A Low-Cost Soft Robotic Hand Exoskeleton for Use in Therapy of Limited Hand–Motor Function

Abstract

We present the design and validation of a low-cost, customizable and 3D-printed anthropomorphic soft robotic hand exoskeleton for rehabilitation of hand injuries using remotely administered physical therapy regimens. The design builds upon previous work done on cable actuated exoskeleton designs by implementing the same kinematic functionality, but with the focus shifted to ease of assembly and cost effectiveness as to allow patients and physicians to manufacture and assemble the hardware necessary to implement treatment. The exoskeleton was constructed solely from 3D-printed and widely available off-the-shelf components. Control of the actuators was realized using an Arduino microcontroller, with a custom-designed shield to facilitate ease of wiring. Tests were conducted to verify that the range of motion of the digits and the forces exerted at the fingertip coincided with those of a healthy human hand.

Design Criteria of Soft Exogloves for Hand Rehabilitation-Assistance Tasks

“…Proportional (P) [68], proportional-derivative (PD) [100,101], or proportional-integral-derivative (PID) [15,71] controllers are widely implemented for flow and force regulation. Pulse width modulation (PWM) signals have been used to open and close solenoid valves [51] and can be implemented in many control strategies for different applications.…”

“…According to [51], an effective soft exoglove should achieve, without problems, 2 hours of continuous operation or from 4 to 6 hours of intermittent operation. Moreover, the runtime of batteries should be more than one hour in order to guarantee the development of a rehabilitation protocol session [100] until its completion or exert from 15 to 20 minutes of passive guidance [88]. Normally, lithium-polymer batteries are used since they can last 3.8 hours of continuous operation [23,51].…”

“…For instance, authors in [34] propose that the assembly should cost less than $30 USD in order to be a competitive choice. Another proposal establishes that manufactuing and electronics should be less than $200 USD [100]. According to [52], soft exosuits for the upper limb should cost less than $1000 USD, $465 USD for the elbow, and $470 USD for the hand.…”

“…Moreover, the runtime of batteries should be more than one hour in order to guarantee the development of a rehabilitation protocol session [ 100 ] until its completion or exert from 15 to 20 minutes of passive guidance [ 88 ]. Normally, lithium-polymer batteries are used since they can last 3.8 hours of continuous operation [ 23 , 51 ].…”

Hand Rehabilitation and Telemonitoring through Smart Toys

“…The first attempts to use technology to support hand rehabilitation come from the robotic field where instrumented gloves [18][19][20][21][22] and exoskeletons [23][24][25][26] have been proposed, also in combination with exergames. These systems have proven to be very useful when dealing with patients who do not have enough muscle power to move their hands on their own.…”