Observer-based cascade control of a 6-DOF parallel hydraulic manipulator in joint space coordinate

This paper addresses the joint space control problem of a 6-DOF (degree of freedom) parallel hydraulic manipulator. High precision motion control of a six-degree parallel manipulator is hardly achieved due to the existence of uncertain payload and other disturbance such as coupling force. A disturbance observer for this parallel manipulator is first constructed to estimate and compensate the unknown disturbance. A cascade control algorithm is then applied to separate the hydraulic dynamics from the mechanical part, which can mask the hydraulic dynamics with an inner loop. With such a control structure, known control design methods within the area of manipulator control can be directly used in the outer loop. In this approach, the complex dynamics and direct kinematics of the parallel manipulator are not required and acceleration feedback is also avoided. Experimental results are presented to show the effectiveness of the proposed scheme.

[1]  George T.-C. Chiu,et al.  Adaptive robust motion control of single-rod hydraulic actuators: theory and experiments , 2000 .

[2]  Bhaskar Dasgupta,et al.  The Stewart platform manipulator: a review , 2000 .

[3]  B. K. Kim,et al.  Robust learning control for robot manipulators based on disturbance observer , 1996, Proceedings of the 1996 IEEE IECON. 22nd International Conference on Industrial Electronics, Control, and Instrumentation.

[4]  HongBo Guo,et al.  Cascade control of a hydraulically driven 6-DOF parallel robot manipulator based on a sliding mode , 2008 .

[5]  H. E. Merritt,et al.  Hydraulic Control Systems , 1991 .

[6]  G. Van Schothorst,et al.  Modelling of long-stroke hydraulic servo-systems for flight simulator motion control and system design , 1997 .

[7]  J. Heintze.  Design and Control of a Hydraulically Actuated Industrial Brick Laying Robot , 1997 .

[8]  Hyungbo Shim,et al.  Design of disturbance observer for non-minimum phase systems using PID controllers , 2007, SICE Annual Conference 2007.

[9]  J. Heintze,et al.  Inner-loop design and analysis for hydraulic actuators, with an application to impedance control , 1994 .

[10]  Reza Haghighi,et al.  Lyapunov-Based Nonlinear Disturbance Observer for Serial n-Link Robot Manipulators , 2009, J. Intell. Robotic Syst..

[11]  Karel Jezernik,et al.  Observer-based sliding mode control of a robotic manipulator , 1994, Robotica.

[12]  Jae-Bok Song,et al.  Position control of a Stewart platform using inverse dynamics control with approximate dynamics , 2003 .

[13]  Evangelos Papadopoulos,et al.  Model-based control of a 6-dof electrohydraulic Stewart–Gough platform , 2008 .

[14]  Dong Hwan Kim,et al.  Robust tracking control design for a 6 DOF parallel manipulator , 2000 .

[15]  Nariman Sepehri,et al.  Cascade control of hydraulically actuated manipulators , 1990, Robotica.

[16]  James E. Bobrow,et al.  Experiments and simulations on the nonlinear control of a hydraulic servosystem , 1999, IEEE Trans. Control. Syst. Technol..

[17]  Maarten Steinbuch,et al.  Modelling and LPV control of an electro-hydraulic servo system , 2006, 2006 IEEE Conference on Computer Aided Control System Design, 2006 IEEE International Conference on Control Applications, 2006 IEEE International Symposium on Intelligent Control.

[18]  Weiping Li,et al.  Applied Nonlinear Control , 1991 .

[19]  Jean-Pierre Merlet,et al.  Parallel Robots , 2000 .

[20]  M. Eghtesad,et al.  Position control of a stewart-gough platform using inverse dynamics method with full dynamics , 2006, 9th IEEE International Workshop on Advanced Motion Control, 2006..

[21]  Costas Kravaris,et al.  Nonlinear observer design for state and disturbance estimation , 2007, Proceedings of the 2004 American Control Conference.

[22]  D. Stewart,et al.  A Platform with Six Degrees of Freedom , 1965 .

[23]  Peter J. Gawthrop,et al.  A nonlinear disturbance observer for robotic manipulators , 2000, IEEE Trans. Ind. Electron..

[24]  S. H. Koekebakker,et al.  Model based control of a flight simulator motion system , 2001 .

[25]  Cheng Guan,et al.  Adaptive sliding mode control of electro-hydraulic system with nonlinear unknown parameters , 2008 .

[26]  S. P. Chan,et al.  A disturbance observer for robot manipulators with application to electronic components assembly , 1995, IEEE Trans. Ind. Electron..

[27]  Toshio Fukuda,et al.  Design of a nonlinear disturbance observer , 2000, IEEE Trans. Ind. Electron..

[28]  Kyo-Il Lee,et al.  Robust nonlinear task space control for 6 DOF parallel manipulator , 2005, Autom..

[29]  Septimiu E. Salcudean,et al.  Nonlinear control of hydraulic robots , 2001, IEEE Trans. Robotics Autom..