Humanoid Robotics Actuation
Joint modules that ship,
Joint modules that ship,
not prototypes
Tendonkindle integrates motor, gearbox, and force-torque sensor into a single sealed actuator module — with a real-time impedance control SDK — so your team goes from hardware receipt to first locomotion test in days, not months.
5
Joint module sizes
<1ms
Force-torque latency
IP54
Sealed, shock-rated
ROS 2
Native HAL support
40–60%
Higher torque-to-weight vs. off-the-shelf servo modules
6-axis
Embedded force-torque sensing per joint module
4 labs
Gen 1 evaluation units in active hardware-in-loop validation
1 SDK
Unified control API — ankle to shoulder, one connector spec
Actuator Technology
Hardware and software co-designed from day one
Six joint module capabilities, each validated on the same production hardware that ships to evaluation partners.
01 / High-Torque-Density Module
Motor, gearbox, and housing as a single sealed unit
Each Tendonkindle joint module integrates a high-efficiency brushless motor with a custom strain-wave gearbox in a single aerospace-grade aluminum housing. The result is a torque-to-weight ratio 40–60% higher than comparable off-the-shelf servo modules at the same joint diameter. Sealed to IP54, the module handles the shock loads and orientation changes of bipedal and quadrupedal locomotion without added protection hardware.
02 / Embedded Force-Torque Sensing
Six-axis joint state data at sub-millisecond latency
A custom six-axis force-torque sensor is embedded in each joint module and streams state data over SPI at sub-millisecond latency — no external load cell or wrist sensor required. This enables closed-loop impedance and contact detection natively in the actuator, removing an entire class of external wiring and calibration complexity from robot integration.
03 / Impedance Control SDK
Real-time compliance and trajectory primitives at first boot
The Tendonkindle motion SDK ships impedance and admittance control loops validated on production hardware. Engineers configure stiffness and damping parameters per joint, enable soft-stop boundaries for collision avoidance, and invoke joint-space trajectory primitives — all from a clean Python or C++ API. No re-implementing compliance from scratch on top of raw torque commands.
04 / ROS 2 and Custom Loop Support
Works with any control stack via a clean hardware abstraction layer
The hardware abstraction layer exposes all joint state and command interfaces through a standard ROS 2 ros2_control plugin, with identical APIs available for teams running custom real-time loops. URDF definitions and motor model exports for MuJoCo are maintained alongside hardware revisions, so sim-to-real pipeline integrity is preserved across SDK updates.
05 / Backdrivable by Design
Compliance mode activates on over-force — safe for human proximity
Unlike traditional industrial gearboxes, the strain-wave reduction stage in every Tendonkindle module is backdrivable at rated torque. When the embedded force-torque sensor detects joint loading above a user-set threshold, the SDK automatically transitions into compliant torque mode — absorbing the overload without mechanical damage or abrupt stop events.
06 / Modular Joint Sizing
Five joint variants on one unified connector and power bus
Tendonkindle ships five joint module sizes targeting ankle, knee, hip, shoulder, and elbow torque and angular-velocity envelopes. All five variants share the same connector specification, power bus voltage range, and SDK communication protocol. Engineers can build a full bipedal kinematic chain using a single cable harness standard and one set of SDK initialization calls.
Research Blog
All articles
Technical depth from the team building it
Evaluation Program
Request a Gen 1 evaluation unit
Qualified robotics teams and research labs can apply for evaluation hardware. We ship Gen 1 actuator modules with full SDK access and hardware-in-loop support.
Apply for Evaluation