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Hello everyone, this is Liu Chunfeng from Kunwei Technology.
In the past two years, driven by the boom in embodied intelligence, a wave of robotic technological innovation has swept across China and the rest of the world. In the research and development of robots, especially humanoid robots, force control technology has become increasingly critical. Precise force sensing is essential for high-precision assembly, safe human-robot interaction, compliant control, and walking balance.
Among these force control solutions, the torque sensor, as the core component for sensing “joint force”, plays an indispensable role.
Recently, during our cooperation with various robotics companies, we have found that many R&D engineers encounter questions or even common pitfalls when selecting, integrating, and debugging torque sensors.
To help you avoid detours, we have systematically sorted out the frequently asked questions and technical difficulties in the debugging process, and created this video series.
This series aims to clarify the key points of joint torque sensors from early R&D to practical application, helping you save valuable development time and advance projects more efficiently.
Selection of robot joint torque scheme
First, let me ask a question: If you are designing a robot that requires precise force control — such as a collaborative robot for safe human interaction or a humanoid robot for stable landing — do you really need to install a torque sensor in the joint?
Today, we will start with the selection of robot joint solutions to help you figure this out, save development costs, and avoid design traps.
Currently, mainstream robot joint solutions on the market fall into two categories.
The first is the high reduction ratio solution, characterized by a small motor paired with a high-reduction-ratio reducer (usually a harmonic reducer or RV reducer), with a reduction ratio typically exceeding 50:1. This solution offers high torque density and high precision, making it the mainstream choice for industrial robotic arms and collaborative robots.
The second is the quasi-direct drive solution, characterized by a high-torque motor paired with a medium-to-low reduction-ratio reducer (usually a planetary reducer or cycloidal pinwheel reducer), with a reduction ratio generally between 5:1 and 15:1. This solution is widely used in the legs of quadruped robots and humanoid robots, as it is back-drivable — meaning the motor can be easily rotated by external force — and features strong impact resistance.
Conclusão
Here comes the question: Do these two solutions have the same requirements for torque sensors? The answer is absolutely not.
In the next episode, I will elaborate on the differences between the two solutions.
That’s all for today’s video. For high-quality force measurement solutions, please follow Kunwei Technology. See you next time!
