Orca Hand Community
Common questions, build tips, and links to the SVRC forum for Orca Hand builders and researchers.
FAQ
What tools do I need for assembly?
A set of precision hex drivers (M2 and M3), needle-nose pliers for tendon routing, and a torque-limited screwdriver for joint fasteners. A magnifying glass or head-mounted loupe is helpful for threading tendons through conduit guides. Refer to the official Orca Hand assembly documentation for the full BOM and tooling list for your hardware revision.
How do I set tendon tension correctly?
Start with slack tendons after initial routing. Run the calibration procedure first to establish open and closed position baselines. Then increase tension at the actuator plate adjustment screws (clockwise to tighten) until each finger reaches full closure under a moderate commanded position. The tendon should feel firm but not cause joint binding when moved by hand with the system unpowered. Over-tensioned tendons will cause the motor to stall at partial closure; under-tensioned tendons will cause the finger to droop at the open position.
A finger doesn't reach full closure after calibration. What's wrong?
The most common causes are: (1) insufficient tendon tension — increase tension at the actuator plate for that finger; (2) tendon routed incorrectly through a conduit guide, causing friction; (3) a joint or pulley not seated fully. Open the finger shell and visually confirm the tendon path, then re-tension. After any hardware adjustment, re-run the calibration procedure to re-establish the position baseline.
How does ROS2 integration work?
The orca_core ROS2 package publishes and subscribes to standard ROS2 topics. Send finger position commands to /orca_hand/finger_cmd using the orca_msgs/FingerCmd message type with the target finger name and normalized position (0.0 = open, 1.0 = closed). State feedback is published to /orca_hand/state. The package includes launch files for standalone hand control and for integration into existing arm workspaces. See the orca_core GitHub repository for full API documentation.
Can I add tactile sensors after assembly?
Yes — the Orca Hand finger housing is designed with tactile sensor mounting positions in the fingertips. If you assemble without sensors initially, you can disassemble the fingertip shells, seat tactile sensor modules, route the sensor cables back through the finger body to the palm connector, then reassemble. No tendon re-routing is required for this upgrade.
What robot arms is the Orca Hand compatible with?
The Orca Hand uses a standard wrist flange mount (ISO 9283-compatible pattern), making it mechanically compatible with any arm that exposes a standard end-effector flange — including OpenArm 101, and most commercial 6-DOF arms. You will need an appropriate flange adapter plate if your arm uses a non-standard bolt pattern. Software integration via ROS2 works with any arm that also runs ROS2.
Where can I find build logs and failure notes from other teams?
The SVRC Orca Hand forum hub is the best place for community build logs, retargeting experiments, and tactile failure patterns that other teams have documented. The SVRC research guide also covers key findings from dexterous manipulation workflows using this hand.