Getting Started

pip install kscale-onshape-library
pip install 'kscale-onshape-library @ git+https://github.com/kscalelabs/onshape.git@master'  //Install from Github
pip install 'kscale-onshape-library[all]' // Install all dependencies

Set you API Key

Obtain from: https://cad.onshape.com/appstore/dev-portal

Then set in your .bashrc (or .zshrc etc.)

export ONSHAPE_ACCESS_KEY=Your_Access_Key
export ONSHAPE_SECRET_KEY=Your_Secret_Key

Minimal Run Example

kol run https://cad.onshape.com/documents/af093f8....

The most frequently used arguments with kol run takes are:

-o "path/to/folderForRobot" to specify location outputs of KOL is stored
-f "configFilePath.yaml

To also convert to a XML for MuJoCo, you need to specify a metadata.json file

Config File Reference

Ignore Welding Joints

By default, fixture joints on the same body gets combined into one body. To avoid this you can set the following params:

ignore_merging_fixed_joints:
  - "imu_link"

merge_fixed_joints: false

Examples

Full Example with Robot

default_revolute_joint_effort: 17
default_revolute_joint_velocity: 360
suffix_to_joint_effort:
  "_00": 14
  "_02": 17
  "_03": 60
  "_04": 120
suffix_to_joint_velocity:
  "_00": 12.566
  "_02": 12.566
  "_03": 6.283
  "_04": 6.283
convex_collision_meshes: true

ignore_merging_fixed_joints:
  - "imu_link"

rotate_joints:
  imu_link: [-90.0, 0.0, 0.0]

max_mesh_triangles: 10000
max_convex_collision_mesh_triangles: 100

exclude_collision_meshes:
  # Shoulder yoke stops.
  - "YOKE_STOP_INNER"
  - "YOKE_STOP_INNER_2"
  # Hip yoke stops.
  - "KB_D_102L_L_Hip_Yoke_Drive"
  - "KB_D_102R_R_Hip_Yoke_Drive"
  # Upper arms
  - "L_Bicep_Lower_Drive"
  - "R_Bicep_Lower_Drive"
  # Forearms
  - "L_Forearm_Upper_Drive"
  - "R_Forearm_Upper_Structural"
  # Knee
  - "KB_D_301R_R_Femur_Lower_Drive"
  - "KB_D_301L_L_Femur_Lower_Drive"
  # IMU
  - "imu"

shrink_collision_meshes:
  # Leg roll
  "RS03_4": 0.8
  "RS03_3": 0.8
  # Ankle
  "KB_D_401R_R_Shin_Drive": 0.85
  "KB_D_402L_L_Shin_Idle": 0.85
  # Wrist
  "KB_C_501X_Bayonet_Adapter_Hard_Stop": 0.8
  "KB_C_501X_Bayonet_Adapter_Hard_Stop_2": 0.8
  # Base
  "KB_B_102B_TORSO_BOTTOM": 0.8

move_collision_meshes:
  "R_Bicep_Lower_Drive": [0.0, 0.0, -0.01]
  "L_Bicep_Lower_Drive": [0.0, 0.0, -0.01]

joint_separation_distance: 0.001

base_rpy:
  - 0
  - 0
  - 4.7123889803 # So that x is forward in mujoco

flip_joints:
  - "left_knee_04"
  - "left_shoulder_roll_03"
  - "right_shoulder_roll_03"
  - "left_hip_roll_03"
  - "right_hip_roll_03"
  - "left_ankle_02"

mjcf_metadata:
  joint_params:
    - name: "motor_00"
      armature: 0.0005
      frictionloss: 0.1
      actuatorfrc: 14
      suffixes: ["_00"]
    - name: "motor_02"
      armature: 0.002
      frictionloss: 0.1
      actuatorfrc: 17
      suffixes: ["_02"]
    - name: "motor_03"
      armature: 0.005
      frictionloss: 0.3
      actuatorfrc: 60
      suffixes: ["_03"]
    - name: "motor_04"
      armature: 0.007
      frictionloss: 0.1
      actuatorfrc: 120
      suffixes: ["_04"]

  # imus:
  #   - body_name: "imu"
  #     acc_noise: 0.01
  #     gyro_noise: 0.01
  #     mag_noise: 0.05
# This is for debugging purposes.
# use_collision_meshes_as_visual_meshes: true

CAD Considerations

Use Fixture joints and Revolute joints only
Set joint limits on all Revolute joints