Automatic Drilling Research Articles

Automatic drill pipe emission control system based on machine vision

Drilling is not as modern as other industries and still has great potential for automatic control. Automatic drill pipe emission control system is mostly used for offshore drilling, and the derrick of the land drilling rig cannot be directly compatible with the mature drill pipe emission system of the offshore drilling rig because of its unique structure. Drill pipe emissions from land drilling are usually done by worker-assisted mechanical arm. In this kind of working environment, workers are labor intensive and prone to fatigue and safety cannot be effectively guaranteed. In order to reduce labor intensity and improve drilling efficiency, this paper presents an automatic control system of drill pipe emission based on machine vision. In the control process of the tripping operations, visual servo control is added, and the visual sensor is used to detect the centerline of the drill pipe in real time. After the system finding the deviation between the drill pipe and the mechanical arm, the posture of the arm is adjusted in real time to compensate for the deviation. When the claw mechanism is aligned with the centerline of the drill pipe, the drill pipe manipulator grabs the drill pipe to complete the emission task. In this paper, four methods for extracting the centerline are compared, and the linear regression method is the best.

Influence of the deformation of riveting-side working head on riveting quality

Automatic drilling and riveting system has been widely used in aircraft manufacture field to satisfy the increasing demands of assembly quality. During the automatic riveting process, the riveting-side working head is the key component to perform the action of pressing rivet and its deformation has a great impact on riveting quality. In this paper, firstly, a theoretical model is established to investigate the factors influencing the deformation of riveting-side working head according to its structure and working situation. Then, the FE models with different squeezing displacements and riveting angles are established to analyze the effort of deformation of the riveting-side working head on driven head dimension, interference, and deformation of riveted hole on panels. Lastly, experiments are performed to verify the simulation results. The results show that the deformation of the riveting-side working head has a significant impact on the final riveting quality, and it can be compensated by increasing the riveting displacement.

运载火箭筒体壳段自动铆接路径的仿真优化分析

运载火箭筒体壳段自动铆接路径的仿真优化分析

Flexible Assembly Tooling Structure and Positioning Accuracy Analysis of Aircraft Fuselage Framework

Aiming at the problems of low efficiency, poor positioning accuracy and unreconstructible of the aircraft assembly process at present, according to the structure of the fuselage section of the aircraft, a flexible tooling for the fuselage frame is developed based on the modular idea. Positioning of different models of the fuselage is achieved by servo motor, manual adjustment and positioner. According to the way of the fuselage section, the structure of the flexible tooling is determined. At the same time, the layout of the automatic drilling and riveting system of the flexible tooling and the composite processing machine tool and the assembly process of the flexible tooling are introduced. Finally, the positioning accuracy of the flexible tooling test platform was analyzed, and the experimental verification was carried out through the experimental platform.

A Novel Design of Through-Hole Depth On-Machine Optical Measuring Equipment for Automatic Drilling and Riveting

In the aerospace manufacturing industry, it is impossible to achieve precise and efficient automatic drilling and riveting for largescale composite board parts. The bottleneck is that the depth detection of rivet holes still relies on manual operation, which seriously affects the assembly efficiency and stability of composite board parts. In order to realize accurate and efficient on-machine automatic measurement for through holes in the automatic drilling and riveting process of largescale composite board parts, this paper presents a novel hole depth measuring device. Its mechanical structure is developed based on our newly designed measurement scheme and optical path, the purpose of which is to convert the hole depth data into displacement data of the probe motion. Its electrical hardware consists of three units: a laser transceiver unit to pick up laser spots; a displacement measuring unit to capture the probe movement in real time; and a driving unit to achieve motion control of the probe. Finally, the experimental results indicated that the proposed method and device are capable of performing automatic measurements for through-hole depth. In addition, factors affecting the measuring accuracy and stability of the device are initially analyzed and discussed, which lay a foundation for subsequent research on error compensation and probe calibration.

