Rotary/Linear Double-Action Metal Tube Ultrasonic Motor with Slanted PZT Ceramic Plates

We designed and manufactured a multi-degree-of-freedom (translational and rotary) ultrasonic motor (USM) by using a single actuator. Using one actuator for obtaining more than one degree of freedom motion allows the robotic systems to be further miniaturized without sacrificing the cost. Therefore, the application fields of small-scale robotics systems can be expanded. Although there have been numerous MDoF actuators reported in the literature, only a few of them cover the combined utilization of rotary and translational motions in a cylindrical-joint type configuration. Cylindrical joints and sliders are two of the most widely used mechanism in robotics. Combining these two motions in one mechanism and controlling this combined motion through a novel USM is the main aim of this work. Here, we use smooth impact drive method (SIDM) with two distinct modes obtained at two distinct frequencies by the help of slanted ceramics and uneven square shaped excitation signals. Because of these, our dual-mode motor can be driven by single source which aids the simplicity of drive and command circuitry in a simple mechanical structure. The prototype of the motor (TR-USM) (5 mm diameter, 30 mm total length) has 5 mm/sec (translational) and 3 rad/sec (rotary) speed even under 4mN blocking force, when the input signal is 50 Vp_p square wave.