Subsystem was developed which provides twelve waveform controls to breath drive mechanism. Twelve position, magnetically actuated rotary switch is connected to one end of crankshaft drive, such that it makes one complete revolution for each simulated breath. Connections with common wired point are included in modifications made to standard motor speed controller

Bartlett, R. G.

Hendricks, C. M.

Morison, W. B.

English

NASA Technical Reports Server

December 1972
	 B72-10661 
NASA TECH BRIEF 
NASA Headquarters 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating tothe Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Simulated Breath Waveform Control 
The problem: 
For proper simulation of human breathing, the breath-
ing metabolic simulator (see Notes) required a subsystem 
to control the bellows driving mechanism which repro-
duced the exhaled breath. The signal supplied to the 
mechanism had to be a nonsymmetrical periodic wave- 
form which would reproduce a complete range, from 
normal breathing to forced exhalation. 
The solution: 
A subsystem was developed which provides twelve 
waveform controls to the breath drive mechanism.
How it's done: 
A twelve position, magnetically actuated rotary switch, 
shown in the figure, is connected to one end of the 
crankshaft drive such that it makes one complete revolu-
tion for each simulated breath (1:1 gearing). The switch is 
wired so that a different connection to a common point is 
maintained through each thirty degrees of crankshaft 
revolution. These
 are included in the modifi-
cations made to a standard motor speed controller. 
Since the bellows drive motor operates the crankshaft 
through a 30 percent gear reduction, each speed adjust-
ment is effective for two and one-half motor revolutions. 
IliijIuu	 Modification	 aifi.	 Existing - 
Total of 12 Waveform Con0trols 
Each Effective During 30 Of 
Crankshaft Revolution 
/ 
in	 Existing 
Regulator 
50 
Mm. Speed
800j 
Breath Rate Adjust 
1500
- Hpp 6 
Mounted To Crankshaft
Of Breath Drive Mechanism
pp
----12 Potion Rotary Switch
(Magnetically Activated,

One At A Time.)
Max. Speed Adjust
10K 
-H
To Controller 
Speed Regulator 
Note: All Resistances Are In Ohms 
15K 
Modifications To Motor Controller 
I	 (continued overleaf) 
/ \	 This document was prepared under the sponsorship of the National
	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States
	 information contained in this document, or warrants that such use 
Government nor anyperson acting on behalf of the United States
	 will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19720000660 2020-03-17T03:42:49+00:00Z
Inertia in the crank, gear train, and motor itself smooths 
the effects of transfer between segments. The twelve 
segments allow independent control of wave shape adjust-
ment for simulated inhalation and exhalation, the slope of 
bellows position, and simulated breath velocity contours. 
The simulated breath waveform control has several 
unique features: 
1. Breath waveform may be adjusted to conform to any 
reasonable simulation of actual human performance 
without changing the simulator configuration. This 
permits rapid changes in test conditions. 
2. Breath waveform may be adjusted remotely. This 
permits changes in simulated loadings without an 
interruption of the test environment conditions.
Notes: 
1. Additional information is contained in the following 
Tech Briefs: B72-10657 (HQN- 10766), B72-10658 
(HQN-10776), B72-10659 (HQN-10777), and 
B72-10660 (HQN-10778). 
2. Requests for further information may be directed to: 
Technology Utilization Officer 
NASA Headquarters 
Code KT 
Washington, D. C. 20546 
Reference: B72-10661 
Patent status: 
NASA has decided not to apply for a patent. 
Source: R. G. Bartlett, C. M. Hendricks, 
and W. B. Morison of
IBM Corp.
under contract to
NASA Headquarters
(HQN- 10779) 
B72-10661	 Category 05


Simulated breath waveform control

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