QDD Series Actuators
xTerra Robotics' QDD (Quasi-Direct Drive) Series actuators deliver cutting-edge performance for next-generation robotic systems, combining high torque density, exceptional backdrivability, and precise force control.
QDD Series Overview
The QDD Series represents xTerra's flagship line of quasi-direct drive actuators, designed from the ground up for demanding robotic applications. Each actuator in the series features:
- Proprietary low-reduction planetary gearbox (6:1 to 9:1 ratio)
- High-torque frameless brushless DC motor
- Integrated high-resolution encoder (absolute or incremental)
- Optimized thermal management
- Compact, modular design
- CAN bus or EtherCAT communication
Product Lineup
QDD A2
Peak Torque: 12 Nm
Peak Power: 500W
Weight: 550g
Next-generation actuator optimized for maximum torque and high performance. Ideal for small-size quadruped robots and small-size industrial robots.
View Details →Series Comparison
| Model | Peak Torque | Peak Power | Weight | Voltage | Typical Applications |
|---|---|---|---|---|---|
| QDD A2 | 12 Nm | 500W | 550g | 10-24V | Quadruped robots, cobot arms, industrial robots |
Common Features Across the Series
Mechanical Design
- Modular Construction: Easy integration and maintenance
- Aluminum Housing: Lightweight yet robust
- Precision Bearings: Low friction, high stiffness
- Sealed Design: IP54 rating for dust and splash resistance
- Multiple Mounting Options: Flexible installation configurations
Electrical & Control
- Integrated Motor Driver: Optional built-in drive electronics
- High-Resolution Encoder: 17-bit to 23-bit absolute position feedback
- Current Sensing: Accurate torque estimation without external sensors
- Temperature Monitoring: Built-in thermal protection
- Communication Protocols: CAN bus, EtherCAT, or RS-485
Performance Characteristics
- Backdrivability: Can be manually moved with minimal force
- Low Backlash: < 0.1° typical
- High Efficiency: > 90% mechanical efficiency
- Fast Response: Low reflected inertia enables rapid acceleration
- Smooth Operation: Low cogging torque and vibration
Technical Specifications Summary
| Specification | QDD A2 |
|---|---|
| Peak Torque | 12 Nm |
| Peak Power | 500W |
| Weight | 550g |
| Voltage Input | 10-24V DC |
| Control Mode | FOC |
| Control Rate | 15-30 kHz |
| Outer Diameter | 77 mm |
| Thickness | 50 mm |
| Power Connector | 2x XT-30 |
| Data Connector | 2x JST PH-3 |
Application Examples
Collaborative Robot Arms
QDD actuators are ideal for cobot applications where human safety and interaction are paramount. High backdrivability ensures safe collisions, while excellent force sensing enables compliant behavior.
Legged Robots
Low reflected inertia and high efficiency make QDD actuators perfect for dynamic legged locomotion. Fast response times enable balance control and reactive behaviors.
Humanoid Robots
Compact size and high torque density allow QDD actuators to fit in anthropomorphic designs while providing human-like force output and motion capabilities.
Mobile Manipulation
Battery-powered robots benefit from QDD's high efficiency and low weight. Backdrivability enables passive compliance for robust grasping and manipulation.
Research and Education
QDD actuators provide an excellent platform for research in control, learning, and human-robot interaction. Complete development kits and open interfaces accelerate innovation.
Development Support
Software & APIs
- ROS/ROS2 Drivers: Full integration with Robot Operating System
- Python SDK: High-level control interface
- C/C++ Library: Low-level access for custom applications
- MATLAB/Simulink Support: Modeling and simulation tools
- Example Code: Sample applications and tutorials
Hardware Accessories
- Motor controllers and drives
- Mounting brackets and adapters
- Power supplies and cables
- Communication interfaces (USB, Ethernet)
- Development boards and test fixtures
Documentation & Training
- Detailed technical manuals
- Quick-start guides
- Video tutorials
- Application notes
- Online community and forum support
Quality & Reliability
Testing & Validation
Every QDD actuator undergoes rigorous testing before shipment:
- 100% functional testing
- Torque and speed verification
- Encoder calibration and validation
- Temperature cycle testing
- Vibration and shock testing
Warranty & Support
- Standard Warranty: 1 year parts and labor
- Extended Warranty: Available up to 3 years
- Technical Support: Email and phone support during business hours
- Repair Service: Factory repair and refurbishment available
- Spare Parts: Replacement parts stocked and available
Ordering Information
QDD Series actuators can be purchased individually or as part of complete robotic systems. Educational and research institutions may qualify for special pricing.
Environmental Specifications
| Parameter | Specification |
|---|---|
| Operating Temperature | -10°C to +50°C |
| Storage Temperature | -20°C to +70°C |
| Humidity | 5% to 95% RH (non-condensing) |
| Vibration | 10g, 10-2000 Hz |
| Shock | 50g, 11ms half-sine |
| IP Rating | IP54 (dust and splash resistant) |
Certifications & Compliance
- CE Marking (EU compliance)
- RoHS Compliant (lead-free)
- ISO 9001 Quality Management
- UL/cUL (select models)