Design of an Adaptive Velocity Controller for a Hydraulic Mini Excavator using a Moving-Horizon-Estimator

Autonomous excavators have great potential to increase productivity and to improve safety. For the design process of autonomous functions, it is advantageous to use an underlying controller for each actuator instead of using the physical system input. This work considers a velocity controller for ea...

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Bibliographic Details
Published in2019 IEEE Conference on Control Technology and Applications (CCTA) pp. 685 - 690
Main Authors Wind, Hannes, Jenisch, Luis, Renner, Anton, Bender, Frank A., Sawodny, Oliver
Format Conference Proceeding
LanguageEnglish
Published IEEE 01.08.2019
Subjects
Actuators
Feedforward systems
Mathematical model
Nonlinear dynamical systems
Pressure sensors
Valves
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Summary:Autonomous excavators have great potential to increase productivity and to improve safety. For the design process of autonomous functions, it is advantageous to use an underlying controller for each actuator instead of using the physical system input. This work considers a velocity controller for each cylinder of a mini excavator. This controller is designed in a two-degree-of-freedom control structure. The feedforward part is a simplified inverse model of the cylinder dynamics and the feedback part consists of a PI controller. Furthermore, the controller considers the pressure difference over the valve and therefore decouples each cylinder. The valve opening area which is generally a nonlinear function is necessary for this controller approach. Since this function is not always known and changes over time, a moving horizon estimator is designed which estimates it in an online fashion. The experimental results on a mini excavator show the ability of the moving-horizon-estimator to estimate the valve opening area. The velocity controller is able to track the reference velocity and to decouple each cylinder.
DOI:10.1109/CCTA.2019.8920496