Design and Evaluation of a Buckled Strip Compliant Actuator

A novel compliant actuator based upon the compliance of a buckled thin strip is presented. It is suggested that the actuator can be used for a point contact attachment or to generate a 2-D or 3-D compliant surface. Compliance variation was obtained by changing the distance between the ends of the buckled strip using a linear actuator and by altering the end attachments from hinged to clamped. A mathematical model is developed and experimentally validated to predict the shape of the compliant surface so that its profile can be controlled and matched to a target surface shape. The general characterization of the actuator is presented here in terms of compliance modification and frequency response. Results demonstrated that actuator compliance could be increased 2× by adjustment of the end boundary attachments, and 8× by adjusting the end displacement as well. These increases could be achieved “on-the-fly”, without reconfiguring the system. The actuator also generated a stable, linear response in the design range of up to 4.0 Hz. In conclusion, we have shown that a buckled strip/linear motor combination can produce an accurate, predictable, and controlled active compliance actuator suitable for a range of applications, but designed here for applications involving interaction with or simulation of biological tissues.