Skyler A. Dalley

Design of a Multifunctional Anthropomorphic Prosthetic Hand With Extrinsic Actuation

This paper presents an anthropomorphic prototype hand prosthesis that is intended for use with a multiple-channel myoelectric interface. The hand contains 16 joints, which are differentially driven by a set of five independent actuators. The hand prototype was designed with the minimum number of independent actuators required to provide a set of eight canonical hand postures. This paper describes the design of the prosthesis prototype, demonstrates the hand in the desired eight canonical postures, and experimentally characterizes the force and speed capability of the device. A video is included in the supplementary material that also illustrates the functionality and performance of the hand.

A Method for the Control of Multigrasp Myoelectric Prosthetic Hands

This paper presents the design and preliminary experimental validation of a multigrasp myoelectric controller. The described method enables direct and proportional control of multigrasp prosthetic hand motion among nine characteristic postures using two surface electromyography electrodes. To assess the efficacy of the control method, five nonamputee subjects utilized the multigrasp myoelectric controller to command the motion of a virtual prosthesis between random sequences of target hand postures in a series of experimental trials. For comparison, the same subjects also utilized a data glove, worn on their native hand, to command the motion of the virtual prosthesis for similar sequences of target postures during each trial. The time required to transition from posture to posture and the percentage of correctly completed transitions were evaluated to characterize the ability to control the virtual prosthesis using each method. The average overall transition times across all subjects were found to be 1.49 and 0.81 s for the multigrasp myoelectric controller and the native hand, respectively. The average transition completion rates for both were found to be the same (99.2%). Supplemental videos demonstrate the virtual prosthesis experiments, as well as a preliminary hardware implementation.

Design of a multifunctional anthropomorphic prosthetic hand with extrinsic actuation

This paper presents an anthropomorphic prototype hand prosthesis that is intended for use with a multiple channel myoelectric interface. The hand contains 16 joints, which are differentially driven by a set of five independent actuators. The hand prototype was designed with the minimum number of independent actuators required to provide a set of eight canonical hand postures. This paper describes the design of the prosthesis prototype, demonstrates the hand in the desired eight canonical postures, and experimentally characterizes the force and speed capability of the device. A video is included in the supplemental material that also illustrates the functionality and performance of the hand.

A multigrasp hand prosthesis for transradial amputees

This paper presents the design of a multi-degree-of-freedom, anthropomorphic hand for transradial amputees, and also presents experimental data characterizing its performance. Unlike state-of-the-art commercially available prosthetic hands, the hand described herein is capable of providing eight canonical postures (and movement between these postures). The experimental characterization includes its capability to provide eight canonical grasp postures; the frequency response of finger motion; and its grasping force capability (as a function of finger position). Other performance specifications, such as total mass and audible noise, are also provided.

A Multigrasp Hand Prosthesis for Providing Precision and Conformal Grasps

This paper presents the design of an anthropomorphic prosthetic hand that incorporates four motor units in a unique configuration to explicitly provide both precision and conformal grasp capability. The paper describes the design of the hand prosthesis, and additionally describes the design of an embedded control system located in the palm of the hand that enables self-contained control of hand movement. Following the design description, the paper provides experimental characterizations of hand performance, including digit force capability, bandwidth of digit movement, physical properties such as size and mass, and electrical power measurements during activities of daily living.

Design of a Multigrasp Transradial Prosthesis

This paper describes the design and performance of a new prosthetic hand capable of multiple grasp configurations, and capable of fingertip forces and speeds comparable to those used by healthy subjects in typical activities of daily living. The hand incorporates four motor units within the palm, which together drive sixteen joints through tendon actuation. Each motor unit consists of a brushless motor that drives one or more tendons through a custom two-way clutch and pulley assembly. After presenting the design of the prosthesis, the paper presents a characterization of the hands performance. This includes its ability to provide eight grasp postures, as well as its ability to provide fingertip forces and finger speeds comparable to those described in the biomechanics literature corresponding to activities of daily living.

Preliminary functional assessment of a multigrasp myoelectric prosthesis

The authors have previously described a multigrasp hand prosthesis prototype, and a two-site surface EMG based multigrasp control interface for its control. In this paper, the authors present a preliminary assessment of the efficacy of the prosthesis and multigrasp controller in performing tasks requiring interaction and manipulation. The authors use as a performance measure the Southampton Hand Assessment Procedure (SHAP), which entails manipulation of various objects designed to emulate activities of daily living, and provides a set of scores that indicate level of functionality in various types of hand function. In this preliminary assessment, a single non-amputee subject performed the SHAP while wearing the multigrasp prosthesis via an able-bodied adaptor. The results from this testing are presented, and compared to recently published SHAP results obtained with commercially available single-grasp and multigrasp prosthetic hands.

Design of a hand prosthesis with precision and conformal grasp capability

This paper presents the design of an anthropomorphic prosthetic hand that provides both precision and conformal grasp capability. Specifically, the design of the hand dedicates three actuators in a direct-drive manner to achieving precision grasp capability. The design additionally dedicates one actuator and six degrees of freedom, in addition to a compliant coupling, to providing a conformal grasping capability to the amputee. The design of the hand is described in this paper, and the various degrees of actuation are characterized with respect to grasp forces and finger speeds.

Functional assessment of the Vanderbilt Multigrasp myoelectric hand: a continuing case study.

This paper presents a case study involving the functional assessment of the Vanderbilt Multigrasp (VMG) hand prosthesis on a single transradial amputee subject. In particular, a transradial amputee subject performed the Southampton Hand Assessment Procedure (SHAP) using the hand prosthesis and multigrasp myoelectric controller in a series of experimental sessions occurring over a multi-week time span. The subjects index of function (IoF) improved with each session, although essentially plateaued after the fourth session, resulting in a IoF score of 87, which compares favorably to SHAP scores published in previous studies.

Functional assessment of a Multigrasp Myoelectric prosthesis: An amputee case study

This work presents a functional assessment of the Vanderbilt Multigrasp Hand prosthesis and Multigrasp Myoelectric Control method which the authors have previously described. In the study, a transradial amputee utilized the prosthetic system to perform the Southampton Hand Assessment Procedure (SHAP), which involves manipulation tasks designed to simulate the activities of daily living. The results of the study indicate 81% restoration of typical hand function and compare favorably to recently published SHAP results for commercially available single-grasp and multigrasp prosthetic hands. A video of the assessment is included as supplementary material.