在以服務型應用為目的的機械手臂中，為考量人機互動的安全性，需降低控制增益來限制機械手臂工作時的速度與力量輸出；在成本效益上，由於服務型任務無須高精度的位置控制，可使用低解析度的感測器來降低成本，然而弱感測器也會使控制系統響應變慢，導致動態控制精度變差。因此本研究基於安全性與降低成本，提出一個低增益與無感測器的無刷馬達控制架構，僅使用霍爾感測器與單個電流感測器進行位置和扭力控制。我們在伺服控制器中加入低通濾波器，來解決感測器取樣不足與訊號干擾的問題。而為了克服伺服控制系統反應過慢，我們在電流控制器中加入動態補償器，透過簡化的機械手臂系統模型與鑑別實驗，可即時的補償運動時各軸馬達所需要的電流，加快伺服控制系統的反應與提高控制精度。
在人機協作的安全控制上，為了減少力感測器和特殊彈性機構的成本，本文提出一種以無感測器的剛性機械手臂為基礎的虛擬力量感測器與剛性控制法，實現即時的碰撞偵測與低精度的力量控制。透過在伺服驅動器中增設一個扭力限制器，能根據外部接觸力的估測值即時調整關節扭力輸出，產生可變剛性的順應控制，並將其運用於安全保護與力量控制中。本研究以別於過去多感測器及彈性機構的方法，基於低成本與無感測器的架構，以機器手臂系統模型為基礎的控制方法產生剛性變化，增進低價機械手臂的使用安全性與力量控制。

Robot arms used for service applications require safe human-machine interactions; therefore, the control gain of such robot arms must be minimized to limit the force output during operation. To improve cost efficiency, low-resolution sensors can be used to reduce cost. However, low-resolution sensors slow the response of closed-loop control systems, leading to low accuracy. Focusing on safety and cost reduction, this dissertation proposed a low-gain, sensorless Brushless DC motor control architecture, which performed position and torque control using only Hall-effect sensors and a current sensor. Low-pass filters were added in servo controllers to solve the sensing problems of undersampling and noise. To improve the control system’s excessively slow response, we added a dynamic force compensator in the current controllers, simplified the system model, and conducted tuning experiments to expedite the calculation of dynamic force. These approaches achieved real-time current compensation, accelerated control response and accuracy.
To protect operators and conform to safety standards for human–machine interactions, the design of collaborative robot arms often incorporates flexible mechanisms and force sensors to detect and absorb external impact forces. However, this approach increases production costs, making the introduction of such robot arms into low-cost service applications difficult. This study proposes a low-cost, sensorless rigid robot arm design that employs a virtual force sensor and stiffness control to enable the safety collision detection and low-precision force control. Additionally, a torque saturation limiter is added to the servo drive for each axis to enable the real-time adjustment of joint torque output according to the estimated external force, regulation of system stiffness, and achievement of impedance control that can be applied in safety measures and force control. The design this study developed is a departure from the conventional multisensor flexible mechanism approach. Moreover, it is a low-cost and sensorless design that relies on model-based control for stiffness regulation, thereby improving the safety and force control in robot arm applications.

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