Tension control with and without tension sensors

摘要

State feedback has become a widely used method of controlling dynamic systems such as moving webs. In a state controller the present value of all states (i.e. tension, motor speed, and motor torque for each web span) are used to calculate the output of the controller. Since it is not cost effective to measure all of these states, state observers are often used to estimate some of the states. Typically, the state to be controlled (tension in this case) is measured, and observers estimate the other states. It is possible, however, to measure a state other than tension (e.g. motor speed) and generate an estimate of the tension using the state observer. Tension sensors are not needed if this estimated tension is controlled instead of the actual tension.