The Experts below are selected from a list of 240 Experts worldwide ranked by ideXlab platform
Henrik C Pedersen - One of the best experts on this subject based on the ideXlab platform.
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an approach for second order control with finite time convergence for electro Hydraulic Drives
ASME BATH 2013 Symposium on Fluid Power & Motion Control FPMC2013, 2013Co-Authors: Lasse Schmidt, Torben Ole Andersen, Henrik C PedersenAbstract:Being a second order sliding algorithm, the super twisting algorithm is highly attractive for application in control of Hydraulic Drives and mechanical systems in general, as it utilizes only the control error while driving the control error as well as its derivative to zero for properly chosen algorithm parameters. However a discontinuous term internally in the control structure may excite pressures of transmission lines in Hydraulic Drives as the control structure strives to maintain the control error and its derivative equal to zero. In this paper a modified version of a controller based on the super twisting algorithm is proposed, with the focus of eliminating the discontinuous term in order to achieve a more smooth control operation. The convergence properties of the proposed controller are analyzed via a conservative phase plane analysis. Furthermore, homogeneity considerations imply finite time convergence of states to the origin under certain model assumptions. Results demonstrate the smooth control operation compared to the direct super twisting control approach while maintaining robustness properties in relation to position tracking of a Hydraulic drive, under parameter perturbations, uncertainties and un-modeled dynamics.Copyright © 2013 by ASME
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a novel control approach based on second order sliding modes its application to Hydraulic Drives
International Conference on Mechatronics and Automation, 2013Co-Authors: Lasse Schmidt, Torben Ole Andersen, Henrik C PedersenAbstract:Sliding modes impose strong robustness toward parametric plant uncertainties and disturbances and accurate tracking performance in control systems. However, in physical systems the application of sliding modes may give rise to undesirable chattering of the control signal due to actuator dynamics. This may be avoided by application of smoothing functions imposing boundary layers on the control constraint, or by carrying out the design in relation to the control derivative. However, such boundary layers introduces additional design parameters and actuator dynamics may not allow the desired control accuracy to be reached. In this paper a novel control approach based on second order sliding modes utilizing the idea of the power rate reaching law is introduced. Dependent on parameters the proposed controller may preserve the main features of sliding controls, while at the same time avoiding control chattering. Simulation studies confirm the announced properties when applied to a Hydraulic drive model subjected to strong variations in supply pressure and friction.
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robust non chattering observer based sliding control concept for electro Hydraulic Drives
IFAC Proceedings Volumes, 2013Co-Authors: Lasse Schmidt, Torben Ole Andersen, Henrik C PedersenAbstract:Abstract This paper presents an observer-based sliding mode control concept with chattering reduction, generally applicable for position tracking control of electro-Hydraulic valve-cylinder Drives (VCD's). The proposed control concept requires only common data sheet information and no knowledge on load characteristics. Furthermore the proposed scheme only employ ***piston-and valve spool positions- and pressure feedback, commonly available in industry. The main target is to overcome problems with linear controllers deteriorating performance due to the inherent nonlinear nature of such systems, without requiring extensive knowledge on system parameters nor advanced control theory. In order to accomplish this task, an integral sliding mode controller designed for the control derivative employing state observation is proposed, based on a generalized reduced order model structure of a VCD with unmatched valve flow- and cylinder asymmetries. It is shown that limited attention can be given to bounds on parameter estimates, that chattering is reduced and the number of tuning parameters is reduced to the level seen in conventional PID schemes. Furthermore, simulation results demonstrate a high level of robustness when subjected to strong perturbations in supply pressure and coulomb friction force, and that tracking accuracy may be reduced to the level of noise. Furthermore, the proposed controller tolerates significant noise levels, while still remaining stable and accurate.
