Sensors of Remotely Controlled Robotic Arm - Essay Example

For desired results, robotic arm or the manipulator must pair with the right functioning robot sensor. The arm performs all moving operations on a workpiece and transfers it to the next robot for other operations. Manipulators feature grips of varying operating positions and have the ability to apply a certain amount of force. Operation of a robotic arm includes motions or force-actuating sensors, which in turn, through a wiring system send information to robot control system as electrical signals to either shut off or put on a motor. The motors can be the electrical, pneumatic, or hydraulic type (Boboulos, 2010). Robots need more information than human senses can provide.

Types of sensors

Robotic sensors are in two categories, the internal, and the external sensors. The robotic arm in the robot design is to use two types of sensors. These are a Linear position sensor, in the internal sensors category required for the basic working of the robot, and the pressure sensors from a class that enables the robot o to interact with the environment (Bouchard, 2014).

The Linear position sensors measure the linear position of a device. They read measurements and covert the encoded position into a signal. The position is then decoded into position by the controller. Determined motion is the change in position over time. The kind of sensors by the type, input voltage, linear range, packaging, and the operating temperature range. The robot design has the option to use the encoder systems described below.

Absolute magnetic encoder system

The sensor designed for motion control is a highly reliable one that uses a contactless absolute measuring technique with a magnetic scale. It offers high accuracy and resolutions up to 0.244 um. Other important characteristics are a range of up to 16.3 m. The system offers a robust measuring system, and its small footprint allows for its simple and fast installation. Additionally, it is best for highly dynamic control loops with a design that allows for drag-chain compatible cable. The design can utilize the sensor as for motion control as a feedback element for position and velocity control loop.

Linear variable differential transformer

Commonly called an LVDT, the electromechanical transducer converts motion or vibrations into an electric signal and electric signals into motion. The robot design can use captive armatures type of LVDT. The make has a major advantage as a guided, and restrained helps prevent misalignments. If used, the design can utilize the sensor to allow mechanisms to work long ranges. Other characteristics include a resolution of accuracy and a range of 1 to 37 inches.

Ultrasonic sensors

Ultrasonic sensors use sound to give solutions for movement in targets and measuring their distance to them in industries. The sensor offers high ranging accuracy, resolution 1cm, range 2cm-500cm. Additionally, the sensors significant advantage is their stable performance and affordability. The design could utilize the sensor to offer solutions for object detection.

The other type of sensors the design utilizes is the pressure sensors. The sensors are touch or force sensors that determine when the robotic arm touches something (Wilamowski & Irwin, 2011). The advantages of these switches are their simplicity and affordability. The design uses this sensor since it only requires the necessary information that the arm reaches an object. Strain gauges and pressure sensitive resistances form the basis upon which the tactile sensors measure the touch pressure (Stephan, Pagounis, Laufenberg, Paul & Ruther, 2011). Pressure sensitive resistances determine the grip pressure on the objects. The comparison between the pressure in the grip and the maximum allowable pressure continually happens to avoid damaging objects. In addition, other touch sensors use mechanical strain gauges measure force and also the gripping pressure. Force sensors, on the other hand, measure the load on the robotic arm. The tactile methods are advantageous if used when handling just one object.

Table SEQ table \* ARABIC 1 Types of pressure sensors

Sensor Accuracy Resolution range Use in the design

Mechanical

Switches High __ unlimited Make contact when the active cord mechanism touches something

Strain gauge force sensor 0.5-0.8 __ unlimited Measure the force the robot is gripping an object

Piezodiode 0.5 __ unlimited Grasp odd shaped articles

Sensors Choice

The use of decision matrices, allows for choosing of the sensors intended for use in the design.

rating scale of high = 3, medium = 2, and low = 1.

Table 2 Decision matrix for three alternatives for linear motion

criteria{weight Affordability Detect object Range score

5 5 3 Absolute magnetic encoder system 3x5=15 1x5=0 3x3=9 24

LVDT 2x5=15 1x5=5 3x3=9 29

Ultrasound transducers 2x5=10 3x5=15 2x3=6 31

Table 3 Decision matrix for three alternatives of pressure sensors

Simplicity Affordability Measures touch pressure Score

Weight 3 5 4 Mechanical

Switches 3x3=9 3x3=9 1x4=4 22

Strain gauge force sensor 2x3= 6 2x5=10 3x4=12 28

Piezodiode 1x3=3 1x5=5 4x4=16 24

The design will utilize the ultrasonic and the strain gauge force sensors. The choices had the scores and carry the expected desired characteristics for use in a robotic arm.

References

Boboulos, M. (2010). Automation and robotics (1st ed., pp. 22, 27). bookboon.com.

Bouchard, S. (2014). 7 Types of Industrial Robot Sensors. Blog.robotiq.com. Retrieved 19 November 2017, from https://blog.robotiq.com/bid/72633/7-Types-of-Industrial-Robot-Sensors

Stephan, J., Pagounis, E., Laufenberg, M., Paul, O., & Ruther, P. (2011). A Novel Concept for Strain Sensing Based on the Ferromagnetic Shape Memory Alloy NiMnGa. IEEE Sensors Journal, 11(11), 2683-2689. http://dx.doi.org/10.1109/jsen.2011.2157489

Wilamowski, B., & Irwin, J. (2011). The industrial electronics handbook. CRC Press.