Hand prostheses commonly advertise on three main selling points: strength, speed and lightweight. Most conventional hand prostheses are only able to combine two of these three attributes. Therefore, combining all three attributes into a single device can result in a commercially
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Hand prostheses commonly advertise on three main selling points: strength, speed and lightweight. Most conventional hand prostheses are only able to combine two of these three attributes. Therefore, combining all three attributes into a single device can result in a commercially attractive hand prosthesis. Another interesting point, particularly for pneumatic prostheses, is the usage time, as historically many have run into problems here and an extended usage time makes it attractive to the user. The goal of this graduation research is, therefore, to design a pneumatically powered hand prosthesis, that combines a high grip strength, a high opening/closing speed and lightweight into a single device, whilst maintaining a reasonable usage time. A hybrid actuated hand prosthesis is designed that combines a finger design based upon the Delft Cylinder Hand, with dual-mode actuation. This dual-mode actuation increases the efficiency of the hand and consist of a CO2 supply with a hydraulic transmission to the fingers. A final prototype of the dual-mode actuation transmission is fabricated and evaluated. Although there is room for improvement in the resistance and timing of the system, the hand has a relatively high pinch force of an estimated 56 N. Furthermore, a grip speed of less than a second makes the hand attractive to be used. With a mass of only 235 grams, the hand weighs less than most of its competitors and is comfortable in use. The dual-mode actuation significantly increases the efficiency of the hand and gives it a usage time of over 400 cycles.