Ferromagnetic shape memory microscanner system for automotive applications

Abstract

A microscanner system for optical sensing of angle and distance is presented, which is controlled by a ferromagnetic shape memory (FSMA) microactuator. The main features of the FSMA microactuator are a large scanning angle up to 60 deg and a large bandwidth of frequencies given by a broad off-resonance regime below the thermal cut-off frequency at about 120 Hz and the resonance regime between 160 and 220 Hz. The small size and low mass of the FSMA microactuator allows the design of a very compact and robust scanner system, which enables new portable and mobile applications. In this paper, the sensing of objects in road traffic is pursued as an application in the automotive field, which requires small moving masses being insensitive to vibrations and shock. The main components of the microscanner system are the FSMA microactuator, a pulsed laser diode, an integrated angle sensor, an avalanche diode and a time-of-flight measurement setup for distance acquisition. The maximum scanning range of the first prototype is about 30 m for cooperative (reflecting) objects. The angular resolution is about 0.5 • .

A review on shape memory alloys and their prominence in automotive technology

“…By applying an alternating electrical current, a periodic oscillation of the actuating element can be realized. This motion is used to operate the scanning micromirror (Brugger et al, 2006; Kohl et al, 2004). The deflection of the micro-meter is determined using the part of the deflected laser reflected back to the position sensing diode.…”

Engineering Aspects of Shape Memory Film Actuators and Sensors

“…Due to the small size and low moving masses, the scanners are predestined for novel SMA film sensors in mobile applications due to their low sensitivity to vibrations and shock [37]. Fig.…”

Overview and Future Advanced Engineering Applications for Morphing Surfaces by Shape Memory Alloy Materials

“…Moreover, they are characterized by superelastic behavior and a high power-to-weight ratio, which make them particularly suitable for the design of adaptive structures [ 10 ]. Several applications related to the adoption of SMA as actuators [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ], in both the automotive [ 22 , 23 , 24 , 25 , 26 , 27 ] and aerospace [ 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 ] fields, can be found, even if application on a large scale is still far from being achieved. However, SMA-based actuation systems are being extensively investigated in the framework of several research studies in order to reduce the complexity, with a consequent reduction of weight, of the traditional electric and hydraulic actuation systems [ 18 , 43 , 44 ].…”