Integrated Control Document

Written by: Luis Martinez

Approved by: Carolina Barrera

The purpose of the Integrated Control Document (ICD) between the Prosthetic Arm and Prosthetic Hand systems, as an integrated Upper-Limb Prosthetic System, is to capture essential categories of interaction between both systems upon their unification. This document details explicit responsibilities and agreements between each of the respective groups, and serves as an approved reference document for both project groups to refer to, as a standard for design objectives shared amongst both groups.

Of key regard amongst shared transactions between both groups are those for power, attachment, mass, size, and volume accommodation. Below is a high-level description of these categories:

Power – The Prosthetic Arm will supply power to the Prosthetic Hand via 3x, 22 AWG cables (12V, 5V, GND), allowing up to 3500 mA on 12V, and 1000 mA on 5V from a 1600-mAh, 14.8-V Lithium-Ion Polymer (LiPo) battery stored in the bicep of the Prosthetic Arm system.

Attachment – The Prosthetic Hand will be responsible for allocation of the wrist, of dimensions 76.2 mm x 76.2 mm ± 12.7 mm (3 in x 3 in ± 0.5 in margin). The mounting interface between both systems will be a squared, plated-screw type consisting of 4x, 4-mm screws and a hollow center, allowing the Prosthetic Arm to feed power cables to the Prosthetic Hand in such a way that they are not operationally inhibited by the rotation of the wrist. Furthermore, the Prosthetic Hand will be responsible for any cabling related to storage of their micro-controller (MCU) and printed circuit board (PCB) components within the Prosthetic Arm portion of the integrated system.

Mass – The forearm, hand, and food sustained by the Upper-Limb Prosthetic System should not exceed a combined weight of 6.83 lbs. to correspond with a torque of 10.634 NM at 35 cm for the stepper motor localized at the elbow by the Prosthetic Arm. From this, the Prosthetic Hand will have an allocation of 1.35 ± 0.23 kg (2.97 ± 0.5 lbs.), with an expected weight for the heaviest food item (21 fl oz. drink) at 0.69 kg (1.52 lb.). Overall, the system should be no heavier than 4.0 ± 0.61 kg (8.82 ± 1.35 lbs.).

Size – The Prosthetic Arm, in conjunction with the Prosthetic Hand should be no longer than 35 cm ± 5 cm (13.78 in ± 1.55 in) from elbow to tip of middle finger, from which the Prosthetic Hand will measure 269 ± 13 mm (10.6 in ± 0.51 in) from end of wrist/ forearm attachment to tip of middle finger.

Accommodation (Volume) – As referenced above, the Prosthetic Arm will provide space accommodations for the MCU, PCB units of the Prosthetic Hand, of dimensions 83 mm x 64 mm x 38 mm (3.25 in x 2.5 in x 1.5 in) in effort to alleviate space constraints faced by the Prosthetic Hand.

After the Preliminary Design Review (PDR), suggestions from the customer and class presidents were taken into consideration by both groups, and agreements were reached with respect to the following new categories:

• Noise: Prosthetic Arm, in conjunction with Prosthetic Hand, will not exceed 60 dB during operation.
• Safety: Prosthetic Arm will implement an electronic kill switch to disconnect the power supply to the Prosthetic Hand and the Upper-Limb Prosthetic System in the case of a perceived emergency situation or safety concern.
• Schedule: Prosthetic Arm and Prosthetic Hand groups will have their respective systems ready for integration by an agreed-upon tentative date of Saturday, 11/19/16
• Aesthetics: Prosthetic Arm, in conjunction with Prosthetic Hand, will have a matching outer appearance, such that in the case of wearing a sleeve and glove respectively, the Upper-Limb Prosthetic System will not attract unwarranted attention.

Moving forward, certain category estimates will be refined, such as the estimated noise threshold to correlate with experimental studies from a McDonalds site visit, and an integrated temperature sensor in the circuitry of the Prosthetic Arm that will be programmed to detect significant deviations from the operating temperature of the Upper-Limb Prosthetic System once integration has been achieved.

Furthermore, an option to vacuu-form, in terms of aesthetics, is being explored by the Prosthetic Arm system in collaboration with the CSULB Design Department pertaining to guidance and permission to use related facilities and equipment. Further changes to this approved document will be submitted for approval, and captured as supplemental revisions.