Robotic Drilling Research Articles

Mathematical modeling of a hydraulic drive for leveling the support table of a robotic drilling platform

The principle of moving a hydraulic drilling platform is described. To study the dynamics of transient response processes of hydraulic drive for leveling, a mathematical model was created. The structural diagrams of mathematical models of the actuator and hydraulic control valve are given. The time dependences of the spool positions of the hydraulic control valve and the hydraulic cylinder rod are presented. The dependences of pressure changes in the rod and piston cavities of the hydraulic cylinder are presented.

A semi-supervised deep learning approach for circular hole detection on composite parts

This paper introduces the usage of semi-supervised learning to obtain competitive detection accuracy of measuring drilled holes on composite parts with very limited noisy training data. An improved texture segmentation algorithm based on local binary patterns algorithm is proposed, named local exponential patterns. The algorithm divides the image texture into nine levels, of which the highest level of texture is selected for contour extraction. An ellipse fitting method is used to fit the target contours and vote for the candidate ellipses. The regions inside the candidate ellipses are taken as the semi-supervised semantic label for images. A new loss named round loss is proposed, and a superior circle segmentation model was trained by learning from incompletely annotated data. To verify the effectiveness of the method, experiments were conducted with the drilled holes on the composite parts. The results show that the proposed semi-supervised deep learning approach is exceedingly suitable for circle detection of holes with different texture information commonly found in robotic drilling. Massive data labeling can be completely avoided with proposed method. The measurement accuracy can reach 0.03 mm, which can meet the visual measurement requirements of the circular holes on composite parts in the robotic drilling system.

Stiffness properties analysis and enhancement in robotic drilling application

Low stiffness and special stiffness properties limit the application of industrial robots in sophisticated manufacturing. The subject of the paper is to investigate the influence of robot stiffness properties on machining quality in drilling application. It is found that unidirectional thrust force could induce three-directional deformation of robot which will directly lead to hole defects during drilling procedure. Firstly, starting from the special characteristics of the robot, the key role of the preload pressing force is pointed out. Equivalent stiffness model under pre-load pressing force is established and stiffness promotion coefficient is defined to evaluate the effects of pressing force quantitatively. The matching criterion of robot drilling posture and thrust force is proposed, and the optimized value of pressing force can be predicted under the condition of stable machining. Limitation on hole diameter and roundness of robot drilling is evaluated too. By applying pre-load pressing force, the stiffness of robot drilling plane is markedly improved, and the drilling stability and hole diameter accuracy are also enhanced. Finally, the proposed method is verified by drilling experiments.

생체모방형 두더지 로봇 개발 및 방향성 시추 메커니즘

Drilling technology has been used in various fields. In recent years, studies have been conducted for extreme areas and space exploration. In addition, technology is being developed for the exploration and mining of new energy resources. Because of the large size and the complicated processes of the existing drilling systems, many limitations and environmental problems exist. In recent years, bio-inspired or bio-mimetic robots that simulate the movement or habitats of living things have been developed actively for efficient operation. This paper proposes an embedded directional drilling robot (Mole-bot) that mimics the biological structure and excavation habits of the mole. The proposed system includes digging, moving, direction changing, locking, and debris removal mechanisms, In conclusion, performance evaluation of the excavation mechanism and direction changing mechanism of the developed robot were carried out.

Inchworm Drilling System for Planetary Subsurface Exploration

The physical properties, sequence structure, and heat flow of planetary regolith are important information to enhance the scientific understanding of lunar evolution and the origin of life, as well as for future planetary activities and resource utilization. An inchworm drilling system for planetary subsurface exploration missions is proposed in this article. The inchworm drilling system consists of an inchworm drill and a chip removal device, and this article provides a detailed description of the system design. Reasonable drilling parameters in the regular drilling condition are recommended based on drilling load analysis, and a manipulation strategy is given for troubleshooting in the faulty drilling condition. Robotic drilling experiments were carried out on a lunar regolith simulant, and the drilling depth of the inchworm drill reached 850 mm in 106 min. In addition, parameter identification tests of the simulant mechanical parameters were carried out during drilling, and the shear strength parameters of the simulant cohesion and internal friction angle at five locations along the depth direction were measured. The experimental results show that the proposed inchworm drilling system can well achieve the mission target of drilling and exploration and is a feasible choice for future planetary exploration missions.

