Scaling hard vertical surfaces with compliant microspine arrays

A new approach for climbing hard vertical surfaces has been developed that allows a robot to scale concrete, stucco, brick and masonry walls without using suction or adhesives. The approach is inspired by the mechanisms observed in some climbing insects and spiders and involves arrays of microspines that catch on surface asperities. The arrays are located on the toes of the robot and consist of a tuned, multi-link compliant suspension. In this paper we discuss the fundamental issues of spine allometric scaling versus surface roughness and the suspension needed to maximize the probability that each spine will find a useable surface irregularity and to distribute climbing tensile and shear loads among many spines. The principles are demonstrated with a new climbing robot that can scale a wide range of exterior walls

Chapter 5 Strategies For System Performance Improvement Using Multi-Polarized Arrays

This paper gives a theoretical best polarization and SINR. The optimal polarization results in higher SINR than either matching the polarization of the desired signal or nulling the interfering signal. 86 In [5.9] a multi-polarized array that consists of four pairs of crossed dipoles is considered. The array was used with and without a flat-backed corner reflector as shown in Fig. 5-5. Figure 5-5. The multi-polarized adaptive array investigated in [5.9] Mutual coupling effects are modeled using a method of moments computer code. With the corner reflector the array has a half power beamwidth of approximately 42 in elevation and 21 in azimuth. Sidelobe levels are-10 dB in elevation and-5 dB in azimuth. For identical desired and interfering signal polarization states, with the desired signal at broadside, the array provided an SINR improvement of 20dB for a 3 difference in azimuth or elevation angles, and 30 dB for a 10 difference. For a 15 difference in polarization angle, the array provides 30 dB SINR improvement without the reflector. The same SINR improvement can be achieved for a 10 difference in polarization angle if the reflector is used. SINR was significantly degraded in cases with 2 or 3 interferers. In [5.10], the LSCMA algorithm and variations are proposed for cross polarized interference cancellation (XPIC). Real and multitarget variations of the algorithm are y z y z 87 considered. Digital and hybrid implementations are shown. Two scenarios were simulated, one for intrasystem interference and another for intersystem interference. In the first scenario two 16 kHz MSK signals having a 45 degree difference in polarization tilt angle coexist on the same frequency. Each signal has a 20 dB SNR and 23dB Eb/No. Accounting for polarization mismatch, SINR in 3 d B..