Flexure based Parallel Mechanisms
Flexure joints are
frequently used in precision motion stages and micro-robotic mechanisms due to
their monolithic construction. The joint
compliance, however, can affect the static and dynamic performance of the overall
mechanism. In our research, we consider
the analysis and design of general platform type parallel mechanisms containing
flexure joints including static performance measures such as task space
stiffness and manipulability, while subject to constraints such as joint
stress, mechanism size, workspace volume, and dynamic characteristics. Based on these performance measures and
constraints, we adopt the multi-objective optimization approach. We first obtain the Pareto frontier, which
can then be used to select the desired design parameters based on secondary
criteria such as performance sensitivity.
To facilitate design iteration, we consider only lumped approximation of
flexure joints in the pseudo-rigid-body approach. Tools that we have developed
can also be applied to a broader class of compliant mechanisms, including
robots with inherent joint flexibility as well as compliant robots for contact
tasks.
MEMS Stage
MEMS Gripper (3 cases: manipulability
only, equally weighted manipulability and stiffness, stiffness only)
Reports and Papers:
- B.H. Kang, J.T. Wen, N.G. Dagalakis, J.J. Gorman, ``Design Optimization for a Parallel
MEMS Mechanism with Flexure Joints,'' International Design Engineering
Technical Conferences, Sept.28-Oct.2, 2004,
- B.H. Kang, J.T. Wen, A. Messac, ''Structural Optimization of a Parallel MEMS
Manipulator with a New Performance Measure,'' 10th AIAA/ISSMO
Multidisciplinary Analysis and Optimization,
- B.H. Kang, J.T. Wen, N.G. Dagalakis, J.J. Gorman, ``Analysis and Design of
Parallel Mechanisms with Flexure Joints,'' IEEE Conference on Robotics and
Automation,
- J. O'Brien and J.T. Wen, ``Singularities in Three-Legged Platform-Type Parallel Mechanisms,'' IEEE Transaction on Robotics and Automation, 19(4), Aug. 2003, pp.720--725.
- J. O'Brien, J.T. Wen, ``Redundant Actuation for Improving Kinematic Manipulability,'' 1999 International
Conference on Robotics and Automation,
- J. O'Brien, J.T. Wen, ``Passive Joint Braking: A Solution to Unstable Singularity,'' Internal Report, May, 2000.
- J. O'Brien, J.T. Wen, ``On Kinematic Instability
of Parallel Robots,'' Second Workshop on Computational Kinematics,
- J. O'Brien, J.T. Wen, ``New Techniques for Eliminating Unstable
Singularity in Parallel Robots,'' 2001 IEEE Conference on Robotics
and Automation,
- John O'Brien. Feasible Solutions to Unstable Singularity in Parallel Robots, Ph.D. thesis, Rensselaer Polytechnic Institute, June, 2001. (available upon request)
- Byoung Kang. Parallel Mechanisms with Flexure Joints: Analysis, Design, and Control, Ph.D. thesis, Rensselaer Polytechnic Institute, Aug. 2004. (available upon request)
Acknowledgment
This work is supported in part by the National
Science Foundation under grant IIS-9820709: Analysis, Synthesis, and
Control for General Parallel Robotic Systems, in part by the Center for
Automation Technologies under a block grant from the New York State Science and
Technology Foundation, and a U.S. Department of Energy Integrated Manufacturing
Predoctoral Fellowship.
Contact Information:
John T. WenOffice: CII 8213
Voice: (518)-276-8744
Fax: (518)-276-4897
Email: wen@cat.rpi.edu