Article published Robotics
Sensorless force feedback arm
The ABLE prosthesis, a motorized external skeleton system, imitates the human arm and provides an unprecedented degree of gesture assistance.
This was one of the novelties at the Automatica fair in June 2008. Developed by CEA LIST, the ABLE external robot arm prosthesis can safely support 1 kg at the arm end. The innovative aspect is the actuation technology, for which several patents have been filed: the rotational motion of the motor is transmitted to the arm via a screw jack and cable system, thus providing linear movement with minimum frictional resistance. “This technology is compact, reversible and highly efficient”, explains Yann Perrot, Head of the robotics and mesorobotics research team at CEA LIST. “It can be used to implement sensorless force feedback interfaces”. The absence of friction facilitates control of the articulation force by simply regulating the current fed to the motor. The resulting robot is safer and more reliable, while eliminating the need for expensive force sensors. The robot operates in a very transparent manner, without disturbing natural arm movements. This technology could eventually be marketed by the company Haption (see page 16) and adapted for different fields of use, such as assistance to handicapped persons, functional reeducation, industrial remote control or virtual reality.
