urkit 0.3.2

Universal Robots e-Series control toolkit built on ur_rtde

URKit

URKit is a Python toolkit for Universal Robots e-Series robots that makes the common stuff simple and gets out of the way for everything else.

Built on ur_rtde, it packages the operations you reach for most: connecting, moving to named points, gripper control, telemetry, and I/O, while exposing the raw RTDE interfaces for anything deeper.

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Table of Contents

• Quick Start
• Interactive CLI
  • Teach Mode
  • Points Explorer
  • Key Map
• API Reference
  • Connecting
  • Grippers
  • Points & Motion
  • Telemetry
  • Digital I/O
• Configuration
• Advanced
  • Raw RTDE Access
  • Connection Lifecycle
  • Error Handling
• Changelog

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Quick Start

pip install -U urkit

The -U (upgrade) flag ensures you always get the latest version — this project is in early development and changes frequently.

Requires Python 3.8+ and a Universal Robots e-Series (UR3e to UR30).

Robot Setup (one-time)

1. Network: ☰ → System → System → Network. Set a static IP on the robot and a matching one on your PC. Both addresses must share the same first three octets (the network), with a different last octet (the host). For example:
   • Robot: 172.31.1.42 / Subnet 255.255.255.0
   • PC: 172.31.1.1 / Netmask 255.255.255.0
   • Verify with ping 172.31.1.42. Connect via direct Ethernet cable or a switch.
2. Remote Control: ☰ → System → Remote Control: Enable. Press the remote/local button on the pendant.
3. Security: ☰ → Security → Services: enable RTDE and disable EtherNet/IP, PROFINET, or MODBUS if they're claiming RTDE registers. Save and restart.

That's it. No .urp files to run, no extra programs needed.

Example

If you have a Robotiq gripper, install the Robotiq Gripper Control URCap first: download from robotiq.com/support, copy the .urcap to a USB drive, and install via ☰ → Settings → System → URCaps.

from urkit import URRobot, ROBOTIQ_HAND_E  # or ROBOTIQ_2F_85, ROBOTIQ_2F_140, or gripper=None

robot = URRobot(ip="172.31.1.42", points="points.db", gripper=ROBOTIQ_HAND_E)
robot.gripper.activate()

robot.move_to("home")
robot.move_to("pick", offset=[0, 0, 0.05, 0, 0, 0])
robot.gripper.close()
robot.move_to("place")
robot.gripper.open()

The typical workflow:

1. Teach points. Use the CLI to position the robot and save named waypoints.
2. Write code. Create a robot, move to points by name, apply offsets, run sequences.
3. Iterate. Add more points, tweak your code, repeat.

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Interactive CLI

URKit provides two CLI tools: teach for interactive robot control, and points for browsing saved waypoints.

Teach Mode

The interactive teach pendant for moving the robot, saving points, and checking telemetry:

urkit teach 172.31.1.42              # with robot IP
urkit teach                          # reads IP from config.yaml

Flags:

Flag	Description
ip	Robot IP address (positional, overrides config)
--gripper	Gripper preset: 2f-85, 2f-140, hand-e, digital, none
--gripper-pin	Digital gripper output pin (default: 0)
--gripper-force	Robotiq force 0-100
--gripper-speed	Robotiq speed 0-100
--gripper-close-on-high	Digital polarity: true or false
--points	Path to points.db file (overrides config)
--config	Path to config file (default: config.yaml in project root or CWD)
-e, --expert	Disable safety speed clamping (full speed for goto/tcp-down)
-v, --verbose	Show verbose output (debug connection issues)

Points Explorer

Browse saved waypoints with real-time search filtering. No robot connection needed:

urkit points                          # uses default points.db
urkit points test_points.db           # use specific database

Key Map

All movement and orientation keys support hold-to-repeat.

