• Robots

    To investigate human and animal locomotion, a number of legged robots were developed in our group since 2004. Read about the bipedal robot BioBiped or the research in the Locomorph project focusing on morphology and morphosis strategies in locomotion.

  • Prostheses

    To investigate models of the muscle-tendon dynamics on humans we developed the research platform PAKO. Using our insights on gait biomechanics, walking and running could be realized with the robotic Walk-Run Ankle prosthesis.

  • Facilities

    Several indoor and outdoor facilities with state-of-the-art measurement equipment helps us to perform experiments on humans, animals and robots. Details can be found here: Facilities.

  • Experiments

    Both in research projects and in teaching courses at the Sports Science Institut at TU Darmstadt experimental studies are performed. Outcomes from student research and educational projects on biomechanics can be found in the awarded Teaching Wiki of our institute.

  • Models

    Models help us to study the fundamental principles of human and animal locomotion. The derived biomechanical concepts can be applied to bipedal robots, exoskeletons or prosthesis. In the European project Balance, we are working on an active orthosis.


  • LEARN&ACT DAY of the Movement Academy Motions and Emotions will be postponed due to the current situation

Latest Publications

A biarticular passive exosuit to support balance control can reduce metabolic cost of walking

In this research the advantages of a biarticular thigh exosuit in supporting human walking is demonstrated. Find the details in our recently published paper (open access) by Barazesh, H and Sharbafi, M. A. in Bioinspiration & Biomimetics.


Nowadays, the focus on the development of assistive devices just for people with mobility disorders has shifted towards enhancing physical abilities of able-bodied humans. As a result, the interest in the design of cheap and soft wearable exoskeletons (called exosuits) is distinctly growing. In this paper, a passive lower limb exosuit with two biarticular variable stiffness elements is introduced. These elements are in parallel to the hamstring muscles of the leg and controlled based on a new version of the FMCH (force modulated compliant hip) control framework in which the force feedback is replaced by the length feedback (called LMCH). The main insight to employ leg length feedback is to develop a passive exosuit. Fortunately, similar to FMCH, the LMCH method also predicts human-like balance control behaviours, such as the VPP (virtual pivot point) phenomenon, observed in human walking. Our simulation results, using a neuromuscular model of human walking, demonstrate that this method could reduce the metabolic cost of human walking by 10%. Furthermore, to validate the design and simulation results, a preliminary version of this exosuit comprised of springs with constant stiffness was built. An experiment with eight healthy subjects was performed. We made a comparison between the walking experiments while the exosuit is worn but the springs were slack and those when the appropriate springs were contributing. It shows that passive biarticular elasticity can result in a metabolic reduction of 14.7±4.27%. More importantly, compared to unassisted walking (when exosuit is not worn), such a passive device can reduce walking metabolic cost by 4.68±4.24%.

For further publications of the author please check: ResearchGate, ORCID or LOOP

Bio-inspired neuromuscular reflex based hopping controller for a segmented robotic leg

The bio-inspired neuromuscular reflex based controller can generate stable hopping motion in a real robot. Check out our recently published paper (open access) by Zhao et al. in Bioinspiration & Biomimetics for more details.


It has been shown that human-like hopping can be achieved by muscle reflex control in neuromechanical simulations. However, it is unclear if this concept is applicable and feasible for controlling a real robot. This paper presents a low-cost two-segmented robotic leg design and demonstrates the feasibility and the benefits of the bio-inspired neuromuscular reflex based control for hopping. Simulation models were developed to describe the dynamics of the real robot. Different neuromuscular reflex pathways were investigated with the simulation models. We found that stable hopping can be achieved with both positive muscle force and length feedback, and the hopping height can be controlled by modulating the muscle force feedback gains with the return maps. The force feedback neuromuscular reflex based controller is robust against body mass and ground impedance changes. Finally, we implemented the controller on the real robot to prove the feasibility of the proposed neuromuscular reflex based control idea. This paper demonstrates the neuromuscular reflex based control approach is feasible to implement and capable of achieving stable and robust hopping in a real robot. It provides a promising direction of controlling the legged robot to achieve robust dynamic motion in the future.

For further publications of the author please check: ResearchGate, ORCID or LOOP

Biarticular muscles in light of template models, experiments and robotics: a review

Read our recent review paper about biarticular muscles to learn about the scientific discoveries from simulation models, evidence from human experiments and beneficial design principles in robotic applications. Link to the published paper (open access): Link to Royal Society Interface.

[[https://doi.org/10.1098/rsif.2018.0413|Link to Royal Society Interface]]

Abstract: Leg morphology is an important outcome of evolution. A remarkable morphological leg feature is the existence of biarticular muscles that span adjacent joints. Diverse studies from different fields of research suggest a less coherent understanding of the muscles’ functionality in cyclic, sagittal plane locomotion. We structured this review of biarticular muscle function by reflecting biomechanical template models, human experiments and robotic system designs. Within these approaches, we surveyed the contribution of biarticular muscles to the locomotor subfunctions (stance, balance and swing). While mono- and biarticular muscles do not show physiological differences, the reviewed studies provide evidence for complementary and locomotor subfunction-specific contributions of mono- and biarticular muscles. In stance, biarticular muscles coordinate joint movements, improve economy (e.g. by transferring energy) and secure the zig-zag configuration of the leg against joint overextension. These commonly known functions are extended by an explicit role of biarticular muscles in controlling the angular momentum for balance and swing. Human-like leg arrangement and intrinsic (compliant) properties of biarticular structures improve the controllability and energy efficiency of legged robots and assistive devices. Future interdisciplinary research on biarticular muscles should address their role for sensing and control as well as non-cyclic and/or non-sagittal motions, and non-static moment arms.

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