WUJI Hand - Frequently Asked Questions (FAQ)

How To
1

1. Product Overview

Q: What are the specifications and performance of the WUJI Hand?
A:

  • High Degrees of Freedom: 20 active degrees of freedom, supporting complex and precise movements.
  • High Reliability: No-load grasp lifespan > 300,000 cycles, verified through rigorous aging tests.
  • Lightweight Design: Weight < 600g, easy to integrate.
  • High-Precision Control: High position feedback accuracy, data feedback frequency up to 1000Hz.
  • Strong Load Capacity: Whole-hand static grasp load up to 10kg, fingertip force 15N.
  • Developer-Friendly: Complete product ecosystem with high scalability.

2. Technical Specifications

Q: What are the dimensions and weight?
A:

  • Weight: < 600g
  • Reference Size: 201 mm × 75 mm × 50 mm
  • Whole-Hand Length: Approx. 20 cm

Q: Which control interfaces and communication protocols are supported?
A:

  • Version 1: USB + RS485
  • Version 2: EtherCAT
  • Optional: CANFD (requires custom arrangement)

Q: What is the load capacity?
A:

  • Fingertip Force: 15 N
  • Whole-Hand Static Grasp Load: 10 kg
  • Single-Finger Hook Grip Static Load: 3 kg
  • Single-Finger Lateral Static Load: 2 kg
  • Maximum Hanging Grip Weight: 5 kg

Q: What are the joint torque and range of motion?
A:

  • Joint Torque: IP joint 0.3 Nm / MCP joint 1.0 Nm
  • Range of Motion: Flexion/extension and lateral swing range for each joint between 60°–130°

3. Performance and Reliability

Q: How accurate is the control?
A:

  • Position Feedback Accuracy: 30 arcmin
  • Repeat Positioning Accuracy: ± 1 mm
  • Data Feedback Frequency: Up to 1000Hz (typically 60Hz sufficient for most applications)

Q: What is the lifespan?
A: No-load grasp lifespan > 300,000 cycles; internal tests verified up to millions of cycles.

Q: What are the drive and control methods?
A: Uses self-locking rotary joints with high-torque drives and FOC (Field-Oriented Control) vector control, ensuring precise and stable motion.

4. Motor Error Codes

Q: (0x20) Bus Overvoltage (ovp_bus)
A:

  • Possible Causes:
    • Bus input voltage exceeds maximum limit
    • Bus voltage sampling abnormality
  • Actions:
    • Wait for bus voltage to return to normal
    • Send clear fault command

Q: (0x40) Bus Undervoltage (uvp_bus)
A:

  • Possible Causes:
    • Bus input voltage below minimum limit
    • Bus voltage sampling abnormality
  • Actions:
    • Wait for bus voltage to return to normal
    • Send clear fault command

Q: (0x80) Bus Overcurrent (ocp_bus)
A:

  • Possible Causes:
    • Motor stall
    • Motor short circuit
    • Excessive load
    • Current sampling abnormality
  • Actions:
    • Wait for bus current to return to normal
    • Send clear fault command

Q: (0x100) Phase Overcurrent (ocp_phase)
A:

  • Possible Causes:
    • Motor stall
    • Motor short circuit
    • Excessive load
    • Current sampling abnormality
  • Actions:
    • Wait for phase current to return to normal
    • Send clear fault command

Q: (0x400) Motor Overload (overload)
A:

  • Possible Causes:
    • Motor overloaded
    • Current sampling abnormality
  • Actions:
    • Reduce motor load to normal range
    • Send clear fault command

Q: (0x2000) MCU Overtemperature (otp_mcu)
A:

  • Possible Causes:
    • Poor heat dissipation
    • High-load motor operation for prolonged periods
  • Actions:
    • Wait for MCU temperature to return to normal
    • Send clear fault command

Q: (0x4000) Onboard Information Error (board_info_error)
A:

  • Possible Causes:
    • Onboard information not programmed
    • Incorrect onboard information programmed
  • Actions:
    • Reprogram correct onboard information
    • Power cycle and verify