Non-Cylindricity of Holes Formed with Robotic Complex

The article describes the technological features of the formation of holes with the help of the created robotic technological complex based on a Kuka robot. The robotic complex for machining allows you to drill holes in the Helmholtz resonators to absorb noise in shells made of polymer composite materials (GFRP and CFRP) of aircraft engines. Holes for noise absorption with a diameter of 1.6–2 mm are required to be shaped in a significant array; 200-300 thousand holes must be drilled on one shell. The technological problems arising from the robotic drilling process are noted. One of the problems is the deviation from the cylindricity of the formed holes, the deviation arises due to the kinematics of the robot. A technical solution to this problem is proposed.

Soil Discharging Mechanism Utilizing Water Jetting to Improve Excavation Depth for Seabed Drilling Explorer

Seabed mineral resources have been found on the bottom of the ocean, and to utilize them, samples must be taken and analyzed. This study develops a seafloor robotic explorer that can excavate and sample seafloor soil. In a previous study, we developed a drilling robot that could excavate 430 mm into the ground while underwater. However, excavation deeper than 430 mm was not possible because the discharging outlet became buried, making it difficult to discharge the drilled soil. In this paper, we develop a discharging mechanism utilizing water jetting to improve the excavation depth to 650 mm and potentially deeper.

Fringe-Projection-Based Normal Direction Measurement and Adjustment for Robotic Drilling

In a large-scale structure assembly, a highly accurate normal direction measurement for robotic drilling is required. However, the robustness and accuracy of the existing normal direction measurement method with a range sensor would dramatically decrease for a high-curvature surface, such as the surface edge, due to the low resolution of the range sensor. To this end, a high-resolution fringe projection sensor is proposed to improve the measurement robustness and accuracy. In this method, different from the control scheme design with a reconstructed three-dimensional point cloud in fringe projection profilometry, which involves a high computational complexity, a novel two-dimensional phase-map-based two-stage control scheme, including coarse and refined normal direction adjustments, is designed to improve the robustness and accuracy. The coarse normal direction adjustment uses a phase map to estimate the normal direction, which is used to synthesize a position-based control scheme, leading to high robustness; the refined normal direction adjustment uses a phase map to synthesize an image-based control scheme, resulting in high accuracy. The proposed method is validated by simulations and experiments, which indicate that the proposed method is effective.

Chatter detection in robotic drilling operations combining multi-synchrosqueezing transform and energy entropy

Robotic drilling shows higher efficiency and precision than the manual drilling, which has great application prospects in the aviation manufacturing. Nevertheless, due to the detrimental effects on surface quality, tool wear, the safety of the robot and machining efficiency, chatter vibration has been a major obstacle to achieve stable and efficient robotic drilling. Therefore, it is particularly significant to detect and manage to suppress the chatter as early as possible. This paper presents a novel approach to identify the chatter in robotic drilling process based on multi-synchrosqueezing transform (MSST) and energy entropy. To begin with, matrix notch filters are designed to effectively eliminate the interference of spindle rotating frequency and its harmonics to the measured vibration signal. Subsequently, the filtered signal is processed by the MSST to obtain concentrated time-frequency representation. Then, the signal is divided equally into finite frequency bands and the subcomponent corresponding to each frequency band is reconstructed through the reverse MSST. Finally, in consideration of the change of the vibration signal in frequency and energy distribution when chatter occurs, the energy entropy is computed as the chatter detection indicator. The proposed chatter detection method was validated by robotic drilling experiments with different tools, machining parameters, and workpiece material, and the results indicate that the proposed method can effectively detect the chatter before it is fully developed and recognize the chatter earlier than the synchroextracting-based method.

