Using nonlinearity blocks the backlash

8 Using nonlinearity blocks the backlash description of valve static friction 

Nonlinear blocks can be very useful aids to programming controller functions, and their use will be discussed in this section. The backlash function will 

The valve travel, x, will follow the quantizer output, z, after an exponential time lag. 

05 as c rises to 0.1. This portion of the graph can be traversed only once, since it is impossible thereafter to reduce z below the value of 0.05 given that the lowest value permitted for controller output, c, is 0.0.] 

The control valve actuator will now respond to the backlash output. Assuming that the valve s velocity limit is not transgressed, the equation governing valve travel in a system with backlash is found by replacing c with z in equation (22.53)  

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