THEMIS V2
Last reviewed
Apr 26, 2026
Sources
28 citations
Review status
Source-backed
Revision
v4 · 4,764 words
Improve this article
Add missing citations, update stale details, or suggest a clearer explanation.
Suggest edit
CtrlK
Last reviewed
Apr 26, 2026
Sources
28 citations
Review status
Source-backed
Revision
v4 · 4,764 words
Add missing citations, update stale details, or suggest a clearer explanation.
| THEMIS V2 | |
|---|---|
| General information | |
| Manufacturer | Westwood Robotics |
| Country of origin | United States |
| Year introduced | 2025 (V2); 2024 (original THEMIS) |
| Status | Pre-commercial / Research |
| Height | 1,600 mm (5 ft 3 in) |
| Weight | 36 kg (79 lb) with battery |
| Degrees of freedom | 40 total |
| Actuation | Proprietary BEAR (Back-drivable Electromechanical Actuator for Robotics) |
| Compute | AMD Ryzen 7840HS; up to 200 TOPS AI compute |
| Max speed | 10 km/h (6.2 mph) |
| Payload capacity | 15 kg (33 lb) |
| Battery life | Up to 3 hours (hot-swappable lithium-ion) |
| Website | westwoodrobotics.io/themis |
THEMIS V2 is a full-size bipedal humanoid robot developed by Westwood Robotics, a Los Angeles-based robotics company founded in 2018 by former members of the Robotics and Mechanisms Laboratory (RoMeLa) at the University of California, Los Angeles (UCLA). Standing 1.6 meters tall and weighing 36 kilograms, THEMIS V2 features 40 degrees of freedom, proprietary BEAR proprioceptive actuators, up to 200 TOPS of onboard artificial intelligence computing power, and hot-swappable batteries that provide up to three hours of continuous operation.
The original THEMIS was first unveiled at the IEEE International Conference on Robotics and Automation (ICRA) in Yokohama, Japan, in 2024. The upgraded V2 variant was introduced in April 2025 with enhanced manipulation capabilities, improved sensing, and greater onboard computing. A further iteration, THEMIS Gen 2.5, was announced in January 2026 with additional hardware and software improvements focused on simultaneous locomotion and object manipulation.[1]
THEMIS V2 is designed for real-world applications in logistics, manufacturing, and service environments. Its combination of dynamic locomotion, dexterous manipulation, and AI-assisted autonomy positions it as a research and industrial platform aimed at bridging the gap between laboratory prototypes and commercially deployable humanoid systems.
Westwood Robotics was founded in 2018 by a team of roboticists who had previously worked at RoMeLa, the Robotics and Mechanisms Laboratory at UCLA.[2] RoMeLa was founded and directed by Dennis Hong, a professor of mechanical and aerospace engineering at UCLA and one of the most prominent figures in American humanoid robotics research. The lab has produced over 50 robots across various configurations, including bipedal humanoids, quadrupeds, hexapods, and robotic manipulators.
The company's CEO and founder is Xiaoguang Zhang, who developed expertise in proprioceptive actuators and dynamic robotic systems during his time at RoMeLa.[3] Westwood Robotics takes its name from the Westwood neighborhood of Los Angeles where UCLA is located, reflecting the company's deep academic heritage.
Dennis Hong, born in 1971 in Los Angeles to a family of South Korean heritage, earned his bachelor's degree in mechanical engineering from the University of Wisconsin at Madison and both his master's (1999) and doctoral (2002) degrees in mechanical engineering from Purdue University.[4] He joined Virginia Tech in 2003 as an assistant professor and founded RoMeLa in 2004 in a modest basement laboratory. In 2014, he moved the lab to UCLA, where it has continued to produce groundbreaking robotic systems.
Hong's career in humanoid robotics spans more than two decades and has produced a succession of influential platforms:
| Robot | Full Name | Year | Key Achievement |
|---|---|---|---|
| DARwIn | Dynamic Anthropomorphic Robot with Intelligence | 2004 | First RoMeLa humanoid; RoboCup KidSize champion (2010, 2011) |
| DARwIn-OP | DARwIn Open Platform | 2010 | Open-source humanoid; 400+ units in use worldwide |
| CHARLI | Cognitive Humanoid Autonomous Robot with Learning Intelligence | 2010 | First full-size autonomous walking humanoid built in the U.S. |
| SaFFiR | Shipboard Autonomous Firefighting Robot | 2012 | Navy-funded bipedal firefighting robot; 33 DOF |
| THOR | Tactical Hazardous Operations Robot | 2012 | DARPA Robotics Challenge competitor; 2015 RoboCup World Champion |
| ARTEMIS | Advanced Robotic Technology for Enhanced Mobility and Improved Stability | 2023 | World's fastest walking humanoid at debut (2.1 m/s); RoboCup 2024 champion |
The DARwIn series, first built in 2004, became one of the most successful open-source humanoid platforms in history. The DARwIn-OP (Open Platform) variant has been adopted by hundreds of universities and research institutions worldwide for robotics education and research.[5] Team DARwIn won the RoboCup KidSize Humanoid League in 2010 and 2011, establishing RoMeLa as a dominant force in competitive humanoid robotics.
