Open architecture hierarchical predictive control for saturation avoidance

The paper presents a hierarchical predictive control structure developed for constraints avoidance within machining centres environment, approaching the constraints problem from a specific open architecture viewpoint combined with advanced control strategies. The saturation of the control signal is avoided by modifying the future setpoint through a "trajectory supervisor". Nevertheless, this modified setpoint might become unacceptable compared to the original one, in terms of profile accuracy. In this case, a "decisional module", based on the error between the modified reference avoiding the saturation and the initial one, starts a procedure for regenerating the remaining trajectory with adapted velocity parameters. The interest for this structure lays in its predictive and open architecture features. Tests performed within an open architecture virtual machining centre validate the effectiveness of this strategy