Motion Control Expert Witness

Motion Control Expert

Central to the task of controlling motion is the concept of negative feedback. As an example of negative feedback, consider what happens when you are hungry. Hopefully, you will be able to get something to eat. As you eat, you become less and less hungry until you eventually stop eating. This is the idea of negative feedback. Imagine if the opposite were true and eating made you hungrier.

Negative feedback in a motion control system proceeds in a similar fashion. There is a desired position for the motor and a feedback sensor that tells the motor it is not at the correct position. In effect, it is "hungry" to get to that position and begins turning towards it. As the motor gets closer to the desired position, the feedback device tells the motor that it is becoming "less hungry" and the motor responds by turning more slowly. In a perfect control system, the motor will get to exactly the right position and then will turn no more until it is commanded to a new desired position.

Motion Control includes much more than servo control. Machine setup, for example, involves a very important set of motion control operations. Machine setup includes operations such as setting feed rates, setting offsets, setting limits and writing files. Similarly querying for feed rates, querying for offsets, querying for limits and reading files are important motion control operations. Sending motion start and motion stop commands are further examples of motion control operations. Querying for machine state is another example of an important motion control operation.

I have extensive professional experience designing machines and motion control systems and can support your litigation efforts as a motion control expert witness. My qualifications include numerous peer-reviewed publications and over thirty years of engineering experience with software, robotics, instrumentation, medical devices, computer-controlled machines and factory automation. 

I accept a small number of litigation support engagements to complement my regular work as a professional engineer designing automation and motion control systems.


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