# A Second-Order Sliding Mode Controller of Quad-Rotor UAV Based on PID Sliding Mode Surface with Unbalanced Load

> Research article (Journal of Systems Science and Complexity, 2020) · cited 46× · AI/ML

**Wikidata**: [openalex:W3098031785](https://www.wikidata.org/wiki/openalex:W3098031785)  
**Source**: https://4ort.xyz/entity/a-second-order-sliding-mode-controller-of-quad-rotor-uav-based-on-pid-sliding-mode-surface-with-unbalanced-load