随着智能化开采的不断发展,刮板输送机直线度控制对于煤矿安全、高效开采具有重要意义。针对刮板输送机的调直精度不高的问题,提出了一种基于空间运动学与长短时记忆神经网络轨迹预测相融合的调直方法。首先,利用工业机器人的空间运动...随着智能化开采的不断发展,刮板输送机直线度控制对于煤矿安全、高效开采具有重要意义。针对刮板输送机的调直精度不高的问题,提出了一种基于空间运动学与长短时记忆神经网络轨迹预测相融合的调直方法。首先,利用工业机器人的空间运动学知识对液压支架和刮板输送机浮动连接机构的运动规律进行了解析,并以C#语言的形式编入Unity3D仿真系统底层,通过推移机构连接头捕捉刮板输送机中部槽上的关键点,实现液压支架与刮板输送机的连接,实现了液压支架的精准推移,较理想化地解决了销耳间隙的影响;其次,综合考虑到传感器噪声与截割底板轨迹对刮板输送机轨迹检测的影响,在仿真系统中进行相关的补偿后,在MATLAB中利用LSTM(Long Short Time Memory)神经网络对刮板输送机的轨迹进行预测;最后,根据实际工况要求建立了目标调直轨迹的修正模型和轨迹-姿态转换模型,以得到的刮板输送机轨迹为基础,确定及时移架后的液压支架位置与对应中部槽的相对位置差,基于浮动连接机构运动规律液压支架精准推移,实现刮板输送机调直。通过虚拟试验的验证,建立的修正模型和转换模型具有较强的可靠性,在仿真系统与实验室条件下分别在底板存在起伏时进行了调直试验,提出的调直方法的直线度误差分别在±0.2 cm和0.08 cm内,符合调直精度要求,研究结果对刮板输送机的调直研究提供了思路。展开更多
Straightness error is an important parameter in measuring high-precision shafts. New generation geometrical product speeifieation（GPS） requires the measurement uncertainty characterizing the reliability of the resul...Straightness error is an important parameter in measuring high-precision shafts. New generation geometrical product speeifieation（GPS） requires the measurement uncertainty characterizing the reliability of the results should be given together when the measurement result is given. Nowadays most researches on straightness focus on error calculation and only several research projects evaluate the measurement uncertainty based on ＂The Guide to the Expression of Uncertainty in Measurement（GUM）＂. In order to compute spatial straightness error（SSE） accurately and rapidly and overcome the limitations of GUM, a quasi particle swarm optimization（QPSO） is proposed to solve the minimum zone SSE and Monte Carlo Method（MCM） is developed to estimate the measurement uncertainty. The mathematical model of minimum zone SSE is formulated. In QPSO quasi-random sequences are applied to the generation of the initial position and velocity of particles and their velocities are modified by the constriction factor approach. The flow of measurement uncertainty evaluation based on MCM is proposed, where the heart is repeatedly sampling from the probability density function（PDF） for every input quantity and evaluating the model in each case. The minimum zone SSE of a shaft measured on a Coordinate Measuring Machine（CMM） is calculated by QPSO and the measurement uncertainty is evaluated by MCM on the basis of analyzing the uncertainty contributors. The results show that the uncertainty directly influences the product judgment result. Therefore it is scientific and reasonable to consider the influence of the uncertainty in judging whether the parts are accepted or rejected, especially for those located in the uncertainty zone. The proposed method is especially suitable when the PDF of the measurand cannot adequately be approximated by a Gaussian distribution or a scaled and shifted t-distribution and the measurement model is non-linear.展开更多
The straightening technics is one of important means to improve the straightness of metal bar. A novel way of predicting the straightening stroke is proposed based on mathematical methods and bending experimental and ...The straightening technics is one of important means to improve the straightness of metal bar. A novel way of predicting the straightening stroke is proposed based on mathematical methods and bending experimental and numerical simulation. The experimental and numerical simulation is conducted by following the mathematical load-stroke model of press straightening process under the elastic-plastic theory. For the linear guide rails, as an example, the stroke-deflection model focusing on the straightening stroke prediction can be achieved by contrasting and integrating the bending experimental results and finite element methods (FEM) simulation data. And then the formula for predicting the straightening stroke is presented based on the precise straightening stroke-deflection model. The stroke prediction formula with high precision can be applied to the straightening stroke prediction in the high straightness metal bar manufacturing process and automatic straightening machine conveniently.展开更多
