Johannes Henikl

Infinite-dimensional decentralized damping control of large-scale manipulators with hydraulic actuation

The control design for decentralized active damping of large-scale manipulators with hydraulic actuation is considered in a distributed-parameter framework. The concepts of modern light-weight construction enable the production of machines like mobile concrete pumps or maritime crane systems with extended operating range and less static load. However, due to the reduced weight the elasticity of the construction elements has a significant influence on the dynamic behavior of the boom. In this paper, a modular decentralized control strategy is presented and the asymptotic stability of the closed-loop system is rigorously proven in the infinite-dimensional setting. The proposed damping control strategy features a robust behavior since it is independent of the number and pose of the boom segments and of the exact knowledge of the system parameters. At the end, the practical implementation of the control strategy is discussed and validated by means of measurements on an industrial mobile concrete pump with four joints and an operating range of about 40?m.

Modeling and Control of a Mobile Concrete Pump

Abstract A decentralized control concept for the active damping of elastic boom vibrations of a mobile concrete pump is presented. The weaknesses of the existing hydraulic actuation concept in view of the control task are identified and an alternative concept is proposed. Furthermore, a systematic approach for the derivation of a tailored simulation model is illustrated. Based on the mathematical description of the hydraulic system a feedforward controler for the cylinder piston velocity is designed. The proposed passivity-based feedback control law is motivated by the analysis of a single rotating flexible beam with the angular velocity as a virtual control input. The methods are tested by means of simulation results on a validated mathematical model of a mobile concrete pump.

Modelling, simulation and identification of a mobile concrete pump

Due to the light-weight construction of modern large-scale manipulators used, e.g., in mobile concrete pumps, the elasticity of the construction elements plays a significant role in the dynamic behaviour of the system. Therefore, current research is concerned with control strategies for active damping of elastic vibrations and trajectory planning. For this purpose, tailored mathematical models are required. Apart from the mathematical modelling, the identification of the model parameters constitutes a challenging task. This is mainly due to the large number of parameters to be identified and, considering the large scale, due to the fact that the boom movement cannot be measured by means of standard sensors. This paper presents a systematic approach for the mathematical modelling and identification of hydraulically actuated large-scale manipulators. The feasibility of the overall approach is demonstrated by means of measurement results of a mobile concrete pump.

Modeling and Simulation of Large-Scale Manipulators with Hydraulic Actuation

Abstract Due to the light-weight construction of modern large-scale manipulators used e.g., in concrete pumps or maritime crane systems, the elasticity of the construction elements plays a significant role in the dynamic behaviour of the overall system. These systems are vulnerable to vibrations caused by external disturbances like the pumping of wet concrete, the wave motions on the sea or disturbances induced by the manual control of the operator. Therefore, current research is concerned with control strategies for active damping of elastic vibrations, trajectory planning and the computation of the inverse kinematics. For the development of such control methods, tailored mathematical models are required. In the considered applications, the inhomogeneous distribution of mass and of the geometrical moment of inertia over the length of the segments of the boom has to be explicitly considered in the model which makes the problem more involved. Furthermore, it is known that significant static friction occurs in the hydraulic cylinders used to actuate the boom. Since this can be a major problem in the design of a control strategy, this effect has to be taken into account in the model. This paper presents a systematic approach for the mathematical modeling of hydraulically actuated large-scale manipulators, taking into account both elasticity and static friction. The feasibility of the modeling approach will be proven by measurement results of an industrial mobile concrete pump.

Infinit-dimensionaler Reglerentwurf für Euler-Bernoulli Balken mit Macro-Fibre Composite Aktoren

Zusammenfassung Dieser Beitrag beschäftigt sich mit der Regelung eines einseitig eingespannten Euler-Bernoulli Balkens mit piezoelektrischen Aktoren, die in Form von Macro-Fibre Composite Patches realisiert sind. Auf Basis des verteilt-parametrischen mathematischen Modells wird eine nicht-kollokierte dynamische Ausgangsregelung entworfen, die die asymptotische Stabilität des geschlossenen Regelkreises gewährleistet. Neben der mathematischen Analyse werden die entwickelten Methoden an einem Versuchsstand experimentell validiert. Die Messergebnisse zeigen die Machbarkeit des vorgestellten Ansatzes. Abstract