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Table 2 Terminal device related observations

From: Case-study of a user-driven prosthetic arm design: bionic hand versus customized body-powered technology in a highly demanding work environment

Task TBI (iLimb) CBPA (body-powered) - Hosmer hook 5XA CBPA (body-powered) - TRS adult prehensor CBPA (body-powered) - Becker hand
Loading car, carrying items for more than 8m distance. Useful grip for cut out box handles, not useful for recessed grip grooves. Limb positioning effect [90, 91] with sudden dropsa. No problem. Great balance for posturec. No problem. Requires focus to keep cable tense (VC paradigm). No problem. Great balance for posture.
Taking notes holding notepad in the field Feasible but not ideal. Clumsy grip types with unforeseeable force vectorsb. No problem.c No problem but requiring focus to keep cable tense (VC paradigm)b. No problem.
Undressing body Grip by far too weakb. Good support, finding right angle for best grip requires attentionb. Perfect support, top application domain for VC control paradigm.c Perfect support due to shape and built-in grip lock.
Turning or transporting body (Fig. 11a-h) Grip by far too weak. Suspension started to come offb. Good support, but grip forces sometimes not large enoughb. Perfect support, top application domain for VC control paradigm.c Good support, but grip forces sometimes not large enoughb.
Lab work (Fig. 11i-k) Grip too weak. Limb positioning effect [90, 91] with sudden dropsa. Unforeseeable grip force vectors [93]b. Good support, but grip forces sometimes not large enough. Perfect support, top application domain for the VC control paradigmc. Good support, but grip forces sometimes not large enough.
Cleaning, disinfecting terminal device. Costly thin cosmetic glove not to be replaced by user; no work rubber glove to be worn according to manufacturer [89]. Metal split hooks easy to swap or disinfect. Wearing thick rubber glove over hook device not technically difficult and not prohibited by manufacturer. Wearing rubber glove fingers to TRS prehensor allows for easy disinfection; not prohibited by manufacturer specifications. Becker hand fits humanly used rubber protection gloves, that can be worn as they both fit well and are not prohibited by manufacturer specifications.
Typing COG too far in front, device too heavy. Device shape and weight cause shoulder pain. Suspension results in severe friction problems on stump skin after long typingab. Perfect.c Good, but Hosmer 5XA has the better angleb. COG too far in front, and Hosmer 5XA has the better angleb.
Meetings, presentations Grip problems as the hand does not handle large pens with difficult to tear of caps well. Loud source of distraction [96, 97]b. Handles paperwork and pens well. Handles paperwork and pens well. Perfect, least amount of distraction with grip suited well to typical tasksc.
Soft covers for terminal device Gloves very thin to avoid impeding hand mechanism. Perforating damage [87], as soon as 10 min into light work. Approved gloves costly, only sold by manufacturer. Silicone tubing affordable, easy to mount, enhance form closure. Under full work load, replace after 1–2 weeks. Sheet rubber, double sided tape and work glove nitrile fingers are placed on the claws to enhance form closure. Under full work load, replace after 1–2 weeks. Fits humanly worn normal work gloves such as nitrile work gloves to enhance form closure and grip. Under full work load, replace after 1–2 weeks.
  1. aNot acceptable / not negotiable in work environment (e.g. due to item being costly or irreplaceable or hazardous or trace relevant or contaminant)
  2. bIs performed just as well or better without prosthesis with result focus on task. VC: voluntary closing
  3. chighlight best choice for terminal device (where applicable)