Application of Mechatronics in Various Fields - Essay Example

Mechatronics Table of Contents PART A – Electronics Section 2 Exercise - Using Proetus 2 Discussion 10 Part B: Mechanical Section 11 Elevator Systems 11 Introduction 11 Lift Operation 12 Actuation 13 Heat Seeking Missiles 13 Introduction 13 Operation 14 Actuation 14 References 16 PART A – Electronics Section Exercise - Using Proetus The relationship between the circuit voltage and current and the transformer turns ratio. (i) Disconnecting the second channel from track A and reconnecting it to track B. The waveforms generated are, The terminal voltage measured at the oscilloscope are: A=490.4mV B=29.48V (ii) Transformer primary inductance is changed (iii) Restore the changes on the transformer primary inductance is changed. (iv) Half wave bridge rectifier fundamentals The voltage reading at the channels are A=615.8mV B=28.74V Adding a 50µF capacitor to the link at R2 and maintaining the previous setup, The output waveforms on the oscilloscope are: (a) At 10 µF (b) At 50 µF (c) At 75 µF (d) At 100 µF (e) At 250 µF (f) At 500 µF Adding different capacitors generates different output voltages, Capacitor (µF) Voltage (v) 10 455.8mV; 28.56V 50 490.4mv; 30.51V 75 606.6mv;32.08V 100 490.4mv; 32.80V 250 490.4mv;34.09V 500 490.4mv;39.38V This table shows the behaviour of the circuit when exposed to different values of capacitance. The input voltage against the output voltage shows that the voltage increases as capacitance increases. (v) Finally, a full wave rectifier is built with four diodes. A comparison is made between the full wave and the half wave. (vi) Using a bode plotter instead of the oscilloscope, (vii) Open loop characteristic transfer of 741 op amp (viii) Using two 741 op amps, the full wheatstone bridge performs a conclusive rectification of the signal for output Discussion The transformer steps up voltage from lower values to higher values. In practise, step up transformers are implemented where industries need supply, or when power needs to be transmitted over long distances. Transmission requires high voltages to ensure no losses especially in the direct form. When voltage is generated, it is achieved in alternating form. The full wave can be rectified to remove the negative part of the wave using a diode at the output. Hence the wave alternates halfway. To achieve an almost direct voltage, capacitors are use. They smoothen the rectified wave to achieve an almost direct voltage. The higher the capacitance, the more the wave is smoothened. At the highest capacitance of 500uF, the waves were almost straight lines. When the Wheatstone bridge with four diodes was used, the output is straight lines. The setup produces direct voltages without having to make alterations using capacitors. (vi) Resonance Circuit of a series resonance filter (RLC series circuit) The phase and frequency response of the RLC circuit is given as, The total impedance is, L C R ω min ω max Measurement 1 100 mH 100 nF 200 Ω 500 rad/s 50000 rad/s Measurement 2 100 mH 100 nF 100 Ω 500 rad/s 50000 rad/s Measurement 3 100 mH 100 nF 50 Ω 500 rad/s 50000 rad/s Measurement 4 100 mH 100 nF 25 Ω 500 rad/s 50000 rad/s Series resonant frequency and Q factor for each measurement. Series resonant frequency occurs at the maximum value of Vout and is defined as The resulting values of Q and resonant frequency are, Q fo 0.25 785.398 0.5 785.398 1 785.398 2 785.398 Part B: Mechanical Section Elevator Systems Introduction A lift/ elevator is a type of vertical transportation that moves people or gods between floors of a structure, usually a building. Lifts are generally powered by electric motors that drive either traction cables & counterweight systems, or pump hydraulic fluid to raise a cylindrical piston [Tur94]. Traditional lifts did not have automatic positioning of the floor in which the cab would stop, and would require manual operation using a rheostat connected to the motor. This method of operation was bound by challenges, such as, industrial action of lift operators or missing the floor which the cab should stop. However, with the advent of electric systems and mechatronics, relay logic circuits were employed to operate lifts automatically. Modern developments in electronics hassled to the replacement of the relay logic circuits with solid-state, microprocessor based controls that have been shown to operate the lifts more efficiently. Lift Operation The following sensors are used in the lift control system, providing input for the encoders to direct the cab [Ele14];- 1 Magnetic and/or photoelectric sensor – This sensor is installed in the cab and picks up signals on the location of the cab. The location of the cab is usually determined by counting the number of holes in the guide rail, or the number of magnetic pulses for the photo electric sensor and magnetic sensor respectively. 2 Infrared sensor – This sensor is installed at the entrance to the cab observing the space between the cab and the floor levels. This sensor is used to detect people entering or leaving the elevator. It helps with access control. 