problem    statement   usually   leads  to  what is commonly   called  "blank   paper   syndrome." Engineers   often  find  themselves   staring at a blank  sheet  of paper  pondering   how  to begin  solving  such  an  ill-defined   problem.

Much of engineering education deals with topics of analysis, which means  to  de- compose, to take apart, to resolve into its constituent parts. This is quite necessary. The engineer must know how to analyze systems  of  various  types,  mechanical,  electrical, thermal, or fluid. Analysis requires a thorough understanding of both the appropriate mathematical  techniques  and  the  fundamental  physics  of  the  system's  function.  But, before any system can be  analyzed,  it must  exist,  and  a blank  sheet  of paper  provides  lit- tle  substance  for  analysis.   Thus  the  first  step  in any  engineering   design  exercise  is that of synthesis,    which  means  putting  together.

The design engineer, in practice, regardless of discipline,  continuously  faces  the challenge  of structuring  the  unstructured  problem.   Inevitably,   the  problem   as posed to the  engineer  is ill-defined  and  incomplete.   Before  any  attempt  can  be  made  to analyze the situation he or she must first carefully define the problem,  using  an engineering  ap- proach, to ensure  that  any  proposed  solution  will  solve  the  right  problem.  Many exam- ples exist of excellent engineering solutions which were ultimately  rejected  because they solved  the  wrong  problem,   i.e.,   a different   one  than  the  client  really had.

Much research has been devoted to the definition of various  "design  processes"  in- tended to provide means to structure  the  unstructured  problem  and  lead  to a viable  solu- tion. Some of these processes present dozens of  steps,  others  only  a few.  The  one  pre- sented  in Table  1-1 contains  10 steps and has, in the author's  experience,  proven   success- ful  in over  30 years  of practice  in engineering     design.

ITERATION  Before  discussing   each  of these  steps  in detail  it is necessary   to  point out that this is not a process in which one proceeds from step one through ten in a  linear fashion. Rather it is, by its  nature,  an  iterative  process  in  which  progress  is made halt- ingly, two steps forward and one step back. It is inherently  circular.  To iterate  means to repeat, to return to a previous state. If, for example,  your  apparently  great  idea, upon analysis, turns out to violate the second law of thermodynamics,  you  can  return  to the ideation step  and  get  a better  idea!  Or,  if necessary,  you  can  return  to an  earlier  step in the process,  perhaps  the  background  research,  and  learn  more  about  the  problem.  With the  understanding  that  the actual  execution  of the process  involves  iteration,  for simplic- ity, we  will  now  discuss  each  step  in the  order  listed  in Table  1-1. 连杆机构英文文献和中文翻译(2):http://www.youerw.com/fanyi/lunwen_79963.html