Fast recognition of elevator buttons is a key step for service robots toride elevators automatically. Although there are some studies in this field, noneof them can achieve real-time application due to problems such a...Fast recognition of elevator buttons is a key step for service robots toride elevators automatically. Although there are some studies in this field, noneof them can achieve real-time application due to problems such as recognitionspeed and algorithm complexity. Elevator button recognition is a comprehensiveproblem. Not only does it need to detect the position of multiple buttonsat the same time, but also needs to accurately identify the characters on eachbutton. The latest version 5 of you only look once algorithm (YOLOv5) hasthe fastest reasoning speed and can be used for detecting multiple objects inreal-time. The advantages ofYOLOv5 make it an ideal choice for detecting theposition of multiple buttons in an elevator, but it’s not good at specific wordrecognition. Optical character recognition (OCR) is a well-known techniquefor character recognition. This paper innovatively improved the YOLOv5network, integrated OCR technology, and applied them to the elevator buttonrecognition process. First, we changed the detection scale in the YOLOv5network and only maintained the detection scales of 40 ∗ 40 and 80 ∗ 80, thusimproving the overall object detection speed. Then, we put a modified OCRbranch after the YOLOv5 network to identify the numbers on the buttons.Finally, we verified this method on different datasets and compared it withother typical methods. The results show that the average recall and precisionof this method are 81.2% and 92.4%. Compared with others, the accuracyof this method has reached a very high level, but the recognition speed hasreached 0.056 s, which is far higher than other methods.展开更多
At the present, the cutters used in button bits and rock bits are mainly cobalt tungsten carbide in our country. Because of its low abrasive resistance, the bit service life and drilling efficiency was very low when t...At the present, the cutters used in button bits and rock bits are mainly cobalt tungsten carbide in our country. Because of its low abrasive resistance, the bit service life and drilling efficiency was very low when the hard and extremely hard formations were being drilled. Owing to its high abrasive resistance, the diamond composite material is widely used in drilling operations. However, its toughness against impact is too low to be used in percussion drilling, only can it be used in rotary drilling. In order to solve the problems encountered by DTH hammer in hard rock drilling, make bit life longer, increase rate of penetration and decrease drilling cost, a new type diamond enhanced tungsten carbide composite button with high abrasive resistance and high toughness against impact, which may be used in percussion drilling, has been developed. The key problems to make the button are to improve the thermal stability of diamond, to increase the welding strength between diamond and cemented tungsten carbide, and to lower the sintering temperature of tungsten carbide. All these problems have been solved effectively by pretreatment of diamond, low temperature activation hot-press sintering and high sintering pressure. (1) To plate tungsten on the surface of diamond. Diamond suffers easily from erosion in the environment of high temperature containing oxygen and iron family elements. There is very high energy between the interface of diamond and bonding metal and so the metallurgical bond can’t form at the interface between diamond and bond metal. This will lower greatly the bending strength and the toughness against impact of diamond enhanced tungsten carbide composite button. In order to improve thermal stability of diamond and increase the bonding strength of the interface between diamond and bond metal, to plate tungsten on the surface of diamond by vacuum vapor deposit is adopted. (2) To lower the sintering temperature by adding nickel, phosphorus and boron etc into conventional mixed powder. In general, the sintering temperature of cemented tungsten carbide is more than 1 350 ℃ in which diamond will suffer from serious heat erosion, so the sintering temperature must be lowered. To add nickel, phosphorus and boron etc into cobalt-base bond whose melting point is more than 1 350 ℃ will lower the sintering temperature to about 1 050 ℃. To add phosphorus can lower the temperature of liquid phase occurring and promote the densification of matrix alloy in advance because the co-crystallization temperature of Ni-P and Co-P is 880 ℃ and 1 020 ℃ respectively. The proper adding amount of nickel, phosphorus and boron etc is a key problem. To substitute nickel for partial cobalt can improve the toughness against impact of diamond enhanced tungsten carbide composite button and lower the sintering temperature. To add boron is helpful for sintering and improving the toughness against impact of diamond enhanced tungsten carbide composite button. (3) To increase the sintering press. Under the same sintering temperature, to improve the sintering press can improve the density and strength of sintering products. In this study to increase the sintering press 35 MPa in the usual conditions to 50～60 MPa in sintering diamond enhanced tungsten carbide button by adopting ceramic material as pressing rod has improved the sintering quality effectively. The properties of the button have been measured under lab conditions. The testing results show that its hardness is more than HRA86 and that its abrasiveness resistance is 100 times more than conventional cemented tungsten carbide, and its toughness against impact is more than 100J. All these data theoretically show that the button has very good mechanical properties that can meet the need of percussion drilling, and can solve the problems encountered with button bit of conventional cemented tungsten carbide.展开更多
基金the Research and Implementation of An Intelligent Driving Assistance System Based on Augmented Reality in Hebei Science and Technology Support Plan (Grant Number 17210803D)Science and Technology Research Project of Higher Education in Hebei Province (Grant Number ZD2020318)Middle School Students Science and Technology Innovation Ability Cultivation Special Project (Grant No.22E50075D)and project (Grant No.1181480).
