Robotic applications have successfully leveraged the capabilities of brushed DC motors to enhance humanoid functionality.

Humanoid robots, some of which are designed to interact seamlessly with humans, heavily depend on precise and controlled joint and limb movements. The selection of high-quality, brushed DC motors that power the axes of movement is crucial.

Alongside excessive torque density and responsiveness, effectiveness in allowing for a lengthy lifespan is crucial. Reliability is essential. Achieving true freedom of motion necessitates the harmonious integration of multiple axes of movement, best accomplished through collaborative effort with a qualified expert in this field.

In educational and therapeutic settings, robots play a crucial role in enhancing hands-on learning and skills development across diverse subject areas and requirements. In the field of engineering, students have the opportunity to cultivate skills in programming. In rehabilitation settings, patients can now receive restorative treatment through innovative interactions with robots.

Humanoid robots may be equipped with bespoke cognitive architectures tailored to their specific tasks, underpinned by targeted software development. Despite their unique characteristics, humans and certain primates share fundamental similarities in their anatomy.

While modular designs may incorporate additional instruments for enhancing human-like dexterity, humanoid robots’ fundamental motor capabilities remain largely consistent across diverse tasks.

Humans are capable of seamlessly processing a multitude of commands and directions with ease.

Given the versatility in human physiology, a single humanoid robot design can serve as a versatile foundation for a range of applications among robotic builders. Despite the need for such a scale of motion, humanoid robots often require optimizing up to 20 or more degrees of freedom to effectively perform diverse tasks. Therefore, ensuring the optimal functioning of actuators powering these axes of motion is crucial for overall system effectiveness.

The company, a renowned designer and manufacturer of miniature motors, recently collaborated on the development of a human-like robot’s propulsion system. To ensure seamless integration with existing equipment, the robotic manufacturer aimed to maintain compatibility with current drives and controls while simultaneously boosting torque density and minimizing mass. By optimising motion management, enhancing responsiveness, and minimising inertia, this development could prove pivotal in significantly improving the robotic’s precision.

To enhance the performance of the robot’s motor, the developer aimed to boost battery life by optimising efficiency. Given the requirement to operate in a variety of environments with over 20 motors per unit and rely on robots, dependability took centre stage as a crucial consideration. As the number of motors per robot increased relatively excessively, coupled with the demand from end-users in the market, it became crucial to strike a balance between cost and value.

The engineering team determined that the characteristics of a brushed DC motor were best suited to meet the requirements. This innovative motor design ensures seamless integration with the humanoid’s existing architecture, simplifying overall management.

While achieving the requisite fee level specified by the original equipment manufacturer (OEM), the inherent characteristics of a brushed DC motor can effectively align with a humanoid’s natural human interaction, where the advantages of high torque at low speed enable beneficial control.

All about brushed DC motors

Why brushed DC motors? The company offers a range of practical solutions that can significantly benefit robotic applications. Here: Right at the outset is a concise outline detailing the design parameters of traditional brushed DC motors, accompanied by an enumeration of the key advantages afforded by their coreless counterparts.

A typical brushed DC motor is comprised of an outer stator, often constructed using either permanent magnets or electromagnetic windings, alongside an internal rotor comprising iron laminations with coil windings. In a well-engineered electrical motor, a segmented commutator and carefully managed brushes orchestrate the precise sequence of rotor winding energization, thereby ensuring consistent and steady rotational movement.

Without a laminated iron core in their rotor, coreless DC motors are able to operate with improved efficiency and reliability. The rotor windings employ a unique, honeycomb pattern to form a self-supporting hollow cylinder, often referred to as a “basket.” Since there’s no iron core to support the windings, they’re usually secured with epoxy instead.

The stator is typically fabricated from a rare-earth magnet material, such as neodymium, AlNiCo (aluminum-nickel-cobalt) or SmCo (samarium-cobalt). The small magnet is situated at the center of the rotor, nestled within its hollow interior.

Brushes used in coreless DC motors are typically made of precious metal or graphite. Sophisticated combinations of treasured metallic brushes, comprising silver, gold, platinum, and palladium, are expertly matched with esteemed metallic commutators. This design exhibits remarkably low contact resistance, making it a popular choice for applications that require minimal current flow.

When using sintered metallic graphite brushes, a copper commutator is typically fabricated. The copper-graphite composite is particularly well-suited for applications demanding higher power density and more robust performance.

The emergence of coreless DC motors yields several advantages compared to traditional iron-core DC motors. With the removal of iron, the rotor’s mass and inertia decrease significantly, enabling rapid acceleration and deceleration capabilities.

While lacking iron cores entirely eliminates iron loss, resulting in coreless designs that boast significantly higher efficiencies – up to 90% – surpassing traditional DC motor performance. The coreless design effectively minimizes winding inductance, thereby diminishing the likelihood of sparks forming between the brushes and commutator, which ultimately enhances motor lifespan and reduces electromagnetic interference (EMI)?

In ironless DC motors, motor cogging, a common issue in conventional designs due to the interaction between permanent magnets and iron laminations, is eliminated by the absence of these laminations. The exceptionally low torque ripple yields a remarkably smooth motor rotation, characterised by negligible vibration and noise.

Due to their frequent use in highly dynamic applications, such as rapid acceleration and braking, these motors require coils within the rotor that can withstand extreme torque loads and efficiently dissipate heat generated by high current peaks. Without an iron core to serve as a heat sink, the motor housing usually features ventilation ports that enable pressurized air cooling.

The compact design of coreless DC motors is particularly suited for applications demanding a high power-to-size ratio, with motor sizes ranging from approximately 6 to 75 millimeters (0.2 to 2.9 inches), while smaller variants down to 1 millimeter (0.03 inch) also exist, and typical energy ratings typically do not exceed 250 watts.

Coreless designs prove to be a particularly effective solution for battery-powered units, allowing them to draw exceptionally low currents even in no-load situations.

Coreless DC motors play a significant role in various medical applications, including prosthetic devices, miniature pumps akin to insulin pumps, laboratory equipment, and X-ray machinery. Their ability to handle swift, high-speed attacks also renders them well-suited for applications in robotics.

Portescap specified a 16DCT Athlonix motor, primarily built upon a coreless design. This design feature safeguards vital mass, offering a significant advantage over traditional iron-core implementations, while also enabling heightened responsiveness and fluid motion, courtesy of diminished inertial forces.

Neodymium magnets can significantly enhance torque density by creating a stronger magnetic field that optimizes interactions with motor windings, thereby boosting overall performance.

The coreless design was engineered to enhance efficiency and reduce power consumption by eliminating the drawbacks of hysteresis and eddy current losses typically associated with traditional iron-core DC motors. Treasured metallic commutations significantly enhance effectiveness by substantially reducing resistance and minimising the voltage drop at the brush-commutator interface, thereby optimising overall system performance.

The optimized ironless design of the motors enabled cooler operation and enhanced energy density. Motor inductances have been carefully calibrated to perfectly align with the demands of the drive, thereby ensuring optimal performance characteristics in terms of speed and torque.

To further reduce weight, the engineers customised the windings with lightweight, self-supporting coils. By integrating coreless designs and high-performance neodymium magnets, the system achieves a notable 8% reduction in motor diameter while maintaining the necessary torque output.

To further boost durability and torque transmission, engineers cleverly integrated the pinion gear directly onto the motor shaft, effectively reinforcing mechanical stability. This approach would optimise alignment and streamline management across all axes, significantly reducing friction and potentially mitigating mechanical wear.

Through collaborative efforts with robotic and movement engineering teams, the developer was able to secure precise measurements and weights, as well as define the necessary movement profiles for each axis.

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