Research Projects

Previous Projects

Parameter optimization framework for pseudo-rigid-body models      general-PRB-model

Pseudo-rigid-body (PRB) models are numerical approximations for compliant members which capture inherent stiffness and kinematic properties. Using a general representation which can incorporate multiple behaviors, they can serve as design and analysis tools for a variety of applications in the field of compliant mechanisms. We developed an optimization framework to determine the best values of the PRB parameters for a given range of loading conditions.

timoshenko-beam-extension-effectsExtension effects in compliant joints

Soft materials can provide viable options in the design of compliant mechanisms, but they can also exhibit significant extension effects. Using a numerical approximation based on a modified form of Timoshenko beam theory, these extension effects were studied in detail. A PRB model was also developed for use in place of such compliant joints.

Mechanism design for a flapping wing MAV

This project focused on the optimization of the mechanism design for a flapping wing micro air vehicle (MAV) fabricated using shape deposition manufacturing (SDM). A dynamic analysis was performed after incorporating aerodynamic forces for calculating lift and drag on the system.

      flapping-wing-MAV-SDM                    parallel-guiding-mechanism-SDM

Topology optimization of compliant mechanisms using PRB models

topology-optimization-using-PRB-models

With a general framework for PRB models, it is possible to utilize them for topology optimization of compliant mechanisms from a given design space subject to constraints. PRB models can possibly offer significant computational advantages over finite element analysis, which can reduce time for design and analysis. Since they are numerical models, the same process can also be used for various types of compliant members and perhaps even include multiple materials.

                                

Curved beams in compliant mechanisms

Curved beams pose unique challenges in the field of compliant mechanisms, and are therefore sparingly used.  However, they can offer better load distributions than straight beam members while also providing more options for design. Using a newly derived PRB model for circular beams with uniform cross-section, we hope to provide an easy-to-use tool for incorporating curved beams in applications of compliant mechanisms.

     curved-beam-PRB      wavy_curved_beam_FEA

Current Projects

Uniform formulation of PRB models for design

The idea of PRB models can be extended to other design applications, but needs to overcome the bottleneck of multiple definitions of similar numerical models. In this research, preliminary steps are taken to introduce a PRB model that can be used for both straight and initially-curved flexures. The concept is illustrated with the design of a constant-force mechanism.

               

Analysis of beams under varying boundary conditions

The load-deflection behavior of a cantilever beam under tip loads is well-studied and documented. In this work, the aim is to derive equations to analyze beams subject to other boundary conditions along longitudinal axis. This is being studied with an eye on developing variable-stiffness beams for robotics applications.