In another work [8], Lopez, Artes and Alejandre analyze possible causes of sources errors when the encoder either is working Inhibitors,Modulators,Libraries under vibrations from a mechanical point of view.Another point of view to improve the accuracy of the sensor is that just based on error compensation from signal processing techniques. Sensor’s Inhibitors,Modulators,Libraries error compensation techniques based on signal processing Inhibitors,Modulators,Libraries constitutes a widely studied research field. The main reason for this lies on the fact that significant improvements of accuracy can be obtained normally at a lower cost than that associated to the introduction of mechanical modifications in the encoder design. There are several methodologies to accomplish encoder’s error compensation [9]: Autocalibration, Look Up Tables (LUT), Filtering, Neural Networks [10], Wavelets and Blocking Amplifiers.
Autocalibration and LUT techniques are of special interest for the purposes of the present work. Probably, Inhibitors,Modulators,Libraries the most referenced technique dealing with autocalibration is that proposed by Heydemann [11]. Basically, the problem is solved introducing in the measurement signals the parameters which produce the encoder metrological errors, arranging the equations in a least squares problem. More recently, Balemi [12] takes this method as a basis to formulate the problem with high computational efficiency to be implemented as an on-line error compensation technique by means of electronic signal processing components. Another point of view to accomplish the compensation has its basis on fitting techniques to the Lissajous figure composed of the deteriorated measurement signals.
Lepple [13] studies the possibility of implementing this technique as an online interpolation procedure for encoders working at high speed. Fitting techniques have also been applied successfully to other position instruments such as interferometers GSK-3 [14]. This methodology contrasts with LUT techniques in the sense that the sensor does not need of any reference to increase its accuracy. Habitually, the elaboration of a LUT implies the use of a sensor of higher accuracy and resolution than the sensor that is going to be compensated [15]. The main advantage of LUT methodologies is that they are easily implemented as on-line procedures due to their high computational efficiency. A similar work close in aim and method to the cited paper [15] is that proposed by Boggarpu et al.
[16], with the difference that no reference sensor is needed and the implementation can be done in a simple cisplatin dna microcontroller rather than more specialized hardware. In this sense, the work developed by de Santiago-Perez et al. [17] remarks the special need for processing encoder’s signals at a low computational cost while maintaining certain level of smoothness in the successive derivations of position up to jerk, in order to allow on-line implementation in obtaining the dynamics parameters from a machine-tool axis.