Timely chatter identification for robotic drilling using a local maximum synchrosqueezing-based method

Induced by flexibility of the industrial robot, cutting tool or the workpiece, chatter in robotic machining process has detrimental effects on the surface quality, tool life and machining productivity. Consequently, accurate detection and timely suppression for such undesirable vibration is desperately needed to achieve high performance robotic machining. This paper presents a novel approach combining the notch filter and local maximum synchrosqueezing transform for the timely chatter identification in robotic drilling. The proposed approach is accomplished through the following steps. In the first step, the optimal matrix notch filter is designed to eliminate the interference of the spindle frequency and corresponding harmonic components to the measured acceleration signal. Subsequently, the high-resolution time–frequency information of the non-stationary filtered acceleration signal is acquired by employing local maximum synchrosqueezing transform (LMSST). On this basis, the filtered acceleration signal is divided into a finite number of equal-width frequency bands, and the corresponding sub-signal for each frequency band is obtained by summing the corresponding coefficient of the LMSST. Finally, to accurately depict the non-uniformity of energy distribution during the chatter incubation process, the statistical energy entropy is calculated and utilized as the indicator to detect chatter online. The effectiveness of the proposed approach is validated by a large number of robot drilling experiments with different cutting tools, workpiece materials and machining parameters. The results show that the presented local maximum synchrosqueezing-based approach can effectively recognize the chatter at an early stage during its incubation and development process.

A pre-generated matrix-based method for real-time robotic drilling chatter monitoring

Currently, due to the detrimental effects on surface finish and machining system, chatter has been one crucial factor restricting robotic drilling operations, which improve both quality and efficiency of aviation manufacturing. Based on the matrix notch filter and fast wavelet packet decomposition, this paper presents a novel pre-generated matrix-based real-time chatter monitoring method for robotic drilling. Taking vibration characteristics of robotic drilling into account, the matrix notch filter is designed to eliminate the interference of spindle-related components on the measured vibration signal. Then, the fast wavelet packet decomposition is presented to decompose the filtered signal into several equidistant frequency bands, and the energy of each sub-band is obtained. Finally, the energy entropy which characterizes inhomogeneity of energy distribution is utilized as the feature to recognize chatter on-line, and the effectiveness of the presented algorithm is validated by extensive experimental data. The results show that the proposed algorithm can effectively detect chatter before it is fully developed. Moreover, since both filtering and decomposition of signal are implemented by the pre-generated matrices, calculation for an energy entropy of vibration signal with 512 samples takes only about 0.690 ms. Consequently, the proposed method achieves real-time chatter monitoring for robotic drilling, which is essential for subsequent chatter suppression.

Prospective Validation of Facial Nerve Monitoring to Prevent Nerve Damage During Robotic Drilling.

Facial nerve damage has a detrimental effect on a patient's life, therefore safety mechanisms to ensure its preservation are essential during lateral skull base surgery. During robotic cochlear implantation a trajectory passing the facial nerve at <0.5 mm is needed. Recently a stimulation probe and nerve monitoring approach were developed and introduced clinically, however for patient safety no trajectory was drilled closer than 0.4 mm. Here we assess the performance of the nerve monitoring system at closer distances. In a sheep model eight trajectories were drilled to test the setup followed by 12 trajectories during which the ENT surgeon relied solely on the nerve monitoring system and aborted the robotic drilling process if intraoperative nerve monitoring alerted of a distance <0.1 mm. Microcomputed tomography images and histopathology showed prospective use of the technology prevented facial nerve damage. Facial nerve monitoring integrated in a robotic system supports the surgeon's ability to proactively avoid damage to the facial nerve during robotic drilling in the mastoid.