CHARLI (Cognitive Humanoid Autonomous Robot with Learning Intelligence), introduced in 2010, was the first full-size, untethered, autonomous walking humanoid robot with four moving limbs and a head ever built in the United States. Standing 1.52 meters tall, CHARLI used an innovative linkage system of pulleys and springs rather than traditional rotational joints, keeping the actuation system lightweight. The robot was built in just 1.5 years on a budget of roughly $20,000 in addition to donated software and hardware. CHARLI-2, an improved version, was named one of Time magazine's Best 50 Inventions in 2011 and won the Louis Vuitton Best Humanoid Award at RoboCup 2011. Team CHARLI secured first place in both the AdultSize and KidSize Humanoid divisions at RoboCup 2012.[6]
SaFFiR (Shipboard Autonomous Firefighting Robot), funded by a $2.6 million grant from the U.S. Navy, was a 5-foot-10-inch, 170-pound bipedal humanoid designed to fight fires aboard naval vessels. Constructed from aluminum with 33 degrees of freedom, SaFFiR could navigate the narrow hallways, sharp turns, and steep ladders found on ships. It carried sensors including gas detectors, LIDAR, and stereo infrared and ultraviolet cameras to detect fires and see through smoke. The robot could send a one-inch blast of water at flames while maintaining its balance, with enough battery power for 30 minutes of firefighting operations.[7]
THOR (Tactical Hazardous Operations Robot) was developed for the DARPA Robotics Challenge, a competition inspired by the 2011 Fukushima nuclear disaster that tasked researchers with creating robots capable of entering dangerous environments. THOR-RD, the competition variant, competed at the DARPA Robotics Challenge Finals in June 2015 at the Pomona Fairplex, where it finished 13th among 24 international teams. A 35-member team of postdoctoral, graduate, and undergraduate students from UCLA and the University of Pennsylvania operated the robot during the competition. Despite its modest placement at the DARPA finals, THOR became the 2015 RoboCup World Champion later that year.[8]
ARTEMIS (Advanced Robotic Technology for Enhanced Mobility and Improved Stability), unveiled in 2023, was the world's fastest walking humanoid robot at the time of its debut, reaching speeds of 2.1 meters per second during lab tests. ARTEMIS was the first humanoid running robot designed in an academic setting and only the third overall. The robot placed third at RoboCup 2023 and won the competition in 2024, marking RoMeLa's sixth RoboCup championship.[9]
This lineage of humanoid platforms, spanning from DARwIn through ARTEMIS, provided the foundational knowledge in actuator design, bipedal locomotion control, and dynamic balance that directly informed the development of Westwood Robotics' BEAR actuators and the THEMIS humanoid platform.
Westwood Robotics' product line centers on three main offerings:
Since launching BRUCE and unveiling THEMIS at ICRA 2024, Westwood Robotics has established partnerships with multiple universities, research laboratories, and leading companies across academia and industry.[11]
At the core of THEMIS V2 is Westwood Robotics' proprietary BEAR (Back-drivable Electromechanical Actuator for Robotics) series of actuators. The BEAR actuators are designed as proprioceptive actuators, meaning they can sense forces and torques at the joint level without requiring external force/torque sensors. This proprioceptive capability enables compliant, force-controlled motion that is essential for safe human-robot interaction and dynamic locomotion.
Traditional robotic actuators typically use high-ratio gear trains that provide high torque but sacrifice backdrivability. When a motor is connected through a high-ratio gearbox, external forces applied to the output shaft cannot easily drive the motor backward, making the joint stiff and potentially dangerous during unexpected contact with humans or the environment. BEAR actuators address this problem by using a low-ratio transmission design that maintains backdrivability while still delivering sufficient torque for dynamic humanoid locomotion.
