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Robots ■ COMAN

COmpliant HuMANoid Platform (COMAN)

COMAN Full Body
Fig. 1 The full body COMAN Humanoid

The COMAN humanoid robot, Fig.1, is being developed within the AMARSI European project which aims to achieve a qualitative jump toward rich motor behaviour in robotic systems, rigorously following a systematic approach in which novel mechanical systems with passive compliance, control and learning solutions will be integrated.

Team members

Project Goals

The development of COMAN body exploits the use of actuation systems with passive compliance.

The goal is:

  • to reduce the distinction between plant and controller that is typical in traditional control engineering to fully exploit complex body properties.
  • to simplify perception, control and learning and to explore how compliance can be exploited for safer human robot interaction, reduced energy consumption, simplified control, and faster and more aggressive learning.

COMAN Mechanics

The COMAN robot is 95cm tall, weighs 31kg and has 25 DOF. Its mechanical components are made from titanium alloy, stainless steel and aluminium alloy, giving it good physical robustness. Its modular joint design uses brushless, frameless DC motors, Harmonic Drive gears and series elastic elements. Leg, waist and shoulder joints have a peak torque capability of 55Nm. Custom torque sensors are integrated into every joint to enable active stiffness control and 6-DOF sensors are included at the ankle to measure ground reaction forces. COMAN can walk and balance using inertial sensors in the pelvis and chest, and its series elastic joint design makes it robust against impacts and external disturbances. COMAN is fully power autonomous. The torso contains a dual core Pentium PC104, onboard battery and battery management system giving up to 2½ hours continuous operation.

CoManWholeBodyFrontView2LegCoMan side
Fig.2 The mechanical assembly of the COMAN.

CoMan Dynamic Models and simulation files

The dynamic model of COMAN is developed in symbolic form using Matlab and Robotran software. The model is also generated in C++, which can be used for simulations in simulink (S-function) or C++ project.

These files contain the dynamic and kinematic paramters of the robot, linearized mass-inertia, coriolis, gravity matrices about the upright (zero angles) posture. Separate symbolic functions exist for direct dynamics, inverse dynamics, cartesian sensors, and adding external forces. Moreover, all the documentation regarding the conventions, converting the CAD data to Robotran convention and actuator models are provided with the models.
In addition, several user functions templates exist within the project files that can be used to customize the equations for the actuators, external forces (ground reaction forces).
Several simulation and control design files are developed to show how to use the direct dynamics for the nonlinear system, add compliant actuators to the robot, control the robot with a discrete time controller (similiar in the actual hardware), detect events such as the centre of mass going out of a certain threshold, and inverse kinematics with visualization of the robot.


A complete version of simulator can be downloaded from gitlab:

This model includes 6 DoF for each leg, 3 DoF for waist and torso, and 7 DoF for each shoulder, arm and fore arm. The dynamics of the series elastic actuators and also ground reaction forces are modeled. In order to run this simulator, the user should have Robotran multibody software installed ( The simulator is completely open source and any recommendations or suggestions are welcome.

In order to receive technical support for the simulator, please register here



Selected publications:

  1. Z. Li, N.G. Tsagarakis, and D.G. Caldwell, “Walking pattern generation for a humanoid robot with compliant joints,” Autonomous Robots, 2013. 
  2. Z. Li, N.G. Tsagarakis, and D.G. Caldwell, “A Passivity Based Admittance Control for Stabilizing the Compliant Humanoid COMAN,” IEEE-RAS International Conference on Humanoid Robots (Humanoids2012), Osaka, Japan (Award for Best Paper Nomination Finalist).
  3. Z. Li, N.G. Tsagarakis, D.G. Caldwell, “Walking Trajectory Generation for Humanoid Robots with Compliant Joints:Experimentation with COMAN Humanoid", IEEE International Conference on Robotics and Automation (ICRA), May,2012, USA.
  4. Z. Li, Bram Vanderborght, N.G. Tsagarakis, L. Colasanto, D.G. Caldwell, “Stabilization for the Compliant Humanoid Robot COMAN Exploiting Intrinsic and Controlled Compliance", IEEE International Conference on Robotics and Automation (ICRA), May, 2012, USA.
  5. N.G. Tsagarakis, S. Morfey, G. A. Medrano-Cerda, Z. Li and D.G. Caldwell "COMAN a Compliant Humanoid: Optimal Joint Stiffness Tuning for Modal Frequency Control", IEEE ICRA 2013
  6. L. Colasanto, N.G. Tsagarakis, D.G. Caldwell, “A Compact Model for the Compliant Humanoid Robot COMAN”, IEEE BIOROB 2012
  7. F.L. Moro, N.G. Tsagarakis, D.G. Caldwell, "Efficient Human-Like Walking for the COmpliant huMANoid COMAN based on Kinematic Motion Primitives (kMPs)", IEEE
  8. International Conference on Robotics and Automation (ICRA), Saint Paul, Minnesota, USA (2012)
  9. F.L. Moro, N.G. Tsagarakis, D.G. Caldwell, "A Human-like Walking for the Compliant Humanoid COMAN based on CoM Trajectory Reconstruction from Kinematic Motion Primitives", IEEE-RAS International Conference on Humanoid Robots (Humanoids), Bled, Slovenia (2011)
  10. B. Ugurlu, J.A. Saglia, N.G. Tsagarakis, D.G. Caldwell, Hopping at the Resonance Frequency: A Trajectory Generation Technique for Bipedal Robots with Elastic Joints, IEEE International Conference on Robotics and Automation, Saint Paul, Minnesota US, 14-18 May, 2012.
  11. M. Mosadeghzad, G. A. Medrano-Cerda, J.A. Saglia,N.G. Tsagarakis, D.G. Caldwell, Comparison of Various Active Impedance Control Approaches, Modeling, Implementation, Passivity, Stability and Trade-offs, IEEE International Conference on Advanced Intelligent Mechatronics, July 11-14, 2012, KaoHsiung, Taiwan.
  12. P. Kormushev, B. Ugurlu, S. Calinon, N.G. Tsagarakis, D.G. Caldwell,  "Bipedal Walking Energy Minimization by Reinforcement Learning with Evolving Policy Parameterization", 2011 IEEE/RSJ International Conference on Intelligent Robots and Systems, pp318-324, (IROS 2011)
  13. N.G. Tsagarakis, Z. Li, J.A. Saglia, D.G. Caldwell, "The Design of the Lower Body of the Compliant Humanoid Robot 'cCub'", IEEE International Conference on Robotics and Automation Conference, pp2035 - 2040 , (ICRA 2011).
  14. Z. Li, B. Vanderborght,N.G. Tsagarakis, D.G. Caldwell, "Fast Bipedal Walk Using Large Strides by Modulating Hip Posture and Toe-heel Motion" , IEEE ROBIO 2010.
  15. N.G. Tsagarakis, B. Vanderborght, M. Laffranchi and D.G. Caldwell, "The Mechanical Design of the New Lower Body for the Child Humanoid robot 'iCub'", IEEE/RSJ International Conference on Intelligent Robots and Systems, pp4962-4968, IROS 2009.
  16. N.G. Tsagarakis, M. Laffranchi, Bram Vanderborght, D.G. Caldwell, "A Compact Soft Actuator Unit for Small Scale Human Friendly Robots", IEEE International Conference on Robotics and Automation Conference, (ICRA 2009), Kobe Japan, pp4356-4362.

Last Updated on Thursday, 08 January 2015 18:15