- 學位論文
三軸工具機伺服調機響應分析
Response Analysis of Servo Adjustment for 3-Axis Machine Tool
摘要
加工精度在CNC工具機中是很重要的關鍵，其中影響加工精度的諸多因素包括控制器的性能、零組件的精度、整體機構的設計以及各運動軸的定位準確度、垂直度、平行度等。並且，工具機的性能可透過雷射校正、硬體及調機方式改善。 本研究係探討參數調整對工具機性能的影響，實驗量測主要分為共振抑制分析及伺服響應分析。共振抑制分析，是先比對動態共振響應量測與馬達響應量測結果中是否有發生峰值之區域相符，若有則藉由馬達端抑制該峰值。於共振響應量測中，馬達端所測三軸之頻率分別為166 Hz、1210 Hz及137 Hz，其與動態共振響應量測所出現峰值之區域相符，接著此等頻率可經由Notch濾波器而達到抑制。於伺服響應分析中，分別探討在位置控制模式及速度控制模式下調整位置迴路比例增益(P2-00)、速度迴路比例增益(P2-04)及速度迴路積分增益(P2-06)三個參數值之響應特性。首先，利用台達調機軟體根據機台來回移動找出適合各軸之負載慣量比並寫入軟體計算各增益值。接著，在各軸有效設定範圍內輸入調整值，藉由可程式邏輯控制器下達輸入脈衝數使床台移動，並透過軟體之示波器功能擷取移動時之圖形變化，最後使用Labview軟體所寫之自動分析來找出響應特性。在位置控制模式下，從P2-00參數之響應特性分析可得知，三軸之響應皆隨著參數值增大而愈大，但Z軸因增益值過大而出現過衝，表示機台產生振動。此外，安定時間隨著參數值愈大而愈小，而穩態誤差則在一定值內變動，受參數值調整影響不大。於P2-00與P2-04之參數響應特性分析中，參數P2-00對P2-04的比例設定最理想為1:5。從實際量測來看，過小及過大的比例容易使系統過衝且具穩態誤差，進而導致系統振動及其精度下降。P2-06參數主要對穩態誤差有較大影響，本實驗機台於設定前穩態誤差超過10個脈衝以上，而設定後則能將穩態誤差抑制到2個脈衝以下。最後，在速度控制模式下，從改變P2-04參數於轉速400 rpm、800 rpm及1200 rpm之響應特性中，可知轉速愈高的情況下過衝愈小，但由於高轉速振動會使穩態誤差增大。
並列摘要
Processing accuracy is critical to CNC machine tool. Many factors could affect the processing accuracy, including controller performance, component precision, mechanism design, positioning accuracy, verticality, parallelism and so on. Performance of machine tool can be improved by laser calibration, hardware and tuning. In this study, analyses of resonance suppression and servo response are performed. First, in the analysis of resonance suppression, the frequency which peak appears in active resonance response is determined that whether it is matched with the frequency which peak appears in motor response. If the frequencies match, these peaks can be suppressed using Notch filter. In the measurement of resonance response, matched frequencies in each axis of the motor occur at 166, 1210 and 137 Hz, which is then successfully suppressed. Second, in the analysis of servo response, three parameters, including position loop proportional gain (P2-00), velocity loop proportional gain (P2-04), and velocity loop integral gain (P2-06) are calculated by load inertia ratio of each axis and adjusted under position-control mode and velocity-control mode. After inputting the calculated gains within the effective range of each axis, results are captured by oscilloscope function of Delta tuning software and analyzed by Labview software. In the servo response analysis of P2-00 under position-control mode, result in each axis shows that the response increases with the parameter and the gain value in Z-axis is too large, which results in overshoot and means resonance. Additionally, settling time decreases with P2-00 increases and steady errors remain within a certain range. Further, the optimal ratio of parameter P2-00 to P2-04 is 1:5, and we noticed that smaller or larger ratio may cause overshoot and steady-state error, which generate oscillation and cause precision reduction. It is also found that parameter P2-06 has larger influence on steady-state error. The steady-state error can be over 10 pulses before setting P2-06 and can be lower than 2 pulses after setting P2-06. In the velocity-control mode, the results of P2-04 adjustment under 400 rpm, 800 rpm, and 1200 rpm show that overshoot could be smaller in higher revolution, and however, the steady-state error increases in higher revolution.