The quantitative evaluation method, as well as the experimental results evaluating different algorithm’s parameters, are provided in Section 5. The experimental results show that the proposed approach to sonar-based localization is able to provide robust and accurate robot pose estimates. Finally, Section 6. concludes the paper.2.?The Polaroid Sensor2.1. OverviewDuring the 80s, Polaroid developed a TOF ultrasonic range sensor for automatic camera focusing. Different versions of these sensors appeared. The third generation was based on the 6,500 ranging module. This module had the ability to detect and report multiple echoes. Moreover, a developer’s kit was released for these sensors, allowing the user to configure the different parameters, such as frequency, gain or maximum range.

Because of this, the 6,500 ranging module was extensively used in mobile robotics.Although the original Polaroid sensors are not being used by recent robotic platforms, the 6,500 series ranging module is still commonly used. The ultrasonic sensors used in this paper are those endowed in a Pioneer 3-DX mobile robot. They are based on the 6,500 series ranging module and a 600 series electrostatic transducer. Throughout this paper, these sensors will be referred to as the Polaroid sensors.In mobile robotics, sonar sensors are commonly used to detect objects which are in the same plane that the sensor itself. This idea will be referred to as the 2D assumption.

Thus, only the cross section of the sonar beam over the sensor plane is
Many traditional devices of microelectromechanical systems (MEMS) do not include contacting surfaces.

However in recent years there is an increasing interest in various microsensors and microactuators that employ contact interaction in their normal mode of operation. This trend is determined by the new developments in MEMS technology and new market demands. Among such devices, the fast development of microswitches AV-951 is very promising. However, insufficient mechanical reliability is one of the main obstacles for wider successful application of these microdevices Dacomitinib [1,2]. Interrelated parasitic vibro-impact effects (bouncing) and stiction (a contraction for ��static friction��) are one of the major reasons that degrade their reliability [1-7].

Due to the elastic response of contacting microstructure of a microswitch, at each on/off cycle, its tip bounces over the substrate a number of times upon contact, as already been reported by K. Petersen in 1979 [8]. This effect is not unexpected, since these switches are essentially a microscopic copy of mechanical relays, in which contact bounce is a well-known phenomenon.