可跳躍之雙輪平衡移動機器人開發

Development of a self-balancing two-wheeled jumping robot

李府威(Fu-Wei Lee)

指導教授 ： 楊燿州

國立臺灣大學/工學院/機械工程學研究所/碩士(2016年)

https://doi.org/10.6342/NTU201603074

摘要

本研究提出了一個可跳躍的雙輪平衡移動機器人。一般而言，雙輪機器人具有高機動性、體積小等優勢。透過在雙輪機器人的基礎上裝設跳躍機構，變能實驗雙輪機器人的跳躍功能，使得機器人能同時具有移動與平衡之功能。
本研究所提出的機器人可分成三部分討論：機器人的跳躍動作、機器人平衡與機器人的移動。在跳躍動作的部分，本研究的跳躍機構包含了凸輪、彈簧與插銷三個部分。藉由操控滑輪，可於機器人移動時完成彈簧的壓縮。彈簧受到壓縮時，能量將以彈力位能的方式儲存。當彈簧釋放，彈力位能瞬間轉換為動能，使得機器人向上方垂直跳躍，完成跳躍的動作。在機器人平衡的方面，其平衡系統由感測器、兩個步進馬達與微控制器組成。其中，感測器將用於量測機器人的傾斜角度。此角度將被作為PID控制器的誤差使用。經由計算後，將決定微控制器的輸出並控制馬達的轉速。利用此方式，便可將完成機器人的平衡。而於機器人的移動方面，則是藉由改變質心的方式實現。藉由RC servo motor配合連桿機構的方式，調整機器人的質心位置。當質心改變時，機器人的平衡會暫時性的受到干擾。此時，機器人將往質心偏移的方向前進，回復機器人本身的平衡，並完成移動之功能。
此外，本研究亦量測了機器人的平衡性能。亦使用了兩種不同彈性係數的彈簧作跳躍測試。量測結果顯示，本研究所提出的機器人之跳躍高度最高可達13公分，能量轉換效率約為40%。

關鍵字

凸輪 ； 雙輪機器人 ； 自平衡 ； 跳躍機器人

並列摘要

This thesis presents the development and characterization of a self-balancing two-wheeled jumping robot, which features advantages such as high maneuverability and small size. By integrating the self-balancing two-wheeled robot and the jumping mechanism, both the jumping motion and moving motion can be achieved.
The proposed robot consists of three parts: the jumping mechanism, the self-balancing system, and the translational motion initialization mechanism. The jumping mechanism consists of a cam, a spring and a latch. By actuating the cylinder cam, the spring is compressed and thus the elastic potential energy is stored in the spring. As the spring relaxed, the elastic potential energy is converted into kinetic energy, thus the robot jumps impulsively upward. The self-balancing system of the robot consists of a motion tracking device, two step motors, and a microcontroller. The tilt angle of the robot is measured and served as the error of the PID controller to determine the controller output. The angular velocity of the step motor is then computed to keep the balance of the robot. The translational motion of the robot can be initialized by changing the center of mass, which is realized by using a linkage mechanism. As the center of mass changes, the balance is disturbed, and the robot responds immediately to recover its balance, which gives rise to the translational motion of the robot.
The balance stabilization and jumping of robot were demonstrated. By using rigid wheels, the jumping height is more than 30 cm with energy conversion efficiency of more than 80%. Soft wheels were also employed for smooth jumping motion. The maximum jumping height is 13cm and the conversion efficiency is 40%.

並列關鍵字

cam ； two-wheeled robot ； self-balancing ； jumping robot

參考文獻

[1] S.-M. Song and K. J. Waldron, "Machines that walk: the adaptive suspension vehicle." MIT press, 1989.

[2] R. B. McGhee and A. L. Pai. "An approach to computer control for legged vehicles." Journal of Terramechanics 11.1 (1974): 9-27.

[3] M. H. Raibert, "Hopping in legged systems—modeling and simulation for the two-dimensional one-legged case." IEEE Transactions on Systems, Man, and Cybernetics 3 (1984): 451-463.

[4] M. H. Raibert, H. B. Brown, and M. Chepponis, "Experiments in balance with a 3D one-legged hopping machine." The International Journal of Robotics Research 3.2 (1984): 75-92.

[5] M. H. Raibert, R. Playter, R. Ringrose, D. Bailey, and K. Leeser, "Dynamic Legged Locomotion in Robots and Animals." MASSACHUSETTS INST OF TECH CAMBRIDGE ARTIFICIAL INTELLIGENCE LAB, 1995.