The alumnus pupils at GIKI have worked on the development of MEMS-based gyroscopes. For this intent a rate tabular array was required for the MEMS lab in order to prove these gyroscopes. Hence this undertaking was undertaken at undergraduate degree in the signifier of a concluding twelvemonth undertaking. The intent of this was to make proficient consciousness of MEMS engineering at an undergraduate degree plus achieve the needed end in a really cost effectual mode. Problem Definition
The undertaking was to indigenously develop a rate tabular array which non merely is cost-efficient but besides delivers public presentation parametric quantities. Aim
The purpose was to plan a single-axis rate tabular array. On the top of the rate tabular array. IC ( gyroscope ) shall be mounted. From a Personal computer through a accountant. the rate table shall be rotated at the needed rate ( revolutions per minute ) . All the connexions to the IC shall be available through the non-rotating base of the tabular array. Time line
Sep ‘08| * Project proposal * Collection of informations * Analysis of Data * Project approval| Oct ‘08| * Understanding of Rate Tables * Initial Design of Rate Table| Nov ‘08| * Simulation consequences * Status study of Hardware & A ; Software| Jan ‘09| * Design of Controller * Design of Rate Table| Feb ‘09| * Implementation of Hardware design * Integration of Hardware & A ; Software| Mar ‘09| * Testing and Troubleshooting|
Apr ‘09| * Open House * Final Report and Thesis|
Milestones with undertaking interruption
* Project proposal * Collection of informations * Analysis of Data * Project approval| * All * Usman & A ; Sarah * Saad & A ; Nabeel * All| * Understanding of Rate Tables * Initial Design of Rate Table| * Usman & A ; Nabeel * Saad & A ; Sarah| * Simulation consequences * Status study of Hardware & A ; Software| * Usman & A ; Saad * Nabeel & A ; Sarah| * Design of Controller * Design of Rate Table| * Saad & A ; Nabeel * Usman & A ; Sarah| * Implementation of Hardware design * Integration of Hardware & A ; Software| * All * All| * Testing and Troubleshooting| * All|
* Open House * Final Report and Thesis| * All * All|
Introduction to Rate Table
Rate tabular array is a device which is widely used for proving and graduating instruments such as preciseness gyros and accelerometers which comprise the basic detectors in high-accuracy inertial counsel systems. Because these sensing instruments are capable of mensurating highly infinitesimal dynamic measures. formidable demands are placed on the rate tabular arraies used for providing known inputs to these instruments. Therefore. to be compatible with the truth of gyros and accelerometers presently in usage. a rate tabular array system must be capable of mensurating and commanding angular speeds down to the order of 0. 001 degree per second. Single-Axis trial tabular arraies provide precise angular place. rate and acceleration for development and production testing of inertial constituents and systems. What is Gyroscope?
Micro machined inertial detectors. dwelling of accelerometers and gyroscopes are one of the most of import types of Si based detectors. A gyroscope is a device for mensurating or keeping orientation. based on the rules of angular impulse.
The Gyroscope developed at GIKI is a thermally actuated 3-DoF micro-machined gyroscope using Chevron thermic actuators to drive proof mass. There are a figure of propulsion mechanisms which include electrostatic. piezoelectric. thermic etc. The benefits of this design will be described subsequently.
These actuators are activated by Joule warming. When a possible difference is applied between two or more points on electrically carry oning stuff it causes flow of electrical current which induces thermic strain due to internal warming. Consequently these thermic strains generate the coveted mechanical distortion or force. These thermic actuators are capable of supplying a big force.
There are two types of thermic actuators: hot/cold arm thermal actuators and ‘V’ or Chevron’ shaped actuators.
The supplanting in Chevron actuators is relative toV2.
Mass M1 is constrained to hover merely in the drive way ( 1-DOF ) whereas the mass M2 is free to hover in both thrust ( X-axis ) and sense ( Y-axis ) way ( 2-DOF ) . This makes the system a 3-DOF 1. Mass M1 is excited in the drive way. When the system is rotated a Coriolis force Acts of the Apostless on mass M2 which can be measured utilizing electrical capacity alterations. This information in bend can be used to find the rotary motion or orientation of the system.
Advantages of this design:
High force. big supplanting and low electromotive force ingestion are the primary concerns for micro-gyroscopes. In comb thrust actuators. a p. d. of 20V causes a supplanting of 5µm whereas in Chevron based thermic actuators a p. d. of merely 0. 1V causes a supplanting of 5. 5µm.
