壓電式力量感測之低頻補償及其於伺服機構之應用

In this project, a force estimation scheme is proposed in combination with using a piezoelectric force sensor in order to produce a high-quality signal of an environmental contact force. There are mainly two categories of how to obtain a force signal: one is using a force sensor and the other is using a force estimation algorithm. Of many kinds of force sensors, the piezoelectric force sensor features high stiffness comparable to steel, extreme compactness, large dynamic range, and wide linear measurement range. However, it is unable to sense static and quasi-static forces. The proposed scheme uses a rigid-body model and an adaptive algorithm to compensate for low-frequency parts of a piezoelectric force sensor’s output. Compared with previous force estimation algorithms, the proposed scheme does not require prior knowledge of system perturbations excluding the environmental contact force. Moreover, the proposed scheme does not require implementation of an additional disturbance observer to compensate for overall system perturbation because the proposed scheme itself produces an estimate of overall system perturbation. Compared with previous piezoelectric static force sensor, the proposed scheme does not require redesign of a sensor structure or an electronic system and is able to sense static and dynamic forces. Compared with a conventional strain gauge-based load cell, the proposed scheme features high stiffness and extreme compactness and does not weaken the mechanical structure. In this project, the proposed scheme is applied to a linear motor-based motion stage. The scheme has been evaluated experimentally in order to investigate their applicability and feasibility. Since the scheme has been practically applied to a physical mechatronic system, the graduate students involved in this project has received advanced training in Mechatronics and System Integration.