Movement	Orientation	Step Size
Key Action W / S +X / -X A / D +Y / -Y Q / E +Z / -Z	Key Action U / O Roll - / + I / K Pitch - / + J / L Yaw - / +	Key Action 1 Set linear step (mm) 2 Set angular step (deg) . Reset defaults (5 mm / 2°)

Gripper	Points	Controls
Key Action X Open C Close V Set position (mm) 6 Set speed (0-100) 7 Set force (0-100) Gripper line shows: `Connected 50.0mm (0%) F=100 S=100`	Key Action B Save current position G Go to saved point (Space to cancel mid-move, ESC to exit) H Delete saved point P Open points explorer R Rename saved point	Key Action F Freedrive (OFF → ALL → XYZ+Rz) M Toggle frame (BASE / TOOL) N Go To mode (Cartesian / Joint) T Orient TCP down (180°) Y Save config to file ESC Exit

Joint Display

The teach pendant shows live joint angles alongside TCP position and orientation:

 Position      X=+0.432  Y=+0.111  Z=+0.227
 Orientation   R=+131.3  P=-121.0  Y= +8.0
 Joints        J1=+150.0  J2=+020.0  J3=+160.0
               J4=+050.0  J5=-080.0  J6=+157.0

Joint angles color-code proximity to mechanical limits:

• Yellow: within 10% of joint range (warning)
• Red: within 5% of joint range (danger)

UR e-Series joint limits:

Joint	Range	Notes
J1 (shoulder pan)	±360°	Full rotation
J2 (shoulder lift)	±360°	Full rotation
J3 (elbow)	±180°	Physically restricted — shoulder lift gets in the way
J4 (wrist 1)	±360°	Full rotation
J5 (wrist 2)	±360°	Full rotation
J6 (wrist 3)	±360°	Tool flange unlimited rotation

Thresholds scale with each joint's range, so warning zones feel proportional across all joints.

Safety

By default, Go To and TCP Down movements use a slow velocity (0.125 m/s) so its safer for anyone standing near the robot. The user's speed slider still applies as a global multiplier on top of this.

Delta movements (W/S/A/D/Q/E) use step-size-based velocities that scale with the speed slider set by the user.

To disable the slow default and use full speed, pass --expert or set expert_mode: true in your config:

urkit teach 172.31.1.42 --expert

# config.yaml
expert_mode: true

---

API Reference

Connecting

from urkit import URRobot, ROBOTIQ_HAND_E

robot = URRobot(ip="172.31.1.42", points="points.db", gripper=ROBOTIQ_HAND_E)

With custom motion defaults:

robot = URRobot(
    ip="172.31.1.42",
    points="points.db",
    gripper=ROBOTIQ_HAND_E,
    default_vel=0.5,    # m/s
    default_acc=0.3,    # m/s²
)

From a config file:

robot = URRobot.from_config("config.yaml")
robot = URRobot.from_config("config.yaml", ip="10.0.0.50")  # override IP

Grippers

Three built-in presets:

Preset	Description
ROBOTIQ_HAND_E	Robotiq 2F-140-E (Hand-E series)
ROBOTIQ_2F_85	Robotiq 2F-85
ROBOTIQ_2F_140	Robotiq 2F-140

robot.gripper.activate()              # required before open/close (Robotiq only)
robot.gripper.is_activated()          # check activation state

robot.gripper.open()                  # fully open (blocking by default)
robot.gripper.close()                 # fully closed, stops on contact
robot.gripper.open(wait=False)        # non-blocking return
robot.gripper.set_position(20)        # 20mm open (Robotiq only, 0 = closed)
robot.gripper.set_force(50)           # grip force: 0-100 (Robotiq only)
robot.gripper.set_speed(80)           # movement speed: 0-100 (Robotiq only)

Override preset values for custom fingers:

robot = URRobot(ip="172.31.1.42", points="points.db", gripper=ROBOTIQ_HAND_E, max_mm=120)

Digital I/O Grippers

Robotiq grippers use a serial protocol over the robot's RS485 port. If you have a suction cup, solenoid, or any actuator controlled by a single digital output pin, use DigitalGripperConfig instead. It just turns that pin on (close) and off (open).

from urkit import URRobot, DigitalGripperConfig

robot = URRobot(
    ip="172.31.1.42",
    points="points.db",
    gripper=DigitalGripperConfig(pin=3),  # pin 3 goes high = close
)

robot.gripper.open()    # turn pin 3 off
robot.gripper.close()   # turn pin 3 on

set_force() and set_speed() are not available for digital grippers.

Points & Motion

The points database is optional. Create a robot without one and attach later:

robot = URRobot(ip="172.31.1.42")
robot.points_db = "points.db"

Moving to Points

robot.move_to("pick")                      # linear move (default)
robot.move_to("pick", linear=False)        # joint move
robot.move_to("pick", vel=1.0, acc=0.5)    # override speed
robot.move_to("pick", asynchronous=True)   # non-blocking, returns immediately

• Linear (moveL): TCP moves in a straight line. Predictable path, slower near complex orientations.
• Joint (moveJ): Each joint moves simultaneously. Faster, but the TCP follows an arc.
• Asynchronous: When asynchronous=True, the move runs in the UR controller's background thread and the method returns immediately.

