Vibration compensation of delta 3D printer with position-varying dynamics using filtered B-splines
Vibration compensation of delta 3D printer with position-varying dynamics using filtered B-splines
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DOI：
10.1007/s00170-022-10789-w
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发表时间：
2022-09
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影响因子：
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通讯作者：
Nosakhare Edoimioya;Cheng-Hao Chou;C. Okwudire
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作者：
Nosakhare Edoimioya;Cheng-Hao Chou;C. Okwudire
Delta 机器人可以达到比熔丝制造 3D 打印中使用的传统串行轴机器更高的速度。然而，与串行机器一样，Delta 打印机在高速下会遭受不良振动，从而降低制造零件的质量。在串行打印机中，使用线性模型反转前馈控制方法（例如滤波 B 样条 (FBS) 方法）可以抑制这种不良振动。然而，像 FBS 方法这样的技术在 Delta 3D 打印机上实施时在计算上具有挑战性，因为它们具有耦合的、位置相关的动态特性。在本文中，我们提出了一种解决计算瓶颈的方法，方法是：（1）离线参数化动态的位置相关部分，以实现在线模型的高效计算，（2）沿给定轨迹的采样点（而不是每个点）计算模型，以及（3）采用 QR 分解来减少与矩阵求逆相关的浮点算术运算的数量。在模拟中，我们报告称，与使用计算成本昂贵的精确 LPV 模型相比，使用所提出的方法可将计算时间减少多达 23 倍，同时保持高跟踪精度。因此，我们证明，与使用一个位置的 LTI 模型的基准替代方案相比，使用我们提出的控制器在商用 Delta 3D 打印机上的各个位置打印的零件的质量显着提高。打印过程中的加速度测量表明，与基线控制器相比，所提议的控制器的打印质量提高了高达 39% 的振动减少。
The delta robot can reach higher speeds than traditional serial-axis machines used in fused filament fabrication 3D printing. However, like serial machines, delta printers suffer from undesirable vibration at high speeds which degrades the quality of fabricated parts. This undesirable vibration has been suppressed in serial printers using linear model-inversion feedforward control methods like the filtered B-splines (FBS) approach. However, techniques like the FBS approach are computationally challenging to implement on delta 3D printers because of their coupled, position-dependent dynamics. In this paper, we propose a methodology to address the computational bottlenecks by (1) parameterizing the position-dependent portions of the dynamics offline to enable efficient computation of the model online, (2) computing models at sampled points (instead of every point) along the given trajectory, and (3) employing QR factorization to reduce the number of floating-point arithmetic operations associated with matrix inversion. In simulations, we report a computation time reduction of up to 23× using the proposed method when compared to using the computationally expensive exact LPV model—all while maintaining high tracking accuracy. Accordingly, we demonstrate significant quality improvements on parts printed at various positions on a commercial delta 3D printer using our proposed controller compared to a baseline alternative, which uses an LTI model from one position. Acceleration measurements during printing show that the improvement in print quality of the proposed controller is due to vibration reductions of up to 39% when compared to the baseline controller.