STRESS AND LOAD VARIATION DETECTOR
A method and apparatus to detect variations in load by comparing signals related to, but not necessarily accurately correlated with, stress/strain states of a load transmitting member. In one embodiment, a first signal (30) is obtained relating to the time rate of change of stress in the member produced by a first loading event or series of events. A second signal (34) is obtained which relates to the time rate of change of stress in the member produced by a second loading event or series of events. The first and second signals are compared (40) to detect significant variations (42) in loading. Each of the two signals may be a composite of other signals. A magnetostrictive sensor may preferably be used to obtain the signals relating to the stress in the load transmitting member. The load may be applied force, stress, strain, or deflection. Environments for use include brake pedal and suspension system.