Non-Blocking Moves

Start a move and do other things while it runs:

robot.move_to("pick", asynchronous=True)

# Poll until done
while robot.is_moving():
    time.sleep(0.01)

# Or cancel mid-move
robot.move_to("pick", asynchronous=True)
while robot.is_moving():
    if should_cancel:
        robot.stop()  # sends stopL + stopJ
        break
    time.sleep(0.01)

Teach pendant Go To uses this pattern internally — Space cancels the move and returns to the menu.

Pose Format

A pose is [x, y, z, rx, ry, rz]: position in meters and orientation as a rotation vector (axis-angle in radians). This is not RPY (roll/pitch/yaw). The teach pendant displays RPY in degrees, which is a different representation. Values you see on the pendant won't match get_tcp_pose() directly.

Offsets

Offsets are 6-element lists [dx, dy, dz, drx, dry, drz]:

robot.move_to("pick", offset=[0, 0, 0.05, 0, 0, 0])  # 5cm above pick

Resolve a Pose

Get a pose without moving. Useful for logging, comparisons, or custom motion:

pose = robot.get_pose("pick")
pose = robot.get_pose("pick", offset=[0, 0, 0.05, 0, 0, 0])  # with offset
robot.move_to(pose)  # move to the resolved pose later

Coordinate Frame

from urkit import MoveFrame

robot.move_frame = MoveFrame.TOOL   # default is BASE
robot.move_relative([0, 0, 0.05, 0, 0, 0])  # 5cm along tool Z

• BASE (default): delta relative to robot base
• TOOL: delta relative to TCP orientation

Points are tool-agnostic

Points are stored in the active TCP frame, so they work with any tool. If you swap grippers and set the correct TCP offset, your saved points remain valid.

Point Management

robot.save_point("here")
robot.point_names()           # ["home", "pick", "place"]
robot.rename_point("old", "new")
robot.delete_point("old")
robot.export_points("backup.json")
robot.import_points("backup.json")

Relative Moves

robot.move_relative([0, 0.01, 0, 0, 0, 0])  # 1cm along Y
robot.move_relative([0, 0, 0.05, 0, 0, 0], frame=MoveFrame.TOOL)  # 5cm along tool Z

Sequences with Blending

robot.move_sequence(["a", "b", "c"])
robot.move_sequence(["a", "b", "c"], blend_radius=0.02)

Contact Detection

robot.move_until_contact([0, 0, -0.02, 0, 0, 0])

Velocity Control

robot.move_velocity([0, 0, -0.02, 0, 0, 0], duration=1.0)

Freedrive Mode

from urkit import FreedriveMode

robot.enable_freedrive()              # all 6 axes free
robot.enable_freedrive(FreedriveMode.XYZ)      # linear axes + Rz rotation
robot.enable_freedrive(FreedriveMode.ROTATION) # rotation only
robot.disable_freedrive()             # disable before sending motion commands
robot.is_freedrive_active             # check state

Speed Control

robot.stop()                          # stop current move immediately (stopL + stopJ)
robot.speed_stop()                    # stop velocity-controlled motion (not E-stop)
robot.set_speed_slider(0.5)           # 50% velocity cap
robot.get_speed_slider()              # read current slider (0.0-1.0)

The speed slider controls the pendant's speed multiplier. It's global, persistent, and affects all motion commands.

Inverse Kinematics

joints = robot.inverse_kinematics([0.5, 0, 0.3, 0, 0, 0])

Telemetry

pose = robot.get_tcp_pose()           # [x, y, z, rx, ry, rz]
joints = robot.get_joint_positions()  # [j0..j5]
force = robot.get_tcp_force()         # [fx, fy, fz, mx, my, mz]
mode = robot.get_robot_mode()         # "REMOTE_CONTROL", "SERVOING", etc.
payload = robot.get_payload()         # kg
robot.is_moving()                     # bool — any joint/TCP velocity non-zero
robot.is_protective_stopped()         # bool
robot.is_emergency_stopped()          # bool
robot.current_point()                 # {"pose": [...], "joints": [...]}
robot.is_at_pose(target)              # bool — TCP within 1mm / 0.5°
robot.is_at_joints(target)            # bool — all joints within 0.001 rad

is_moving() is the simplest way to poll — is_at_pose() / is_at_joints() for precise target checking:

robot.move_to("pick", asynchronous=True)

