Application of the Kalman Filters in the Self-Commissioning High-Performance Drive System with an Elastic Joint

Torsional vibrations limit the performance of many industrial drives. They decrease the system reliability, product quality in some specific cases they can even lead to instability of the whole control structure. The problem of damping of torsional vibrations originates from the rolling-mill drive, where large inertias of the motor and load parts with a long shaft create an elastic system (Hori et al., 1999), (Szabat & Orlowska-Kowalska 2007), (Pittner & Simaan, 2008). Similar problems exist in paper and textile industry, where the electromagnetic torque goes through complex mechanical parts of the drive (Valenzuela et al., 2005). The damping ability of the system is also a critical issue in conveyer and cage-host drives (Hace et al., 2006). Originally the elastic system has been recognized in high-power applications. However, due to the progress in power electronic and microprocessor systems, which allow controlling the electromagnetic torque almost without delay, the torsional vibrations appear in many medium and small power applications. Today they are acknowledged in servo-drives, throttle drives, robot arm drives including space applications, and others (Hamamoto et al., 2003), (O’Sullivan et al., 2007), (Shen & Tsai, 2006), (Katsura & Ohnishi,, 2005) and (Vasak et al., 2007). Since the classical PI controller is not effective in the two-mass drive system different control concepts have been developed. As has been shown in (Zhang & Furusho, 2000), the application of the PID controller ensures effective suppression of the torsional vibrations. This approach is easy to implement and designated for the system with an accurate speed sensor. Torsional vibrations can be damped effectively by inserting additional feedback from selected state variable(s) of the two-mass system. The survey of those structures is presented in (Szabat & Orlowska-Kowalska 2007) and (Nordin & Gutman, 2002). The structure with one additional feedback can damp the torsional vibration effectively, yet the settling time of the system cannot be set freely. The more advanced control concept relies on the inserting of all states of the control structure, which allows the free location of the system closed-loop poles. The cascade control structure with two additional feedbacks or the structure with the state controller are illustrated in (O’Sullivan et al., 2007) and (Szabat & Orlowska-Kowalska, 2008). Also the nonlinear and adaptive control have been proposed to control the two-mass system in order to eliminate the effect of the parameter uncertainties and disturbances e.g. in papers O pe n A cc es s D at ab as e w w w .in te ch w eb .o rg