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A novel control approach based on second order sliding modes & its application to Hydraulic Drives
2013 IEEE International Conference on Mechatronics and Automation, 2013Co-Authors: Lasse Schmidt, Torben O. Andersen, Henrik C PedersenAbstract:Sliding modes impose strong robustness toward parametric plant uncertainties and disturbances and accurate tracking performance in control systems. However, in physical systems the application of sliding modes may give rise to undesirable chattering of the control signal due to actuator dynamics. This may be avoided by application of smoothing functions imposing boundary layers on the control constraint, or by carrying out the design in relation to the control derivative. However, such boundary layers introduces additional design parameters and actuator dynamics may not allow the desired control accuracy to be reached. In this paper a novel control approach based on second order sliding modes utilizing the idea of the power rate reaching law is introduced. Dependent on parameters the proposed controller may preserve the main features of sliding controls, while at the same time avoiding control chattering. Simulation studies confirm the announced properties when applied to a Hydraulic drive model subjected to strong variations in supply pressure and friction.
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An approach for state observation in dynamical systems based on the twisting algorithm
2013 IEEE International Conference on Mechatronics and Automation, 2013Co-Authors: Lasse Schmidt, Torben O. Andersen, Henrik C PedersenAbstract:This paper discusses a novel approach for state estimation in dynamical systems, with the special focus on Hydraulic valve-cylinder Drives. The proposed observer structure is based on the framework of the so-called twisting algorithm. This algorithm utilizes the sign of the state being the target for the observation, not directly implying its applicability for state observation. However it is shown that in the discrete case this approach may be applied to obtain a real time derivative using an intermediate integral process. Furthermore, different types of gains for the algorithm are suggested and analyzed via Lyapunov arguments, and a special version of the observer is proposed specifically for Hydraulic Drives utilizing online available plant information. The proposed observer with different observer gains are subjected to simulation studies in order to evaluate the exact properties, and results confirm that the proposed observer structure is easily implemented, produces very limited phase shift and is highly robust toward measurement noise.
Lasse Schmidt - One of the best experts on this subject based on the ideXlab platform.
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a class of energy efficient self contained electro Hydraulic Drives with self locking capability
Energies, 2019Co-Authors: Lasse Schmidt, Soren Ketelsen, Morten Helms Brask, Kasper Aastrup MortensenAbstract:Pump controlled and self-contained electro-Hydraulic cylinder Drives may improve energy efficiency and reduce installation space compared to conventional valve solutions, while being in line with the trend of electrification. The topic has gained increasing interest in industry as well as in academia in recent years. However, this technology has failed to break through in industry on a broad scale, with the reason assumed to be lack of meeting industry requirements. These requirements include high drive stiffness enabling a large application range, and the ability to maintain cooling and filtration in required ranges, enabling proper reliability and durability. Furthermore, at this point the cost of realization of such Drives is comparable only to high end valve drive solutions, while not providing dynamics on a similar level. An initiative to improve this technology in terms of a class of Drives evolving around a Hydraulic cylinder locking mechanism is proposed. The resulting class of Drives generally rely on separate cylinder forward and return flow paths, allowing for fluid cooling and filtration as well as control of the drive stiffness. The proposed class of Drives is analyzed regarding energy loss and recovery potential, a basic model based control design is realized, and the industrial feasibility of the drive class is considered. It is found that the proposed class of Drives may be realized with standard components maintained in their design ranges at competitive costs compared to conventional valve solutions. Furthermore, it is found that pressure levels may be controlled in a proper way, allowing to produce either highly efficient operation or a high drive stiffness.
