Underactuated Cable-Driven Parallel Robots (CDPR) employ a number of cables smaller than the degrees of freedom (DoFs) of the end-effector (EE) that they control. As a consequence, the EE is underconstrained and preserves some freedoms even when all actuators are locked, which may lead to undesirable oscillations. This paper proposes a methodology for the computation of the EE natural oscillation frequencies, whose knowledge has proven to be convenient for control purposes. This procedure, based on the linearization of the system internal dynamics about equilibrium con_gurations, can be applied to a generic robot suspended by any number of cables comprised between 2 and 5. The kinematics, dynamics, stability and stiffness of the robot free motion are investigated in detail. The validity of the proposed method is demonstrated by experiments on 6-DoF prototypes actuated by 2, 3, and 4 cables. Additionally, in order to highlight the interest in a robotic context, this modelling strategy is applied to the trajectory planning of a 6-DoF 4-cable CDPR by means of a frequency-based method (multi-mode input shaping), and the latter is experimentally compared with traditional non-frequency-based motion planners.


    Access

    Download


    Export, share and cite



    Title :

    Natural oscillations of underactuated cable-driven parallel robots


    Contributors:

    Publication date :

    2021-01-01



    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English



    Classification :

    DDC:    629



    A New Performance Index for Underactuated Cable-Driven Parallel Robots

    Idà, Edoardo / Carricato, Marco | TIBKAT | 2021


    Pose-Estimation Methods for Planar Underactuated Cable-Driven Parallel Robots

    Gabaldo, Sara / Idà, Edoardo / Carricato, Marco | Springer Verlag | 2023


    A New Performance Index for Underactuated Cable-Driven Parallel Robots

    Ida E. / Carricato M. | BASE | 2021

    Free access

    A New Performance Index for Underactuated Cable-Driven Parallel Robots

    Idà, Edoardo / Carricato, Marco | Springer Verlag | 2021