In this work, a model-free sliding mode control technique for linear and nonlinear uncertain multi-input multi-output systems is proposed. The developed method does not require a mathematical model of the dynamic system. Instead, knowledge of the system’s order, state measurements, and control input gain matrix shape and bounds are assumed to develop the control law and drive the system’s states to track a desired trajectory. The control system relies on estimating the error between previous and current control inputs to stabilize the system. Lyapunov’s stability criterion is used in the derivation process to ensure closed-loop asymptotic stability. High frequency chattering of the control input and higher-order states, often observed with the sliding mode control method, is eliminated using a smoothing boundary layer. Simulations are performed on a variety of linear and nonlinear systems, including a quadrotor model, to test the performance of the control law. Finally, the model-free sliding mode control system is modified to account for the effects of actuator time-delays.

Library of Congress Subject Headings

Sliding mode control; Lyapunov stability

Publication Date


Document Type


Student Type


Degree Name

Mechanical Engineering (MS)

Department, Program, or Center

Mechanical Engineering (KGCOE)


Agamemnon Crassidis

Advisor/Committee Member

Mark Kempski

Advisor/Committee Member

Jason Kolodziej


Physical copy available from RIT's Wallace Library at TJ220.5 .E5 2017


RIT – Main Campus

Plan Codes