Advanced Control Designs for Output Tracking of Hydrostatic Transmissions

Taking the practical considerations as a guideline, the work addresses simple but efficient model descriptions in a combination with advanced control and estimation approaches to achieve an accurate tracking of the desired trajectories. The proposed control designs are capable of fully exploiting the wide operation range of HSTs within the system configuration limits. The dissertation develops a new trajectory planning scheme for the output tracking of HST systems that efficiently and simultaneously uses both the primary and secondary control inputs. Based on this control scheme, simple design models or even purely data-driven models are envisaged and deployed to develop and investigate several advanced control approaches for HST systems: optimal control, estimator-based feedback linearization control, active disturbance rejection control and model-free control approaches. The use of tracking differentiators -- which can be interpreted as a model-free way to determine time derivatives of noise-afflicted measurements and substitute classical state transformations corresponding to a classical model-based approach -- is investigated in many of the mentioned control structures. Thereby, a practical view on the applicability of such technical measures for effective and robust control designs on HST systems is provided.