  This paper presents redundancy resolution and disturbance rejection via
torque optimization in Hybrid Cable-Driven Robots (HCDRs). To begin with, we
initiate a redundant HCDR for nonlinear whole-body system modeling and model
reduction. Based on the reduced dynamic model, two new methods are proposed to
solve the redundancy resolution problem: joint-space torque optimization for
actuated joints (TOAJ) and joint-space torque optimization for actuated and
unactuated joints (TOAUJ), and they can be extended to other HCDRs. Compared to
the existing approaches, this paper provides the first solution (TOAUJ-based
method) for HCDRs that can solve the redundancy resolution problem as well as
disturbance rejection. Additionally, this paper develops detailed algorithms
targeting TOAJ and TOAUJ implementation. A simple yet effective controller is
designed for generated data analysis and validation. Case studies are conducted
to evaluate the performance of TOAJ and TOAUJ, and the results suggest the
effectiveness of the aforementioned approaches.
