This paper presents the design optimization of a mechanically decoupled six-axis force/torque (F/T) sensor by minimization of cross coupling error. The new term 'principal coupling' is proposed to define the largest cross coupling error. In the first design step of the F/T sensor, the locations of twenty-four strain gages in a sensor structure are predetermined, and four structural design variables are selected to be optimized. In the second step, an optimization framework that reduces principal coupling is developed. Multiple constraints on good isotropic measurement and safety are considered and formulated using the output strain of each strain gauge circuit. The optimal design utilizes FEM software and MATLAB interactively to perform effective shape optimization. As a result of shape optimization, principal coupling of a six-axis F/T sensor was reduced from 35% to 2.5% with good isotropy. The final design of the F/T sensor was fabricated for experimental verification and there was only 0.7% difference in principal coupling and 5.2% difference in the overall strain output between the numerical and experimental results. The optimal design results in this paper are expected to provide a design guideline for multi-axis F/T sensors with significantly reduced cross coupling error, one of the biggest technical obstacles in developing F/T sensors.
Bibliographical noteFunding Information:
This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (No. 2011-0026344 ) and by the Industrial Strategic Technology Development Program ( 10035431 , Development of Wearable Robot for Industrial Labor Support) funded by the Ministry of Trade, Industry & Energy (MI, Korea) . We also would like to thank Samsung Electronics for providing initial financial support.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Surfaces, Coatings and Films
- Metals and Alloys
- Electrical and Electronic Engineering