SPIE Proceedings [SPIE Sixth International Symposium on Instrumentation and Control Technology: Sensors, Automatic Measurement, Control, and Computer Simulation - Beijing, China (Friday 13 October 2006)] Sixth International Symposium on Instrumentation and Control Technology: Sensors, Automatic Measurement, Control, and Computer Simulation - Chaos control for nonlinear system of a gear pair with backlash using the constrained feedback method