A new type of inner-side working head for automatic drilling and riveting system

PurposeThe purpose of this paper is to design, analyze and optimize a new type of inner-side working head for automatic horizontal dual-machine cooperative drilling and riveting system. The inner-side working head is the key component of automatic drilling and riveting system, and it is a challenge to design an inner-side working head which must be stiffness and stable with a compact structure to realize its functions.Design/methodology/approachAccording to the assembly structure features of large aircraft panels and riveting process requirements, a new type of inner-side working head is designed for pressure riveting. The force condition of the inner-side working head during the riveting process is analyzed and the deformation model is established. Design optimization is performed based on genetic algorithm and finite element analysis. The optimized inner-side working head is tested with automatic horizontal dual-machine cooperative drilling and riveting system.FindingsThe deformation model provides the precision compensation basis for control system. Application test results show that the automatic drilling and riveting system can realize assembly of large aircraft panel with high efficiency and quality through the inner-side working head.Research limitations/implicationsThe inner-side working head has been used in aircraft panel assembly.Practical implicationsThe inner-side working head has been used in aircraft panel assembly.Originality/valueThis paper presents the design, analysis and optimization of a new type of inner-side working head which can realize automatic riveting for aircraft panel. The research will promote the automation of aircraft panel assembly.

Improvements in the Hole-Drilling Test Method for Determining Residual Stresses in Polymeric Materials

Abstract This article describes some improvements of the hole-drilling test method to increase the accuracy in determining residual stresses in polymeric materials. Unlike traditional applications of the hole-drilling technique to metals, when applied to polymers, it is essential to take into account important aspects such as the influence of ambient temperature, local heating, and thermal and mechanical effects generated by drilling operations. Unfilled polymers have a great coefficient of linear thermal expansion range, but the strain gauges for residual stresses available on the market are self-compensated only for some metallic materials. Furthermore, their low thermal diffusivity and the strong temperature dependence of their mechanical properties, notably, elastic modulus, creep, and relaxation, could determine local heating problems. The article investigates the hole-drilling technology on these materials and presents a testing procedure suitable for minimizing sources of error. The tests are carried out in a temperature-controlled test environment, and drilling is performed using the automatic drilling technique with a remote control, rather than a manual, drilling technique. Selections of the drilling rotational speed, feed rate, and type of drilling cutter are examined in detail. In order to validate the measurement approach, the experimental results obtained with a bending test bench on a polyethylene terephthalate sample are shown.

Robotic System for Bone Drilling Using a Rolling Friction Mechanism

Bone drilling procedures are frequently performed in various surgical fields using computed tomography. The robotic systems employed to perform such procedures can improve the targeting accuracy and reduce the radiation exposure to surgeons. This report presents the mechanism, navigation system, and experimental evaluation of a proposed robotic drilling system. This system provides automatic drill tip alignment and target drilling. Unlike previously proposed robotic drilling systems, the system developed here employs a drilling mechanism based on rolling friction and an orientation mechanism using a four-bar linkage with a linear actuator. It also implements a release mechanism between the robot and drill to enhance surgical safety. The proposed orientation mechanism was proven to provide a high drilling location accuracy. To guide the robot and enable automatic target drilling, we developed a vision-guided navigation system, which was integrated with the proposed robot using a stereo camera. The effectiveness of the proposed robotic system was demonstrated by performing ex vivo drilling on swine femur samples.

A novel control system design for automatic feed drilling operation of the PLC-based oil rig

Aiming at the difficulties in realizing the accurate control due to the nonlinearity of the automatic drilling system of oil drilling rig, a design scheme is proposed by giving a constant drilled-pressure to the rig for fuzzy control. Sampling error with changes in the signal was sent into the fuzzy controller, which turned the signal into a fuzzy volume. Subsequently, a precise volume was obtained accordingly and then added to an actuator for the motor control. According to the MATLAB simulation results, the response could be faster and more stable compared with the traditional control.

