13-03-2014, 03:49 PM
STUDY OF MECHANICAL PART OF ROBOT
Wheeled
In terms of energy efficiency on flat surfaces, wheeled robots are the most efficient. This is due to the fact that an ideal rolling (but not slipping) wheel loses no energy. A wheel rolling at a given velocity needs no input to maintain its motion. This is in contrast to legged robots which suffer an impact with the ground at heelstrike and lose energy as a result. There are many different types of wheeled robots, the most common being the Reed Shepps type and the unicycle type. The major concern in the motion planning of wheeled robots are the holonomic that the robot is subject to. These are decided by the type of wheels, number of wheels and the direction of the axes of rotation of the wheels.
Hopping
Several robots, built in the 1980s by Marc Raibert at the MIT Leg Laboratory, successfully demonstrated very dynamic walking. Initially, a robot with only one leg, and a very small foot, could stay upright simply by hopping. The movement is the same as that of a person on a pogo stick. As the robot falls to one side, it would jump slightly in that direction, in order to catch itself. Soon, the algorithm was generalised to two and four legs. A bipedal robot was demonstrated running and even performing somersaults. A quadruped was also demonstrated which could trot, run, pace, and bound. For a full list of these robots, see the MIT Leg Lab Robots page
[b]Humanoid robot[/b]
A humanoid robot is a robot with its body shape built to resemble that of the human body. A humanoid design might be for functional purposes, such as interacting with human tools and environments, for experimental purposes, such as the study of bipedal locomotion, or for other purposes. In general, humanoid robots have a torso, a head, two arms, and two legs, though some forms of humanoid robots may model only part of the body, for example, from the waist up. Human cognition is a field of study which is focused on how humans learn from sensory information in order to acquire perceptual and motor skills. This knowledge is used to develop computational models of human behavior and it has been improving over time. Besides the research, humanoid robots are being developed to perform human tasks like personal assistance, where they should be able to assist the sick and elderly, and dirty or dangerous jobs. Regular jobs like being a receptionist or a worker of an automotive manufacturing line are also suitable for humanoids. However, the complexity of doing so is deceptively great.
Ultrasonic sensors
Measuring principle
The sensor emits a sound pulse that is reflected from the object to be detected. The sensor reads in the reflected pulse and the distance to the object is determined by means of a runtime ultrasonic sensors which provide excellent repeatability and linearity in detecting the precise position of objects. The sensors provide high precision performance on any material of any colour, irrespective of external light levels. They produce accurate results even when used with highly transparent objects such as film or glass surfaces and are completely unaffected by normal levels of soiling on the sensor surface. The sensors are also characterised by high sound intensity that makes it possible to detect even the smallest of objects with extremely high reliability. This ability to maintain outstanding performance and reliability, even with the presence of suspended particles or water vapour, means that ultrasonic sensors are in daily use all over the World in a diverse range of demanding industrial applications.