Adaptive control of the Hexaglide, a 6 dof parallel manipulator

This paper presents the dynamic equation, nonlinear control and dynamic parameters identification of the Hexaglide, a new 6-DOF parallel manipulator intended to be used as a high speed milling machine. Using a method based on the virtual work principle, the dynamic equation is found in a compact linear form and then used in a nonlinear adaptive control algorithm based on the minimization of the tracking error. The dynamic parameters are learned during motion and introduced in an inverse dynamic model used as a feedforward compensator. Specific trajectories, exciting the parameters separately, enable a fast stepwise learning of the 12 parameters. A simulation demonstrates the validity of the approach.

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

[2]  D. Stewart,et al.  A platform with 6 degrees of freedom , 1966 .

[3]  John J. Craig,et al.  Introduction to Robotics Mechanics and Control , 1986 .

[4]  S. Shankar Sastry,et al.  Adaptive Control of Mechanical Manipulators , 1987 .

[5]  Brian Armstrong.  On finding 'exciting' trajectories for identification experiments involving systems with non-linear dynamics , 1987, Proceedings. 1987 IEEE International Conference on Robotics and Automation.

[6]  Weiping Li,et al.  Adaptive manipulator control a case study , 1987, Proceedings. 1987 IEEE International Conference on Robotics and Automation.

[7]  Brian Armstrong,et al.  On Finding Exciting Trajectories for Identification Experiments Involving Systems with Nonlinear Dynamics , 1989, Int. J. Robotics Res..

[8]  Roberto Horowitz,et al.  Stability and Robustness Analysis of a Class of Adaptive Controllers for Robotic Manipulators , 1990, Int. J. Robotics Res..

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

[10]  Daniel E. Koditschek,et al.  Comparative experiments with a new adaptive controller for robot arms , 1991, IEEE Trans. Robotics Autom..

[11]  Zhiming Ji.  Study of the effect of leg inertia in Stewart platforms , 1993, [1993] Proceedings IEEE International Conference on Robotics and Automation.

[12]  J.M. Hollerbach,et al.  Identifying mass parameters for gravity compensation and automatic torque sensor calibration , 1996, Proceedings of IEEE International Conference on Robotics and Automation.

[13]  Etienne Burdet,et al.  A body-oriented method for finding a linear form of the dynamic equation of fully parallel robots , 1997, Proceedings of International Conference on Robotics and Automation.