Design of Semi-physics Simulation Training System for Offshore Drilling Electrical Engineers

As the automatic drilling control system is more widely adopted in the field of offshore oil drilling, the integration of the control system has brought the electrical engineers more challenges to the system troubleshooting. There is an urgent need to propose a low-cost training solution for electrical engineers. Therefore, a semi-physics simulation training system of offshore drilling specifically designed for electrical engineers is addressed in this paper. To maintain high simulation fidelity, driller chairs and PLC controllers are copied and realized from field. Mathematical models are built to simulate both normal and fault state of the drilling control system. Different faults are realized by changing the setting parameters of model or switching between faulty models. Finally, with the help of virtual reality technology, the 3-D environment of drilling operation is realized to improve the vision performance. Moreover, an instructor station subsystem is designed to evaluate trainer’s performance. Through this simulation training system, the electrical engineers can not only master drilling control system, but also improve the troubleshooting skill.

Dynamic Characteristics of the End-effector of a Drilling Robot for Aviation

This study discusses the dynamic stiffness of the End-effector of a drilling robot for aircraft. In view of the requirements of automatic drilling processing for aircraft parts, based on the analysis of the working process of the automatic drilling End-effector, the End-effector of drilling unit has been employed in precision machine tools, It can provide very smooth motion and good verticality. In the design of the machines, it is necessary to obtain the stiffness of these guideway. Therefore, an identification method of the guideway stiffness is verified in this paper. In this method, the guideway stiffness is identified from the natural frequency of the moving body. First, a virtual prototype of the End-effector of drilling unit flexible is constructed by jointly using both ANSYS, which provides a foundation for further dynamic characteristic simulations. Next, the impact test is carried out for a drilling tool to obtain the vibration mode of its moving body, and simple vibration model is developed based on the obtained vibration mode to identify the natural frequency of the guideways. For further verification, natural frequencies of the moving body are calculated by FEM with the identified natural frequency and compared with the measured natural frequencies. The results shows that : the natural frequencies were calculated almost correctly with the identified equivalent stiffness, and which provides theoretical reference for improving the drilling efficiency and assembly quality of aircraft components.

A united kinematic calibration method for a dual-machine system

PurposeThis paper aims to propose a united kinematic calibration method for a dual-machine system in automatic drilling and riveting. The method takes both absolute and relative pose accuracy into account, which will largely influence the machining accuracy of the dual-machine system and assembly quality.Design/methodology/approachA comprehensive kinematic model of the dual-machine system is established by the superposition of sub-models with pose constraints, which involves base frame parameters, kinematic parameters and tool frame parameters. Based on the kinematic model and the actual pose error data measured by a laser tracker, the parameters of coordinated machines are identified by the Levenberg–Marquardt method as a multi-objective nonlinear optimization problem. The identified parameters of the coordinated machines will be used in the control system.FindingsA new calibration method for the dual-machine system is developed, including a comprehensive kinematic model and an efficient parameter identification method. The experiment results show that with the proposed method, the pose accuracy of the dual-machine system was remarkably improved, especially the relative position and orientation errors.Practical implicationsThis method has been used in an aircraft assembly project. The calibrated dual-machine system shows a good performance on system coordination and machining accuracy.Originality/valueThis paper proposes a new method with high accuracy and efficiency for the dual-machine system calibration. The research can be extended to multi-machine and multi-robot fields to improve the system precision.

Automatic bone drilling by femoral head structure detection

ABSTRACTThere is an increase in the incidence of hip fractures worldwide in recent years, associated with the upward trend in the life expectancy of the human population. Hip fractures occur mostly in patients aged over 60 years. Therefore, the task for optimization of hip fracture treatment and maximal patients’ recovery is of serious social importance. Many scientists devote their efforts to improving the solutions to such cases. This work presents a specific algorithm developed for registration of human femoral head far cortex and human femoral head end. Its realization is a very successful robot application in the orthopaedic surgery – automatic bone drilling. The experimental specimens are human hip heads obtained during hip-joint excision arthroplasty. The device indicates the maximal hole depths which could be reached. Such information helps to determine and calculate the accurate implant size to ensure its positioning in the desired area of the hip head and reaching maximal fixation strength. The risk of penetration into the joint capsule is eliminated by software defence that the robot is responsible for. The proposed solution is a promising approach towards improvement of the precision and outcome of hip fracture treatment.

