TABLE OF CONTENTS "The proof of the pudding is in the eating," as the saying goes, and the proof of a cam-follower system's performance is in the testing. The dynamic performance of internal combustion (IC) engine cam-follower systems is usually measured in some fashion during their development, but this is less often done for cam-follower systems that are used in industrial machines. When it is done in either venue, the results seldom bear very close resemblance to the theoretical follower motions as designed. (Though, if the system was dynamically modeled, the test data should look similar to the model's simulated results.) There are many reasons for the disparities between theory and experiment, some of which were mentioned in Chapter 14 on cam manufacturing. Other issues will be discussed here.
Significant improvements in measurement technology have occurred in recent years. Dynamic phenomena such as angular position, follower displacement, velocity, acceleration, force, and strain can be measured with very good accuracy, high bandwidth, and excellent repeatability at relatively low cost. This is mainly due to advances in microprocessor and integrated circuit technology that have significantly affected transducer design. The high speed computational capability of modern microcomputers also makes it possible to do extensive analysis of dynamic measurements in real time and use the results for machine or process control as well as for off-line analysis.
Many types of transducers are available for the measurement of dynamic parameters relevant to cam-follower performance. Some of them will be described briefly here.
