TY - JOUR
T1 - A novel high-resolution optical encoder with axially stacked coded disk for modular joints
T2 - physical modeling and experimental validation
AU - Paul, Sarbajit
AU - Chang, Junghwan
AU - Fletcher, John Edward
AU - Mukhopadhyay, Subhas
PY - 2018/7/15
Y1 - 2018/7/15
N2 - A novel approach to realize a high-resolution absolute encoder with compact disk size for the application in a light weight robotic arm modular joint is proposed in the present research. First, the high resolution coded disk of the absolute encoder is designed using graph theory-based Hamiltonian cycle. Unlike the traditional 1-D binary coded tracks, the proposed generated code is a 2-D n × n matrix code with 0s and 1s as the matrix elements and n numbers of uniquely coded tracks. The 2-D matrix code improves the code density of the encoder system by 2n2 compared with that of the traditional 1-D codes (2n). Second, the coded tracks are arranged axially along Z-axis to stack the tracks within a constant disk diameter and to avoid the radially divergent track patterns. These combined operations result in a high-resolution absolute encoder with a compact constant disk diameter which is essential to comply with the size constraint of the modular joint. With the proposed designed framework, a prototype with n= 2 is manufactured using 3-D printing technology. The designed encoder with two tracks is tested on a rotary system and the absolute angle values are obtained using the unique codes generated by the photosensors installed in the prototype.
AB - A novel approach to realize a high-resolution absolute encoder with compact disk size for the application in a light weight robotic arm modular joint is proposed in the present research. First, the high resolution coded disk of the absolute encoder is designed using graph theory-based Hamiltonian cycle. Unlike the traditional 1-D binary coded tracks, the proposed generated code is a 2-D n × n matrix code with 0s and 1s as the matrix elements and n numbers of uniquely coded tracks. The 2-D matrix code improves the code density of the encoder system by 2n2 compared with that of the traditional 1-D codes (2n). Second, the coded tracks are arranged axially along Z-axis to stack the tracks within a constant disk diameter and to avoid the radially divergent track patterns. These combined operations result in a high-resolution absolute encoder with a compact constant disk diameter which is essential to comply with the size constraint of the modular joint. With the proposed designed framework, a prototype with n= 2 is manufactured using 3-D printing technology. The designed encoder with two tracks is tested on a rotary system and the absolute angle values are obtained using the unique codes generated by the photosensors installed in the prototype.
KW - Absolute encoder
KW - axially stacked disk
KW - directed graph
KW - high resolution
KW - modular joint
UR - http://www.scopus.com/inward/record.url?scp=85048015812&partnerID=8YFLogxK
U2 - 10.1109/JSEN.2018.2841982
DO - 10.1109/JSEN.2018.2841982
M3 - Article
AN - SCOPUS:85048015812
VL - 18
SP - 6001
EP - 6008
JO - IEEE Sensors Journal
JF - IEEE Sensors Journal
SN - 1530-437X
IS - 14
ER -