Sensitivity analysis of temperature and force in robotic bone drilling process using Sobol statistical method

ABSTRACTThe bone drilling process is indispensable in orthopaedic surgeries and treating bone breakages. It is also very important in dentistry and bone sampling operations. Bone is a very complex material and the process of drilling is very sensitive. Thus, bone drilling is one of the most important, common in the field of biomedical engineering. The bone drilling process can be promoted using automatic drilling machines and surgery-assisting robots. The problematic issue during operation is the high increase in drilling process temperature (higher than 47 °C) which leads to the so-called ‘thermal necrosis’ or cell death, and local burn in bone tissue. Furthermore, imposing higher forces to bone might yield to breaking or cracking, and consequently causes serious damages in bone. In this paper, the tool rotational speed, feed ratio and tool diameter were taken into account as process input parameters, and process temperature and thrust force were taken as output parameters. Design of experiments using response surface methodology was followed. Then, second linear governing equation was assigned to the model and its accuracy was evaluated. Later, Sobol statistical sensitivity analysis was used to ascertain the effect of process input parameters on process temperature and force. The results showed that among all effective input parameters, the tool rotational speed, feed rate and tool diameter have the highest influence respectively on process temperature and force. The behaviour of each output parameter with variation in each input parameter was further investigated.

An approach to countersink depth control in the drilling of thin-wall stacked structures with low stiffness

The deformation of thin-wall stacked structures with low stiffness has been a common problem in the aircraft assembly process, making it difficult to achieve tight tolerance of the countersink depth in one-shot stack drilling. This difficulty is attributed to the complex tool position relative to the workpiece during the machining process. In this paper, an approach to countersink depth control composed of real measurement of the workpiece deformation and compensation of the tool position is presented. The deformation of the workpiece is divided into the following two categories: the rotation angle perpendicular to the feed direction and the deformation along the feed direction. These types of deformation are analysed regarding their influence on the countersink depth error. Effective measures are taken to ensure the countersink depth accuracy; such measures include the adjustment of the normal vector of the drilling position after the clamping process, the error monitoring of the normal vector during machining, and the multi-level compensation during machining. Theoretical analysis and validation of the proposed solution via comparative experiments showed a clear understanding of the coupled interaction of the thrust force with the workpiece deformation and corresponding reduction in the countersink depth error. The compensation solution requires simple computation and is straightforward to implement in industrial automatic drilling applications.

Effect of riveting parameters on the quality of riveted aircraft structures with slug rivet

Slug rivet should be installed by automatic drilling and riveting machine due to its special structure. The investigation on slug rivet is limited. In order to promote the application of slug rivet...

A frequency-domain propagation model of bypass downlink system with transfer matrix method

Although many patents have introduced the principle of bypass downlink system for automatic drilling, and the downlink systems have been used to communicate from the surface equipment to the bottom-hole-assembly (BHA) for thousands of meters, there are few literature reports of propagation theory of the downlink telemetry. In order to increase the transmission rate of downlink system, it is necessary to study mathematical model of the downlink communication channel. In this paper, a frequency-domain model of the downlink communication for the bypass downlink system is established based on the transfer matrix method, which describes the relationships between the transmitted flow rate pulses from the downlink equipment on the surface and the received voltage signals from downhole turbine generator, and can be used to predict downhole signal waveform. The prediction result is compared to that of the method of characteristic (MOC) algorithm and validated by the experiments. Simulation and experimental results show that the proposed model is correct and feasible.