# Simple: wait until robot stops
while robot.is_moving():
    time.sleep(0.01)

# Precise: check against specific target
while not robot.is_at_pose(target_pose):
    time.sleep(0.01)

Digital I/O

robot.set_digital_output(0, True)
robot.set_digital_outputs({0: True, 1: False, 8: True})
robot.set_digital_outputs(False)      # clear all

robot.get_digital_input(0)
robot.get_analog_input(0)
robot.get_tool_input(0)

robot.wait_for_input(0, True, timeout=10.0)  # block until pin 0 goes high

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Configuration

URKit uses a YAML config file (config.yaml) to persist settings between sessions.

Location

URKit searches for config.yaml in this order:

1. Explicit path via --config flag or load_config("path")
2. Project root (where src/urkit lives)
3. Current working directory

Keys

Key	Description	Example
robot_ip	Robot IP address	172.31.1.42
points_path	Path to SQLite points database	points.db
gripper	Gripper preset name	hand-e, 2f-85, 2f-140, digital
default_vel	Default linear velocity (m/s)	0.5
default_acc	Default linear acceleration (m/s²)	0.3
expert_mode	Disable safety speed clamping	false

Gripper Config

gripper: digital
gripper_config:
  pin: 3
  close_on_high: true

gripper: hand-e
gripper_config:
  force: 50
  speed: 80

CLI Override Precedence

1. CLI flags. urkit teach 172.31.1.42 --gripper none
2. Config file. Values from config.yaml
3. Built-in defaults. points.db, no gripper, 0.5 m/s velocity

Saving Config

The CLI never modifies your config file automatically. Press Y inside the teach pendant to save. This way you only save settings you've actually tested.

urkit teach 172.31.1.42 --gripper hand-e  # test, then press Y
urkit teach                               # next time: reads from config

Multiple workcells:

urkit teach --config station_a.yaml   # press Y to save
urkit teach --config station_b.yaml   # separate config

Programmatic

from urkit import load_config, resolve_config

config = load_config()                          # auto-resolve
config = load_config("/path/to/my.yaml")        # explicit path
path = resolve_config()                         # returns Path or None
robot = URRobot.from_config({"robot_ip": "172.31.1.42", "gripper": "2f-85"})

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Advanced

Raw RTDE Access

URKit doesn't try to wrap everything. Access the raw ur_rtde interfaces for advanced features:

robot.rtde_control.forceMode(...)
robot.rtde_control.servoJ(...)
robot.rtde_receive.getActualCurrent()

Full ur_rtde documentation: https://sdurobotics.gitlab.io/ur_rtde/

Connection Monitoring

robot.connection_lost       # bool: check if RTDE dropped
robot.reconnect_rtde()      # reconnect after a drop

disconnect() is called automatically when the robot object is garbage collected.

Error Handling

from urkit import URKitError, MotionError, PointError

try:
    robot = URRobot(ip="172.31.1.42", points="points.db")
except RobotNotInRemoteModeError:
    print("Enable remote control on the teach pendant!")
except RtdeRegisterConflictError:
    print("Disable EtherNet/IP, PROFINET, or MODBUS!")
except URKitError as e:
    print(f"Error: {e}")

Common runtime errors:

Exception	When
MotionError	Unreachable pose, bad TCP offset, freedrive failure
PointError	Point not found, no points database configured
GripperError	Gripper activation or communication failure
URKitIOError	Invalid pin number, I/O read/write failure
TelemetryError	Cannot read pose, joints, force, etc.

When the robot enters protective stop or the RTDE connection drops, motion commands raise URKitConnectionError and the program should exit. The CLI handles this automatically.

Connection Notes

The URRobot constructor takes a few seconds on first call: it validates the connection, checks remote mode, powers on the robot, releases brakes, and connects RTDE. Subsequent calls are faster if the robot is already running.

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Changelog

See CHANGELOG.md for the full version history.

Recent Changes

• v3.2 — Gripper speed/force keys (6/7), force/speed display
• v3.1 — Async motion, Space cancel, progress bar, joint display
• v0.3.0 — Safe/expert mode, speed_stop on exit, safety features
• v0.2.1 — get_pose() method
• v0.2.0 — README restructure
• v0.1.1 — --gripper none, --config flag, save config on demand
• v0.1.0 — Initial release