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FourByThree proposes the development of a new generation of modular industrial robotic solutions that are suitable for efficient task execution in collaboration with humans in a safe way and are easy to use and program by the factory workers.

The project was active for three years, December 2014-2017.

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A proposed unified framework for the recognition of human activity by exploiting the characteristics of action dynamics

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Highlights:

  • A combined algorithm based on shape and motion features of human activity.
  • A single key pose is used for estimation of shape using edges.
  • A single global key pose is extracted from video signal by exploiting local notion.
  • The temporal motion feature is computed using R-transform.
  • Robustness of the algorithm is demonstrated on the varied dataset.

Abstract:

The aim of this paper is to present a novel integrated framework for the recognition of human actions using a spatial distribution of edge gradient (SDEG) of human pose and detailed geometric orientation of a human silhouette in a video sequence. The combined descriptor endows a wealthy feature vector dictionary having both the appearance and angular kinematics information that significantly wraps the local and global information and provides discriminative depiction for the action recognition. The SDEG is computed on a still image at different levels of resolution of sub-images, and still images of the human poses are extracted from the input video sequence using fuzzy trapezoidal membership function based on the normalized histogram distance between the contiguous segment frames. The change of geometric orientation of human silhouette with time is computed using normalized R-Transform. To validate the performance of the proposed approach, extensive experiments are conducted on five publicly available human action datasets i.e. Weizmann, KTH, Ballet Movements, Multi-view i3dPost, and IXMAS. The recognition accuracy achieved on these datasets demonstrates that the proposed approach has an abundant discriminating power of recognizing the variety of actions. Moreover, the proposed approach yields superior results when compared with similar state-of-the-art methods.

Mechanical Design and Analysis of the Novel 6-DOF Variable Stiffness Robot Arm

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Abstract:

This paper proposes four types of conceptual models of the 6-DOF variable stiffness robot arms based on the antagonistic driven joints (ADJs). For convenience of control, the equivalent quadratic torsion spring (EQTS) is selected as the elastic element of the ADJ. The relationship between the output stiffness and the angular displacement of the EQTS is fairly linear. The elastic actuating torque of the ADJ is related to the initial amount of deformation of the EQTS and the angular deflection of the ADJ. The output stiffness of the ADJ is a linear function of the initial amount of deformation of the EQTS. The convenience control of the torque and stiffness of the ADJ will be beneficial to reduce the complexity of the control strategy, and this feature is beneficial for real-time control. In the mechanical solutions, nine types of conceptual models of the EQTSs are presented, and nine types of conceptual models of the ADJs are demonstrated. The cam parameters and the spring parameters of the EQTSs are given. The cam profiles and the pressure angles of the cam-roller mechanisms are illustrated. The elastic actuating torque and output stiffness of the EQTSs and the ADJs are shown. The structure features and actuation characteristics of the EQTSs and the ADJs are compared and analyzed. Since the actuation requirements of the joints of the robot arm differ significantly, four types of conceptual models of the 6-DOF robot arms are assembled based on the different ADJs.

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