then finalise current, velocity and position loops. Tune one motor of each pair and copy its configuration to the other leg.

    CHECKLeft and right motors of each pair track the same position trajectory with overlapping plots in Elmo.

    This step can hurt a person or ruin parts. Its instructions need sign-off by a human who has done it before relying on them. Stop and ask if anything differs from what you see.

    Parts in

    • Motor controller assembly (Elmo-based EtherCAT drive, CiA 402), one per motorelectronics.motor-controller
    • Motorevo PA-100-2018 geared motor, 18:1 (rated 40 Nm / 20 A), hip yaw, hip roll, kneeactuator.pa100-18
    • Motorevo PA-100-2020 geared motor, 20:1 (rated 44.8 Nm / 20 A), hip pitchactuator.pa100-20
    • Motorevo PA-100-2010 geared motor, 10:1 (rated 22.4 Nm / 20 A), ankleactuator.pa100-10

    Tools

    Elmo Application Studio II (Windows)

    Torque

    —

    Time

    —

    After

    13

    Source

    notion.so

15. 15

    Build host software and flash the Teensy

    Clone DukeHumanoidv1 with submodules, create the py38 environment, build the SOEM-based ethercat_motor_py extension with CMake, and upload teensy_comm.ino with the TCA9548 and Packetizer libraries. In MicroStrain SensorConnect set the IMU to 921600 baud and save without 'sample on startup'.

    CHECK`sudo chrt -f 99 $(which python) -u sensor_controller.py` streams IMU orientation and four load-cell readings (unloaded values inside the FX29's 300-1700 count zero band).

    Parts in

    • Linux PC, Ubuntu 22.04 + CUDA 12.3, Ethernet port used as EtherCAT master (e.g. enp3s0)compute.host
    • PJRC Teensy 4.0 with pins (sensor hub: IMU over UART, load cells over I2C)electronics.teensy40

    Tools

    micromamba, vcpkg (msgpack, eigen3, iir1), CMake + GCC 12, Arduino IDE + Teensyduino

    Torque

    —

    Time

    —

    After

    11, 13

    Source

    github.com

16. 16

    Joint initialization with the alignment jigs

    Safety · human-verified required

    Constrain every joint in its zero pose with the hip, thigh and ankle jigs, then run motor_controller.py, which records the encoder offsets per motor. This is needed after every power-on, because the encoder position repeats once per reduction-ratio sector.

    CHECKAfter removing the jigs, `trajectory_PD_test.py` holds the robot in the zero configuration, standing with straight knees.

    This step can hurt a person or ruin parts. Its instructions need sign-off by a human who has done it before relying on them. Stop and ask if anything differs from what you see.

    Parts in

    • Joint zeroing jigs: A_hip_0_2_5_7, A_knee_ankle_3_4_L, A_knee_ankle_8_9_R, A_hip_1_L, A_hip_6_R (one of each design)printed.alignment-jigs

    Tools

    —

    Torque

    —

    Time

    —

    After

    15, 14, 08

    Source

    notion.so

17. 17

    Sim-to-real trajectory matching on the gantry

    With the robot hanging, run `bash run.sh match_dyn` in legged_env, `trajectory_PD_test.py` on the robot and `sshkeyboard_pd_test.py` to drive both, then compare /sim and /real in PlotJuggler and adjust armature, friction and damping.

    CHECKJoint position traces for /sim and /real overlap for every joint through a keyboard-commanded trajectory.

    Parts in

    —

    Tools

    PlotJuggler (msgpack, port 9870)

    Torque

    —

    Time

    —

    After

    16, 03

    Source

    notion.so

18. 18

    Run the published walking policy

    Safety · human-verified required

    Run `biped_controller.py` with the baseline or passive ONNX checkpoint and `gamepad.py` in a second terminal. Start on the gantry with a hand on the e-stop.

    CHECKThe robot walks forward and stops on gamepad command without falling for 30 s, with the gantry line slack.

    This step can hurt a person or ruin parts. Its instructions need sign-off by a human who has done it before relying on them. Stop and ask if anything differs from what you see.

    Parts in

    • 8BitDo Ultimate controller with 2.4 GHz adapter (velocity commands)electronics.gamepad

    Tools

    —

    Torque

    —

    Time

    —

    After

    17

    Source

    github.com

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