As humanoid robots, collaborative robots, exoskeletons, and intelligent automation systems continue to evolve, the harmonic robot joint actuator has become one of the most important components in modern robotics. It determines not only how a robot moves, but also its precision, load capacity, reliability, and overall performance.

This article begins with the principle of cogging torque in frameless motors, explains how slotless core technology eliminates torque ripple and vibration, and highlights the three major breakthroughs achieved by frameless torque motors in 2025: increasing low-speed torque through high pole-pair designs exceeding 32 pole pairs, adopting hollow frameless structures for compact and lightweight designs, and utilizing high-grade NdFeB permanent magnets to enhance torque density.

HONPINE FM1 Frameless Brushless DC (BLDC) Motors are compact, high-performance, and cost-effective products. Available in four sizes (φ50mm–φ115mm), with rated speeds ranging from 650 rpm to 5250 rpm, torque from 0.3 Nm to 9.32 Nm, and power from 165 W to 920 W. Rated voltages range from 24 V to 70 V, with optional Hall sensors, temperature sensors, and wiring configurations. They are widely used in collaborative robots, humanoid robots, quadruped robots, and medical rehabilitation robots.