> ## Documentation Index > Fetch the complete documentation index at: https://docs.wuji.tech/llms.txt > Use this file to discover all available pages before exploring further. # Hardware and Software Integration > [!NOTE] > > This page covers mechanical mounting, coordinate frames and model assets, and power and network integration for 2.1 devices. The palm mounting interface and the overall structure don't change between 2.1 and 2.2, while the model assets live in separate directories. For step-by-step first-connection instructions, see [Quick Start](https://docs.wuji.tech/docs/en/wuji-hand/beta1/quick-start). ## Mechanical Integration The hand mounts to a robot arm or a fixture through the wrist flange or the palm interface. Mounting dimensions, model frame conventions, left and right hand differences, and load and cable limits together decide which mounting options work. ### Wrist Mounting Interface The wrist ships with a standard flange, and the box includes an adapter mount and an adapter flange (see [Package Contents](https://docs.wuji.tech/docs/en/wuji-hand/beta1/overview.md#package-contents)). Those parts cover desktop mounting and common flange interfaces. ### Palm Mounting Interface The bottom of the palm provides a standard mounting interface for machining an arm-side adapter plate. Left and right hands share the same interface, and 2.1 matches 2.2: | Item | Specification | | - | - | | Threaded hole 1 | M3×0.5 fine 6H, thread depth over 5.5 mm, ⌀4 (0/+0.05) counterbore 2.35 ± 0.03 deep | | Threaded holes 2 and 3 | M4×0.5 fine 6H, thread depth over 4 mm, ⌀7 (0/+0.06) counterbore 1 mm deep | | Datum | Located by the 28.00 (0/−0.05) and 5.15 (+0.15/−0.05) datum dimensions | For how to get the palm mounting interface STEP assembly and the single-page A3 dimensioned drawing, see [Palm Mounting STEP and Drawings](#palm-mounting-step-and-drawings). ### Left and Right Hand Differences Left and right hands are mirrored parts with symmetric meshes. Factory default IPs differ by handedness, described under [Network Configuration](#network-configuration). ### Load and Cable Limits > [!WARNING] > > The following integration limits aren't published yet and will follow in a later update: allowed wrist load, bending moment, and shock limits, minimum cable bend radius and exit direction, motion clearance, and mounting screw specifications with recommended torque. Confirm the limits with technical support before finalizing an integration design. * Evaluate wrist load, bending moment, and shock against the actual duty cycle, and avoid high loads and impacts until the limits are confirmed. * Reserve cable bend radius, exit direction, and motion clearance in the integration design. * Always run the hand with the soft pad and skin fitted. The flex cables on the finger surfaces are fragile, so handle them briefly and only during maintenance, described in [User Notice](https://docs.wuji.tech/docs/en/wuji-hand/beta1/user-notice.md). ### Palm Mounting STEP and Drawings The paths below provide the palm mounting-interface STEP files and drawings. For the Beta full-hand STEP assemblies, use [wuji-description v2026.9.11](https://github.com/wuji-technology/wuji-description/tree/v2026.9.11). | Resource | Path and purpose | | - | - | | Palm mounting interface STEP | `hand2/hand2_1/attachment/wuji-hand2-description-{left,right}-mount_hand2_1_step.STEP`, covering the palm and harness only, for a custom arm-side adapter or fixture | | A3 dimensioned drawing | `hand2/hand2_1/attachment/wuji-hand2-description-{left,right}-mount_hand2_1.pdf`, marking the threaded holes the adapter mates with, with specifications under [Palm Mounting Interface](#palm-mounting-interface) | Left and right files mirror each other. The palm mounting interface is identical between 2.1 and 2.2, and the version marker in each filename only aligns with its directory. `attachment/` sits outside the ROS 2 package root at `body/`, so colcon doesn't install it. ## Coordinate Frames and Models ### Model Assets The 2.1 model assets live under `hand2/hand2_1/` and don't collide with the `hand2/hand2_2/` assets for 2.2. | Item | 2.1 convention | | - | - | | Joints | 20 revolute joints per hand | | Naming | Anatomical: thumb, index, middle, ring, and pinky | | Root link | Arm flange mount `{l,r}_mount` | | Actuators | `{l,r}_{THJ｜FFJ｜MFJ｜RFJ｜LFJ}{0-3}` | | Fingertip sites | Five query sites per hand, for grasp-point queries and fingertip trajectory evaluation | | ROS 2 package | `wuji_hand2_1_description`, package root `hand2/hand2_1/body/` | The model is rooted at the arm flange mount, with the wrist shell connected through a fixed joint. Use the URDF definition for the relationship between the wrist mounting frame and the root link. > [!WARNING] > > 2.1 provides rigid-body models that include the soft-pad geometry. Deformable-body simulation isn't supported yet. For model differences, see [Version Identification and Compatibility](https://docs.wuji.tech/docs/en/wuji-hand/beta1/version-identification-and-compatibility). ### Requirements | Use | Requirement | | - | - | | MuJoCo | Python and the `mujoco` package | | ROS 2 and RViz | ROS 2 Lyrical, Ubuntu 26.04 | | Isaac Sim USD | Isaac Sim | | URDF preview | Any URDF viewer, such as urdf-viz | | STEP / CAD | A CAD tool that supports STEP, such as FreeCAD or SolidWorks | ### Get and Load ```bash theme={null} git clone --depth 1 https://github.com/wuji-technology/wuji-description.git cd wuji-description ``` MuJoCo: ```bash theme={null} # Right hand python -m mujoco.viewer --mjcf=hand2/hand2_1/body/mjcf/right.xml # Left hand python -m mujoco.viewer --mjcf=hand2/hand2_1/body/mjcf/left.xml ``` For dependencies, description packages, and launch commands, see [ROS 2 Integration](https://docs.wuji.tech/docs/en/wuji-hand/beta1/ros2-integration.md). Isaac Sim USD: | Variant | Path | | - | - | | Left hand | `hand2/hand2_1/body/usd/left/wujihand2_1.usd` | | Right hand | `hand2/hand2_1/body/usd/right/wujihand2_1.usd` | URDF preview: ```bash theme={null} cargo install urdf-viz urdf-viz hand2/hand2_1/body/urdf/right.urdf ``` ### Verify 1. Confirm MuJoCo or the URDF viewer opens with no missing meshes. 2. Confirm the model shows 20 revolute joints. 3. Confirm the directory and ROS 2 package name match 2.1. A model that loads confirms the assets, paths, and visualization path work. Firmware, networking, and real-device control need a connected device to verify. ## Electrical and Network Integration ### Power Supply > [!WARNING] > > 2.1 supports 12 V DC only. Connect exactly 12 V, because other voltage ranges aren't compatible. The external interface form and the supply voltage range change in later revisions, so leave room in the integration design. | Item | Specification | | - | - | | Operating voltage | 12 V DC | | Recommended supply rating | 200 W or higher, which the bundled adapter meets | | External harness | XT30 and RJ45 lead straight out of the wrist | | Network port | Standard RJ45, 100BASE-TX | See [Electrical and Power](https://docs.wuji.tech/docs/en/wuji-hand/beta1/usage-constraints.md#electrical-and-power-strong-constraints) in Usage Constraints. ### Power-Up and Power-Down Sequence Power up by connecting the device-side XT30 first, then plugging in the adapter. Power down by confirming the device is at rest, disconnecting power, then unplugging the cables. ### Network Configuration The device uses a static IP and doesn't support DHCP. Factory default addresses: | Item | Left hand | Right hand | | - | - | - | | IP | 192.168.1.110 | 192.168.1.111 | | Gateway | 192.168.1.1 | 192.168.1.1 | | Subnet mask | 255.255.255.0 | 255.255.255.0 | Set the host adapter to a static IP on the same subnet, such as `192.168.1.50`. Changing the IP takes four steps: set the new address, reboot the device, reconnect at the new IP, and get to confirm. See [SDK Reference](https://docs.wuji.tech/docs/en/wuji-hand/beta1/sdk-reference/device-operations#ip-set/get). ### Multiple Devices and Clients * With several devices on one subnet, factory IPs differ by handedness, so a third device needs its IP changed before it joins. * Target a device with `--sn` or `manager.connect(sn=...)` to avoid connecting to the wrong one. ### Timeouts, Disconnection, and Reconnection For stop behavior on a communication break, the reconnection strategy, and the fault-clearing flow, see [Maintenance](https://docs.wuji.tech/docs/en/wuji-hand/beta1/maintenance#safe-stop-and-fault-recovery). This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.