Spatial In-Parallel Wire-Driven Mechanism with Six Degrees of Freedom

For Haptic Interface Applications (1998)

We have proposed an index for evaluating the force transmission characteristics in general N degree-of-freedom (dof) in-parallel wire-driven mechanisms (PWDMs) with N+1 wires. The relationship between input force and output force in an N dof in-parallel actuated mechanism with only rigid links was used for defining the transmission index for a PWDM. The transmission index TIW has the following features that are preferable as an index for mechanism synthesis and trajectory planning.

1. TIW is a nondimensional value which varies within [0,1].

2. TIW is defined only by the geometric condition of the mechanism.

3. A bigger value of TIW indicates the better force transmission characteristics from the wires to the output link.

4. When TIW is equal to zero, the mechanism is located at a singular point.

Using the transmission index for PWDM, kinematic syntheses of two types of spatial six-dof PWDMs with seven wires have been carried out, and novel spatial PWDMs with high force transmissibility and large practical working space have been obtained. Working spaces and force transmission characteristics of the synthesized mechanisms have been investigated, and experimental results of trajectory control of an experimental spatial PWDM have been also conducted.

Mechanism Configuration (Type(3,31))

Photograph

References

1. Yukio Takeda and Hiroaki FUNABASHI : Kinematic Synthesis of Spatial In-Parallel Wire-Driven Mechanism with Six Degrees of Freedom with High Force Transmissibility, to be appeared in Proc. ASME-DETC2000, Sept.10-13,2000, Baltimore, Maryland, USA.