Initial-Pose Self-Calibration for Redundant Cable-Driven Parallel Robot Using Force Sensors Under Hybrid Joint-Space Control
Zhen Liu, Zhiwei Qin, Haibo Gao, Guangyao Sun, Zhongshan Huang, Zongquan Deng
Abstract
This letter investigates initial-pose estimation (Cartesian position and orientation) for redundant cable-driven parallel robots (CDPRs). As the forward kinematics cannot be performed if the robot is equipped with incremental sensors, a calibration method using force sensors is proposed. The self-calibration problem is formulated as a non-linear least-squares optimization problem based on the hybrid joint-space control strategy. The redundant cables are tension-controlled; the other cables are maintained at a fixed length in the joint space. A position-determined cable adjustable force (P-CAF) performance index and the concept of calibratable space were proposed to maintain the quasi-static conditions. A simulated case study was used to validate the calibration process.