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Ultrasonic Motor Applications
Published in Kenji Uchino, Micro Mechatronics, 2019
We have considered in this chapter the essential elements involved in the development of ultrasonic motors. In particular, we should examine the following key concepts: Basic Materials Development: identifying materials with low loss that are able to sustain high vibration rates.Methods for Measuring High Field Electromechanical CouplingsFundamental Ultrasonic Motor Design Considerations:Displacement Magnification Mechanisms: such as the horn and hinge lever mechanisms.Basic Ultrasonic Motor Types: classified according to their mode of operation, such as the standing-wave type and the traveling-wave type.Frictional Contact: between the stator and moving parts of the motor.Drive and Control of the Ultrasonic Motor:High Frequency/High Power SuppliesResonance/Antiresonance Modes of Operation
Small Motors
Published in Dorin O. Neacşu, Automotive Power Systems, 2020
An ultrasonic motor is an electric motor powered by the ultrasonic vibration of a component identified as the stator. This stator is placed against another component. If the movement is a rotation, the second component is called the rotor. If it is a linear translation, it is called the slider.
Design and Control of a Novel Multi-Degree-of-Freedom Spherical Induction Motor
Published in Electric Power Components and Systems, 2023
Zhentao Ding, Tao Deng, Zhenhua Su, Changjun Wu, Yanli Yin
Depending on driving principles, the spherical motors can be divided into mechanical, piezoelectric, and electromagnetic types. Nagasawa and S. Honda [19] proposed a spherical structure actuator driven mechanically using wires. A spherical rotor and four single DOF rotating motors were connected by wires. By tightening or loosening those wires, the motion direction of the rotor can be changed. However, due to the parallel drive by single-axis motors, it is essentially analogous to the traditional multi-DOF mechanism. Takemura et al. [20] designed a compact ultrasonic motor with a planar stator. The stator was composed of brass parts, resin parts, and piezoelectric parts. It can effectively reduce motor size, but the weaknesses were the low dynamic performance. In fact, multi-DOF spherical actuators mainly adopt the electromagnetic driving techniques, including induction motors, PM motors, and reluctance motors [21]. Compared with other types of spherical motors, for SIM, it is unnecessary to design magnetic poles on the rotor, which has the advantages of simple mechanical structure and unrestricted range of motion. It is expected to be used in future urban intelligent transportation.
High-performance finger module for robot hands with pneumatic cylinder and parallel link mechanism
Published in Advanced Robotics, 2021
Table 1 shows the existing examples of robot hands with multiple DoF fingers and an actuator in the hand structure. The grasping force represents the rated output or the range in which precise force control is possible. The grasping force-to-weight ratio is the grasping force divided by the hand weight. As shown in Table 1, the grasping force tends to decrease as the number of actuators increases. However, the Keio hand has a high grasping force-to-weight ratio when compared with the number of actuators, which deviates from this tendency. This is because it uses an ultrasonic motor for the actuator. This deviation can be addressed by using actuators other than the electric actuator in the Keio hand. However, from the viewpoint of cost, it is preferable to reduce the number of actuators to the extent possible. Moreover, it also uses a spring-and wire-driven mechanism for back-drivability, which gives it the disadvantages of the wire-driven type configuration mentioned in the previous section.
Electric behaviour of soft and hard lead zirconate titanate ceramics under electromechanical loading
Published in Phase Transitions, 2019
J. Suchanicz, K. Konieczny, N.-T.H. Kim-Ngan, D. Sitko, A.G. Balogh
Polycrystalline lead zirconate-lead titanate (PZT) system has been widely used in the field of piezoelectric applications. It is possible to optimise some material properties for a specific application by including various dopants. In general, there are two categories of doping: donor or acceptor substitution. Typical donor modifications of PZT are the substitution of the La3+ cation on the Pb2+- site, which creates A-site vacancies in order to compensate the charge imbalance, or of Nb5+ on the B-site. Relaxor ferroelectric behaviour appears at higher concentrations of the donor dopant the. Fe3+ or Mn3+ cations on the B-site are typical acceptor substitutions, which create additional oxygen vacancies to compensate the charge imbalance. Acceptor dopant substitutions do not cause an appearance of the relaxor ferroelectric behaviour. Donor-doped materials are so-called soft because they behave electrically softer than hard acceptor-doped ones. However, poled hard PZT exhibits an ageing effect which is much larger than that of soft PZT. The higher piezoelectric coefficients of soft PZT are suitable for positioning actuator applications, while the hard PZT is particularly suitable for ultrasonic motor applications.