The Frequency-Variable Rotor-Blade-Based Two-Degree-of-Freedom Actuation Principle for Linear and Rotary Motion

Abstract

Piezoelectric accurate actuation plays an important role in industrial applications. The intrinsic frequency of previous actuators is invariable. However, variable frequency can approach the range near the low-intrinsic-frequency and realize a high actuation capability. The frequency-variable linear and rotary motion (FVLRM) principle is proposed for rotor-blade-based two-degree-of-freedom driving. Inertial force is generated by frequency-variable piezoelectric oscillators (FVPO), the base frequency and vibration modes of which are adjustable by the changeable mass and position of the mass block. The variable-frequency principle of FVPO and the FVLRM are recognized and verified by the simulations and experiments, respectively. The experiments show that the FVLRM prototype moves the fastest when the mass block is placed at the farthest position and the prototype is at the second-order intrinsic frequencies of 42 Hz and 43 Hz, achieving a linear motion of 3.52 mm/s and a rotary motion of 286.9 mrad/s. The actuator adopts a lower operating frequency of less than 60 Hz and has the function of adjusting the natural frequency. It can achieve linear and rotational motion with a larger working stroke with 140 mm linear movement and 360° rotation.

Closed-Loop Optical Tracking of a Micro-Conveyor over a Smart Surface

“…A retro-reflective element is placed onto the micro-conveyor surface to ensure that the reflected beam is parallel to the incident beam. This optical remote method can be applied for any kind of micro-conveyor system such as: i-Aerodynamic based system, where the micro-conveyor movement is subjected to air jets or an injection of a fluid [23,24], ii-Electrostatic based system utilizes electrostatic induction motors to transport dielectric items [25,26], iii-Piezoelectric based system, where the micro-conveyor's motion is ensured according to the principle of micro-sliding [27,28], iv-Electromagnetic based system, the motion of the micro-conveyor is ensured via the Lorentz force, which is generated by the interaction of the magnetic field from permanent magnet and current carrying conductors [29,30], etc.…”