In this contribution, we propose a novel linear piezoelectric motor with a compact stator that is driven by a single mode. The linear piezoelectric motor can realize bidirectional motion by changing the vibration modes of the stator. Finite element analysis is performed to determine the required vibration mode of the stator and obtain the optimal stator structure and dimensions. Furthermore, the trajectories of the driving foot are analyzed with and without consideration of the mechanical contact with the slider. It is shown that the trajectory of the driving foot is an oblique line when disregarding the contact, and the trajectory becomes an oblique ellipse while taking into account the contact. Finally, a prototype of the motor is fabricated based on the results of finite element analysis. The optimization results show that the motor reaches its maximum thrust force of 4.0 kg, maximum thrust–weight ratio of 33.3, maximum unloaded velocity of 385 mm/s under the excitation of Mode-B, and maximum unloaded velocity of 315 mm/s under the excitation of Mode-L.

In this paper, a novel rectangular structure linear piezoelectric actuator that utilizes two lower order decoupled vibration modes is developed and investigated. A noticeable trait of the linear piezoelectric actuator is that it can realize bi-directional motion by changing the vibration mode of the stator with different exciting frequencies. Modal and harmonic analysis of the stator are performed by the finite element method to determine the actuator structure and dimensions and stablished that the driving tip trajectories are diagonal lines. The direction of the actuator is controlled by the orientation of the diagonal motion generated at the driving tip. When the diagonal motion is inclined right as the driving tip approaches the linear guide, it will move the linear guide right. Correspondingly, the linear guide will move to the left, if the diagonal motion inclines left. In addition, a prototype linear piezoelectric actuator is fabricated and experimented. The results of the experiments indicate that the actuator has good mechanical output characteristics. Typical output of the prototype is no-load speed of 504 mm s ⁻¹ and maximum mechanical load of 6.5 kg.

It is a challenging task for an aerial manipulator to complete dual-arm cooperative manipulation in an outdoor environment. In this study, a new dual-arm aerial manipulator system with flexible operation is developed. The dual-arm manipulator system is designed for the application of aerial manipulation, and it has the characteristics of low weight, low inertia, and a humanoid arm structure. The arm structure is composed of customized aluminum parts, each manipulator contains four degrees of freedom, similar to the arrangement of human joints, including shoulder yaw, shoulder pitch, elbow pitch, and wrist roll. Next, the workspace of the dual-arm manipulator is simulated and analyzed, and the relevant kinematic and dynamic models are deduced. Finally, through the lift load, accuracy and repeatability, cooperative bimanual manipulation tests on the test bench, and multiple groups of outdoor flight tests, the relevant performance analysis and verification of the dual-arm aerial manipulator system are carried out. The test results evaluate the feasibility of the designed dual-arm aerial manipulator system for outdoor cooperative manipulation.

In order to meet the demand of a linear ultrasonic motor with large thrust in narrow space, a novel Π-type linear ultrasonic motor with double driving feet is proposed. In this paper, the structure of a stator is designed. The working mode and structure size are determined by finite element simulation. To amplify the amplitude of driving foot, an optimization design for the stator is performed. After that, a novel pre-load device that separates from the stator is put forward, which can not only improve the output but also help to improve the operation stability and prolong the life of motor. Additionally, a prototype of the proposed motor with the novel pre-load device was fabricated and the performance tests were implemented. The experimental results show that the suggested motor has structural stability and high dynamic performance, such as a no-load speed of 273 mm/s and 238 mm/s in two directions, corresponding to a maximal thrust of 80 N and 110 N.