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In this episode, the robotics channel Rough Robotics conducted a comprehensive hands-on test of the CubeMars AK45-10 V3.0 KV75 and AK45-36 V3.0 KV80 robotic actuators.
This in-depth evaluation not only demonstrates the practical improvements brought by the V3.0 upgrade, but also successfully builds a complex 3-axis bilateral control system. Through the developer’s perspective, the video explores the potential of CubeMars QDD (Quasi-Direct Drive) actuators in compliant force control and teleoperation applications.
When using early single-encoder robotic actuators, developers often encountered a common challenge: after the system was powered off and restarted, the absolute angle of the output shaft (load side) could be lost, requiring additional mechanical homing procedures before operation.
The CubeMars AK45 V3.0 series directly addresses this challenge by introducing a dual encoder design:
Motor-side encoder: Provides high-precision rotor position feedback, ensuring smoother and more efficient FOC (Field-Oriented Control) performance.
Output-side encoder: Directly measures the absolute position of the gearbox output shaft.
Real Test Experience: During the evaluation, the developer highly appreciated this upgrade. With dual encoders, the system can immediately identify the actuator’s absolute physical position after power-on, eliminating the need for repeated manual calibration and significantly improving robotic system reliability and development efficiency.
The core advantage of QDD (Quasi-Direct Drive) technology lies in its low reduction ratio, which enables excellent backdrivability and highly transparent force control.
In the video, the developer conducted a direct physical comparison between two actuators with different reduction ratios:
AK45-10 (10:1 Reduction Ratio): The test showed that the AK45-10 can be rotated smoothly by hand when powered off, with extremely low resistance. This excellent backdrivability allows the actuator to achieve highly compliant motion when operating in MIT mode (impedance control), creating a more natural, muscle-like response. It makes the AK45-10 well suited for applications such as lightweight robotic arms and quadruped robot leg joints that require flexible interaction and dynamic response.
AK45-36 (36:1 Reduction Ratio): With a higher reduction ratio, the AK45-36 provides greater output torque and stronger static holding capability. However, the increased reduction ratio also results in higher resistance during backdriving. The evaluation objectively demonstrates that when an application prioritizes higher load capability and position holding rather than maximum compliance and force transparency, the AK45-36 becomes a more suitable option. This comparison helps developers select the actuator that best matches their application requirements — whether the priority is compliant interaction or higher output strength.
Beyond the MIT mode impedance control test, one of the biggest highlights of this evaluation is the successful implementation of a 1-axis and 3-axis bilateral control system using CubeMars AK45 actuators.
What Is Bilateral Control? Bilateral control enables an operator to control a remote robotic system through a master device, while receiving real-time force feedback from the remote environment through the system.
How CubeMars Actuators Support Bilateral Control: High-quality bilateral control requires actuators with high control frequency, low communication latency, and accurate real-time torque feedback. In the video, the AK45 actuators demonstrate their strong underlying control capabilities by accurately reproducing the operator’s movements while transmitting environmental interaction forces back to the user. This highlights the potential of CubeMars actuators in advanced applications such as teleoperation, robotic manipulation, and embodied intelligence data collection.
Through this video, viewers can directly observe the performance of CubeMars AK45 V3.0 actuators:
Dual encoder demonstration: Showing how the system instantly recognizes and maintains the current absolute physical position after power cycling.
Backdrivability comparison: The developer manually rotates the AK45-10 and AK45-36 to demonstrate the smooth QDD characteristics enabled by the 10:1 reduction ratio.
3-axis bilateral control demonstration: Showing synchronized master-slave robotic arm movement and how the force feedback system responds when encountering obstacles.
Q1: Which actuator should I choose for applications requiring high compliance and safe human-robot interaction, AK45-10 or AK45-36?
A: The AK45-10 (10:1) is recommended for applications that prioritize compliance and interaction safety. Its lower reduction ratio provides excellent backdrivability and force transparency. When operating in MIT mode, it enables highly compliant motion and natural following behavior, making it suitable for applications such as collaborative robotic arms and quadruped robot joints.
Q2: Does the V3.0 dual encoder design increase control complexity?
A: No. CubeMars firmware integrates and optimizes the dual encoder data internally. For upper-level developers, communication remains simple through standard CAN protocols. Users can send position, velocity, or torque commands in the same way as with single-encoder actuators while benefiting from more reliable absolute position feedback.
Q3: Are there resources available for developers who want to build their own teleoperation or bilateral control systems with CubeMars actuators?
A: Yes. CubeMars provides detailed CAN communication protocol documentation, including high-frequency torque feedback reading and impedance control parameter configuration. For customers with advanced development requirements, our technical team can also provide support for low-level algorithm integration.
Thanks to Rough Robotics for providing this professional and in-depth evaluation of the AK45 V3.0 series. If you are interested in CubeMars AK45 V3.0 robotic actuators, you can access detailed technical specifications or explore more high-performance robotic actuator solutions from CubeMars.
[Learn more about CubeMars AK Series specifications and dimensions]
