A review of command shaping techniques for elimination of residual vibrations in flexible-joint manipulators

Abstract

Command shaping is an important open-loop control method for improving the settling time and positioning accuracy. This technique also minimizes residual vibrations. Shaped command profiles are formed by convolving a sequence of impulses or solving special functions for the desired command signal. To determine the input shaper controller commands, estimated values of the system natural frequency and damping ratio are required to make the necessary calculations. However, real systems cannot be modelled precisely, while robustness of the shaper to modelling errors is an important design consideration. Many robust input shapers have been developed and reported in the literature. It has been observed that the robust shapers typically have longer travelling time durations that lead to slow system response. This makes a relationship between shaper rising/travelling time and robustness. This paper presents a review of command shaping methods and analyses the compromise between duration of motion and shaper robustness for positive and smoothly shaped reference commands.

Identifying and mitigating residual vibrations in wave-based control of lumped, flexible systems

“…Regarding residual vibrations specifically, there is a sense in which all strategies for flexible system control are also about attempting to control residual vibrations. For example, see references [13][14][15][16][17][18][19][20][21][22]. In input shaping, for example, there is focus on making the controller more robust (or less sensitive) to departures of flexible system dynamics from nominal values.…”

Fuzzy logic–based decision support system for selection of optimum input shaping techniques in point-to-point motion systems

“…They reported that the vibration caused by motor motion has been reduced with the applied controller. Conker et al 21 reviewed 15 different input shapers in detail. They compared both the simulations and experimental results.…”

Shaping the Transient Response of Nonlinear Systems to Satisfy a Class of Integral Constraints

“…In [13], the open-loop nature of input shaping is considered for vibration control of flexible systems, in the presence of known and finite duration disturbances. Input shaping has been extensively used for vibration control (see [14] and references therein). Transient response of nonlinear systems is addressed in fewer works in the literature, with some examples being [15,16].…”