5/51 4.3 Relative Displacement:Translational and Rotational I. Calibration ll.Resistive Potentiometers Ill.Resistance Strain Gage IV.Differential Transformers V.Synchros and Resolvers VI.Variable-Inductance Variable-Reluctance Pickups VIl.Eddy-Current Noncontacting Transducers VIll.Capacitance Pickups IX.Piezoelectric Transducers X.Electro-Optical Devices XI.Photographic and Electronic-Imaging Techniques XIl.Photoelastic,Brittle-Coating,and Moir Fringe Stress-Analysis Techniques XIll.Displacement-to-Pressure(Nozzle-Flapper)Transducer XIV.Digital Displacement Transducers(Translational and Rotary Encoders) XV.Ultrasonic Transducers 6/51 4.3 Relative Displacement:Translational and Rotational I.Calibration-Translational Displacement Translation:a uniform movement without rotation ◆Static calibration of translational平移/平动)devices using micrometers(千分尺)usually has accuracy of0.01mm ◆Using level(杠杆)devices or wedge-type(楔形)mechanisms for motion reduction to achieve smaller resolution ◆Using linear encoder(编码器)scales or laser interferometers(千涉仪)to realize greater accuracy ◆Gage Blocks(量块：small blocks of hard,dimensionally stable steel or other material made in sets that can be stacked to provide accurate dimension over a wide range and in small steps. When transducers are calibrated to very high accuracy,it is extremely important to control all interfering and/or modifying inputs such as ambient temperature,electrical excitation to the transducer,etc.4.3 Relative Displacement: Translational and Rotational I. Calibration II. Resistive Potentiometers III. Resistance Strain Gage IV. Differential Transformers V. Synchros and Resolvers VI. Variable-Inductance & Variable-Reluctance Pickups VII. Eddy-Current Noncontacting Transducers VIII. Capacitance Pickups IX. Piezoelectric Transducers X. Electro-Optical Devices XI. Photographic and Electronic-Imaging Techniques XII. Photoelastic, Brittle-Coating, and Moir Fringe Stress-Analysis Techniques XIII. Displacement-to-Pressure (Nozzle-Flapper) Transducer XIV. Digital Displacement Transducers (Translational and Rotary Encoders) XV. Ultrasonic Transducers 5/51 4.3 Relative Displacement: Translational and Rotational I. Calibration – Translational Displacement ‹ Translation: a uniform movement without rotation ‹ Static calibration of translational( 平 移 / 平 动 ) devices using micrometers(千分尺) usually has accuracy of 0.01mm ‹ Using level(杠杆) devices or wedge-type(楔形) mechanisms for motion reduction to achieve smaller resolution ‹ Using linear encoder(编码器) scales or laser interferometers (干涉仪) to realize greater accuracy ‹ Gage Blocks (量块): small blocks of hard, dimensionally stable steel or other material made in sets that can be stacked to provide accurate dimension over a wide range and in small steps. ‹ When transducers are calibrated to very high accuracy, it is extremely important to control all interfering and/or modifying inputs such as ambient temperature, electrical excitation to the transducer, etc. 6/51