关键词: 滤波器, 起重机, 柔性, 优化, 振荡, 刀刃接触区间, 平头立铣刀, 五轴宽行加工, 自由曲面, 铣削力预报

Abstract: When time-delayed filtering techniques are used in the high speed and large tonnage cranes, the residual oscillations of the payload can be efficiently suppressed, simultaneously, impact motion of drive mechanism is induced and the response speed of the system is slowed. Aiming at the problems, the limited-jerk optimal time-delayed filter, which combines the limited-jerk theory and optimization theory, is presented. Based on the idea of reducing motion impact of the rigid body in flexible systems, the limited-jerk control command is designed, which can suppress the high frequency components in the control input and reduce the excitation to un-modeled harmonic modes. Then, taking the state vector of payload oscillation as quadratic objective function, the delay time with the least payload swing is calculated according to the optimization theory and the optimal time-delayed filter with appropriate time-delay is developed, which make the system have satisfying response speed. The limited-jerk control commands from the filter are composed of a sequence of ramp signals, whose time-ratio of variation will not exceed the permissible value, thus the motion impact of rigid body is suppressed. A set of simulation system and a set of experiment system for gantry cranes are built, in which the validity of the proposed control technique are proven.

Key words: Crane, Filter, Flexibility, Optimization, Vibration, Five-axis wide strip machining, Flat end milling, In-cut cutting edge, Sculptured surface, Prediction of milling force