文摘Fast recognition of elevator buttons is a key step for service robots toride elevators automatically. Although there are some studies in this field, noneof them can achieve real-time application due to problems such as recognitionspeed and algorithm complexity. Elevator button recognition is a comprehensiveproblem. Not only does it need to detect the position of multiple buttonsat the same time, but also needs to accurately identify the characters on eachbutton. The latest version 5 of you only look once algorithm (YOLOv5) hasthe fastest reasoning speed and can be used for detecting multiple objects inreal-time. The advantages ofYOLOv5 make it an ideal choice for detecting theposition of multiple buttons in an elevator, but it’s not good at specific wordrecognition. Optical character recognition (OCR) is a well-known techniquefor character recognition. This paper innovatively improved the YOLOv5network, integrated OCR technology, and applied them to the elevator buttonrecognition process. First, we changed the detection scale in the YOLOv5network and only maintained the detection scales of 40 ∗ 40 and 80 ∗ 80, thusimproving the overall object detection speed. Then, we put a modified OCRbranch after the YOLOv5 network to identify the numbers on the buttons.Finally, we verified this method on different datasets and compared it withother typical methods. The results show that the average recall and precisionof this method are 81.2% and 92.4%. Compared with others, the accuracyof this method has reached a very high level, but the recognition speed hasreached 0.056 s, which is far higher than other methods.
文摘At the present, the cutters used in button bits and rock bits are mainly cobalt tungsten carbide in our country. Because of its low abrasive resistance, the bit service life and drilling efficiency was very low when the hard and extremely hard formations were being drilled. Owing to its high abrasive resistance, the diamond composite material is widely used in drilling operations. However, its toughness against impact is too low to be used in percussion drilling, only can it be used in rotary drilling. In order to solve the problems encountered by DTH hammer in hard rock drilling, make bit life longer, increase rate of penetration and decrease drilling cost, a new type diamond enhanced tungsten carbide composite button with high abrasive resistance and high toughness against impact, which may be used in percussion drilling, has been developed. The key problems to make the button are to improve the thermal stability of diamond, to increase the welding strength between diamond and cemented tungsten carbide, and to lower the sintering temperature of tungsten carbide. All these problems have been solved effectively by pretreatment of diamond, low temperature activation hot-press sintering and high sintering pressure. (1) To plate tungsten on the surface of diamond. Diamond suffers easily from erosion in the environment of high temperature containing oxygen and iron family elements. There is very high energy between the interface of diamond and bonding metal and so the metallurgical bond can’t form at the interface between diamond and bond metal. This will lower greatly the bending strength and the toughness against impact of diamond enhanced tungsten carbide composite button. In order to improve thermal stability of diamond and increase the bonding strength of the interface between diamond and bond metal, to plate tungsten on the surface of diamond by vacuum vapor deposit is adopted. (2) To lower the sintering temperature by adding nickel, phosphorus and boron etc into conventional mixed powder. In general, the sintering temperature of cemented tungsten carbide is more than 1 350 ℃ in which diamond will suffer from serious heat erosion, so the sintering temperature must be lowered. To add nickel, phosphorus and boron etc into cobalt-base bond whose melting point is more than 1 350 ℃ will lower the sintering temperature to about 1 050 ℃. To add phosphorus can lower the temperature of liquid phase occurring and promote the densification of matrix alloy in advance because the co-crystallization temperature of Ni-P and Co-P is 880 ℃ and 1 020 ℃ respectively. The proper adding amount of nickel, phosphorus and boron etc is a key problem. To substitute nickel for partial cobalt can improve the toughness against impact of diamond enhanced tungsten carbide composite button and lower the sintering temperature. To add boron is helpful for sintering and improving the toughness against impact of diamond enhanced tungsten carbide composite button. (3) To increase the sintering press. Under the same sintering temperature, to improve the sintering press can improve the density and strength of sintering products. In this study to increase the sintering press 35 MPa in the usual conditions to 50～60 MPa in sintering diamond enhanced tungsten carbide button by adopting ceramic material as pressing rod has improved the sintering quality effectively. The properties of the button have been measured under lab conditions. The testing results show that its hardness is more than HRA86 and that its abrasiveness resistance is 100 times more than conventional cemented tungsten carbide, and its toughness against impact is more than 100J. All these data theoretically show that the button has very good mechanical properties that can meet the need of percussion drilling, and can solve the problems encountered with button bit of conventional cemented tungsten carbide.
