Abstract: A mass on-line control type impact inertial piezoelectric actuator with a bionic wheat structure is proposed in this work. Inspired by the anisotropic friction mechanism of natural wheat awns, a bioinspired mechanism is used to achieve the designed driving strategy based on the asymmetric-mass control method that mimics bidirectional motion characteristics of wheat awn. A lumped parameter theoretical model is established, and the numerical simulation results have verified the designed bionic working principle and revealed the key system parameters. Experimental results show that the prototype has the bi-directional motion ability inherited from anisotropic friction of wheat awn, with theoretically infinite stroke and can easily obtain the required step displacement and velocity by conveniently adjusting the voltage. It can achieve a resolution of 0.7 μm, and a forward and backward maximum velocity of 12.7 μm/s and 90.72 μm/s respectively. In addition, the actuator also has the advantages of good stability, control convenience, and ease of integration. Besides, the actuator is capable of adjusting motion direction via voltage, providing a significant advantage in precise bidirectional control. This study confirms that the proposed mass on-line control type actuator embodies a successful bionic translation from plant morphology to precision engineering, and adds a new member to the family of impact inertial piezoelectric actuators, which completes the last piece of the puzzle for the impact inertial driving mechanism. It promotes the further development of inertial precision driving and control technology and is expected to expand the scope of application. Future work will focus on optimizing performance and developing applications.

Key words: Bionic, Bi-directional motion, Inertial, Mass on-line control, Piezoelectric actuator')">Bionic, Bi-directional motion, Inertial, Mass on-line control, Piezoelectric actuator