* In gyroscope proving we stimulate the gyroscope by mounting it on the rate tabular array. * Rate tabular array provides the gyroscope precise angular gesture about one or several axis. * This angular gesture causes electrical capacity alterations in the gyroscope. * This electrical capacity alteration will be used to mensurate rotary motion and orientation Commercially available Rate Table
Rate tabular arraies are designed to supply precise place. rate and acceleration gesture for development or production testing. This trial instrument is used for the testing and standardization of detectors and gyroscopic instruments which require a precise and accurate angular speed. During the survey we came across the sellers of the proving equipment. Ideal Aerosmith. EVO-10 and Acutronic are the market leaders.
Below are stated generic specifications of a few rate tabular arraies.
PHYSICAL CONFIGURATION AND SPECIFICATION|
Specifications| 1291BR| 1270VS| 1280T|
Table top surface features * Diameter * Material| 8inchesAluminum| 12 inchesAluminum| 14 inchesAluminum| Controller * Type * Comm. Interface * Speed| InternalRS-232 19200 baud| RS-2329600 baud| AERO 800 Test Table ControllerRS-232 criterion. | Power requirements| Standard 115 VAC. 50/60HzOptional 230 VAC. 50/60Hz| 115 VAC. 50/60 Hz Standard ( 230 VACoptional ) | Standard: 115 VAC. 50/60 Hz Optional: 230 VAC. 50/60Hz| Drive type| DC torsion motor with servo controlled system| DC Servo Motor| Direct-drive. DC brush-type servo system| Operating Environment| 50 to 95? F ( 10 to 35? C ) 20 % to 85 % non-condensing| 32° to 130° F ( 0° to 54° C ) . 20 % to 85 % non-condensing| 50 to 95? F ( 10 to 35? C ) . comparative humidness 20 % to 85 % non-condensing| Slip ring package| Standard: 34 lines Optional: 66 lines | Standard:16 linesOptional: 22. 28. or 66 lines| 48 lines|
PHYSICAL CONFIGURATION AND SPECIFICATION|
Specifications| EVO-10S| EVO-10| EVO-10M| EVO-10L|
Tabletop Diameter| 300mm| 300mm| 300mm| 300mm| Drive mechanism| Direct/brushless motor|
Slip rings| 34 lines| 34 lines| 34 lines| 34 lines| Controller| Small accountant unit| Modular control unit with modular power unit| Comm. Interface| | RS232. Ethernet|
PHYSICAL CONFIGURATION AND SPECIFICATION|
Specifications| AC1125| AC-DC130| AC 1135|
DimensionsDiameter| 500 mm| 16 inches| |
Slip Rings| 30 lines| 30 lines| 30 lines|
Drive System| Brushless AC motors| High torsion direct thrust brushless servo motors| Brushless torsion motor| Controller| ACT3000 series| ACUTROL3000-PA or ACUTROL3000| ACUTROL ACT 3000 |
Comm. Interface| RS232. Ethernet |
The hardware demand for the fiction of the rate tabular array is: * Motor
* Gyroscope IC
* DC power supply
* Slip rings
* RS 232 Interface
* Lathe Machine
* Shaper Machine
* Personal Computer ( Personal computer )
* Micromachining Device
A brushless DC motor ( BLDC ) is a synchronal electric motor which is powered by direct-current electricity ( DC ) and which has an electronically controlled commuting system. alternatively of a mechanical commuting system based on coppices. In such motors. current and torsion. electromotive force and revolutions per minute are linearly related. BLDC motors are considered to be more efficient than brushed DC motors. BLDC motors offer several advantages over brushed DC motors this includes higher efficiency and dependability. reduced noise. longer life-time ( no coppice eroding ) . riddance of ionising flickers from the commutator. and overall decrease of electromagnetic intervention ( EMI ) . Comparison of conventional and brushless DC motors:
| Conventional motors| Brushless motors|
Mechanical structure| Field magnets on the stator| Field magnets on the rotor. Similar to AC synchronal motor| Distinctive features| Quick response and first-class controllability | Long lasting and easy care | Winding connections| Ring connexions. The simplest ? connexion. | ? or Y connections| Commutation method | Mechanical contact between coppices and commutators. | Electronic exchanging through transistor| Detecting method of rotor’s place | Automatically detected by brushes| Hall component. optical encoder| Change by reversaling method| By a contrary of terminal| Rearranging logic sequencer|
The motor used in the Rate Table is a brushless DC motor and driver bundle with digital operator. It is a merchandise of Oriental Motors. It is the BLF series with the theoretical account figure BLF 460C-200.
