Design, Implementation and Analysis of Novel Motor Units and Joint Torque Concepts

The goal of this thesis is to analyze novel motor unit and joint torque concepts regarding their potential use in full scale torque controlled light weight robots. Meeting the guidelines of building a robot with a payload of 5−7 kg and an overall weight of less than 15 kg requires the design and construction of extreme light-weight structures, including a thorough investigation of different motor control strategies tailored to the respective design.
For this, suitable sensors (e.g. torque and position sensor) and actuators (e.g. motors) of a single joint need to be selected/designed with respect to the overall robot kinematics and dynamics. To facilitate such an analysis, different rough CAD designs of full scale manipulators are used to derive the dynamic parameters for the entire robot, which are then transformed into the respective dynamics model. Having a reasonable forecast available for the full robot, the respective joint unit specifications can be formulated. The outcome shall then be use to design and experimentally validate a motor test unit, including closed-loop control. This servers for an in-depth analysis of a set of available motors, while having the overall robot dynamics in mind. Next, a novel joint torque sensor concept is to be developed. This shall then be experimentally validated on an existing joint torque sensor test unit.

Tasks:

• Analysis of robot kinematic architectures for deriving joint specifications: from CAD design to model
based closed-loop control simulation
• Design and construction of a mechanical motor test bench
• Design and implementation of motor control techniques including disturbance compensation
• Conception of a torque sensor test bench and analysis of a concrete torque sensor prototype

 

Bibliography:
[1] Albu-Sch¨affer, Alin, et al. ”The DLR Lightweight Robot - Lightweight Design and ”Soft Robotics” Control Concepts for Robots in Human Environments”, Industrial Robot Journal, Vol. 34, No. 5, 2007, pp. 376-385
[2] Hirzinger, G., et al. ”A Mechatronics Approach to the design of light-weight arms and multifingered hands”, Proceedings of the 2000 IEEE, International Conference on Robotics & Automation, San Francisco, CA April 2000
[3] Hirzinger, G., et al. ”DLR’s torque-controlled light weight robot III-are we reaching the technological limits now?”, Robotics and Automation, 2002. Proceedings. ICRA ’02. IEEE International Conference on , vol.2, no., pp.1710,1716 vol.2, 2002