Small Motors, Big Moves: SMC-Enabled Geometries Accelerate Robotics

Imagine walking into a hospital where a robot greets you at the door, wheels a supply cart down a crowded hallway, and assists nurses with lifting heavy trays—all without slowing down workflow or needing special infrastructure. That’s the promise of humanoid robots: machines built not just to work for humans, but to work and engage with us in the spaces we already inhabit. Unlike traditional industrial robots that are locked inside cages, humanoids are designed to fit into our world, navigating stairs, handling objects, and moving with human-like dexterity.

The payoff is big. Humanoids could help fill persistent labor shortages, take on repetitive or hazardous jobs, and support in a wide range industries, such as logistics, manufacturing, healthcare, and retail. Global investment is accelerating with companies like Schaeffler, Boston Dynamics, Agility Robotics, and Apptronik pushing real-world deployments. What once looked like science fiction is rapidly moving toward homes, factory floors, and hospital wards.

Behind the excitement, however, lies a hard truth: making humanoids truly viable requires innovation in motor design.

Why Motors Are the Bottleneck for Humanoid Robots

The closer robots get to human form, the more complex their mechanical and electrical design becomes. Unlike industrial arms bolted to a floor, humanoids must house dozens of motors inside slender limbs and compact joints, enabling them to balance, walk, and carry weight.

This poses several design challenges for engineers:

• Space constraints: Motors must fit into hips, knees, wrists, and ankles without bulking up the robot’s frame.
• Torque density vs. weight: Every extra gram adds to strain on batteries and actuators.
• Heat management: Compact motors run hot when on continuous duty.
• Scalability: Building a handful of prototypes is one thing; manufacturing thousands with repeatability is another.

Companies are investing in partnerships and developing drive modules specifically for use in humanoids, acknowledging that motor innovation is the linchpin to making humanoids practical and manufacturable.

Why Motor Topology Matters

Traditionally, engineers have relied on radial flux motors built with laminated steel cores. These motors have served well in automotive and industrial applications, but humanoid robots require something more.

• Axial flux motors (including yokeless designs) offer higher torque density in flatter packages, making them ideal for joints.
• Segmented or modular topologies allow designers to customize motors for tight spaces like wrists or ankles.
• Novel motor designs, such as spherical or pan tilt motors, enable rotational angular movement within a single motor design.
• Novel flux paths can unlock efficiency and reduce heat, which is critical for long-duty cycles.

The catch is that laminated cores simply don’t allow the geometrical freedom needed for these new motor topologies. That’s where Horizon Technology’s expertise comes in.

The SMC Advantage

Soft magnetic composites (SMCs) are game changers for motor design. Unlike traditional steel laminations, SMCs are pressed from powder and insulated particle by particle, producing a 3D isotropic material that is both magnetic and electrically resistive.

This holds distinct advantages for humanoid robot design:

• 3D Net Shape Cores—Designers can create geometries that follow the natural contours of a joint rather than a boxy shape, making it possible to create a slimmer hip or wrist.
• Lower Eddy Current Losses—Because of their high electrical resistivity, SMCs reduce losses in complex flux paths, allowing axial flux and yokeless designs to deliver reduced heat generation and residual heat buildup in the artificial limbs—without the need for secondary cooling.
• Improved Torque Density—Higher saturation flux density and optimized topologies mean more torque in a smaller volume, enabling lighter, more capable limbs.
• Manufacturability at Scale—Powder metallurgy processes make near-net shape cores, pre-wound stators, and modular designs possible. What’s more, they can be produced repeatably, moving smoothly from R&D to global mass production.

SMCs eliminate the compromises engineers have long accepted. It’s now possible to have it all: power, size, and manufacturability.

Design Examples: How Horizon Helps Humanoids Move

Case Example 1: Compact Hip Actuators

A humanoid’s hip joint is one of its most demanding actuators, requiring high torque in a limited space. By using a yokeless axial-flux stator built with SMC cores, engineers can reduce motor stack length while increasing torque density. The result is a slimmer hip module that reduces overall robot mass and improves energy efficiency.

Case Example 2: Wrist and Ankle Joints

In smaller joints, modular SMC stators enable pre-wound coils and improved cooling paths. This design not only improves thermal performance for continuous duty but also makes assembly faster and more repeatable, which is critical when scaling production beyond prototypes.

Why This Matters for Manufacturers and Suppliers

For companies advancing humanoid robotics, the optimization of motor design for limbs offers both opportunities and challenges. The market is moving fast, and motor performance is a key differentiator. Horizon is not just another supplier of components; we’re an experienced partner in co-development.

• We work with design teams early to model and simulate SMC-based geometries.
• We provide rapid prototyping to validate concepts.
• We help designs scale into production through our global mass production network, offering regionalized manufacturing partners to ensure a robust supply chain with cost-effective, cutting-edge solutions.

This collaborative model allows manufacturers to move faster, reduce risk, and ensure manufacturability is baked in from the very beginning.

Small Motors, Big Moves.

Humanoid robots promise to reshape industries, but only if their motors can deliver the right balance of power, size, and efficiency. With our expertise in SMC-enabled motor topologies, Horizon Technology is helping unlock that future. We’re not just providing materials; we’re enabling new designs, new possibilities, and new levels of manufacturability.

One exciting emerging opportunity lies with the pan tilt motor design. While it’s still early in design development, SMCs offer isotropic performance and ease of manufacturing to enable this-next generation market.

Ready to take the next step?
 Book a design workshop with our team to explore how Horizon can help accelerate your humanoid robotics program.