ECE5320 Mechatronics Assignment#01: Literature Survey on Sensors and Actuators Topic: AccelerometersOutlineTo explore further (survival pointers of web references etc)Major applications1. Working Principles 1) Dynamics Model1. Working Principles 2) Structure Model1. Working Principles 3) CharacteristicsBasic configurationsSlide 9Slide 10Slide 11Slide 12Slide 13Slide 14Specifications OverviewSlide 16Slide 17Slide 18Slide 19Common Types of AccelerometersUsesSELECTION CRITERIAAmplitude RangeSlide 24Frequency ResponseSlide 26Slide 27ENVIRONMENTALSlide 29Slide 30CONCLUSIONECE5320 MechatronicsAssignment#01: Literature Survey on Sensors and Actuators Assignment#01: Literature Survey on Sensors and Actuators Topic: Accelerometers Prepared by: Aldo G. RodriguezDept. of Electrical and Computer Engineering Utah State UniversityE: ; T: (435)797-6115; F: (435)797-3054 (ECE Dept.)3/10/200601/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-2Outline –Reference list–To probe further–Major applications–Basic working principle illustrated–A typical sample configuration in application (application notes)–Major specifications–Limitations–And many more relevant issues in applications (such as, how to choose, cost information, where to buy etc.)01/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-3To explore further (survival pointers of web references etc) •http://www.davidson.com.au/products/vibration•http://www.onosokki.co.jp/English/hp_e/whats_new/SV_rpt/SV_1/sv1.htm•http://www.texasinstruments.com•http://www.wikipedia.com01/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-4Major applications •Typical Accelerometer Applications Typical Accelerometer Applications••Tilt / Roll•• Vibration / “Rough-road” detection•– Can be used to isolate vibration of mechanical system from outside•Sources. •• Vehicle skid detection•– Often used with systems that deploy “smart” braking to regain control of•Vehicle. •• Impact detection•– To determine the severity of impact, or to log when an impact has•Occurred.•• Input / feedback for active suspension control systems•– Keeps vehicle level.01/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-51. Working Principles1) Dynamics ModelPicture obtain from chen kaiyu sensor ppt01/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-61. Working Principles2) Structure ModelPicture obtain from chen kaiyu sensor ppt01/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-71. Working Principles3) Characteristics•Piezoresistance Effect. Piezoresistive sensing is accomplished by diffusing stress-sensitive resistors into the springs at the location of peak stress.•Extremely Small in Size and Mass•Low Cost•DC Response•Moderate Output Level•Temperature Dependent Sensitivity01/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-8Basic configurations•Three basic structural designs are used in manufacturing industrial accelerometers. •They are the flexural, compression and shear designs. All three designs contain the basic components of the piezoelectric element, seismic mass, base, and housing.01/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-9•In the flexural design the piezoelectric element is secured to the seismic mass in the form of a double cantilever beam. Flexural designs have lower resonant frequency and are generally not well-suited for machinery monitoring applications. •Because of their very high output (up to 100 V/g), flexural designs excel in low level, low frequency seismic applications. The flexural element is often epoxied which limits its application in high shock environments.01/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-10•Figure 1 shows the sensing element/mass system being driven at the fulcrum or the base.http://www.davidson.com.au/products/vibration01/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-11•The compression design is generally the simplest and easiest to understand. The crystal, quartz or ceramic, is sandwiched between the seismic mass and the base with an elastic pre-load bolt. Motion (vibration) into the base squeezes the crystal creating an output. http://www.davidson.com.au/products/vibration01/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-12•Compression designs are much more suited than flexural designs for industrial machinery monitoring applications because of their high resonance and more durable design. •Compression designs generally have thick bases and should be used on thick walled structures because of base strain and thermal transient sensitivities.01/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-13•The shear design subjects the sensing element to a shear stress. The piezoelectric sensing element and seismic mass are secured to a center post/base standing upright via a retaining ring as shown in figure 3. http://www.davidson.com.au/products/vibration01/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-14•This preload produces a stiff structure with good frequency response and greater mechanical integrity. As the sensitive axis is not in-line with the mounting surface, adverse environmental conditions such as base strain and thermal01/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-15 Specifications Overview Zero g offset (i.e. voltage output at 0g)•– May vary from sensor to sensor•– Can be trimed out at system level using the Earth’s gravity as reference inputSensitivity (i.e. voltage output per g)•– May vary from sensor to sensor•– Can be adjusted at system level using the Earth’s gravity as reference input Noise•– Noise determines the minimum resolution of the sensor•– Noise floor can be lowered by restricting bandwidth if the noise is Gaussian01/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-16Temperature Range Bias drift with temperature•– How does the zero g output change with temperature•– Can be trimmed out at system level by several methodsSensitivity drift with temperature•– How does the output per g change with temperature•– Difficult to trim out at
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