Wall climbing robots (WCRs) are those that have the capacity to move against gravity and reach out to places where it is difficult for human access. For example, cleaning the inner surfaces of hot boilers in industries, painting highly raised buildings etc. In order to carry out these works, the WCRs must move over rough vertical walls. It is possible that, the WCR might tip over due to the uneven nature of the wall. The forces and moments acting upon the WCR while climbing a vertical wall have huge impact over the stability. Apart from rough surfaces, the WCRs might encounter few obstacles. The forces and magnitudes must aid the WCRs surpass these obstacles as well as rough surfaces and climb over the wall and ceiling. This paper studies the various forces and moments acting on the WCRs while climbing a vertical wall. Mathematical insight about the changes in forces and moments to maintain stability for various cases such as WCRs with payload, with two or more suction chambers, with many suction chambers with payload are discussed in detail.

Robots have become a priceless remedy that can be deployed in places and applicative areas where humans have restrictions and risks. For example, painting of hi

A polarization agile patch antenna resonating at 2.4 GHz ISM band is presented. The antenna is based on a rectangular radiating element along with reconfigurable parasitic patches located at its periphery of the radiating element. Two switching diodes are used to reconfigure the geometry of the radiating element. Upon proper biasing of the switching diodes the antenna attains linear or circular (LHCP/RHCP) polarization states. The entire antenna is modelled using a high-frequency structure simulator and is validated using an Agilent network analyser (N9925A) and antenna test systems for measuring impedance and radiation characteristics. Over the entire operating band, the antenna shows better impedance matching and achieves −10 dB impedance bandwidth of 100 MHz (2.40-2.5 GHz) in linear state and 85 MHz (2.41-2.495 GHz) in the circularly polarization states along with peak gain of 5.61 dBi for LP state and 4.98 dBi for CP state in the operatingrange.

The problem of noise is becoming more acute since the prevalence of industrial and medical equipment, appliances, and consumer gadgets increases. Active noise c The problem of noise is becoming more acute since the prevalence of industrial and medical equipment, appliances, and consumer gadgets increases. Active noise c