State Key Laboratory of Material Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, China.
Sensors (Basel). 2019 Feb 26;19(5):996. doi: 10.3390/s19050996.
The ram speed of a steam hammer is an important parameter that directly affects the forming performance of forgers. This parameter must be monitored regularly in practical applications in industry. Because of the complex and dangerous industrial environment of forging equipment, non-contact measurement methods, such as stereo vision, might be optimal. However, in actual application, the field of view (FOV) required to measure the steam hammer is extremely large, with a value of 2⁻3 m, and heavy steam hammer, at high-speed, usually causes a strong vibration. These two factors combine to sacrifice the accuracy of measurements, and can even cause the failure of measurements. To solve these issues, a bundle-adjustment-principle-based system calibration method is proposed to realize high-accuracy calibration for a large FOV, which can obtain accurate calibration results when the calibration target is not precisely manufactured. To decrease the influence of strong vibration, a stationary world coordinate system was built, and the external parameters were recalibrated during the entire measurement process. The accuracy and effectiveness of the proposed technique were verified by an experiment to measure the ram speed of a counterblow steam hammer in a die forging device.
蒸汽锤冲头速度是影响锻工成形性能的一个重要参数，在工业实际应用中必须定期监测。由于锻造设备的工业环境复杂且危险，非接触式测量方法，如立体视觉，可能是最佳选择。然而，在实际应用中，测量蒸汽锤所需的视场（FOV）非常大，达到 2⁻3 米，而高速运行的重型蒸汽锤通常会引起强烈的振动。这两个因素结合起来牺牲了测量的准确性，甚至可能导致测量失败。为了解决这些问题，提出了一种基于束调整原理的系统校准方法，以实现大视场的高精度校准，即使校准目标不是精确制造的，也可以获得准确的校准结果。为了减小强烈振动的影响，建立了一个静止的世界坐标系，并在整个测量过程中重新校准外部参数。通过在模具锻造装置中测量反击式蒸汽锤冲头速度的实验验证了该技术的准确性和有效性。
