The “Heart” of Robot Dogs: Frameless Torque Motors and Permanent Magnet Materials
I. Robot Dogs: Rising Technological Stars from Sports Arenas to Battlefields
At the athletics events of the Hangzhou Asian Games, robot dogs became a unique sight. Acting as “porters”, they were actively involved in the competitions. Whenever a discus was thrown, the robot dogs would quickly dash to the landing point. Staff would place the discus on their backs, and then they would promptly return to the athletes. After completing the task, they would obediently “lie down” beside the field, waiting for the next command. These robot dogs, developed by Hangzhou Unitree Robotics Co., Ltd., can reach a maximum running speed of 4.7 meters per second, comparable to the jogging speed of humans. Throughout the event, they were responsible for transporting discuses, covering a running distance of over 7,000 meters, equivalent to running around a football field 18 times. In addition, they also took on the task of transporting javelins. Their presence not only ensured the efficient progress of the event but also added a sense of technology and fun to the competition, providing the audience with an unprecedented viewing experience. This was also the first time that robot dogs were used to transport equipment such as discuses in a global event.
In the military field, robot dogs also demonstrate huge application potential. In complex battlefield environments, they can undertake reconnaissance and surveillance missions. With their flexible figures and strong environmental adaptability, robot dogs can penetrate dangerous areas and transmit real-time images and data back to the command center, providing crucial basis for combat decision-making. In terms of material transportation, robot dogs can carry heavy equipment and supplies and traverse rugged terrains, greatly improving logistical efficiency and safety. Moreover, due to their autonomous navigation capabilities, they can complete tasks even under enemy fire. Traditional manual mine clearance and bomb disposal operations are extremely risky, but robot dogs can replace soldiers in performing such dangerous tasks. Through remote control or autonomous modes, they can detect and defuse mines or other explosives, maximizing the protection of soldiers’ lives. Additionally, the audio and visual senses of robot dogs are extremely sensitive. They can monitor the surrounding environment continuously for 24 hours and issue timely alarms whenever any abnormal situation is detected, greatly enhancing the safety factor.
II. Frameless Torque Motors: The Core Driving Force of Robot Dogs
The outstanding performance of robot dogs in different scenarios is primarily driven by frameless torque motors. Frameless torque motors do not have components such as traditional motor casings, end covers, and bearings. They are only composed of rotors and stators. This makes their structure simpler, effectively reducing the overall weight and volume, thus providing a lightweight design for the limited space of robot dogs.
In terms of working principle, frameless torque motors control three-phase electricity of U/V/W through drivers to form a rotating electromagnetic field. The permanent magnets on the rotor generate an electromagnetic torque under the action of this electromagnetic field, thereby driving the rotor to rotate. This design enables the motor to directly output a large torque and operate stably at low speeds, which highly meets the requirements of robot dogs for frequent starts and stops and precise torque control in complex terrains.
In frameless torque motors, permanent magnet materials play a crucial role. The frameless torque motors produced by Hangzhou Magnet Power Technology Co., Ltd. adopt high-performance neodymium-iron-boron permanent magnet materials. Neodymium-iron-boron permanent magnet materials have extremely high magnetic energy product and coercive force, which can generate a strong magnetic field, enabling the motor to output a larger torque in a smaller volume. However, as many enterprises in the market cannot provide these high-performance permanent magnet materials and struggle to meet the demand in terms of production volume, many enterprises use grades such as 52UH and 54SH. Hangzhou Magnet Power Technology Co., Ltd., on the other hand, has the ability to mass-produce permanent magnet materials of grades such as 54UH and 54SH, which can better support the performance requirements of robot dogs.
