Improvement of cable tension observability through a new cable driving unit design

International audienceThe context of this paper is a research project on a Cable-Driven Parallel Manipulator uses to reproduce the free flight condition of aircraft models in wind tunnels (SACSO Project). The force control of the CDPM enables to simulate the thrust of the aircraft engine, and to modify the scale model mass and inertia. A very important point for an efficient force control is an accurate estimation of the cables tension. In this paper, an original Cable Driving Unit with an integrated 3D force sensor is developped to improve the cable tension observability. An associated Extended Kalman Filter implementation is then proposed to estimate the cables tension. © Springer International Publishing AG 2018

Stiffness Oriented Tension Distribution Algorithm for Cable-Driven Parallel Robots

International audienceA novel criterion is introduced in this paper to determine the set of cable tensions for Cable-Driven Parallel Robots (CDPRs) with the aim of maximizing the robot stiffness along a specific direction. Based on the feasible polygon of the CDPR and its stiffness matrix, an algorithm selects the set of admissible cable tensions leading to the smallest moving-platform displacement, the moving-platform being subject to an external wrench. The proposed tension distribution is implemented in a control scheme and experimented on a fully-constrained CDPR for a window cleaning application

Sensitivity analysis of the elasto-geometrical model of cable-driven parallel robots

International audienceThis paper deals with the sensitivity analysis of the elasto-geometrical model of Cable-Driven Parallel Robots (CDPRs) to their geometric and mechanical uncertainties. This sensitivity analysis is crucial in order to come up with a robust model-based control of CDPRs. Here, 62 geometrical and mechanical error sources are considered to investigate their effect onto the static deflection of the moving-platform (MP) under an external load. A reconfigurable CDPR, named “CAROCA”, is analyzed as a case of study to highlight the main uncertainties affecting the static deflection of its MP

Diagnosis and treatment of rotatory knee instability

BACKGROUND Rotatory knee instability is an abnormal, complex three-dimensional motion that can involve pathology of the anteromedial, anterolateral, posteromedial, and posterolateral ligaments, bony alignment, and menisci. To understand the abnormal joint kinematics in rotatory knee instability, a review of the anatomical structures and their graded role in maintaining rotational stability, the importance of concomitant pathologies, as well as the different components of the knee rotation motion will be presented. MAIN BODY The most common instability pattern, anterolateral rotatory knee instability in an anterior cruciate ligament (ACL)-deficient patient, will be discussed in detail. Although intra-articular ACL reconstruction is the gold standard treatment for ACL injury in physically active patients, in some cases current techniques may fail to restore native knee rotatory stability. The wide range of diagnostic options for rotatory knee instability including manual testing, different imaging modalities, static and dynamic measurement, and navigation is outlined. As numerous techniques of extra-articular tenodesis procedures have been described, performed in conjunction with ACL reconstruction, to restore anterolateral knee rotatory stability, a few of these techniques will be described in detail, and discuss the literature concerning their outcome. CONCLUSION In summary, the essence of reducing anterolateral rotatory knee instability begins and ends with a well-done, anatomic ACL reconstruction, which may be performed with consideration of extra-articular tenodesis in a select group of patients