Double Kikken Announces Ultra-Compact 'D-Drive Module (DDM)' – A Motor-in-Finger Actuator Enabling Human-Sized Multi-Fingered Robotic Hands

Double Kikken Co., Ltd. (Sagamihara City, Kanagawa Prefecture, President: Hajitatsu Wada) has announced the commercial launch of the D-Drive Module (DDM), an ultra-compact actuator module designed for humanoid robots and multi-fingered robotic hands.

In recent years, the development of humanoid robots and AI-powered robots has accelerated globally.

However, achieving human-like dexterous motion with high degrees of freedom requires compact, lightweight, and high-performance actuators that can be embedded directly within robotic fingers.

The D-Drive Module (DDM) has been developed specifically to address this challenge—an ultra-miniature, all-in-one motion module engineered for robotics applications.

This module integrates the following components into a single compact unit:

- Ultra-compact slotless BLDC motor - High-precision planetary gear reduction mechanism - Closed-loop control driver - Position, velocity, temperature, and current feedback functionality

It is specifically designed for integration into Motor-in-Finger configurations.

The DDM is currently being implemented in Double Kikken’s in-development multi-fingered robotic hand, "D-Hand 5MT," contributing to the realization of a compact, lightweight robotic hand weighing approximately 400g—comparable in size to a human hand.

Key Features:

- Ultra-lightweight design suitable for integration inside fingers (~10g) - Built-in 28:1 gear reduction - 168-step closed-loop control - Low backlash structure - UART communication support - Position, velocity, temperature, and current feedback support

Main Specifications:

Model Numbers: DDM-1017-R28-U / DDM-1117-R28-U

Dimensions: φ10×17mm / φ11×17mm

Motor: Slotless BLDC

Weight: Approx. 15g

Gear Ratio: 28:1

Maximum Current: 1.5A

Communication: UART

(Future support planned for RS485 / CAN / I2C / SPI)

Future Applications:

- Humanoid robots - Prosthetic hands - Wearable exoskeletons - Research and development

Alongside expanding into these fields, Double Kikken will continue advancing key technologies such as:

- Quasi Direct Drive (QDD) - Further low-backlash reduction mechanisms

to evolve the DDM into a next-generation actuator for advanced robotic hands.

The company has long developed the D-Hand series utilizing underactuated mechanisms. Since last year, it has been actively developing the "D-Hand 5MT," an all-in-one type robotic hand that integrates motors, gearboxes, and drivers within the hand structure (fingers and palm).

The development concept of the D-Hand 5MT is to achieve a compact, lightweight, all-in-one robotic hand that combines human-like multi-degree-of-freedom motion with the integration of motors, gear systems, and control controllers entirely within the hand.

In particular, the Motor-in-Finger architecture—embedding motors and gear mechanisms within each finger—aims to simultaneously achieve:

- A human-sized robotic hand weighing approximately 400g - High manipulability through independent multi-finger control

We are now pleased to announce the external commercialization of this ultra-compact motor module, the DDM!