【正文】 traight walking. A. Wave gait Robot with wave gait () is the easiest gait to turn around. But it is very plex to control because every leg has a different gait. For the wave gait, the leg’s structure is as in Fig. 6. There are two revolute joints along axes Y, one along axes Z, its foot, contacting with the ground bees a spherical joint (with three revolute freedoms). During walking, there will be three legs to support the body, and three legs wave ahead (Fig. 5). The whole body’s simple structure is as Fig. 6(b). There are 12 links, 13 revolute joints, two spherical joints in this configuration. The positon is described in a space coordinate frame. The number of degrees of freedom of the robot is puted as follows : F=12*65*123*2=6 In this case, every supporting leg has three freedoms, which makes control very plex.B. Crab gait Another gait for hexagonal robot is ‘crab gait’ or ‘kickup gait’ [8], which is a continuous gait.. Six legs are also grouped into two patterns, 1+3+5 and 2+4+6. There willbe 3 legs for supporting while three legs rise to walk ahead at every time. The track of foot is a parabola ( see ): y=ax^2+b ‘b’: is the maxmimal height that the robot’s feet can raise. While passing small obstacles, ‘b*fh’ is the height of obstacle, ‘2*sqrt(by)*fw’ is the width of obstacle, given that, ‘fh’ and ‘fw’ are factors of obstacle’s height and width, 0‘fh, fw’1. In figure 7(a), legs in solid line are in the supporting phase, legs in dashed line are in the walking phase. From simple structure (see (b)), the number of degrees of freedom of the robot is: F=3*52*6=3. From the above analysis, the crab gait is simpler than the wave gait. However, it also needs special gaits for turning. Turning To realize turning motion, there are two cases. For small angle turning, turning can be realized during walking, the robot does not need to stop. The turning angle must be less than 30 degrees to avoid walking legs colliding with supporting legs. See in . For large angle turning, three steps are needed. There are always four legs standing on the ground to support the body, and the other two legs rise to adjust direction. Fig. 9 and Fig. 10 listed the steps of 60 degrees and 90 degrees turning cases. Quadrangles in the above figures are areas of support。 ADAMS are shown in . 16. Gaits with sick legs Fault Tolerant Lootion Because of the plex lunar environment, the robot’s legs may be damaged during working. If one or two legs are broken, it still can run with wheels and walk with the other four or five legs with two kinds of gait. Even if three legs are broken, the robot can still walk with a suitable gait [8]. However, if two interphase legs are out of action, the crab gait is impossible. It is still possible for supporting and running, but if three adjoining legs are broken (see Fig. 17) walking is almost impossible. Figure 18 shows how the robot can run with two legs out of action. Gaits with wheels Because wheels can provide higher speed lootion than legs, our robot will run with wheels in the case of a smooth surface on the Moon. All wheels will be grouped into two branches, one on the left, the other on the right. The robot runs like a car. It can realize turning through changing the velocity difference between these two groups of wheels, which had been studied intensively. The ideal velocity for forward motion[9] is, v(t)=(vl(t)+vr(t))/2 (3) vl (t):velocity of left group。 If | vl (t)||vr (t)|, then robot turns right。 If vl (t)= vr (t), then w(t)0 and v(t)=0, robot turns without displacement. According to experience, Fuzzy Logic is most suitable for controlling the wheel velocities. V. Prototype test Based on system design and simulation, one prototype was build (see ). The prototype has 24 motors (Servos Hitec HS475HB) and a main board (Servopod). The Servopod has the ability to control more than 26VI. Conclusion and Future work Robots with wheel type lootion can have high velocity on smooth surfaces, but cannot run on rough terrain. Robots with leg type lootion are more agile, but usually only walk with low speed. Therefore, the robot with a hybrid lootion using both legs and wheels will be a good choice for a lunar rover. From the above analysis, the hexagonal structure for a hexapod is more agile than the rectangular one. Because the crab/kickup gait is like a human’s gait, it is simpler to control and easier to implement. The wave gait is more plicated,. However, when one or two legs are damaged, the crab gait is very hard to use while the wave gait is still available. Therefore, the lootion of the crab gait coupled with the wave gait is more suitable for a lunar rover. This papaer mainly focus on a parative study of rectangular hexapod robot and hexagonal hexapod robot, and the analysis of the wave gait and crab gait was investigated. There are still many other gaits for this kind of lunar robot, such as climbing slope, overtaking gouge, and detailed gaits when one or two legs are broken. As for fault tolerant gaits, only runing with wheels is studied here, more work will be done on fault tolerant legwalking gaits in the future. II. Acknowledgment Thanks to the China NSFC (Grant no. 50475001), HITECH RESEARCH AND DEVELOPMENT PROGRAM OF CHINA (863 PROGRAM: Grant no. 2006AA04Z207) AND the Samp。一項比較的研究,立基于在敏捷, 安定和多余, 總結(jié)出六邊形機器人在建筑學(xué)上比矩形的好。關(guān)鍵詞：最完美的設(shè)計；精確性；平行的機械手在最近的幾年行星的漂泊者已經(jīng)變得一個流行的話題。有輪的類型機器人包括 Gyrover[1] 的單一輪子, 四輪的RATLER[2] 和其他的輪子。腿的類型包括漫步者、但丁和但丁 2 世。但丁和但丁 2 世有八只腿 [4] 。VNIITRANSMASH 中的軌道 1, 來自美國 和 ANDROS Mark VA和來自ACEC的ACEC 機器人都是履帶機器人。然而, 直到現(xiàn)在, 已經(jīng)成功地在行星上登陸的機器人是全部旋轉(zhuǎn)的類型。它離地球很遠(yuǎn)，幾乎沒有空氣, 那在月球之上的地心引力是 在地球上的1/6，而且在月球上有一層很厚的灰塵。輪子也容易陷在灰塵中。 然而, 它運動速度比較慢速度。因此, 腿/輪子類型的漂泊者已經(jīng)變成我們月球探險的首選。月球探險者因為學(xué)術(shù)和技術(shù)限制還不能夠發(fā)明類似于人類大腦。這樣看來一四腳的——漂泊者是一好選擇。另一方面，幾乎所有的昆蟲有六個腳。以下是昆蟲漂泊者的一些優(yōu)勢。