An efficient error compensation method for coordinated CNC five-axis machine tools

Abstract The paper introduces a new automatic drilling and riveting system for aircraft assembly which is composed of two five-axis machine tools in coordination. As a dual-machine system, relative position and orientation accuracy of coordinated machines is the decisive factor for high fastening quality. Considering all static/quasi-static error sources deteriorating relative positioning accuracy, an effective error compensation method which consists of a new error prediction model and an error compensation strategy is proposed for coordinated five-axis machines. Based on the decomposition concept, the coordinated workspace of dual machines is described as the superposition of the coordinated workspace of prismatic joints (CWP) and the coordinated workspace of revolute joints (CWR). They are separated to study the influence on the objective error, and a combined interpolation algorithm based on the shape functions is proposed for error prediction, which can avoid the curse of dimensionality essentially and be efficient to predict the relative position and orientation errors at any desired pose in the coordinated workspace of dual machines. For the error compensation of dual-machine system, a basic strategy is proposed which is to take the position and orientation of the driving machine as the reference and compensate the predicted error for the driven machine through the motion commands modification. To verify the feasibility of proposed method, experiments have been performed on the developed dual-machine system with different error compensation methods. The results show that the proposed method is more efficient which needs less time for sampled data measurement and calculation, and the relative positioning accuracy of the compensated dual-machine system is improved to 0.072 mm and 0.017° which meet the requirements for automatic drilling and riveting in aircraft assembly.

Kinematic modeling and base frame calibration of a dual-machine-based drilling and riveting system for aircraft panel assembly

The paper introduces a new automatic drilling and riveting system for aircraft panel assembly which is composed of two five-axis machines in coordination. Kinematic modeling and base frame calibration are fundamental problems for the dual-machine system to improve its positioning accuracy. In this paper, a comprehensive kinematic model for the dual-machine system is established based on the modularization concept, and a new base frame calibration method is proposed which consists of the direct calibration based on laser tracker and calibration error compensation based on a specially designed instrument. In the kinematic modeling stage, the kinematic model of the dual-machine system is divided into three parts and three corresponding sub-models are established. With the pose constraints of coordinated machines, a comprehensive kinematic model of the dual-machine system is built. In the base frame calibration stage, the base frames of dual machines are firstly established by laser tracker. Due to many error sources in the calibration process, the relative pose errors of dual machines exist with the relationship between the base frames of coordinated machines. Then, the calibration error is measured by a specially designed instrument and used to modify the primary base frame calibration results. To verify the validity of the proposed method, experiments have been performed and the results have shown great improvement in base frame calibration accuracy. With the advantage of easy operation and high accuracy, this method can be extended to other multi-machine and multi-robot systems.

Automatic bone drilling using a novel robot in orthopedic trauma surgery

Background: Currently, applications of robotized systems in orthopedic trauma surgery steadily increase due to their functional abilities facilitating surgeon skills. The aim of this study is to present the functional advantages of a recently developed robot for bone drilling.Methods: Ex-vivo experiments were performed on fresh porcine and bovine bones, as well as on fresh and embalmed human bones such as femora, vertebrae and rips, by the use of the robot for bone drilling to identify diverse control parameters and analyse thrust force and drill bit temperature during drilling.Results: Experimental data during drilling is shown, control algorithms are described and bone drilling modes are characterized. Maximal values of thrust force and temperature are detected. Controlling thrust force seems to be the proper way to reduce force resistance and hence temperature during drilling. In automatic drilling mode, preliminary defined channel depth is drilled with accuracy of 0.1 mm, and far cortex end recognition is proved to work reliably for automatic stop with minimal controlled soft tissue penetration. Cortex and bone marrow thickness are measured and analysed in real time.Conclusion: The bone drilling robot is programmed to follow with high accuracy parameters defined by the surgeon. Enhancing surgeon’s freedom and responsibility to make decisions, it can perform precise manipulations, decreasing the influence of subjective factors and increasing patient’s safety.