More sophisticated example
Suppose that a simple robot has two wheels which can both move forward or reverse and that they are positioned parallel to one another, and equidistant from the center of the robot. Further, assume that each motor has a rotary encoder, and so one can determine if either wheel has travelled one "unit" forward or reverse along the floor. This unit is the ratio of the circumference of the wheel to the resolution of the encoder.
If the left wheel were to move forward one unit while the right wheel remained stationary, then the right wheel acts as a pivot, and the left wheel traces a circular arc in the clockwise direction. Since one's unit of distance is usually quite small, one can approximate by assuming that this arc is a line. Thus, the original position of the left wheel, the final position of the left wheel, and the position of the right wheel form a triangle, which one can call A.
Also, the original position of the center, the final position of the center, and the position of the right wheel form a triangle which one can call B. Since the center of the robot is equidistant to either wheel, and as they share the angle formed at the right wheel, triangles A and B are similar triangles. In this situation, the magnitude of the change of position of the center of the robot is one half of a unit. The angle of this change can be determined using the law of sines.
In navigation, dead reckoning is the process of calculating the current position of a moving object by using a previously determined position, or fix, and incorporating estimates of speed, heading, and elapsed time. The corresponding term in biology, to describe the processes by which animals update their estimates of position or heading, is path integration.
A tachometer is an instrument measuring the rotation speed of a shaft or disk, as in a motor or other machine. The device usually displays the revolutions per minute (RPM) on a calibrated analogue dial, but digital displays are increasingly common.
Roomba is a series of autonomous robotic vacuum cleaners made by the company iRobot. Introduced in September 2002, they have a set of sensors that enable them to navigate the floor area of a home. These sensors can detect the presence of obstacles, particularly dirty spots on the floor, and steep drops.
A rotary encoder, also called a shaft encoder, is an electro-mechanical device that converts the angular position or motion of a shaft or axle to analog or digital output signals.
In cryptography, the M-209, designated CSP-1500 by the United States Navy is a portable, mechanical cipher machine used by the US military primarily in World War II, though it remained in active use through the Korean War. The M-209 was designed by Swedish cryptographer Boris Hagelin in response to a request for such a portable cipher machine, and was an improvement of an earlier machine, the C-36.
Electronic brakeforce distribution or electronic brakeforce limitation (EBL) is an automobile brake technology that automatically varies the amount of force applied to each of a vehicle's wheels, based on road conditions, speed, loading, etc, thus providing intelligent control of both brake balance and overall brake force. Always coupled with anti-lock braking systems (ABS), EBD can apply more or less braking pressure to each wheel in order to maximize stopping power whilst maintaining vehicular control. Typically, the front end carries more weight and EBD distributes less braking pressure to the rear brakes so the rear brakes do not lock up and cause a skid. In some systems, EBD distributes more braking pressure at the rear brakes during initial brake application before the effects of weight transfer become apparent.
A scroll wheel is a wheel used for scrolling. The term usually refers to such wheels found on computer mice. It is often made of hard plastic with a rubbery surface, centred around an internal rotary encoder. It is usually located between the left and right mouse buttons and is positioned perpendicular to the mouse surface. Sometimes the wheel can be pressed left and right, which is actually just two additional macros buttons.
The south-pointing chariot was an ancient Chinese two-wheeled vehicle that carried a movable pointer to indicate the south, no matter how the chariot turned. Usually, the pointer took the form of a doll or figure with an outstretched arm. The chariot was supposedly used as a compass for navigation and may also have had other purposes.
A wheel speed sensor (WSS) or vehicle speed sensor (VSS) is a type of tachometer. It is a sender device used for reading the speed of a vehicle's wheel rotation. It usually consists of a toothed ring and pickup.
A cyclocomputer, cycle computer, cycling computer or cyclometer is a device mounted on a bicycle that calculates and displays trip information, similar to the instruments in the dashboard of a car. The computer with display, or head unit, usually is attached to the handlebar for easy viewing. Some GPS watches can also be used as display.
The mecanum wheel is an omnidirectional wheel design for a land-based vehicle to move in any direction. It is sometimes called the Swedish wheel or Ilon wheel after its inventor, Bengt Erland Ilon (1923–2008), who conceived of the concept while working as an engineer with the Swedish company Mecanum AB, and patented it in the United States on November 13, 1972.
A mobile robot is an automatic machine that is capable of locomotion. Mobile robotics is usually considered to be a subfield of robotics and information engineering.
Omni wheels or poly wheels, similar to Mecanum wheels, are wheels with small discs around the circumference which are perpendicular to the turning direction. The effect is that the wheel can be driven with full force, but will also slide laterally with great ease. These wheels are often employed in holonomic drive systems.
Super Select is the brand name of a four-wheel drive system produced by Mitsubishi Motors, used worldwide except for North America, where it was initially known as Active-Trac. It was first introduced in 1991 with the then-new second generation of the Mitsubishi Pajero.
Legged robots are a type of mobile robot which use articulated limbs, such as leg mechanisms, to provide locomotion. They are more versatile than wheeled robots and can traverse many different terrains, though these advantages require increased complexity and power consumption. Legged robots often imitate legged animals, such as humans or insects, in an example of biomimicry.
Webots is a free and open-source 3D robot simulator used in industry, education and research.
In robotics and computer vision, visual odometry is the process of determining the position and orientation of a robot by analyzing the associated camera images. It has been used in a wide variety of robotic applications, such as on the Mars Exploration Rovers.
Robotino is a mobile robot system made by Festo Didactic, and used for educational, training and research purposes.
A wheelchair trainer or wheelchair treadmill is an apparatus that allows a manual wheelchair user to simulate linear (translational) travel while remaining stationary in a manner similar to an ambulatory person walking or running on a treadmill or a cyclist pedaling a bicycle on a bicycle trainer. The rear wheelchair wheels are placed in contact with vertical or horizontal rollers which may also be attached to flywheels, mechanical resistance or braking mechanisms, motors and various speed and force sensors. Flywheels may be sized to provide a user of a certain mass with a rotational inertia equivalent to their translational (linear) inertia in order to more realistically approximate actual wheelchair propulsion.
The WonderBorg is a programmable consumer robot kit first released for the Bandai WonderSwan and Microsoft Windows PCs in 2000. It is intended to match both the external appearance and mode of transport of a beetle, with functioning antennae and a six-legged design.