The key advantages of BEAR's proprioceptive design include:
Westwood Robotics offers three main families of BEAR actuators, each optimized for different application requirements:
| BEAR Variant | Target Application | Key Characteristics |
|---|---|---|
| Koala BEAR | End-effectors, small legged robots, medical devices | Smallest and lightest; optimized for compact applications; force sensing and live compliance |
| Panda BEAR | Legged mobile robots, service robots, entertainment robots | Balanced torque, weight, and form factor; excellent dynamic performance; stall torque up to 26.5 Nm (15 s) / 67 Nm (1.5 s) for Panda BEAR Plus |
| Mountain BEAR | Walking humanoids, industrial manipulators | Maximum torque output; 120%+ more torque capacity than previous designs; ~80% less heat generation |
The Koala BEAR series includes the Koala BEAR Muscle Build V1 (KBMB01), which delivers up to three times the torque of the standard Koala BEAR V2 while maintaining the compact form factor.[13] The Panda BEAR series serves as the general-purpose workhorse, balancing torque output, weight, and dynamic performance across a wide range of applications. The Mountain BEAR series, introduced with the THEMIS Gen 2.5 update, represents the strongest actuator line and is specifically engineered for the high-torque demands of full-size humanoid hip joints.
Some BEAR actuator variants incorporate liquid cooling systems to manage thermal output during intensive, sustained operations. This thermal management is particularly important for actuators in high-load joints such as the hips and knees, where continuous torque demands can generate significant heat.[14]
Westwood Robotics provides open-source software support for the BEAR actuators through PyBEAR, a Python driver library hosted on GitHub, enabling researchers and developers to integrate BEAR actuators into custom robotic platforms.[15]
Before THEMIS, Westwood Robotics developed BRUCE (Bipedal Robot Unit with Compliance Enhanced), a kid-size humanoid robot that served as both a commercial product and a technology demonstrator for the BEAR actuator platform.
| Specification | Value |
|---|---|
| Height | 70 cm (27.6 in) |
| Weight | 4.8 kg (10.6 lb) |
| Degrees of freedom | 16 |
| Battery | 3,000 mAh lithium |
| Battery life | ~20 minutes (continuous dynamic motion) |
| Actuators | Koala BEAR proprioceptive actuators |
| Price | ~$16,000 |
BRUCE was originally developed at RoMeLa in a joint effort with Westwood Robotics. The robot is one of the few humanoid platforms in its size class capable of jumping, a capability enabled by the explosive power and dynamic performance of the Koala BEAR actuators. BRUCE has been adopted by multiple universities, research labs, and leading companies as an open platform for reinforcement learning, bipedal locomotion research, and STEAM education.[16]
The experience gained from developing, manufacturing, and deploying BRUCE at scale provided Westwood Robotics with critical insights into actuator reliability, control software architecture, and the practical requirements of robotic systems operating in real-world research environments. These lessons directly informed the design of the full-size THEMIS platform.
The original THEMIS humanoid robot was unveiled at ICRA 2024 in Yokohama, Japan, where it took a remote-controlled walk as part of a live demonstration. This first version showcased Westwood Robotics' ability to scale its BEAR actuator technology from the kid-size BRUCE platform to a full-size humanoid capable of dynamic bipedal locomotion. THEMIS was introduced as a general-purpose humanoid robot designed for advanced dynamic locomotion and precise manipulation in both research and industrial contexts.[17]
The ICRA 2024 debut attracted attention within the robotics community for THEMIS' smooth, compliant movement quality, a direct result of the BEAR actuators' proprioceptive capabilities. The robot's relatively lightweight construction, compared to many competing full-size humanoids, was also noted as a distinguishing characteristic.
THEMIS V2 was introduced in April 2025 as a substantially upgraded version of the original platform. The V2 update brought improvements across manipulation, sensing, and onboard computing:
The V2 was demonstrated at the Robotics Summit and Expo in Boston on April 30 through May 1, 2025, at Booth 650, where it mingled with attendees and served coffee at the event's "Robot Coffee Corner."[19]
On January 29, 2026, Westwood Robotics announced THEMIS Gen 2.5, which the company described as "the first commercially viable humanoid to reliably work on the move." The Gen 2.5 update focused on enabling simultaneous locomotion and manipulation, a capability that most humanoid robots at the time could not perform reliably. Rather than following a "stop, think, act" sequence, THEMIS Gen 2.5 can manipulate objects while walking, making it practical for dynamic warehouse and factory environments.[20]
Key hardware improvements in Gen 2.5 included:
The Gen 2.5 update also introduced AOS (AI-Augmented Humanoid Operating System), a comprehensive software framework discussed in the Software and Control section below.
