Inverse Feedback Shapers for Coupled Multibody Systems

Control design and experimental validation for flexible multi-body systems pre-compensated by inverse shapers

“…An enhanced robustness in mode compensation can be achieved by a shaper of higher complexity known as EI (extra insensitive) shaper [27], see also references therein, where the design is done by optimizing the residual vibration characteristics. The feedback interconnection with the inverse shaper proposed in [20]…”

“…Another point that needs to be mentioned is that in the scheme with the inverse shaper applied in [11,15,16], it was assumed that there is no backward coupling from the the flexible system part to the controlled main body. Recently, it was shown in [20] that when the mutual coupling between these two subsystems takes place, a special attention needs to be paid to deriving the mode to which the shaper needs to be tuned. Note that as a rule, this mode is not present in the overall system dynamics.…”

“…Note that as a rule, this mode is not present in the overall system dynamics. To determine the mode a method has been proposed in [20] based on an input-output transformation of the multi-body system into the controlled subsystem, the attached residual oscillatory dynamics, and an internal feedback loop representing the dynamical coupling. The transformation eliminating the system input is performed over the time domain system equations.…”

“…Even though the benefit of including an inverse shaper to the feedback in order to pre-compensate oscillations induced by both set-point changes and disturbances [11,20], the control design of arising infinite dimensional system has not been properly addressed. As documented in [11], for simple structure systems, no special attention needs to be paid to the controller design as including the inverse shaper to the loop does not affect the closed-loop characteristics substantially.…”

“…The first contribution of this paper consists of a transfer function based method for determining the target oscillatory mode of the systems based on transfer function approach, which is easier to apply compared to relatively complex methodology presented in [20]. As the second, key contribution, a modified closed-loop scheme with an inverse shaper and a fixed order controller is proposed to control efficiently multi-body flexible systems.…”