3 Load sensor – This sensor is installed at the bottom of the cab and warns the control system if the total load exceeds the design load prescribed (maximum load) 4 Primary velocity transducer (PVT) – This sensor detects the velocity of the drive shear There are three types of lift control systems, namely;- a Single automatic operation – this is activated either by pressing a single button on each floor or a button for a single floor while inside the cab. This operation happens when no one is using the lift, and the passenger has exclusive use of the lift until they reach their destination b Selective collective operation – the lift remembers and answers calls in a single direction, then reverses when all calls are through. This is the most common operation in application c Group automatic operation – this operation is implemented in large buildings, where the lifts have programmable micro-processers to control their movement The selective collective operation is governed by the ‘elevator algorithm’ which can be summarized as, “continue travelling in the same direction while there are remaining calls in that direction; if none, become idle or change direction if there are calls in the other direction”. Heuristic algorithms have been developed in the recent past, providing a more complex operating procedure for the lift. Actuation The elevator remains ‘idle’ when there are no requests in the system. A request can be generated by pushing any of the external control buttons on each level, or the level buttons within the cab itself. When two or more requests are made, the elevator algorithm will rank these requests and perform them accordingly. Heat Seeking Missiles Introduction Warfare is an integral part of human history, and has helped shaped the balance of power more often than other factors. The application of mechatronics in war has led to the development of highly efficient and accurate weapons that hit the intended targets. This has numerous advantages, such as, tactical advantage, reducing the collateral damage, and negates the need to deploy numerous troops to the battlefield, effectively reducing the number of people put in harm’s way. Heat seeking missiles make use of a technology referred to as infrared homing, which is a guidance system which uses the infrared light emission (heat track) from a target to track and follow it. [Sin11] notes that the use of modern technology in missiles has significantly increased their rate of efficiency and effectiveness. Studies have shown that an infrared seeker can locate a three-engine bomber at 5km with a 0.1 degree of accuracy [Kut57]. Operation The heat seeking missile has an array of infrared sensors installed, usually at the tip, and a computer or simple electronic circuit analyses the patterns of the signal to determine the position of the target and readjusts the course of the missile accordingly. The computer system allows the array of sensors to narrow their field of view towards the target, which has the effect of bringing the missile to within the lethal radius of it warhead. The reduction of the field of view also helps to eliminate any background sources of infrared or ultra- violet emissions, which improve the tracking of the missile. However, narrowing the field of view too quickly could result in loss of the target, thus the onboard computer must determine the optimum rate to narrow the field so as to track and reach the target within the limits of its propelling mechanism. Apart from the infrared sensor, other sensors onboard the missile include;- 1 Altitude sensor – this captures input on the altitude of the missile to determine its location, which is usually done by pressure measurements 2 Ultra violet sensor – this is found on more advanced missile types, allowing them to differentiate the target from any counter-mechanisms deployed, such as flares The modes of scanning used by the infrared sensors include;- a Linear scanning – vertical and horizontal slits are moved back and forth in front of the detector, which compares the time the flash was received to the scanner location at that time. b Spin scanning – a transparent plate with a sequence of opaque segments is placed in front of the infrared detector and spun at a fixed rate. Calculating the time difference between when the flash is received through the transparent segments allows the missile to track its target c Imaging systems – this provide an infrared image resembling that of a digital camera, allowing for more accurate tracking and defense against counter-measures. However, these systems require significantly higher signal processing Actuation Once the missile has been fired, the infrared array system actively scans its view to identify the heat source target. When the heat source has been isolated, the signal is directed to the onboard computer which adjusts the thrusters accordingly to direct the missile towards its target. Once the target is within the lethal radius of the missile’s warhead, the onboard computer sends a signal to detonate the explosive warhead. References Tur94: , (Turvey, 1994), Ele14: , (ElectricKnowhow, 2014), Sin11: , (Singh, 2011), Kut57: , (Kutzscher, 1957), Read More