A Simplified TDT Sensor for Wire Driven Joint
Satoshi Yoshinari,* Nobuaki Imamura* and Makoto Kaneko**
*Electronics Research Laboratory of Kobe Steel, Ltd., 1-5-5, Takatsukadai, Nishi-ku, Kobe, Hyougo 651-22, Japan
**Kyushu Institute of Technology, 680-4, Kawatsu, Iizuka, Fukuoka 820, Japan
A simple torque sensor for tendon-driven manipulators is proposed. The finger joint torque around a drive pulley is proportional to the.difference in tension between the two ends of the pulley. By using a coupling mechanism between tendons, this difference in tension can be measured directly, without sensing individual tendon tensions. The tension differential type torque (TDT) sensor is based on this idea and is useful for compensating friction existing in a transmission such as a manipulator. However, present TDT sensors require at least one tension pulley to support a driving tendon. This paper shows that it is able to design a TDT sensor without any tension pulley while its principle is maintained. A torque sensor installation on a movable link makes it possible to eliminate the tension pulley and downsize it.