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an approach for second order control with finite time convergence for electro Hydraulic Drives
ASME BATH 2013 Symposium on Fluid Power & Motion Control FPMC2013, 2013Co-Authors: Lasse Schmidt, Torben Ole Andersen, Henrik C PedersenAbstract:Being a second order sliding algorithm, the super twisting algorithm is highly attractive for application in control of Hydraulic Drives and mechanical systems in general, as it utilizes only the control error while driving the control error as well as its derivative to zero for properly chosen algorithm parameters. However a discontinuous term internally in the control structure may excite pressures of transmission lines in Hydraulic Drives as the control structure strives to maintain the control error and its derivative equal to zero. In this paper a modified version of a controller based on the super twisting algorithm is proposed, with the focus of eliminating the discontinuous term in order to achieve a more smooth control operation. The convergence properties of the proposed controller are analyzed via a conservative phase plane analysis. Furthermore, homogeneity considerations imply finite time convergence of states to the origin under certain model assumptions. Results demonstrate the smooth control operation compared to the direct super twisting control approach while maintaining robustness properties in relation to position tracking of a Hydraulic drive, under parameter perturbations, uncertainties and un-modeled dynamics.Copyright © 2013 by ASME
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a novel control approach based on second order sliding modes its application to Hydraulic Drives
International Conference on Mechatronics and Automation, 2013Co-Authors: Lasse Schmidt, Torben Ole Andersen, Henrik C PedersenAbstract:Sliding modes impose strong robustness toward parametric plant uncertainties and disturbances and accurate tracking performance in control systems. However, in physical systems the application of sliding modes may give rise to undesirable chattering of the control signal due to actuator dynamics. This may be avoided by application of smoothing functions imposing boundary layers on the control constraint, or by carrying out the design in relation to the control derivative. However, such boundary layers introduces additional design parameters and actuator dynamics may not allow the desired control accuracy to be reached. In this paper a novel control approach based on second order sliding modes utilizing the idea of the power rate reaching law is introduced. Dependent on parameters the proposed controller may preserve the main features of sliding controls, while at the same time avoiding control chattering. Simulation studies confirm the announced properties when applied to a Hydraulic drive model subjected to strong variations in supply pressure and friction.
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robust non chattering observer based sliding control concept for electro Hydraulic Drives
IFAC Proceedings Volumes, 2013Co-Authors: Lasse Schmidt, Torben Ole Andersen, Henrik C PedersenAbstract:Abstract This paper presents an observer-based sliding mode control concept with chattering reduction, generally applicable for position tracking control of electro-Hydraulic valve-cylinder Drives (VCD's). The proposed control concept requires only common data sheet information and no knowledge on load characteristics. Furthermore the proposed scheme only employ ***piston-and valve spool positions- and pressure feedback, commonly available in industry. The main target is to overcome problems with linear controllers deteriorating performance due to the inherent nonlinear nature of such systems, without requiring extensive knowledge on system parameters nor advanced control theory. In order to accomplish this task, an integral sliding mode controller designed for the control derivative employing state observation is proposed, based on a generalized reduced order model structure of a VCD with unmatched valve flow- and cylinder asymmetries. It is shown that limited attention can be given to bounds on parameter estimates, that chattering is reduced and the number of tuning parameters is reduced to the level seen in conventional PID schemes. Furthermore, simulation results demonstrate a high level of robustness when subjected to strong perturbations in supply pressure and coulomb friction force, and that tracking accuracy may be reduced to the level of noise. Furthermore, the proposed controller tolerates significant noise levels, while still remaining stable and accurate.
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A novel control approach based on second order sliding modes & its application to Hydraulic Drives
2013 IEEE International Conference on Mechatronics and Automation, 2013Co-Authors: Lasse Schmidt, Torben O. Andersen, Henrik C PedersenAbstract:Sliding modes impose strong robustness toward parametric plant uncertainties and disturbances and accurate tracking performance in control systems. However, in physical systems the application of sliding modes may give rise to undesirable chattering of the control signal due to actuator dynamics. This may be avoided by application of smoothing functions imposing boundary layers on the control constraint, or by carrying out the design in relation to the control derivative. However, such boundary layers introduces additional design parameters and actuator dynamics may not allow the desired control accuracy to be reached. In this paper a novel control approach based on second order sliding modes utilizing the idea of the power rate reaching law is introduced. Dependent on parameters the proposed controller may preserve the main features of sliding controls, while at the same time avoiding control chattering. Simulation studies confirm the announced properties when applied to a Hydraulic drive model subjected to strong variations in supply pressure and friction.
Torben O. Andersen - One of the best experts on this subject based on the ideXlab platform.
