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Projektgruppen im Wintersemester 2011/2012

The "Steady Hand Game” with a multi-flexible-link robot arm



The next generations of robots is expected to assist their human owners safely and dependably in various every day scenarios. A descriptive example would be a household service robot, that can help carrying even heavy luggage or shopping from the boot of a car into the housing space. However, the rigid but massive design of today’s conventional robots implies a substantial injury potential in the case of unforeseen collisions between the human and a robot.

Abbildung 1: Das Experimentalsystem TUDORThis observation recently motivated the emergence of lightweight manipulators. The intentional introduction of passive elasticity to the robot structure improves the inherent safety and by construction already reduces the injury potential of the robot. The intrinsic compliance allows for the implementation of control concepts that actively control the robot reaction during the post-impact phase.

The new capabilities come at the cost of an increased complexity of the robot kinematics as well as dynamics. Fast movements induce structural oscillations whereas static configuration and load dependent deflections aggravate the precise end-effector positioning. The 3-degree-of-freedom flexible link robot arm TUDOR (Technische Universität Dortmund, omnielastic Robot) has been developed to study modelling techniques and control schemes that achieve ac-curate positioning and path tracking in spite of these unwanted dynamics.


The project implements the “Steady Hand Game” with TUDOR. The “Steady Hand Game” tests the hand-eye cooredination and the motor skills of the player. It consists of a meandering wire and an additional wire loop enclosing it. The challenge is to guide the wire loop along the meandering wire without contact.

To tackle the challenge the project group constructs the “Steady Hand Game” hardware and equips TUDOR with a gripper and a fourth degree of freedom at the wrist. This allows TUDOR to guide the loop wire. Furthermore a Kinect RGB-D-sensor is mounted on the robot structure enabling simultaneous localization and mapping (SLAM) of the robot within the environment. The map is represented by a point cloud and used to recognize the meandering wire. An existing position control concept, which rapidly dampens induced vibrations, is extended to a trajectory tracking controller. Intermediate results from each work package are continuously integrated into a simulation framework based on Matlab and Simulink.


Work packages:

  1. Construction of the “Steady Hand Game“-Hardware as well as the Gripper.

  2. Simultanous Localisation and Mapping (SLAM) with the Kinect RGB-D sensor and recognition of the meandering wire.

  3. Design and implementation of the trajectory tracking controller.

  4. Implementation of the simulation environment and continuous integration of inter-mediate results.


  • Enthusiasm for the challenging topic.

  • Fundamental knowledge of either of the fields: control theory, robotic manipulators or computer vision.

  • Experiences with Matlab and C++ are appreciated.

Important dates and how to register:

A&R-students interested in participating in the project please submit a recent transcript of grades to


Please include the work packages you would like to work on ordered by descending priority.

The final submission due is Friday 22nd July.

The notification of acceptance is Monday 25th July.




Dr.-Ing. Jörn Malzahn
Wissenschaftlicher Mitarbeiter