An Examination of the Trajectories Traveled by Two-Mode Flexible Systems

J. de Juanes Márquez (Spain), D. Kim, and W. Singhose (USA)


Vibration, Oscillation, Input Shaping, Crane Control


Problematic flexibility in machinery can arise from the physical hardware or from the feedback controller. In either case, the effect of the flexibility must be reduced to be low a tolerable level so that the system can be positioned to within some specification. Flexibility can pose even bigger challenges when the system is required to follow precise spatial trajectories, rather than just perform point-to-point motion. In cases where trajectory following is required, the performance specifications are more complex than for point-to-point motion. Simple performance measures such as step-response rise time, overshoot, and settling time may not be enough to ensure satisfactory performance. The system performance must be accessed in terms of deviations throughout the intended trajectory. This paper examines the trajectory-following performance of systems that contain two flexible modes. The responses of such systems to standard trapezoidal velocity profiles are examined as a function of both system parameters and spatial trajectory parameters. The effect of input shaping the commands is then examined. The contribution is insight into how two mode flexible dynamics affect trajectory tracking and how input shaping can improve the tracking of such systems.

Important Links:

Go Back