The “Work Statement” for a mechatronic system is a very complex undertaking. From the theory standpoint there is no single systematic explanation that can serve as a guideline to assist us in creating a high quality work statement. This is a major problem because the work statement is the most critical means of understanding the requirement correctly.
Maybe the reason a work statement is not popularly used is because in the field of mechatronics it can encompass a wide range of information. This has lead some manufacturers to generate incredibly long and complication application forms for electric motors. To be effective, these forms need to anticipate every possible constraint on the equipment. Even altitude of elevation get a line. Let’s face it, above 5000 feet of elevation, the air is thinner and thermal dissipation in an extremely high load can be an issue.
We need to try and come up with a flowchart or something to assist this process. This is because understanding the work statement is key to navigating the technology trade off, at least to facilitate coming up with good choices to evaluate. This stage is crucial in defining solutions that work and are cost effective at the same time. As part of the cost aspect we should include life cycle cost and certain types of cost avoidance.
Can we get some guidelines in place for a competent work statement? There would have to be a good description of the mechanical work to be performed. How much inertia, what rate of acceleration, maximum speed, what kind of deceleration, what is the duty cycle or “on time” of the application? Note that many of these parameters have a significant dependence on time. Time is the dimension that ties everything together.
Inertia has an incredible impact on the work statement. Across a range of loads, high inertia systems have definite limits that are based on the physics of moving large masses. An 800 pound roll of newsprint will only accelerate as fast as the inertia will allow because the energy necessary to increase the acceleration profile is increasing arithmetically as the time to accelerate is decreased.
Mechanical work is just the starting point. Then there are all the environmental conditions. What is the ambient operating temperature, temperature range, air flow, humidity, exposure to caustic chemicals for food industry wash down protocols, hazardous chemicals, explosive atmospheres, etc. Guys in the Navy can tell you amazing stories about the difficulties of dealing with salt water corrosion or the problems of controlling shipboard magnetic contactors when a ship is hit by a torpedo. Aerospace rated hydraulic actuators are sometimes required to be backed up with hand operated components, and the electronics used in aircraft have to be tested to many G’s of acceleration to insure they don’t fail or come apart in the real world.
Hopefully this is a decent starting point for creating a tool that works.