III. Permanent Magnet Materials: The “Energy Source” of Frameless Torque Motors
(I) The Superior Performance of Neodymium-Iron-Boron
Among the various components of frameless torque motors, permanent magnet materials are the core part, serving as the “energy source” of the motor. Neodymium-iron-boron permanent magnet materials stand out as the top choice. One of the remarkable advantages of neodymium-iron-boron permanent magnet materials is their high power density. This enables frameless torque motors to output a larger torque within a limited space. For robot dogs, this means they can carry heavier loads and maintain a stable movement posture in complex terrains. When climbing slopes or traversing obstacles, robot dogs can easily handle the challenges and demonstrate excellent mobility, thanks to the powerful torque provided by neodymium-iron-boron permanent magnet materials.
In addition, the application of neodymium-iron-boron permanent magnet materials has significantly improved the response speed of the motor. Robot dogs can quickly react after receiving commands, achieving rapid starts, stops, and precise turns. When performing reconnaissance tasks, robot dogs can quickly change their traveling directions, flexibly avoid obstacles, and promptly capture target information.
(II) CJL’s Technological Breakthroughs
Hangzhou Magnet Power Technology Co., Ltd. has made remarkable progress in the research, development, and production of permanent magnet materials. Currently, the company can stably produce neodymium-iron-boron permanent magnet materials of grades such as 54UH and 54SH. These grades of materials possess good comprehensive properties and can meet the requirements of frameless torque motors in most application scenarios.
In practical applications, the 54UH grade permanent magnet materials, with their relatively high coercive force and magnetic energy product, enable frameless torque motors to maintain stable performance in high-temperature environments. In hot desert areas or high-temperature industrial environments, robot dogs equipped with this material can operate normally, ensuring the smooth execution of tasks. The 54SH grade permanent magnet materials, on the other hand, perform outstandingly in terms of magnetic field stability. They can provide a continuous and stable magnetic field for the motor, guaranteeing the smoothness and reliability of the movement of robot dogs.
Moreover, Hangzhou Magnet Power Technology Co., Ltd. actively invests in research and development resources and is committed to developing higher-performance grades such as 58SH and 56UH. These new grades of permanent magnet materials are expected to further enhance the power density and torque output of frameless torque motors, providing stronger support for the performance improvement of robot dogs.
(III) Halbach Array: A New Solution to Enhance Performance
When a single permanent magnet material cannot meet the strict torque requirements of frameless torque motors, Halbach array technology emerges as an innovative solution. The Halbach array is a special arrangement of permanent magnets, which was discovered and gradually improved by American scholar Klaus Halbach during an electron acceleration experiment in 1979.
Its principle is to arrange permanent magnets with different magnetization directions according to specific rules, causing the magnetic field lines to converge on one side of the array, thereby enhancing the magnetic field strength on that side, while weakening the magnetic field lines on the other side, forming an approximately ideal unilateral magnetic field. This unique magnetic field distribution can effectively increase the torque output of frameless torque motors. In the case of the same volume and amount of permanent magnet materials used, motors employing the Halbach array can achieve a significantly higher torque compared to traditional motors.
Applying Halbach array technology to the frameless torque motors of robot dogs can provide them with more powerful power support during operation. When climbing steep slopes or dragging heavy objects, robot dogs can easily complete the tasks with the enhanced torque. However, due to the extremely compact internal space of robot dogs, assembling a Halbach array in such a narrow space requires extremely high technological requirements. CJL engineers need to accurately calculate the arrangement and angles of the permanent magnets to ensure that each magnet can perform at its best.
IV. Permanent Magnets Open up a New Journey
From the perspective of market demand, as robot dogs become more widely used in various fields, the demand for high-performance permanent magnet materials will increase significantly. As the core component, permanent magnet materials will also face higher requirements and challenges. Higher demands are placed on performance indicators such as the power density, torque output, and efficiency of frameless torque motors. This means that permanent magnet materials need to have higher magnetic energy product and coercive force to further enhance the performance of motors. Alternatively, exploring other new types of permanent magnet materials will become the future research and development direction of robot dogs.
The future development of robot dogs is inseparable from the technological innovation and breakthroughs of permanent magnet materials. In the future, with the continuous improvement of the performance of permanent magnet materials and the continuous refinement of application technologies, robot dogs will play important roles in more fields, bringing more convenience and surprises to people’s lives and work.
