Posture Control Laboratory
This project employs a Neurorobotics approach. It analyses and models human sensorimotor control with emphasis on postural control. The model is tested by embodiment into a postural control robot, which allows to directly compare its balancing responses to external disturbances with those of humans. The robot's performance captures important aspects of the human postural control. It may therefore serve as a blueprint for neuroprostheses, exoskeletons, and rehabilitation devices, which patients may better accept than current devices.
Our approach is special in that it strongly builds on sensor-derived internal reconstruction of the physical environment.
Eigenmovements on Posturob ll
This film shows examples of testing the Eigenmovement concept of Alexandrov and Frolov (Biol. Cybern. 84, 425–434, 2001). The tests were performed in the robot PostuRob II by A.V. Alexandrov, V. Lippi , T. Mergner, А.А. Frolov, G. Hettich, D. Husek. The sequences show PostuRob II controlling stance: (Experiment 1) Rapid trunk bending (at 1.2 Hz). (Experiment 2) Trunk bending (0.2 Hz) during sinusoidal support surface (SS) translations. (Experiment 3) Balancing during transient SS translations. (Experiment 4) Balancing during pseudorandom SS translations. (Experiment 5) Balancing during sinusoidal SS tilts (0.1 Hz) of 4° peak amplitude. For Exp. 5, fusing the robot’s IMU signal of sagittal trunk rotation in space with the proprioceptive signal of leg rotation with respect to the trunk, an estimate of the leg’s orientation in space was obtained and was used for balancing. Click here for video.
November 2015: In a collaboration between the Neurology’s Posture Lab and DLR (German Aerospace Center), the DLR robot Toro uses the Freiburg DEC model of human-derived sensorimotor control for squatting movements while compensating for various external disturbances. (The IEEE Robotics and Automation Magazine, IEEE-RAM, vol.23, no.1, pp.22-33, march 2016; click here for short Toro video). Our new robot Lucy tries to do the same and includes the frontal plane. (see below)
Posturob 3, alias "Lucy", has 14 DoF. She has learned to combine sway movements in the frontal plane with squatting in the sagittal plane, so that something like a Hula dance results. She likes Vittorio. Click here for short Lucy Posturob video.
A more accurate consideration of the human balancing requires to include in addition to the ankle joints also the hip joints. This concept was realized in Posturob II.
Humans tend to respond to moderate external disturbances by balancing biped stance mainly in the ankle joints. This allows to consider the most relevant aspects of the balancing biomechanics in terms of a single inverted pendulum. This concept was implemented in Posturob I.