Control Engineering

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Steam Powered Servo Motor
May 9, 2008

STEERING ENGINE  (Steam Servomechanism)
Negative feedback is one of the magical elements used by automation and control engineers, well at least it seems magical to people are seeing it for the first time. The difference between the position of where something is and where you would prefer it to be can be used as a control signal to correct the difference or error. The principles of cybernetics and servomechanism control were established long before electricity and electronics came onto the scene. Over the years, it has been my job to certify the proper operation and repair steam servomechanisms that move and hold the position of the rudders on steamships. The steering engine is one of the most fascinating pieces of machinery on a ship to watch in operation because it is precision machined of metal with massive cross section, amazingly powerful, yet precise in its movement. Rudders usually move only sixty degrees, thirty degrees left or right of center and this is accomplished in six to ten revolutions of the pilothouse steering wheel. The movement of the steering wheel, through the follow-up mechanism, admits steam to the steering engine and it is the motion of the steering engine, through the follow-up mechanism, that cuts off the steam when the steering wheel is brought to a halt. The follow-up mechanism is composed of a threaded shaft and a threaded gear, both of which turn. The steering wheel turns the threaded gear which pulls or pushes the threaded shaft linked to the steam control valve and the movement of the steering engine rotates the threaded shaft to return the control valve to the neutral position. A good example of this action can be demonstrated in the workshop with a bolt and nut. If you turn the nut and the bolt in the same direction at the same time there is no relative motion. If you turn one or the other there is relative motion. The distance and direction from neutral is the error signal, which operates the control valve.



THE VALUE OF AUTOMATION
Bruce Soloway of Northern Oil & Mill (no web page), which produces vegetable oil for use as diesel fuel, estimates that automating his plant to make it a continuous process rather than a batch process would allow his company to process two or three times as much oil a day as it is now processing. More economical production of farmer grown fuel for diesel engines is in everyone's best interest and here is a measure of what automation is worth to the customer. The biodiesel market now and for the near future is consists of a series of small plants scattered around the country, close to the sources of the materials and the customers who would use it. The owners of these small plants will each need the assistance of automation and control engineers to automate their copy of the manual process. Each of them then will probably build additional small plants in order to expand, rather than one centrally located large plant. The automation consultants who learn how to automate these small plants and deal with the small but numerous customers should do quite well financially. You might even opt to take your payment in the form of fuel which you could either use or convert to cash easily.

INDUSTRIAL FILMS - REAL LIFE DRAMA
Consider for a moment what you or your co-workers do in a day. Would documenting the best parts of this inspire young people to want to do the job that you and your fellow workers do? Do you have professional advice that you would want to share with others in your field or profession? Well if you have thought of this before and decided not to; take a fresh look again at the project, especially if you could produce the film in Michigan. The new financial incentives offered by the Michigan state government change the economics quite a bit. With 42% of your production cost rebated, along with 50% of wages paid available, as a training rebate, along with about 15 other cash incentives - if you ever thought of making a movie the balance has shifted making it easier than it was before. One of the additional incentives, which is not cash, but could cut your costs considerably, is free use of Michigan owned property. The Department of Natural Resources has some exotic looking vehicles; the National Guard has military vehicles, etc. etc. With all of this available, I am sure some of us could think of a way to make use of it... and make some money to cover our expenses doing it. If your idea would have just barely broken even before, it should make a substantial profit now. The educational value, the inspirational value, the PR value, the fun of making an industrial short film could help the Michigan economy - which still leads the nation in number of workers available for hire.


Sandra, AIM Support Staff volunteer taking a turn at the truck's steering wheel.

GO ROBOTS !

Paul F. Grayson - Chief Engineer
AMERICAN INDUSTRIAL MAGIC, LLC
Racing to build technology that saves soldier's lives.
390 4-Mile Rd. S.
Traverse City, MI 49686-8411
(231) 946-0187, (231) 883-4463 Cell
pgrayson@aimagic.org  
AIM: http://aimagic.org  
Robot Club: http://tech.groups.yahoo.com/group/robotcluboftraversecitymi/  
CE Magazine: http://www.controleng.com/blog/1180000318.html  

Posted by Paul Grayson on May 9, 2008 | Comments (0)