Model BLF460C-?Combination Type – Parallel Shaft Gear head| Rated Output Power ( Continuous ) W ( HP ) | 60 ( 1/12 ) | Rated voltage V| Single-Phase 200–240 _10 % | Rated frequence Hz| 50/60 _5 % | Rated input current A| 1. 2| Maximum input current A| 3. 0| Rated Torque N_ m ( oz-in ) | 0. 2 ( 28. 4 ) | Get downing torque N_ m ( oz-in ) | 0. 4 ( 56. 8 ) | Rated speed r/min| 3000| Speed control scope r/min| 80_4000|
A faux pas ring is an electromechanical device that allows the transmittal of power and electrical signals from a stationary to a rotating construction. Besides called a rotary electrical articulation. aggregator or electric swivel. a slip ring can be used in any electromechanical system that requires un-restrained. intermittent or uninterrupted rotary motion while conveying power and/or informations. It can better mechanical public presentation. simplify system operation and extinguish damage-prone wires swinging from movable articulations. The faux pas ring used in the Rate Table is by MOOG Inc. . theoretical account no. AC 6355- 36. The specification and the diagram for the faux pas rings are stated below. Operating Speed| 250 rpm|
Circuit Configurations| 36 pealing 36 @ 2 amp 4 @ 5 A ; 28 @ 2 A 4 @ 10 A ; 20 @ 2 amp| Lead Length| 24 inch ( 600 millimeter ) |
Voltage| 210 VDC|
Operating Temp. | -40°C to +80°C|
Contact Material| Gold-on-gold signal ; gold-on-gold power| Housing| Plastic|
Lead Size/ Type| 2 A. 26 AWG5 A. 20 AWG10 A. 16 AWG| Dielectric Strength| 250 VAC @ 60 Hz. between each circuit and all other circuits| Insulation Resistance| 1000 mega ohms max tested @ 500 VDC| Electrical Noise| 60 milliohms soap when tested @ 6VDC50 milliamps when running @ 10 rpm|
Mercotac are mercury-based electrical connections superior to steal rings. The electrical conductivity way is a liquid metal that is molecularly bonded to the contacts. This creates a connexion that is changeless and unchanged for the life of the connection. Mercotac connections are maintenance free. make non degrade the signal over clip and last much longer than slip rings. They transmit with close zero electrical noise. therefore the same connection can be used for power and signal transmittal.
Amongst the assorted theoretical accounts available. the most appropriate 1 that seemed for the Rate Table was Model 830. Below are the specifications and diagram for the theoretical account.
Model No. | Conductors| Description| Voltage AC/DC| Max. Freq. MHz| Contact Resistance| Max OP. RPM| AMP Ratingat 240 VAC| TemperatureMax. F ( C ) / Min. F ( C ) | RotationTorque ( gm-cm ) | 830| 8| Standard Model| 0-250| 100| & lt ; 1m| 200| [ electronic mail protected ][ electronic mail protected ]| 140 ( 60 ) /-20 ( -29 ) | 1000| 830 SS| 8| Stainless Steel Bearing| 0-250| 100| & lt ; 1m| 200| [ electronic mail protected ][ electronic mail protected ]| 140 ( 60 ) /-20 ( -29 ) | 1000|
First. we are grateful to Allah Almighty for his grace and clemency he bestowed upon us throughout. We thank Him for his approvals and counsel. We would wish to show profound gratitude to our adviser. Dr. Shafat. A. Bazaz. for his priceless support. encouragement. supervising and utile suggestions throughout this undertaking work. His moral support and uninterrupted counsel enabled us to finish our work successfully. We are besides extremely grateful to Faculty of Electronics Engineering. GIKI. for their valuable suggestions throughout this survey. From the staff. Mr. Iftikhar ( store keeper ) and Mr. Abdullah Jan ( PS to dean ) are particularly thanked for their attention and attending. We would besides wish to thank Faculty of Mechanical Engineering for their engagement and support during the undertaking. We are as of all time. particularly indebted to our parents for their love and support throughout our lives. We besides wish to thank our siblings for their support and apprehension during our survey. Furthermore. our sincere thanks to our GIKIAN friends. who shared their love and experiences with us. Mohammad Usman Ehsan