Comparison of input shaping techniques for speed-critical multi-mode flexible systems

To achieve the highest level performance with computer controlled machines, the flexibility of the system must be taken into account. Feedforward methods are often the most desirable means of eliminating vibration. The fastest motions can be obtained by using the time-optimal flexible-body command. These commands depend on the system parameters, actuator limits, and the desired motion. Input shaping is another feedforward method which does not depend on actuator limits and motion parameters, only the system natural frequencies and damping ratios. Input shaping and time-optimal control are compared for use on multi-mode flexible systems. The two methods are compared in terms of moving speed, robustness to modeling errors, transient deflection, and ease of implementation.