文摘随着智能化开采的不断发展,刮板输送机直线度控制对于煤矿安全、高效开采具有重要意义。针对刮板输送机的调直精度不高的问题,提出了一种基于空间运动学与长短时记忆神经网络轨迹预测相融合的调直方法。首先,利用工业机器人的空间运动学知识对液压支架和刮板输送机浮动连接机构的运动规律进行了解析,并以C#语言的形式编入Unity3D仿真系统底层,通过推移机构连接头捕捉刮板输送机中部槽上的关键点,实现液压支架与刮板输送机的连接,实现了液压支架的精准推移,较理想化地解决了销耳间隙的影响;其次,综合考虑到传感器噪声与截割底板轨迹对刮板输送机轨迹检测的影响,在仿真系统中进行相关的补偿后,在MATLAB中利用LSTM(Long Short Time Memory)神经网络对刮板输送机的轨迹进行预测;最后,根据实际工况要求建立了目标调直轨迹的修正模型和轨迹-姿态转换模型,以得到的刮板输送机轨迹为基础,确定及时移架后的液压支架位置与对应中部槽的相对位置差,基于浮动连接机构运动规律液压支架精准推移,实现刮板输送机调直。通过虚拟试验的验证,建立的修正模型和转换模型具有较强的可靠性,在仿真系统与实验室条件下分别在底板存在起伏时进行了调直试验,提出的调直方法的直线度误差分别在±0.2 cm和0.08 cm内,符合调直精度要求,研究结果对刮板输送机的调直研究提供了思路。
基金supported by National Natural Science Foundation of China (Grant No. 51075198)Jiangsu Provincial Natural Science Foundation of China (Grant No. BK2010479)+2 种基金Innovation Research of Nanjing Institute of Technology, China (Grant No. CKJ20100008)Jiangsu Provincial Foundation of 333 Talents Engineering of ChinaJiangsu Provincial Foundation of Six Talented Peak of China
文摘Straightness error is an important parameter in measuring high-precision shafts. New generation geometrical product speeifieation（GPS） requires the measurement uncertainty characterizing the reliability of the results should be given together when the measurement result is given. Nowadays most researches on straightness focus on error calculation and only several research projects evaluate the measurement uncertainty based on ＂The Guide to the Expression of Uncertainty in Measurement（GUM）＂. In order to compute spatial straightness error（SSE） accurately and rapidly and overcome the limitations of GUM, a quasi particle swarm optimization（QPSO） is proposed to solve the minimum zone SSE and Monte Carlo Method（MCM） is developed to estimate the measurement uncertainty. The mathematical model of minimum zone SSE is formulated. In QPSO quasi-random sequences are applied to the generation of the initial position and velocity of particles and their velocities are modified by the constriction factor approach. The flow of measurement uncertainty evaluation based on MCM is proposed, where the heart is repeatedly sampling from the probability density function（PDF） for every input quantity and evaluating the model in each case. The minimum zone SSE of a shaft measured on a Coordinate Measuring Machine（CMM） is calculated by QPSO and the measurement uncertainty is evaluated by MCM on the basis of analyzing the uncertainty contributors. The results show that the uncertainty directly influences the product judgment result. Therefore it is scientific and reasonable to consider the influence of the uncertainty in judging whether the parts are accepted or rejected, especially for those located in the uncertainty zone. The proposed method is especially suitable when the PDF of the measurand cannot adequately be approximated by a Gaussian distribution or a scaled and shifted t-distribution and the measurement model is non-linear.
基金Supported by China Ministry of Education Visiting Scholar Fund(Grant No.2005383)Hubei Province Science Foundation(Grant No.2008CDB274)Wuhan High-Tech Development Project Foundation(Grant No.200812121559)
文摘The straightening technics is one of important means to improve the straightness of metal bar. A novel way of predicting the straightening stroke is proposed based on mathematical methods and bending experimental and numerical simulation. The experimental and numerical simulation is conducted by following the mathematical load-stroke model of press straightening process under the elastic-plastic theory. For the linear guide rails, as an example, the stroke-deflection model focusing on the straightening stroke prediction can be achieved by contrasting and integrating the bending experimental results and finite element methods (FEM) simulation data. And then the formula for predicting the straightening stroke is presented based on the precise straightening stroke-deflection model. The stroke prediction formula with high precision can be applied to the straightening stroke prediction in the high straightness metal bar manufacturing process and automatic straightening machine conveniently.
