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The main goal of the Symbitron project was to develop a safe, bio-inspired, personalized wearable exoskeleton that enables SCI patients to walk without additional assistance, by complementing their remaining motor function. Here we give an overview of major achievements of the projects.

The purpose of this work is to study the effect of placing passive storage elements (springs) along the robot legs on its performance. We first present the model of a planar passive dynamic walker with compliant ground contact model, then replace its rigid legs with compliant legs. Simulation results validate the effectiveness of compliant legs in improving the performance (robustness and velocity) of the robot.

In this work, we present the design and the implementation of an innovative knee locking mechanism for a dynamically walking robot. The mechanism consists of a four-bar linkage that realizes a mechanical singularity for locking the knee when the leg is in the extended position. Once extended, the knee remains locked without energy consumption, while unlocking it only costs a small amount of energy. Tests showed that the robot walks robustly and that the energy consumption of the new system is low.

The TUlip robot was created to participate in the teensize league of Robocup. The TUlip robot is a bipedal robot intended for dynamic walking. It has six degrees of freedom for each leg: three for the hip, one for the knee and two for the ankle. This paper elaborates on the algorithm for the sideways control during gait. The algorithm uses the extrapolated center of mass (XcoM) to achieve limit cycle stability. The algorithm is tested in simulation using a linear inverted pendulum and, then, experimentally applied to the TUlip robot. The result is an adaptive behavior of the TUlip robot, promising for future application to legged robot stability.

For walking robots, the robot’s absolute position must be re- flected in the state. Usually one chooses to include the pose and velocity of the torso in the state (i.e., the torso is taken as the reference body). However, sometimes it is useful to choose a different reference body; in particular the stance foot is a good choice.

At the Control Engineering group of the University of Twente, we are conducting research on control of bipedal robots. In our search for robust and energy efficient control, we are making extensive use of simulation. In order to facil- itate the development of algorithms, we want to design con- trollers that work in a space of “meaningful variables‿; i.e. we don’t control joint angles directly but we control things as “position and velocity of center of mass‿, “shape of the robot’s locked inertia ellipsoid‿ [1] and “foot position‿.

In this abstract we introduce velocity control for our 2D dynamic walking robot Dribbel [1] (figure 1) and show that, by ‘closing the loop’, this automatically leads to increased robustness. Takuma and Hosoda [2] also have used active gait adaptation by using step-by-step feedback, but their research was largely based on experimental results, whereas this research is more theoretical.