【正文】 FS=NbrFS=(N1+N2)(3)only one pression spring is needed, whose position in the square HS can be adjusted to meet the optimal working condition of fr1≈fr2≈frbr。200 V maximum operating voltages), respectively. A cut(with diamond saw)through two opposite boundaries of the quadrants is made from the sapphire ring at one end of the PST into about 92% of the tube length toward the other end. The uncut sapphire ring is the base ring, whereas the other is cut into two semi rings which are called clamping semi rings(will clamp hold a mobile HS).Each pair of the neighboring electrodes with no cut in between is wired together, resulting in two semicylindrical electrodes, one is arbitrarily called the ?rst electrode (E1)for convenience and the other, the second electrode(E2).The two halves of the PST that E1 and E2 control are abbreviated as P1 and P2, respectively.The moving part of the motor is a titanium HS that is inserted into the PST as shown in (a).We have studied a circular and a square HS as illustrated in (b). For the circular one(length=45mm,inner diameter=, and outer diameter= mm which can pass through the sapphire rings at the PST ends with a small gap of mm),a wire cut through the axis is made from each end toward the other end with the cutting planes perpendicular to each two cuts do not go through the entire HS and a small length of mm remains uncut at each end. The pair of the HS cut slits having the opening toward the same direction as that of the PST slits is arranged in the same plane with the PST slits. A stronger pression spring is secured in the HS at one end, pushing the HS to open wider and press against the clamping semi rings with forces N1 and N2,respectively,whereas a weaker pression spring in the HS at the other end presses the HS on the base ring with a total pressing force three pressing forces N1,N2,and Nbr are set roughly equal by the above stronger and weaker pression springs. Accordingly, the maximum static friction forces on the HS due to these three pressing forces are approximately equal in value(directions may be opposite as discussed below)if equal friction coef?cients are assumed.One big advantage of this mutual clamping between the PST and HS at both ends is that this structure is very ?rm(resistant to vibration noise)and can be installed in any direction. Also note that the clamping is elastic(long range forces),implying that large temperature variations will not change the clamping forces signi?cantly and the three maximum static frictions remains equal in value.To operate the motor, two driving voltages D1 and D2 of (a)type applied to the electrodes E1 and E2 of the PST, respectively(the inner electrode voltage is ?xed at 200 V), which will deform the corresponding semitubular actuators P1 and P2 as follows. P1 and P2 are initialized to expansion states during the ?rst 1/6 period(T1).In T2,P2 shrinks while P1 stays unchanged. This results in a sliding between the free end of P2 and HS rather than a sliding between the base ring and HS, because P2toHS maximum static friction fr2 is smaller than the sum of the P1toHS and ringtoHS maximum static frictions, fr1+ frbr(assuming these frictions are much smaller than the blocking forces Fbl1 and Fbl2 of P1 and P2). Next, in T3, P1and P2 both stay in the previous state. This purely “wait”state is a preparation for good synchrony in the next action,which is not necessary and can be dropped to save time. In T4, P1 shrinks while P2 stays unchanged. This induces a sliding between the free end of P1 and HS(y the similar reason to the T2 action).Up to now, both P1 and P2 have changed the states from expansion to contraction without moving the HS with reference to the base ring. T5 is another wait which is again the last 1/6 period(T6),P1 and P2 both expand simultaneously. This time, the sliding happens only between the base ring and HS because frbrfr1+fr2, meaning that P1 and P2 together drag the HS to move one step in the expansion direction from the base , P1 and P2 return to the initial states and the HS has moved one step. This sequence can be repeated to achieve a large travel range. The HS can also move in the opposite direction using the driving voltage given in (b)and the principle is very similar.Apart from the circular HS described above, we have also tried a square HS (42 mm long by mm wide, wall thickness is mm),which is wire cut from each end to the other end(cutting length= 35 mm)with the cutting planes parallel to each other, forming a serpentine structure as exhibited in (b). The distance between the cutting planes is mm. This design is better than its circular counterpart in the following aspects:(1)the sliding of the HS on the sapphire rings is like ice skating shoes sliding on ice, allowing bigger pressing forces more rigid without increasing the frictions。 published online 14 August 2009.We present a novel piezoelectric stepper motor featuring high pactness, rigidity, simplicity, andany direction operability. Although tested in room temperature, it is believed to work in lowtemperatures, owing to its loose operation conditions and large step size. The motor is implementedwith a piezoelectric scanner tube that is axially cut into almost two halves and clamp holds a hollow shaft inside at both ends via the spring parts of the shaft. Two driving voltages that singly deform the two halves of the piezotube in one direction and recover simultaneously will move the shaft inthe opposite direction, and vice versa. 169。早在論文開題之時，趙老師就為我詳細的介紹了各個課題的要求，使我對畢業(yè)設計有了初步的了解，在我的課題選定之后，阮學長又細心的為我講解課題的難點、要點，幫我建立了論文的基本框架和論文設計原則，提出了具有指導性的建議；伴隨我整個畢業(yè)設計過程當中，鄧老師對我的一些疑問進行了具有針對性的講解與訓練；最后定稿之時，趙老師更是仔仔細細的查閱了我的論文，為我指出并修改了許多問題，我可以毫不猶豫的說，我這篇論文能夠順利的完成，是無法和趙老師等的辛勤付出所分割開來的！趙老師在工作中以嚴謹的教學態(tài)度、高超的教學水平、開放的教學理念贏得了學生們的廣泛尊重；在生活中以幽默的處事風格、樂觀的生活態(tài)度、高尚的人格情操成為了學生們不可多得的良師益友，在此，我對趙老師的悉心指導致以崇高的敬意和衷心的感謝！附錄 1 系統(tǒng)硬件電路原理圖2 外文文獻A simple, pact, and rigid piezoelectric step motor with large step sizeQi