Repetitive manual operations can degrade the work efficiency of a human operator over time, with the cumulative stresses of repetitive motion potentially affecting the resultant product quality and/or process efficiency. Accordingly, a lightweight, motorized device has been created that a user/operator may wear on a hand and forearm to augment the innate ability to flex his or her fingers, thumbs, and various connecting phalanges of a hand, thus optimizing the amount of grasping force applied to an object. The amount of augmenting tensile force provided by the motorized device may be controlled by the user via force-based contact sensors positioned at a distal end of each finger. As the operator exerts a grasping force on an object, a microcontroller, which may be embedded within (or connected to) a flexible band or strap portion of the device, automatically executes an algorithm to thereby calculate and/or select an optimal amount of augmenting tensile force required for executing the grasping action.
The device may include a glove portion and a motorized tendon drive system (TDS). The TDS is adapted for applying an augmenting tensile force to one or more individual tendons. The tendons may be connected on one end to a motorized actuator of the TDS, and at the other end to one or more respective phalange support rings circumscribing a distal end of a respective finger(s) or thumb of the operator. The contact sensors may be disposed on a respective phalange support ring, and likewise positioned at the distal end of a respective finger or thumb of the operator.
The grasp assist device includes a glove portion having phalange rings, contact sensors for measuring a grasping force applied by an operator wearing the glove portion, and a TDS. The device has flexible tendons connected to the phalange rings for moving the rings in response to feedback signals from the sensors. The TDS is connected to each of the tendons, and applies an augmenting tensile force via a microcontroller adapted for determining the augmenting tensile force as a function of the grasping force. A method of augmenting a grasping force of an operator includes measuring the grasping force using the sensors, encoding the grasping force as the feedback signals, and calculating the augmenting tensile force as a function of the feedback signals using the microcontroller.
This work was done by Myron Diftler of Johnson Space Center, and Douglas Linn and Chris Ihrke of General Motors. For more information, contact the Johnson Space Center Technology Transfer Office at 281-483-3809. MSC-24741-1