THEMIS V2 stands 1,600 mm (5 feet 3 inches) tall and weighs 36 kg (79 pounds) with its battery installed. Its lightweight construction, relative to many competing humanoid platforms that weigh 50 kg or more, is achieved through the compact design of the BEAR actuators and careful material selection throughout the frame.
| Specification | THEMIS V2 | THEMIS Gen 2.5 |
|---|---|---|
| Height | 1,600 mm (5 ft 3 in) | 1,600 mm (5 ft 3 in) |
| Weight | 36 kg (79 lb) | ~36 kg |
| Total DOF | 40 | 40+ |
| Arm DOF | 6 per arm | 7 per arm |
| Hand DOF | 7 per hand | 7 per hand |
| Head DOF | 2 | 2 |
| Max speed | 10 km/h (6.2 mph) | 10 km/h (6.2 mph) |
| Payload capacity | 15 kg | 5+ kg per arm |
| Battery life | Up to 3 hours | Up to 3 hours |
| AI compute | Up to 200 TOPS | Up to 200 TOPS |
| Impact resistance | Baseline | ~40% improvement |
The 40 degrees of freedom are distributed across the full body, including the legs, hips, torso, arms, hands, and a 2-DOF head for active vision tracking. The three-fingered hands with 7 DOF each provide sufficient dexterity for grasping a range of objects, from rigid industrial parts to delicate items, with force control enabling adaptive grip strength.
THEMIS V2 integrates multiple sensing modalities for balance, navigation, and manipulation:
| Sensor | Details |
|---|---|
| Head cameras | Stereo vision cameras (2-DOF pan-tilt head) |
| Body cameras | Body-mounted stereo vision cameras |
| IMU | MicroStrain 3DM-CV7-AHRS; >1,000 Hz sampling rate |
| Joint sensors | Integrated force sensors in BEAR actuators |
| Hand sensors | Force control with optional touch sensing |
The MicroStrain 3DM-CV7-AHRS inertial measurement unit (IMU) provides tactical-grade orientation data, including roll, pitch, and yaw measurements, along with real-time acceleration information at a 1 kHz output rate. This high-frequency sensing is critical for maintaining balance during dynamic movements such as walking, running, and obstacle navigation. The IMU's compact and lightweight design minimizes the weight penalty on the robot, and its built-in software libraries provide seamless compatibility with ROS (Robot Operating System).[22]
The stereo vision cameras on both the head and body provide depth perception for object detection, obstacle avoidance, and spatial mapping. The dual camera placement ensures that the robot maintains visual awareness of both its surroundings and its workspace during manipulation tasks.
The onboard computing system is built around an AMD Ryzen 7840HS processor, with AI inference capabilities reaching up to 200 TOPS (tera operations per second) distributed across vision processing units mounted in the head and body. This computing power enables real-time perception, motion planning, and autonomous decision-making without relying on cloud connectivity.[23]
| Component | Details |
|---|---|
| Main processor | AMD Ryzen 7840HS |
| AI compute | Up to 200 TOPS |
| Storage | Up to 8 TB |
| Connectivity | Wi-Fi (2.4/5 GHz), Bluetooth, USB ports |
| Safety | Wireless emergency stop system |
| Cloud dependency | None (fully autonomous on-device operation) |
The wireless emergency stop system provides a critical safety mechanism for operators, allowing the robot to be halted immediately from a distance during testing or deployment.
THEMIS V2 uses dual high-capacity lithium-ion battery packs that provide up to 180 minutes (3 hours) of continuous operation. The batteries are hot-swappable, meaning one pack can be replaced while the other continues powering the robot, enabling near-continuous operation without downtime. An intelligent Battery Management System monitors cell health, temperature, and charge state to ensure safe and efficient operation.[24]
The thermal management system includes liquid cooling for certain high-load BEAR actuator variants, particularly those in the hip and knee joints where sustained torque demands generate significant heat. This cooling approach helps maintain consistent actuator performance during extended operation periods.
With the Gen 2.5 update, Westwood Robotics introduced AOS (AI-Augmented Humanoid Operating System), a software framework built on top of ROS (Robot Operating System) that tightly integrates perception, planning, and control. AOS comprises three core components:
Whole-body loco-manipulation controller: Uses sensor-fusion-based state estimation to maintain balance and precision while the robot walks and handles objects simultaneously. This controller coordinates the movements of the legs, torso, and arms in real time to ensure that manipulation tasks do not destabilize locomotion and vice versa.
Navigation module: Provides multi-layer mapping and semantic environmental understanding, allowing THEMIS to navigate complex indoor environments while avoiding obstacles and planning efficient paths.
