Browsing by Author "Plettenberg, Dick H."

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    PROSTHETIC ACTUATION: A CASE FOR PNEUMATICS.
    (2002) Plettenberg, Dick H.
    Electrically actuated hand prostheses have the disadvantage of a high prosthetic mass, a slow cycle time, vulnerability, and an excessive volume. Pneumatical actuation can overcome these disadvantages. To demonstrate the feasibility of pneumatic actuation a pneumatically powered hand prosthesis has been developed. A careful assessment of the system choice, the friction losses, the dead spaces, and the supply pressure level resulted in a low gas consumption, enabling the use of small disposable gas containers. The mass of the hand mechanism is 60 grams, the operating cycle takes less than one second, the hand size is comparable to the hand of a 2.5 – 4 year old child, and the prototype functioned well in the laboratory for over 75000 cycles. These results show that pneumatic actuation of hand prostheses excels electrical actuation.
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    PROSTHETIC CONTROL: A CASE FOR EXTENDED PHYSIOLOGICAL PROPRIOCEPTION.
    (2002) Plettenberg, Dick H.
    To achieve subconscious prosthetic control the patient feedback present must be employed as completely as possible. This implies the use of control methods based upon the principles of extended physiological proprioception. The harnessing of body movements has the inherent ability to fully employ the principles of extended physiological proprioception. However, the present harnessing techniques often fail to do so and are generally of a dreadful engineering quality. Myoelectrical control must be considered as an open loop system. It lacks by principle any useful feedback. The challenge for the prosthetic profession is to focus research on [improvement of] control options that comply with the rules of extended physiological proprioception. Promising future control options may result from the research into miniature cineplasties, in combination with neuro-muscular reorganization, and from the research into neuroelectrodes.
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    THE WILMER APPEALING PREHENSOR
    (2005) Plettenberg, Dick H.
    A new type prosthetic prehensor for children aged 4 – 9 has been designed, constructed and build in an attempt to improve the appearance of the split-hook prosthesis. The new prehensor is a mechanically operated voluntary opening device. All mechanical parts are within the frame, and covered by a polyurethane cosmetic cover, which can be made in almost any color desired. Clinical testing of the prehensor by 4 children with a total time of use of over 170 months, revealed the mechanism to be very robust and reliable. The colorful hook cover is highly appreciated by the children. Encouraged by this success, a second larger size has been made intended for children aged 7 - 14. This medium size prehensor is now in clinical use by 1 child for over 12 months. Again, the appearance of the hook is highly appreciated, and again, the mechanism proves to be very reliable.