Micropositioning mechatronics system based on FPGA architecture

High resolutions and positioning accuracies are often required in precision engineering and microsystems' technologies. An experimental ultra-precision mechatronics system with long travel ranges is conceived in this work. The mechanical design of the system is optimized in order to achieve ultra-precision displacements. The control system of the device is integrated into a high-speed FPGA-based module as a virtual instrument (VI), where closed loop feedback is obtained by employing microstepping control. User controls are programmed as an independent Host VI. A linear incremental encoder with a sinusoidal output signal, which is interpolated and converted into a TTL signal, is employed for position feedback. Experimental validation of the achieved results is conducted by using laser interferometry. A set of short and long step point-to-point positioning experiments are performed and true sub-micron positioning repeatability and accuracy are obtained.

Ultra-high precision mechatronics positioning systems are critical devices in current precision engineering and micro- and nano-systems’ technologies, as they allow repeatability and accuracy in the nanometric domain to be achieved. The doctoral thesis deals thoroughly with nonlinear stochastic frictional effects that limit the performances of ultra-high precision devices based on sliding and rolling elements. The state-of-the-art related to the frictional behavior in the pre-sliding and sliding motion regimes is considered and different friction models are validated. Due to its comprehensiveness and simplicity, the generalized Maxwell-slip (GMS) friction model is adopted to characterize frictional disturbances of a translational axis of an actual multi-degrees-of-freedom point-to-point mechatronics positioning system aimed at handling and positioning of microparts. The parameters of the GMS model are identified via innovative experimental set-ups, separately for the actuator-gearhead assembly and for the linear guideways, and included in the overall MATLAB/SIMULINK model of the used device. With the aim of compensating frictional effects, the modeled responses of the system are compared to experimental results when the system is controlled by means of a conventional proportional-integral-derivative (PID) controller, when the PID controller is complemented with an additional feed-forward model-based friction compensator and, finally, when the system is controlled via a self-tuning adaptive regulator. The adaptive regulator, implemented within the real-time field programmable gate array based control system, is proven to be the most efficient and is hence used in the final repetitive point-to-point positioning tests. Nanometric-range precision and accuracy (better than 250 nm), both in the case of short-range (micrometric) and long-range (millimeter) travels, are achieved. Different sensors, actuators and other design components, along with other control typologies, are experimentally validated in ultra-high precision positioning applications as well.

Conciencia Tecnologica, 2013

2012 IEEE/ASME International Conference on Advanced Intelligent Mechatronics (AIM), 2012

IEEE/ASME Transactions on Mechatronics, 2000

This work describes a computer simulation of the dynamics and control of a robotic micropositioner. The robotic micropositioner is a parallel link manipulator which has six actuators, each controlled independently by a hydraulic system. The dynamic equations of the micropositioner are derived. The control algorithm for path tracing is formulated and tested. In this work the performance of the micropositioner is investigated as function of damping, speed, payload, and location of target.

HAL (Le Centre pour la Communication Scientifique Directe), 2012

… , IEEE Transactions on, 2000

The 6-Degree of Freedom Tri-Stage Micro Positioner (6DFTSMP) can generate high accuracy, small displacement, and high-resolution motions. The moving platform of the device has six degrees (6-D) of freedom motions (translation and rotation about three orthogonal axes, X-Y-Z). The 6DFTSMP is unique because it derives its input motion from a monolithic tri-stage base plate and has struts that may have specially designed flexures. The 6DFTSMP capitalizes on the availability of inexpensive high quality planar micro-positioning stages for the control of its moving platform. Because the struts, which connect the planar micro positioning stages with the moving platform are oriented in a parallel mechanism fashion the in plane motion of the stages is converted into a translation and rotation about three orthogonal axes. Two experimental prototypes of the 6DFTSMP have been built and various mathematical models have been developed. A micro-position and orientation measurement sensor nest has b...