Robotic sensors are used to estimate a robot's condition and environment. These signals are passed to a controller to enable appropriate behavior. [1] [2]
Sensors in robots are based on the functions of human sensory organs. Robots require extensive information about their environment in order to function effectively.
Sensors provide analogs to human senses and can monitor other phenomena for which humans lack explicit sensors.
Sensors can measure physical properties, such as the distance between objects, the presence of light and the frequency of sound. [3] They can measure:
Motion controllers, potentiometers, tacho-generators and encoder are used as joint sensors, whereas strain-gauge based sensing is used at the end-effector location for contact force control.
It is the part of the robot. Internal sensors measure the robot's internal state. They are used to measure position, velocity and acceleration of the robot joint or end effectors.
Position sensors measure the position of a joint (the degree to which the joint is extended). They include:
A velocity or speed sensor measures consecutive position measurements at known intervals and computes the time rate of change in the position values.
In a parts feeder, a vision sensor can eliminate the need for an alignment pallet. Vision-enabled insertion robots can precisely perform fitting and insertion operations of machine parts. [5]
A potentiometer is a three-terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider. If only two terminals are used, one end and the wiper, it acts as a variable resistor or rheostat.
An industrial robot is a robot system used for manufacturing. Industrial robots are automated, programmable and capable of movement on three or more axes.
A transducer is a device that converts energy from one form to another. Usually a transducer converts a signal in one form of energy to a signal in another. Transducers are often employed at the boundaries of automation, measurement, and control systems, where electrical signals are converted to and from other physical quantities. The process of converting one form of energy to another is known as transduction.
An accelerometer is a tool that measures proper acceleration. Proper acceleration is the acceleration of a body in its own instantaneous rest frame; this is different from coordinate acceleration, which is acceleration in a fixed coordinate system. For example, an accelerometer at rest on the surface of the Earth will measure an acceleration due to Earth's gravity, straight upwards of g ≈ 9.81 m/s2. By contrast, accelerometers in free fall will measure zero.
In control engineering, a servomechanism, usually shortened to servo, is an automatic device that uses error-sensing negative feedback to correct the action of a mechanism. In displacement-controlled applications, it usually includes a built-in encoder or other position feedback mechanism to ensure the output is achieving the desired effect.
In control theory, an open-loop controller, also called a non-feedback controller, is a control loop part of a control system in which the control action is independent of the "process output", which is the process variable that is being controlled. It does not use feedback to determine if its output has achieved the desired goal of the input command or process setpoint.
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.
Domo is an experimental robot made by MIT designed to interact with humans. The brainchild of Jeff Weber and Aaron Edsinger, cofounders of Meka Robotics, its name comes from the Japanese phrase for "thank you very much", domo arigato, as well as the Styx song, "Mr. Roboto". The Domo project was originally funded by NASA, and has now been joined by Toyota in funding robot's development.
Motion control is a sub-field of automation, encompassing the systems or sub-systems involved in moving parts of machines in a controlled manner. Motion control systems are extensively used in a variety of fields for automation purposes, including precision engineering, micromanufacturing, biotechnology, and nanotechnology. The main components involved typically include a motion controller, an energy amplifier, and one or more prime movers or actuators. Motion control may be open loop or closed loop. In open loop systems, the controller sends a command through the amplifier to the prime mover or actuator, and does not know if the desired motion was actually achieved. Typical systems include stepper motor or fan control. For tighter control with more precision, a measuring device may be added to the system. When the measurement is converted to a signal that is sent back to the controller, and the controller compensates for any error, it becomes a Closed loop System.
Odometry is the use of data from motion sensors to estimate change in position over time. It is used in robotics by some legged or wheeled robots to estimate their position relative to a starting location. This method is sensitive to errors due to the integration of velocity measurements over time to give position estimates. Rapid and accurate data collection, instrument calibration, and processing are required in most cases for odometry to be used effectively.
A servomotor is a rotary actuator or linear actuator that allows for precise control of angular or linear position, velocity, and acceleration. It consists of a suitable motor coupled to a sensor for position feedback. It also requires a relatively sophisticated controller, often a dedicated module designed specifically for use with servomotors.
A positioning system is a system for determining the position of an object in space. One of the most well-known and commonly used positioning systems is the Global Positioning System (GPS).
A variable reluctance sensor is a transducer that measures changes in magnetic reluctance. When combined with basic electronic circuitry, the sensor detects the change in presence or proximity of ferrous objects.
A position sensor is a sensor that detects an object's position. A position sensor may indicate the absolute position of the object or its relative position (displacement) in terms of linear travel, rotational angle or three-dimensional space. Common types of position sensors include the following:
A string potentiometer is a transducer used to detect and measure linear position and velocity using a flexible cable and spring-loaded spool. Other common names include string pot, cable-extension transducer, draw wire sensor, and yo-yo sensor.
Webots is a free and open-source 3D robot simulator used in industry, education and research.
In computing, an input device is a piece of equipment used to provide data and control signals to an information processing system, such as a computer or information appliance. Examples of input devices include keyboards, mouse, scanners, cameras, joysticks, and microphones.
A tactile sensor is a device that measures information arising from physical interaction with its environment. Tactile sensors are generally modeled after the biological sense of cutaneous touch which is capable of detecting stimuli resulting from mechanical stimulation, temperature, and pain. Tactile sensors are used in robotics, computer hardware and security systems. A common application of tactile sensors is in touchscreen devices on mobile phones and computing.
In kinematics, absement is a measure of sustained displacement of an object from its initial position, i.e. a measure of how far away and for how long. The word absement is a portmanteau of the words absence and displacement. Similarly, absition is a portmanteau of the words absence and position.
Robotic prosthesis control is a method for controlling a prosthesis in such a way that the controlled robotic prosthesis restores a biologically accurate gait to a person with a loss of limb. This is a special branch of control that has an emphasis on the interaction between humans and robotics.