Geometric Sensitivity and Orientation-Induced Error Amplification in a Mobile Cable-Driven Parallel Robot on Inclined Surfaces

초록

Mobile cable-driven parallel robots improve deployment flexibility by defining pulley positions through multiple mobile platforms. However, on uneven terrain, tilting of the mobile platforms changes the pulley positions and degrades end-effector tracking accuracy. This paper proposes a tilt-aware real-time kinematics computation method based on three-dimensional localization of each mobile platform. The pulley frames and end-effector anchor points are modeled using homogeneous transformation matrices, and pulley kinematics are incorporated to compute cable lengths more accurately under tilted conditions. A sensitivity analysis is also presented to quantify the effects of platform roll and pitch on cable-length variation caused by pulley offsets. Experiments on an 8-cable, 4-platform mobile cable-driven parallel robot under single- and multi-platform tilting scenarios show that ignoring platform tilting increases the mean tracking error from 5.66 mm to up to 16.77 mm, whereas the proposed method reduces the error to below 6.92 mm while mitigating platform oscillation. These results demonstrate the effectiveness of the proposed method for accurate end-effector control in uneven-terrain environments.

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