提出了直线超声电机异步并联的概念以提高精密定位平台驱动单元的位移分辨率、输出力及速度。基本原理是若干定子(或振子)在一个振动周期内交替驱动动子(或转子)，使实际的驱动频率成倍提高，可以获得更好的输出性能。分析显示，提高定子与动子之间的接触频率可以提高输出力和速度，改善瞬态响应特性，并可避免同步并联方式下定子的相互干扰问题。两种电机异步并联的实验结果表明，两个定子异步并联时的最大负载力比两个定子同步并联提高了30%以上，比两个定子单独驱动时的推力之和提高25%以上。最小分辨率测试实验表明，异步并联时最小位移分辨率达到32.6 nm，是单个电机的62.8%，是同步并联的38.5%。单驱动头电机的实验还表明，异步并联时空载直线速度比单个定子和两个定子同步并联时都提高了10%以上，最大效率比两个定子同步并联驱动时提高约50%，瞬态响应时间比同步并联更短，约为单个定子驱动时的50%。

A concept of Asynchronous Bundle of Linear Ultrasonic Motor (ABLUSM) was proposed to improve the resolution, thrust and the speed of driving unit for a precision positioning stage. It points out that a numbers of stators (vibrators) alternately drive a mover (rotor) in a vibration cycle, the actual driving frequency is increased doubly, and better output performance can be expected. An analysis shows that increasing the contact frequency between stator and mover is able to improve the output force, speed and transient response characteristics of a Linear Ultrasonic Motor (LUSM). Meanwhile, it can avoid the mutual interference of different stators in Synchronous Bundling of LUSM (SBLUSM). Experimental results of two types of motors show that the maximum load force of the ABLUSM is 30% upon that of the SBLUSM or 25% over that of the sum of two motors when they drive the slider respectively. Results of minimum resolution test show that the minimum displacement resolution of the ABLUSM is 32.6 nm, which is 62.8% that of a single LUSM or 38.5% that of the SBLUSM. The mechanical characteristic experiments of the LUSM with one driving tip also prove that the no-load speed of ABLUSM has increased by 10% as compared with that both of the single stator and the SBLUSM. Moreover, the maximum efficiency has by 50% over that of the SBLUSM. Transient response time is shorter than SBLUSM, which is about 50% of a single stator.