- 學位論文
氣壓人造肌肉致動器應用於二自由度機械臂設計及控制之研究
Design and Control of a 2-DOF Forearm Robotic System Driven by Pneumatic Artificial Muscle Actuators
摘要
在20世紀下半葉，輔助機器人和外骨骼的出現，成為一種可為四肢受損的病患提供輔助或增強人類的力量新型機器人。儘管電磁馬達是機器人領域中最廣泛被使用的致動器，氣壓致動器也有諸如輕量、乾淨以及方便維護的優點。由於氣壓人造肌肉固有的順應性和高功率重量比，即使有高非線性的缺點，仍是所有的氣壓致動器中，最適合作為驅動復健機器人的致動器。 本論文旨在設計和控制由兩對氣壓人造肌肉驅動的二自由度機械臂，繼續[1]的研究，作為本實驗室未來在上肢復健機器人發展目標的一環。由於本研究略涉及人體的基本知識，故先對相關的基本生物力學簡要地討論，然後闡釋機械臂的建構以及系統的試驗平台。為了理解該系統的性能，而推導機構的運動學和動態模型，接著建立系統中所使用的氣壓元件之數學模型，有助於控制器的設計。氣壓人造肌肉的內壓是其出力和收縮量的函數，藉由其數學模型易於算出在欲達到的出力與特定收縮量下所需的氣壓值。在控制器的設計中，首先設計一種基於模型的前饋控制器和反饋PID控制器的力矩控制器，然後再與滑動模式控制器結合，以作為關節角度控制器。此外藉由速度估測器可得合理的速度信號而用以控制系統。此外，干擾估測器所估測的干擾可有效增進角度追蹤的效果。 為了測試系統模型和控制器的性能，而對肘關節進行模擬，並對機械臂系統進行實驗，以驗證其設計與控制的效能。實驗結果顯示角度控制器仍可達成平滑的追蹤。
並列摘要
During the second half of the 20th century, assistive robotics and exoskeletons appeared as a new type of robots that can either provide assistive support for patients with impaired limbs or augment the strength of human beings. Although electromagnetic motors may be the most widely used actuators in the robotic area, pneumatic actuators have their own advantages, such as lightness, cleanness and easy maintenance. Of all the pneumatic actuators, pneumatic artificial muscles (PAMs) may be the most promising one for the design of assistive or rehabilitation robots because of their inherent compliance and high power to weight ratio, despite their high nonlinearity. This thesis aims to design and control a 2-DOF forearm robotic system actuated by two pairs of PAMs, following the research of [1], as a step toward our future objective of the development of an upper-limb rehabilitation robot. For the purpose of the study, basic biomechanics of the human body is briefly discussed, and then the design as well as the test rig of the robotic system is demonstrated. To understand the properties of the system, the kinematic and dynamic models of the mechanism are derived, followed by the mathematical modeling of the pneumatic components used in the system. These modeling approaches lend themselves to the controller design, in that the pressures of the PAMs that are required to produce a desired force under a certain contraction ratio can be easily calculated, such that a model-based controller can be designed. For the controller design, a torque controller with a model-based feedforward controller and a feedback PID controller is first developed, and then a sliding mode controller is combined with the torque controller to form a joint angle controller. With the help of a velocity observer, a decent velocity signal can be employed for the control of the system. In addition, the estimated disturbance by the disturbance observer is used as a cancellation signal for better angle tracking performance. Simulations are carried out on the elbow joint to test the model and the controller, and experiments are conducted to verify the efficacy of the design and control of the system. The results show that the smooth angle tracking performance can be achieved.
參考文獻
延伸閱讀
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