Yong Ren 0003 Zhibao Song Ping Li 0027 Hui Ye 0001 Boundary Control for a Suspension Cable System of a Helicopter With Saturation Nonlinearity Using Backstepping Approach. 114213-114222 2019 7 IEEE Access https://doi.org/10.1109/ACCESS.2019.2935899 db/journals/access/access7.html#RenSLY19