Sliding Mode Controller on an electro-pneumatic benchmark in Nantes

Implicit and explicit discrete-time twisting controllers from Olivier Huber on Vimeo.

This short video illustrates the difference between two implementations of the twisting controller on an academic benchmark.

The control problem is to make the mass coupling the two pistons follow a sinusoidal trajectory. The left piston is the one we control, whereas the right one is used to impress a perturbation force of 1000N in magnitude, switching between positive and negative sign. This information is not available to the control loop.

The first controller is obtained with an explicit discretization. The chattering, due to this bad choice of discretization method, make the pneumatic-powered distributors produce a lot of noise.

In the second part of the video the implicitly discretized control law is used. The chattering behaviour is not present. As a result, the performance is also greatly improved and the wear on the actuators is reduced.

This experiments confirm the superiority of the implicit discretization as shown by the theoretical analysis in the following papers: Huber, Acary & Brogliato 2016, Acary, Brogliato & Orlov 2012, and Acary & Brogliato 2010.