# A Low-Cost Soft Robotic Hand Exoskeleton for Use in Therapy of Limited Hand-Motor Function
## 4 Discussion  
The results verify that the range of motion of the digits and the forces exerted at the fingertips coincide with those of a healthy human hand. While it cannot be expected for a soft-robotic hand exoskeleton driven by external anchored soft tendons to exactly mimic a healthy individual's natural range of motion, the results show that our design can do so successfully with a low relative error. The satisfactory results, coupled with the fact that our soft robotic hand exoskeleton is built entirely out of commercial-off-the-shelf components on a budget of less than $200 make our design unique and accessible in an ecosystem of proprietary, close-sourced, bulky and unaffordable options. Compared to the two previously mentioned non-customizable commercially available systems, The Hand of Hope [17; 30] and Festo Exohand [31], our design provides an improvement in several respects. Both of these designs use serial link manipulators to actuate fingers, while our design uses compliant soft tendon-driven actuation, while improving on the limited range of motion in the metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints. Although our design is like the Festo Exo-Hand [31] in respect to user-specific dimensioning through the use of 3D scanners and a laser sintering process, the improvement is in our design's portability and total weight. When compared to the soft robotic glove of [PERSON] et al. [32], although our designs are similar in the robotic exoskeleton design's pliability, their fabrication method using custom designed, naturally compliant soft-actuators and custom-molded, hydraulically controlled actuators created from a soft silicone rubber compound reinforced with mesh is much more complicated and arduously replicable by lay end-users. Their systems also require attachment to a hydraulic pump weighing over 3 kg for untethered use, while our system is portable and untethered by design weighing less than 400 g, including the weight of the battery, which is 132 g alone. What makes our soft robotic exoskeleton truly unique from the competition are not only its low cost, portability and accessibility, but also the therapy modality. Our platform benefits from our web-based patient-doctor interface, as shown in Figure 13. Much of the research that has been done on rehabilitation robotics has focused solely on the accuracy of the kinematics and dynamics of the mechanical system. This volume of research and development has produced a myriad of solutions that often remain inaccessible to patients not only due to their cost and/or weight but, most importantly, because they were simply not built to be standalone take-home solutions, meant to be used with minimal guidance from physicians. The key to a successful therapy regimen is consistency,a requirement often met with difficulty by patients in remote areas, with limited mobility and access to modern medical services. By making an accessible device that can be consistently used by patients with minimal supervision from therapists, we would only tackle half of the problem. We believe that a readily available communication channel between patients and their physicians is equally important to the successful implementation of robotic therapy regimens. The cloud-based telemedicine platform, illustrated in Figure 13, consists of smartphone applications for therapists and patients enabling first and foremost direct communication between the users as well as remote control of the medical device. The platform enables real-time control of the medical device by the practitioner, effectively enabling them to prescribe and execute a live therapy session for the patient. Alternatively, the prescribed regimen could be executed remotely by the patient at their own convenience later. The platform may store personal device calibrations and diagnostic data so that the therapists can be assured that the medical device is fit to perform the duty of remotely assisted physical therapy.