This paper emphasis the need for developing the legged robots rather than wheeled robots. Among these legged robots mentioned in this paper, we will particularly study about the cockroach-like hexapod robot and it’s importance. Over the undulated surfaces, robot movement with wheels becomes difficult. For working and exploring in unknown and rough terrain the use of legged robots is advantageous because their movement is less constrained by the shape of the surface on which they have to travel. The anti-personnel mines of over 100 million is injuring or killing more than 2000 people a month. Under this ultimate environment, a walking robot may be an effective and efficient means of detecting and removing mines while ensuring the safety of local residents and people engaged in the removal work. Hence, insect movement with legs is considered most stable. The present paper proposes an improved six-legged walking robot.

The basic need for transportation of material is satisfied with wheel movement for ages. All the robots have been designed for their movements in the similar fashion. In the industries, movements on a straight path normally are done on automatic guided vehicles (A.G.V’s) with sensors on touch/no touch. A substantial portion of the Earth is inaccessible to wheeled mechanisms—natural obstacles like large rocks, loose soil, deep ravines, and steep slopes conspire to render rolling locomotion ineffective. The sea floor, moon, and planets are similarly challenging. In natural terrains, legs are often superior to wheels; they avoid undesirable footholds and make discrete contacts where wheels must propel with continuous rolling contact. One of the most versatile vehicle architecture for working on rough terrain is a legged vehicle. This is true because, walking machines only require non–continuous spots of solid ground for moving; whereas wheeled vehicles normally need large continuous extensions of relatively flat surface to move. There are a number of simple legged robots whose foot trajectories are fixed to follow a certain route for swing (or return stroke) and stance (or power stroke). These types of vehicles are not so different from wheeled vehicles, as the behavior of their legs could be interpreted as a special type of the wheel. But, when the wheels fail to function properly, legs become the more suitable solution for moving in more demanding terrains. The legged robots are built to improve the speed and to climb the obstacle’s height easily.

The cockroach-like hexapod is considered to be the best-legged robot now a day because of its capability of running fast and climbing. The robot is designed with five, four, and three degrees of freedom in the front, middle and rear legs, respectively, to permit it to mimic the different functions of cockroach legs.