Interaction module: Powered by an Object-Centric Vision-Action Model (OC-VAM), this module links visual perception directly to physical actions. It enables task planning and execution by identifying objects in the scene and determining the appropriate manipulation strategies.[25]
THEMIS V2's control system combines model-based controllers with reinforcement learning for real-time adaptation to changing environments and task requirements. The model-based controllers provide stable, predictable behavior for standard locomotion and manipulation tasks, while reinforcement learning policies enable the robot to adapt to novel situations, uneven terrain, and unexpected disturbances.
The system supports multiple control interfaces:
THEMIS V2 can walk at normal human walking speeds and run at speeds up to 10 km/h (6.2 mph, or 2.8 m/s). The BEAR actuators' high dynamic performance enables advanced mobility including sprinting, jumping, and parkour-inspired maneuvers such as navigating obstacles and maintaining balance in unusual configurations. The robot can traverse uneven terrain and handle variations in ground surface that would challenge humanoids with stiffer, less compliant actuation systems.[27]
The proprioceptive sensing provided by the BEAR actuators, combined with the high-frequency IMU data, gives THEMIS V2 rapid feedback about ground contact forces and body orientation. This information feeds into the whole-body controller, enabling the robot to adjust its gait and posture in real time to maintain stability.
The V2's manipulation capabilities represent a significant upgrade over the original THEMIS. Each arm provides 6 degrees of freedom (upgraded to 7 in Gen 2.5), and each three-fingered hand adds 7 DOF with force control and optional touch sensing. The wrists offer 180 degrees of both pitch and yaw flexibility, enabling the hands to reach a wide range of orientations for grasping and placement tasks.
With the Gen 2.5 update and the AOS software stack, THEMIS can perform loco-manipulation: grasping, carrying, and placing objects while walking. This capability is critical for practical applications in logistics and manufacturing, where robots need to move through environments while handling materials rather than stopping at each interaction point.[28]
THEMIS V2 has a maximum payload capacity of 15 kg, and the Gen 2.5 arms can handle a peak load of over 5 kg per arm during manipulation tasks. The three-hour battery life with hot-swappable packs enables the robot to operate through a full work shift with brief battery exchanges, positioning it for practical deployment in industrial settings where continuous operation is necessary.
Westwood Robotics has identified several primary application domains for THEMIS V2:
THEMIS V2 enters an increasingly crowded field of full-size humanoid robots. Its positioning emphasizes agility, lightweight construction, and proprioceptive actuation, distinguishing it from heavier industrial-oriented platforms.
| Robot | Manufacturer | Height | Weight | DOF | Max Speed | Actuation |
|---|---|---|---|---|---|---|
| THEMIS V2 | Westwood Robotics | 160 cm | 36 kg | 40 | 10 km/h | BEAR (proprioceptive) |
| Atlas | Boston Dynamics | 150 cm | 89 kg | 28 | ~5.3 km/h | Electric (2024+) |
| Optimus | Tesla | 173 cm | 57 kg | 28+ | ~8 km/h | Rotary + linear actuators |
| Figure 03 | Figure AI | 170 cm | 70 kg | 42 | N/A | Proprietary |
| GR-2 | Fourier Intelligence | 175 cm | 63 kg | 53 | 5 km/h | FSA actuators |
| NEO | 1X Technologies | 167 cm | 30 kg | 75 | 12 km/h | Tendon drive |
At 36 kg, THEMIS V2 is lighter than most competing full-size humanoids (with the exception of 1X's NEO at 30 kg), which gives it potential advantages in energy efficiency and agility. Its 10 km/h running speed places it among the faster humanoid platforms, and the BEAR actuators' proprioceptive capabilities provide a degree of compliance and force sensing that many competing designs achieve only through additional external sensors.
However, Westwood Robotics is a significantly smaller company than competitors like Tesla, Boston Dynamics, and Figure AI, which have raised billions of dollars in funding and employ hundreds or thousands of engineers. The company's academic pedigree and deep expertise in actuator technology provide technical differentiation, but scaling production and commercializing the platform will require significant capital and manufacturing infrastructure.
THEMIS V2's development is deeply rooted in more than two decades of academic research in humanoid robotics conducted at RoMeLa. The progression from DARwIn (2004) through CHARLI, SaFFiR, THOR, and ARTEMIS established a body of knowledge in bipedal locomotion, actuator design, and whole-body control that distinguishes Westwood Robotics from competitors whose humanoid programs lack comparable academic foundations.
Several specific technical contributions from RoMeLa's research program are visible in THEMIS V2:
Dennis Hong, while not the direct founder of Westwood Robotics, serves as a central figure in the intellectual lineage that connects RoMeLa's academic achievements to Westwood's commercial products. The company represents one of the more prominent examples of a university robotics lab successfully spinning off a commercial humanoid robotics company in the United States.