LinkerBot Arm Python SDK

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All four arm models use CANTransport by default. Set LINKERBOT_ARM_TRANSPORT=dispatcher to explicitly use the low-level backend. Both backends require the current transport source. Arm calls remain unchanged; failed connections require closing and recreating the arm. See the backend guide for installation, recovery and validation scope.

Python SDK for A7, A7lite, P7 and H75 robotic arms, with joint control, feedback and forward/inverse kinematics. Requires Python 3.10+. Install linkerbot-arm and import linkerbot_arm.

Installation

The base SDK requires NumPy >=1.24, SciPy >=1.10, Pydantic 2.x and linkerbot-transport[can]. The source repository is linker-bot/linkerbot-arm-python-sdk, with main as its default branch. The distribution and import names remain linkerbot-arm and linkerbot_arm. To obtain and install the source from GitHub, run:

git clone --branch main https://github.com/linker-bot/linkerbot-arm-python-sdk.git
cd linkerbot-arm-python-sdk
python3 -m venv .venv
source .venv/bin/activate
python -m pip install --force-reinstall --no-deps -r requirements/transport.txt
python -m pip install -e '.[kinetix]'

See the installation guide for environment configuration.

All four arm constructors require Pinocchio; the current validation baseline is 4.1.0. The kinetix extra declares pin>=4.1.0 for pip dependency installation. SDK kinematics are available with the base package when compatible Pinocchio is already present; install it with python -m pip install -e .. ROS2 environments should install the base package and compatible system Pinocchio. See the ROS2 guide for the validated Jazzy combination and deployment lock.

Quick start

Configure CAN, connect and power the arm, then run:

from linkerbot_arm import A7

with A7(side="left", interface_name="can0") as arm:
    print(arm.get_angles())  # Seven joint angles in radians
    print(arm.get_pose())  # TCP pose

Replace A7 with A7lite, P7 or H75 for other models, and use side="right" for a right arm. Construction opens CAN, checks the motors and reads their initial state. The context manager closes the connection. P7 also checks the PTM mode of joints 6 and 7. When necessary it enters Rest, writes and saves the Flash mode, then verifies the readback; an existing PTM configuration skips writes. Set velocity and acceleration explicitly before moving. See the P7 reference.

P7 move_j() and move_p() use host-side joint acceleration/deceleration profiles. External _set_angles() commands are velocity- and acceleration-limited: the first cycle holds feedback positions, and periodic input is required to approach the target. blocking=False still sends the complete host trajectory synchronously. A7lite software stops remain latched until explicit enable() or successful PP home() recovery; cancellation or failure keeps the stop. PP/CSP hold zero speed limits and replace pending targets with cached feedback; MIT holds use at least Kp=20 and Kd=1. These commands do not confirm a physical stop. close() waits for motion parameter restoration before closing CAN and does not disable motors. P7 move_l() constrains the TCP path and does not guarantee per-joint profile limits near singularities. See the behavior migration notes.

H75 supports PP/CSP and brakes on joints 1/2. Use get_currents() for amperes; torque conversion is unavailable. Check the upstream scaling defaults against your motor and firmware.

Documentation

• Installation
• A7 API
• A7lite API
• P7 API
• H75 API
• CAN
• Feedback freshness and lightweight state reads
• ROS2
• Migration from the legacy SDK
• Changelog

See Development checks for project-specific development and testing.

Contributing and license

English and Chinese contributions are welcome. Follow the Linkerbot contribution guide. Report vulnerabilities privately using the organization security policy.

Licensed under the MIT License.