Freeway traffic control via second-order sliding modes generation

The paper deals with the design of a Suboptimal Second-Order Sliding Mode (SSOSM) control algorithm for local ramp metering of freeway systems. Indeed, sliding mode control is well-known for its robustness in front of uncertain terms and it perfectly fits to solve the control problem in case of traffic systems. Moreover, the proposed control law is able to steer the so-called sliding variable, chosen as the error between the density of the cell in the vicinity of the ramp and its reference value, to zero in a finite time. The traffic flow is modeled by means of the macroscopic second-order METANET model and the approach is finally assessed in simulation with satisfactory results.