About 109 muscle actuators
The university page and a 2011 presentation count 109 muscle actuators; the page also describes a four-segment spine. [1][3]
Kojiro
Specs, price & availability · verified Oct 2026
Kojiro is a 135 cm, 45 kg biped from University of Tokyo (Japan), discontinued with no published price.
- Price
- Not disclosed
- Height
- 135 cm
- Weight
- 45 kg
- Total DoF
- 58
Last verified Oct 10, 2026
Listed in:New humanoid robots
Price & availability
University of Tokyo has not published a price
Discontinued
Current dataset status: Discontinued.
Product overview
About Kojiro
Kojiro is a musculoskeletal humanoid from the University of Tokyo, dated 2007 on the university's exhibit page. A presentation delivered by researcher Yuto Nakanishi in 2011 labels the Kojiro project as running from 2008 and gives the robot's specifications as 135 cm, 45 kg, 58 joint degrees of freedom and 109 muscle actuators. The one-year date difference appears to reflect the exhibit date versus the continuing project timeline.
Rather than placing a motor directly at every joint, Kojiro uses electric motors to pull tendon-like cables. The lab tested two-legged standing, sensor-based reflexive walking, Japanese drumming and spine-driven movement. The body has a four-segment spine, and the shoulder arrangement gives the upper limbs a wide range of motion. IEEE Spectrum rounded the degree-of-freedom count to about 60 in its 2010 coverage.
Kojiro is the base design for the later Kenshiro and Kengoro robots, which the university exhibit names as successors that evolved its design. The displayed robot has no price or sales channel and is a historical research platform, so it is classed as discontinued.
Capabilities
Key features
Sensor-based reflexive walking
Experiments included two-legged standing, sensor-based reflexive walking, Japanese drumming and spine-driven motion. [1]
Light and agile design goal
The team aimed for light, agile humanoids, arguing that DC-motor joints make standard robots hard and heavy. [2]
Base for later robots
The university's page names Kojiro as the base design for Kenshiro and Kengoro. [1]
Motor and joint sensing
IEEE Spectrum (2010) describes a rotary encoder and tension sensor per motor unit, joint-angle sensors, six-axis force sensors at the ankles, and gyros with an accelerometer in the head. [2]
Hardware profile
Specifications
Official — stated by the manufacturer or organizerReported — stated by a credible third partyEstimated — derived or approximate
Body
Mobility
Compute & Sensing
- Sensors
- Rotary encoder and tension sensor per motor unit, Joint-angle sensors, Six-axis force sensors at the ankles, Gyros and a three-axis accelerometer in the headReported — stated by a credible third party[2]Proprioceptive sensing only; IEEE Spectrum names no perception sensors (2010)
Show unknown fields (11)
Mobility
- Maximum speed
- Not published
- Peak joint torque
- Not published
Power
- Battery
- Not published
- Runtime
- Not published
- Charge time
- Not published
- Swappable battery
- Not published
Hands & Manipulation
- DoF per hand
- Not published
- Payload
- Not published
- Hand / end effector
- Not published
Compute & Sensing
- Onboard compute
- Not published
- AI stack
- Not published
Quick answers
Kojiro FAQ
Can you buy Kojiro?
No general order page is verified. Kojiro is currently classified as discontinued. [1]
How tall is Kojiro and how much does it weigh?
Kojiro is 135 cm tall and weighs 45 kg (Per the lab's exhibit page). [3][1]
How many degrees of freedom does Kojiro have?
Kojiro has 58 listed degrees of freedom; Researcher presentation gives 58 joint DoF; IEEE Spectrum rounded this to about 60. [3]
Who makes Kojiro?
Kojiro is made by University of Tokyo, based in Japan. [1]
What is the predecessor or successor of Kojiro?
Kenshiro is its successor. [1]
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Lineage
Model family
Evaluation footprint
Benchmarks & competitions
No benchmark embodiments or results reference this robot yet.
Related
Similar robots
Evidence
Sources
- [1]Musculoskeletal Humanoid 'Kojiro' (HASEKO-KUMA Hall exhibit page) ↗The University of Tokyo, Faculty of Engineering · official · accessed Oct 8, 2026
- [2]Kojiro musculoskeletal humanoid robot (IEEE Spectrum) ↗IEEE Spectrum · press · accessed Oct 10, 2026
- [3]Challenge to Design and Control of More Humanlike Tendon-Driven Musculoskeletal Humanoids ↗Yuto Nakanishi, JSK Robotics Laboratory, The University of Tokyo · paper · accessed Oct 8, 2026