Analytical modeling, optimization and testing of a compound bridge-type compliant displacement amplifier

• Published in: Mechanism and machine theory Vol. 46; no. 2; pp. 183 - 200
• Main Authors: Xu, Qingsong, Li, Yangmin
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.02.2011; Elsevier
• Subjects: Amplification; Amplifiers; Applied sciences; Compliant mechanisms; Displacement; Drives; Exact sciences and technology; Finite element method; Finite-element analysis; Flexure hinges; Linkage mechanisms, cams; Mathematical analysis; Mathematical models; Mechanical amplifier; Mechanical engineering. Machine design; Nanostructure; Optimization; Optimum design; Piezoelectric actuation; Precision engineering, watch making; Stiffness; Flexure hinges; Optimum design; Compliant mechanisms; Finite-element analysis; Mechanical amplifier; Piezoelectric actuation; Compliant mechanism; Positioning; Evolutionary algorithm; Mechanical drive; Bernoulli Euler model; Amplifier; Experimental study; Modeling; Particle swarm optimization; Finite element method; Nanometer scale; Resonance frequency; Piezoelectricity; Actuator; Workspace
• ISSN: 0094-114X; 1873-3999
• DOI: 10.1016/j.mechmachtheory.2010.09.007

This paper investigates a flexure-based compound bridge-type (CBT) displacement amplifier for piezoelectric drives. In addition to the advantages of large amplification ratio and compact size, the CBT amplifier has a larger lateral stiffness and is more suitable for actuator isolation and protection than the ordinary bridge-type amplifier. An analytical model for amplification ratio calculation is established based on the Euler–Bernoulli beam theory because other simple theoretical approaches cannot predict the ratio properly. The reason why those approaches fail is discovered by resorting to the elastic model. The input stiffness and resonance frequency of the amplifier are also analytically modeled and verified by finite-element analysis (FEA). The derived models are utilized to optimize the amplifier structure through particle swarm optimization (PSO) to obtain a large resonance frequency subject to other performance constraints. The performances of the fabricated amplifier with optimized parameters are confirmed by both FEA simulation and experimental studies. Because an output displacement over 1 mm is achieved by the designed amplifier, it is employable to develop micro/nanopositioning stages with a cubic millimeter sized workspace. [Display omitted] ►The analytical models of a compound bridge-type displacement amplifier are established. ►It is found that the compliances of connecting arms of the amplifier have a great influence on the amplification ratio. ►A prototype of the amplifier is fabricated by the wire-EDM process. ►The relationship between the output and input displacements of the amplifier is almost linear.