Adaptive control of piezoelectric walker actuator

IECON 2016 - 42nd Annual Conference of the IEEE Industrial Electronics Society

Golubovic²,

Şabanoviç

2016

Abstract-This paper is concerned with the force control of a walking piezoelectric motor, a commercially available Piezo LEGS motor. The motor is capable of providing high precision positioning control on nanometer scale, but also relatively high forces up to 6 N. The proposed force control algorithm is very simple, but effective, and it is based on a recently presented coordinate transformation. The transformation allows definition of the driving waveforms for the motor according to a desired motion of the motor legs in the plane of motion. Such a possibility opens a path for creating the y-direction interaction force between the motor legs and the rod which is enough to ensure no relative motion between the legs and the rod. Once that is achieved, one can control the x-direction force imposed by the motor rod on its environment. The presented force control scheme has been successfully validated through a series of experiments.

Section: System Descriptionmentioning

confidence: 66%

“…Delay varying repetitive control was introduced in [18] and utilized for positioning control of a stage driven by a walking piezoelectric motor. Adaptive control of the Piezo LEGS motor was in the focus of the authors in [19]. In [20], gain scheduling control of a walking piezo actuator was discussed.…”

Section: Introductionmentioning

confidence: 99%

Force control of piezoelectric walker

IECON 2016 - 42nd Annual Conference of the IEEE Industrial Electronics Society

Golubovic²,

Şabanoviç

2016

“…Driving waveforms can be modulated by varying amplitude, phase and frequency. Amplitude and phase difference of a waveform correspond to step size, and frequency is proportional to the speed of stepping [20]. The motor can be driven in two modes; discontinuous and continuous modes.…”

Section: Problem Formulationmentioning

confidence: 99%

“…In this approach overshoots are significantly improved by varying amplitude and phase of the waveforms with overlapping trajectories. Since phase and amplitude of applied waveform is related to the step size [20], by modulating these parameters the step size can be controlled. Authors proposed an adaptive controller scheme for step size control by changing amplitude and phase difference between sinusoidal waveforms to improve positioning precision and overshoots.…”

Section: Introductionmentioning

confidence: 99%

Nanometric positioning of a piezo walker

Zhakypov

Golubovic

IECON 2013 - 39th Annual Conference of the IEEE Industrial Electronics Society

et al. 2013

This work presents functional description of a walking piezoelectric motor and its control in nanometer precision. For this purpose a dynamical model of the actuator is derived based on simple mass spring damper system. Model parameters are estimated from step response plot and the system is expressed with second order transfer function. Additional identification experiments verified the theoretical kinematics of the bimorph legs. These experiments demonstrate approximately linear relation between the legs displacement in x and y directions to the applied voltages. Based on derived system model and identification results a PI controller followed by Hadamard transformation is proposed as a controller scheme. Experimental results for staircase and sinusoidal references reveal precise positioning capabilities of the system with the proposed control scheme down to few nanometers.

“…Delay varying repetitive control was used in [18] for positioning control of nanomotion stage driven by a walking piezo motor. In [19], adaptive control of the Piezo LEGS motor is discussed. In addition, the authors have presented theoretical/experimental evaluation of step-size dependence on the characteristics of driving voltages.…”

Section: Introductionmentioning

confidence: 99%

Control system for high precision positioning applications based on piezo motors

2015 IEEE International Conference on Mechatronics (ICM)

Golubovic

Kebude

et al. 2015

In this paper implementation of a control system for high precision applications is presented. The control system is developed for a Piezo LEGS motor, which is a walking piezo motor that can be employed in nanometric precision applications. In the control system structure, two main components are digital signal controller which executes control algorithm and power driver that is generating driving voltages for the motor. The waveforms of the driving voltages are designed using a recently presented coordinate transformation. This transformation enables synthesis of driving waveforms according to design requirements regarding force imposed to the motor's rod and rod's x-direction trajectory profile. In this work, the waveforms are selected to ensure no relative motion between the motor's legs and rod, and constant velocity of the rod within one step. Control algorithm is named as virtual time control. Despite its simplicity, the algorithm allows high precision positioning which is very close to theoretically achievable one.