Sliding mode control

In <a href="/facts/Control_system/8CEjIDlS">control systems</a>, sliding mode control (SMC) is a <a href="/facts/Nonlinear_control/KScKca1A">nonlinear control</a> method that alters the <a href="/facts/Dynamic_system/782gREl5">dynamics</a> of a <a href="/facts/Nonlinear_system/4aYItALC">nonlinear system</a> by applying a <a href="/facts/Discontinuous/TGLMsQom">discontinuous</a> control signal (or more rigorously, a set-valued control signal) that forces the system to "slide" along a cross-section of the system's normal behavior. The <a href="/facts/State_space_(controls)/Jf4EanCP">state</a>-<a href="/facts/Feedback/XnuWH3zp">feedback</a> control law is not a <a href="/facts/Continuous_function/sKbl02pB">continuous function</a> of time. Instead, it can switch from one continuous structure to another based on the current position in the state space. Hence, sliding mode control is a <a href="/facts/Variable_structure_control/eS36x1y4">variable structure control</a> method. The multiple control structures are designed so that trajectories always move toward an adjacent region with a different control structure, and so the ultimate trajectory will not exist entirely within one control structure. Instead, it will slide along the boundaries of the control structures. The motion of the system as it slides along these boundaries is called a sliding mode and the geometrical <a href="/facts/Locus_(mathematics)/t4swdGJq">locus</a> consisting of the boundaries is called the sliding (hyper)surface. In the context of modern control theory, any <a href="/facts/Variable_structure_system/96xBWPnl">variable structure system</a>, like a system under SMC, may be viewed as a special case of a <a href="/facts/Hybrid_system/wk7Dfdup">hybrid dynamical system</a> as the system both flows through a continuous state space but also moves through different discrete control modes.

Sliding mode control open-in-new

Sliding mode control