Pierre-Jean Barre

Influence of a Jerk Controlled Movement Law on the Vibratory Behaviour of High-Dynamics Systems

Abstract The focus of this paper is on the formalisation of the influence of a jerk-controlled movement law on the vibrations of industrial high-speed systems, i.e. systems for which axes are submitted to significant dynamical demands. Analysis of the physical relationship between the jerk limit and the maximum vibratory amplitude is conducted on a simplified axis drive model that simultaneously accounts for axis control parameters and predominant mode effects. Experimental measurements conducted on three tests-setups demonstrate the effectiveness of the proposed approach in accurately predicting the evolution of the vibration level according to the constant jerk stages time and the axis drive parameters.

Influence of High-Speed Machine Tool Control Parameters on the Contouring Accuracy. Application to Linear and Circular Interpolation

In this paper, we investigate the servo parameters and axis dynamics influences on the contouring accuracy for practical applications such as contouring control of manufacturing systems (robot, machine tool...). The analytical formulation of contouring error in the case of straight line, circle and corner crossing is derived using a simplified axis drive model including the main servo parameters and dominating mechanical mode. The effectiveness of the proposed formulation in estimating the evolution of the final contour error is demonstrated experimentally on a two-axis machine tool.

Control of an Industrial Robot using Acceleration Feedback

A controller using acceleration feedback has been applied to a flexible robot for which the position and velocity of the load are not measured. It is shown that acceleration feedback allows an exact tracking of the motor position, irrespective of the non-linear flexibilities of the axes and of the measurement disturbances. This easy-to-tune algorithm whose main control parameters are the modal masses of the motor and load part, and only consists of a positive acceleration feedback plus a PD controller, has been validated on an industrial robot with orthogonal axes.

High performance control of the permanent magnet synchronous motor using self-tuning resonant controllers

The permanent-magnet synchronous motors (PMSM) have been widely used in high-performance variable speed drives. However, any non-ideal conditions, such as nonsinusoidal distributed rotor permanent magnet flux or the cogging effects, may bring on ripples in the output torque. In this paper, we propose to suppress the torque ripple of the PMSM in the stationary reference frame by using self-tuning multiple-frequency resonant controllers. This kind of controller is usually used to track the non-sinusoidal command and/or reject some kind of higher-order harmonic disturbances in AC current control system. We first present how to design the robust self-tuning resonant controller using pole assignment technique, in which the influence of unit time-delay is compensated. After that, the optimal excitation current waveforms are designed to suppress the torque ripples caused by the back-EMF harmonics. The torque ripples can be completely eliminated up to an arbitrary order. By using the self-tuning multiple-frequency resonant controllers, the regulated currents can perfectly track the optimal excitation currents, and the undesired torque ripple is therefore efficiently suppressed. The experimental results confirm the validity and effectiveness of the proposed method

Modelling and Axis Control of Machine Tool for High Speed Machining

Abstract The main objective of an efficient axis control is to reproduce on the tool (or the workpiece), the reference wished for machining accuracy. Every process control requires the knowledge of its input-output relationships. One problem is looking for a compromise between a model, a real system and a dynamic control performances. The present paper proposes an energetic approach in which the control specifications are directly deduced from the inversion of the process causalities.

Model-based control of a dual-drive H-type gantry stage on a decoupling base

Widely used for high-speed high-precision motion control in the electronics, nuclear and automotive industries, gantry stages are usually controlled using independent axis control. In order to avoid the effects of the mechanical coupling over synchronization and tracking errors, we propose a control on a modal reference frame. First, the system is modeled with respect to the center of mass of the moving beam and a modal transformation is applied to obtain the motion equations on a decoupling base. Next, a model-based control scheme is deduced with the minimization of synchronization and tracking errors as objectives. Finally, experimental results show that the proposed modal control scheme leads to an improved motion control of the point-tool in comparison with the present industrial control.

Physical dynamic modelling and systematic control structure design of a double linear drive moving gantry stage industrial robot

Industrial control of dual-drive moving gantry stage robots is usually achieved by two independent position controllers. This control structure does not take into account the mechanical coupling between the two actuators that leads to a reduction of the overall performances. In this paper, a physical dynamic lumped parameters model of an industrial robot based on structural, modal, and finite element method analysis is proposed, experimentally identified and validated. Then, using simple inversion rules of the causal ordering graph formalism, a control structure is deduced in a systematic way. The solution is finally simulated and shows that it is possible to obtain better performances than the industrial control.

Decoupling basis control of dual-drive gantry stages for path-tracking applications

Dual-drive gantry stages are used for high-speed high-precision motion control applications such as flat panel display manufacturing and inspection. Industrially, they are usually controlled using independent axis control without taking into consideration the effect of inter-axis mechanical coupling over positioning accuracy and precision. To improve this and minimize the effect of mechanical coupling over synchronization and tracking errors, we propose to model and control the dual-drive gantry stage on a decoupling basis. This approach allows representing the highly coupled Multiple Input Multiple Output (MIMO) system as a set of independent Single Input Single Output (SISO) systems. Based on this representation, a model-based feedback-feedforward control scheme is deduced. Experimental results show that the proposed decoupling basis control scheme leads to an improved motion control of the point-tool in comparison to the present industrial control.

Complementary use of BG and EMR formalisms for multiphysics systems analysis and control

In this paper, a complex multiphysics system is modeled using two different energy-based graphical techniques: Bond Graph and Energetic Macroscopic Representation. These formalisms can be used together to analyze, model and control a system. The BG is used to support physical, lumped-parameter modeling and analysis processes, and then EMR is used to facilitate definition of a control structure through inversion-based methodology. This complementarity between both of these tools is set out through a helicopter flight control subsystem.© 2012 ASME

Control of a Symmetrical Dual-drive Gantry System using Energetic Macroscopic Representation

Dual-drive gantry systems are commonly used in many industrial applications. However, as few papers are available in the literature, this kind of system is difficult to broach. Based on an energetic approach so-called Energetic Macroscopic Representation (EMR), this paper presents a graphical modelling based on lumped-parameters. The initial drive is decomposed into a set of decoupled fictitious systems using a mathematical transformation. Since the modelling respects the integral causality, inversion-based controls are thus deduced. More generally, this approach proposes a way to analyze and deduce models and controls of multi-drive mechatronic systems.