資料公開
| タイトル | Improvement of Motion Accuracy and Energy Consumption of a Mechanical Feed Drive System Using a Fourier Series Based Nonlinear Friction Model |
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| カテゴリ | 研究論文 |
| 概要 | Friction occurring in all mechanical systems such as computer numerical controlled (CNC) machine tools is an important issue in achieving the high accurate performance. Friction adversely affects not only motion accuracy of drive axes but also excessively consumes energy. Feed drives of CNC machines normally operate all day and night around the world, and therefore consumed energy reduction is highly expected. The motivation behind this work is to construct a novel friction model that can comprise many unknown friction sources in both low and high velocity regions and enable a friction compensator to precisely describe actual frictional behavior. Sliding mode control (SMC) is designed to verify the effectives of the proposed friction model in a biaxial feed drive system. Experimental results confirm that a combination of SMC and the proposed friction can effectively improve tracking accuracy and further achieve significant reduction of consumed energy compared to combining with the conventional model. Results show that the proposed approach can largely decreased the mean tracking error to less than 5 μm for each axis. The new friction also achieved effective reduction of control variance by 7.62%. Consequently, consumed energy of feed drives significantly improved by 12.83% compared to using the conventional model. |
| タイトル | Adaptive Sliding Mode Contouring Control with a Nonlinear Sliding Surface for Feed Drive Systems |
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| カテゴリ | 研究論文 |
| 概要 | Reduction of contour error and saving energy are major essential requirements in computer numerical control (CNC) machines. This paper introduces a novel adaptive sliding contouring control using a nonlinear sliding surface to achieve higher machining accuracy without any increase of consumed energy. The main objective of this approach is that control gains are automatically adapted based on the contouring error to simultaneously generate appropriate control signals. The proposed controller has constantly improved the machining accuracy and achieved a perfect performance with shorter rise time and lower overshoot. To verify the proposed approach, simulation results for a biaxial feed drive system demonstrate a significant contouring performance for circular and non-circular trajectories. The adaptive algorithm decreases a contour error by about 31% and 29% than sliding mode control without adaptation through circular and non-circular trajectories, respectively. |
| タイトル | Energy Saving in Biaxial Feed Drive Systems Using Adaptive Sliding Mode Contouring Control with a Nonlinear Sliding Surface |
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| カテゴリ | 研究論文 |
| 概要 | Energy saving and producing highly accurate products are major essential demands in computer numerical control (CNC) machines. These machines operate all day and night for a long time, therefore they largely consume energy all over the world. This paper proposes adaptive sliding mode contouring control (ASMCC) with a nonlinear sliding surface (NSS) to reduce consumed energy and further improve machining accuracy for a biaxial feed drive system. The control gain of the proposed scheme is formulated to be mainly relied on a contour error. Once the contour error is changed, the control gain is adjusted simultaneously to generate appropriate control signal. ASMCC constantly reduces consumed energy and improves machining accuracy by reducing the resultant contour error. In order to verify the effectiveness of ASMCC, simulation and experiment are carried out on a biaxial feed drive system using a circular trajectory. Results show that the adaptive algorithm significantly reduces the mean contour error by 37.62% and 34.65% compared to sliding mode control (SMCC) without any additional energy on simulation and experiment, respectively. In addition, the proposed approach reduces experimentally consumed energy and control input variance by 8.20% and 17.29%, respectively. |
| タイトル | Enhancement of Energy Saving and Precision Motion for Industrial Machines by Adaptive Sliding Mode Control and Friction Compensation |
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| カテゴリ | 研究論文 |
| 概要 | Improvement of consumed energy reduction and motion accuracy in industrial machines is a significant requirement in manufacturing applications. The motion accuracy of industrial feed drives typically can be improved by increasing control gains of their feedback control algorithms. Although this strategy may improve tracking performance of the control system, it increases energy consumption. Another concern in most industrial machines is mechanical friction, which adversely affects not only the tracking performance but also energy consumption. In this paper, a new control scenario, which consists of adaptive sliding mode control (ASMC) and nonlinear friction compensation is proposed to enhance the motion accuracy and energy saving in an industrial feed drive system. The presented friction model can be flexibly extended to multiple nonlinear terms to well describe an actual frictional property, and therefore control efforts dissipated due to unknown frictional effects can be reduced. Furthermore, the applied adaptation scheme is able to simultaneously provide appropriate control signals based on tracking errors. Hence, the proposed control approach is expected to achieve higher motion accuracy and energy saving. Experimental results show the effectiveness of the proposed scheme on reducing energy consumption and also achieving a precise tracking to desired motion. |
| タイトル | Design and Experimental Verification of Adaptive Sliding Mode Control for Motion Accuracy and Energy Saving in Industrial Feed Drive Systems |
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| カテゴリ | 研究論文 |
| 概要 | Reduction of energy consumption is one of the fundamental requirements in industry, in particular computer numerical controlled (CNC) machines. Because these machines operate for a long time and extensively contribute in diverse applications all over the world, reducing even a small percentage of consumed energy can lead to significant energy saving in manufacturing sectors. This paper concerns with improving motion accuracy and energy saving based on adaptive sliding mode control (ASMC) for industrial feed drive machine tool. The proposed control approach is derived based on the Lyapunov stability theory and its control gain is designed to be mainly relied on resultant motion errors of drive axes. Once the tracking error is changed, the control gain is simultaneously adjusted to generate appropriate control signal to provide good tracking performance with reducing energy consumption. Furthermore, the proposed adaptive gain does not alter only during the reaching phase but also through the sliding phase, and hence consumed energy reduction is further expected. In order to verify the effectiveness of the proposed approach, it was compared with non-adaptive and typical adaptive sliding mode control approaches with a circular trajectory of an industrial feed drive system. Experimental results show that the mean and maximum tracking errors of the proposed scenario could be largely reduced by 34.81% and 33.66% on average compared to a constant control gain without any increase of consumed energy, respectively. The proposed approach effectively improved the control input variance by 1.54% and 2.34% compared to constant and typical adaptive gains, respectively. Consequentially, consumed energy was reduced by 2.89% and 1.26% on average. |