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A novel control approach based on second order sliding modes & its application to Hydraulic Drives
2013 IEEE International Conference on Mechatronics and Automation, 2013Co-Authors: Lasse Schmidt, Torben O. Andersen, Henrik C PedersenAbstract:Sliding modes impose strong robustness toward parametric plant uncertainties and disturbances and accurate tracking performance in control systems. However, in physical systems the application of sliding modes may give rise to undesirable chattering of the control signal due to actuator dynamics. This may be avoided by application of smoothing functions imposing boundary layers on the control constraint, or by carrying out the design in relation to the control derivative. However, such boundary layers introduces additional design parameters and actuator dynamics may not allow the desired control accuracy to be reached. In this paper a novel control approach based on second order sliding modes utilizing the idea of the power rate reaching law is introduced. Dependent on parameters the proposed controller may preserve the main features of sliding controls, while at the same time avoiding control chattering. Simulation studies confirm the announced properties when applied to a Hydraulic drive model subjected to strong variations in supply pressure and friction.
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An approach for state observation in dynamical systems based on the twisting algorithm
2013 IEEE International Conference on Mechatronics and Automation, 2013Co-Authors: Lasse Schmidt, Torben O. Andersen, Henrik C PedersenAbstract:This paper discusses a novel approach for state estimation in dynamical systems, with the special focus on Hydraulic valve-cylinder Drives. The proposed observer structure is based on the framework of the so-called twisting algorithm. This algorithm utilizes the sign of the state being the target for the observation, not directly implying its applicability for state observation. However it is shown that in the discrete case this approach may be applied to obtain a real time derivative using an intermediate integral process. Furthermore, different types of gains for the algorithm are suggested and analyzed via Lyapunov arguments, and a special version of the observer is proposed specifically for Hydraulic Drives utilizing online available plant information. The proposed observer with different observer gains are subjected to simulation studies in order to evaluate the exact properties, and results confirm that the proposed observer structure is easily implemented, produces very limited phase shift and is highly robust toward measurement noise.
Torben Ole Andersen - One of the best experts on this subject based on the ideXlab platform.
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an approach for second order control with finite time convergence for electro Hydraulic Drives
ASME BATH 2013 Symposium on Fluid Power & Motion Control FPMC2013, 2013Co-Authors: Lasse Schmidt, Torben Ole Andersen, Henrik C PedersenAbstract:Being a second order sliding algorithm, the super twisting algorithm is highly attractive for application in control of Hydraulic Drives and mechanical systems in general, as it utilizes only the control error while driving the control error as well as its derivative to zero for properly chosen algorithm parameters. However a discontinuous term internally in the control structure may excite pressures of transmission lines in Hydraulic Drives as the control structure strives to maintain the control error and its derivative equal to zero. In this paper a modified version of a controller based on the super twisting algorithm is proposed, with the focus of eliminating the discontinuous term in order to achieve a more smooth control operation. The convergence properties of the proposed controller are analyzed via a conservative phase plane analysis. Furthermore, homogeneity considerations imply finite time convergence of states to the origin under certain model assumptions. Results demonstrate the smooth control operation compared to the direct super twisting control approach while maintaining robustness properties in relation to position tracking of a Hydraulic drive, under parameter perturbations, uncertainties and un-modeled dynamics.Copyright © 2013 by ASME
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a novel control approach based on second order sliding modes its application to Hydraulic Drives
International Conference on Mechatronics and Automation, 2013Co-Authors: Lasse Schmidt, Torben Ole Andersen, Henrik C PedersenAbstract:Sliding modes impose strong robustness toward parametric plant uncertainties and disturbances and accurate tracking performance in control systems. However, in physical systems the application of sliding modes may give rise to undesirable chattering of the control signal due to actuator dynamics. This may be avoided by application of smoothing functions imposing boundary layers on the control constraint, or by carrying out the design in relation to the control derivative. However, such boundary layers introduces additional design parameters and actuator dynamics may not allow the desired control accuracy to be reached. In this paper a novel control approach based on second order sliding modes utilizing the idea of the power rate reaching law is introduced. Dependent on parameters the proposed controller may preserve the main features of sliding controls, while at the same time avoiding control chattering. Simulation studies confirm the announced properties when applied to a Hydraulic drive model subjected to strong variations in supply pressure and friction.
