Piezoelectric MEMS Linear Motor for Nanopositioning Applications

Abstract

This paper reports the design, fabrication, and performance of piezoelectric bidirectional conveyors based on microelectromechanical systems (MEMS) and featuring 3D-printed legs in bridge resonators. The structures consisted of aluminum-nitride (AlN) piezoelectric film on top of millimeter-sized rectangular thin silicon bridges and two electrode patches. The position and size of the patches were analytically optimized for travelling or standing wave generation, while the addition of 3D-printed legs allowed for a controlled contact and amplified displacement, a further step into the manufacturing of efficient linear motors. Such hybrid devices have recently demonstrated the conveyance of sliders of several times the motor weight, with speeds of 1.7 mm/s by travelling waves generated at 6 V and 19.3 kHz. In this paper both travelling and standing wave motors are compared. By the optimization of various aspects of the device such as the vibrational modes, leg collocation and excitation signals, speeds as high as 35 mm/s, and payloads above 10 times the motor weight were demonstrated. The devices exhibited a promising positional resolution while actuated with only a few sinusoidal cycles in an open-loop configuration. Discrete steps as low as 70 nm were measured in the conveyance of 2-mg sliders.

Data-driven model-free adaptive sliding mode control for electromagnetic linear actuator

“…From equation (7), the key to designing the control law is to obtain the value of the PPD. However, since the system model is unknown and the PPD is a time-varying parameter, it is difficult to obtain the exact true value at each moment, so the following estimation criterion function is proposed:…”

Nonlinear Model Predictive Motion Control of Linear Motor Drive for Micro/Nano-Positioning Applications

“…where f (x(k), u(k) and g(x(k)) represent the dynamics of the system (3). However, a challenge of controlling the system (8) is that the lumped disturbance fd is not exactly known and cannot be measured. Moreover, the model (8) has uncertain system parameters, M and B.…”

“…The accuracy that can be achieved by a control system is therefore physically limited by the structural flexibility and backlash [4]. Direct drive linear motors which eliminate the need for mechanical transmission system were then widely investigated and proposed for high precision positioning systems [6], [7], [8].…”

3D-Printed Miniature Robots with Piezoelectric Actuation for Locomotion and Steering Maneuverability Applications

“…The locomotion of the robot was based on the generation of standing waves (SW) in the two plate resonators, in combination with an appropriate location of legs [13]. This configuration was successfully applied to the bidirectional linear motion of millimetersized robots by means of two consecutive flexural modes [15,22]. The two plates of our design could be considered as independent SW motors and were designed as such.…”

“…Figure 2 shows a 1D representation of the considered mode shapes. In order to optimally excite either of these modes, the piezoelectric patch should cover the area at which the curvature of the mode shapes has a constant sign [15,22]. In our case, in the search of the ease of fabrication, a patch length of 5 mm on both plates allowed for an efficient actuation of both modes.…”