Conference Paper

Kinematically Optimal Catching a Flying Ball with a Hand-Arm-System

DLR Inst. of Robot. & Mechatron., Wessling, Germany
DOI: 10.1109/IROS.2010.5651175 Conference: Proc. IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)
Source: IEEE Xplore


A robotic ball-catching system built from a multi- purpose 7-DOF lightweight arm (DLR-LWR-III) and a 12 DOF four-fingered hand (DLR-Hand-II) is presented. Other than in previous work a mechatronically complex dexterous hand is used for grasping the ball and the decision of where, when and how to catch the ball, while obeying joint, speed and work cell limits, is formulated as an unified nonlinear optimization problem with nonlinear constraints. Three different objective functions are implemented, leading to significantly different robot movements. The high computational demands of an online realtime optimization are met by parallel computation on distributed computing resources (a cluster with 32 CPU cores). The system achieves a catch rate of > 80% and is regularly shown as a live demo at our institute.

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Available from: Thomas Wimböck, Oct 10, 2015
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    • "We now consider the problem of intercepting a ball as presented in [2]. Assume the situation of Fig. 6, where two robots R 1 , R 2 are chasing a ball B. The movement of the robot R 1 with respect to the robot R 2 is represented by "
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    • "The ball is tracked by two overlapping high speed stereo vision setups with 200Hz cameras. The position of the ball on 1 Instead of employing the concept of a catching plane, more advanced criteria like " minimal movement of the end-effector " could be employed to determine the catching point [4]. Fig. 4: The BioRob and the Barrett WAM playing catch. "
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    • "The general interception problem has been studied in an optimal control context for several decades (see, for example, [5] and references therein). Variations of the problem have also been studied in robotics (e.g. for robotic arms [1] and ground robots [22]) For quadrotor applications, interception problems have been treated in a number of scenarios, including ball juggling, where the interception was more strongly constrained to occur at a specified velocity and attitude [21]. In [3], a ball flight path was intercepted on a given plane by setting the controller reference position to the interception point. "
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