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robust non chattering observer based sliding control concept for electro Hydraulic Drives
IFAC Proceedings Volumes, 2013Co-Authors: Lasse Schmidt, Torben Ole Andersen, Henrik C PedersenAbstract:Abstract This paper presents an observer-based sliding mode control concept with chattering reduction, generally applicable for position tracking control of electro-Hydraulic valve-cylinder Drives (VCD's). The proposed control concept requires only common data sheet information and no knowledge on load characteristics. Furthermore the proposed scheme only employ ***piston-and valve spool positions- and pressure feedback, commonly available in industry. The main target is to overcome problems with linear controllers deteriorating performance due to the inherent nonlinear nature of such systems, without requiring extensive knowledge on system parameters nor advanced control theory. In order to accomplish this task, an integral sliding mode controller designed for the control derivative employing state observation is proposed, based on a generalized reduced order model structure of a VCD with unmatched valve flow- and cylinder asymmetries. It is shown that limited attention can be given to bounds on parameter estimates, that chattering is reduced and the number of tuning parameters is reduced to the level seen in conventional PID schemes. Furthermore, simulation results demonstrate a high level of robustness when subjected to strong perturbations in supply pressure and coulomb friction force, and that tracking accuracy may be reduced to the level of noise. Furthermore, the proposed controller tolerates significant noise levels, while still remaining stable and accurate.
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sliding control with chattering elimination for Hydraulic Drives
Applied Mechanics and Materials, 2012Co-Authors: Lasse Schmidt, Torben Ole Andersen, Henrik C Pedersen, Michael Moller BechAbstract:This paper presents the development of a sliding mode control scheme with chattering elimination, generally applicable for position tracking control of electro-Hydraulic valve-cylinder Drives. The proposed control scheme requires only common data sheet information, no knowledge on load characteristics, and employs piston- and valve spool positions- and load- and supply pressure feedback. The main target is to overcome problems with linear controllers deteriorating performance due to the inherent nonlinear nature of such systems. In order to accomplish this task, an integral sliding mode controller is developed for the control derivative based on a reduced order model. Simulation results demonstrate strong robustness when subjected to parameter perturbations and that chattering is eliminated.
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2 smc of electro Hydraulic Drives using the twisting algorithm
Applied Mechanics and Materials, 2012Co-Authors: Lasse Schmidt, Torben Ole Andersen, Henrik C Pedersen, Michael Moller BechAbstract:In this paper a controller utilizing second order sliding modes, generally applicable for position tracking control of electro-Hydraulic valve-cylinder Drives (VCD), is proposed. The proposed controller requires pressure measurements, and only the signs of the valve spool position and piston position- and velocity. The main objective is to introduce a control concept that provide for increased performance compared to linear controllers, in the presence of the inherent nonlinear nature characterizing such systems. To accomplish this task, a controller based on the twisting algorithm and knowledge of system gain variations is proposed. Results demonstrate strong robustness when subjected to parameter perturbations and that control chattering is eliminated.
B. Riege - One of the best experts on this subject based on the ideXlab platform.
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Nonlinear control of Hydraulic differential cylinders actuating a flexible robot
Proceedings of the 36th IEEE Conference on Decision and Control, 1997Co-Authors: W. Bernzen, B. RiegeAbstract:Using robots for heavy loads and/or huge operating ranges causes on the one hand that elastic deformations have to be taken into account. On the other hand, these robots demand actuators with a significant power density able to produce the desired high forces. This can profitably be reached by the use of Hydraulic Drives. A laboratory testbed of a flexible robot for testing various control concepts is considered. It is a robot with elastic links manufactured of spring steel. The three rotary joints are driven by Hydraulic translation Drives within closed kinematic loops to transform the translation of the Drives into a rotation of the joints. To realize complex control concepts, e.g. for vibration damping, it is necessary to develop decentralised controllers for position and/or force control of the Hydraulic actuators in a first step. One modern nonlinear control technique is the exact linearization via feedback which is used to develop a nonlinear controller to compensate the main nonlinear effects of a Hydraulic differential cylinder.