Simulation and Experimental Research on Robot Drilling

This paper describes the experimental and analytical performance of robot drilling on alloy materials. In heavy structures manual drilling consumes time and quality of holes drilled is unstable. The industrial robot with agile motion is possible to machine a component. Industrial robots with high precision and six axis Degree of freedom are considered for better robot manufacturing processes. This work is to significantly improve performance of robot drilling over conventional drilling. The industrial manipulator used is ABB - IRB1410 with work volume of 2.6 meters and controlled by IRC5 Controller. Drilling machine utilized is specified with maximum speed of 3000 RPM. The speed of the drilling machine can be varied by voltage regulator and maintain different speeds at a difference of 100 RPM. The parameters like surface roughness, time consumed, circular entry and exit, roundness is considered. Relay is utilized to turn on/off the drill at the required places. The industrial manipulator robot and vertical CNC machine drillings are compared by random values of Design of Experiments. The process parameters like drill bit size, speed of drill and feed rate are considered. Conventional material removal techniques like CNC have been proven to be able to tackle nearly any machining challenge but major drawback of using conventional CNC machine is restricted work volume

Robotic middle ear access for cochlear implantation: First in man.

To demonstrate the feasibility of robotic middle ear access in a clinical setting, nine adult patients with severe-to-profound hearing loss indicated for cochlear implantation were included in this clinical trial. A keyhole access tunnel to the tympanic cavity and targeting the round window was planned based on preoperatively acquired computed tomography image data and robotically drilled to the level of the facial recess. Intraoperative imaging was performed to confirm sufficient distance of the drilling trajectory to relevant anatomy. Robotic drilling continued toward the round window. The cochlear access was manually created by the surgeon. Electrode arrays were inserted through the keyhole tunnel under microscopic supervision via a tympanomeatal flap. All patients were successfully implanted with a cochlear implant. In 9 of 9 patients the robotic drilling was planned and performed to the level of the facial recess. In 3 patients, the procedure was reverted to a conventional approach for safety reasons. No change in facial nerve function compared to baseline measurements was observed. Robotic keyhole access for cochlear implantation is feasible. Further improvements to workflow complexity, duration of surgery, and usability including safety assessments are required to enable wider adoption of the procedure.

The progress of extraterrestrial regolith-sampling robots

Space exploration has significantly enriched humanity’s understanding of the space environment in which our Earth resides and the evolution of the Solar System. What we know about a celestial body can be greatly enhanced through a thorough analysis of regolith samples. Extraterrestrial regolith-sampling robots are instrumental in acquiring regolith samples for return or in situ analysis in deep-space exploration. This Perspective systematically summarizes the history and latest developments of these robots, covering the basic concepts, historical context and evolution. Extensive insights into the challenges and constraints in sampling extraterrestrial celestial bodies are then explored. An in-depth analysis of the key ground-test technologies that guarantee the reliability and security of extraterrestrial sampling robotic systems is then presented. Next, a comprehensive perspective of the main technical trends in the development of new extraterrestrial regolith-sampling robots is given. Finally, a technical roadmap of China’s future space exploration missions is provided. Extraterrestrial regolith-sampling robots have made great achievements and changed our understanding of the Universe in the past. They will continue to innovate extraterrestrial regolith-exploring methods in even more fundamental ways, and greater achievements are underway. The future of Solar System exploration lies in the subsurface of rocky bodies, including planets. Robots provide a relatively cost-effective and safe method of probing the subsurface; this Perspective summarizes recent efforts in robotic drilling and regolith-sampling methods, concluding with a summary of China’s future space exploration plans.

Industrial Robot Accuracy Degradation Monitoring and Quick Health Assessment

Robot accuracy degradation sensing, monitoring, and assessment are critical activities in many industrial robot applications, especially when it comes to the high accuracy operations which may include welding, material removal, robotic drilling, and robot riveting. The degradation of robot tool center accuracy can increase the likelihood of unexpected shutdowns and decrease manufacturing quality and production efficiency. The development of monitoring, diagnostic and prognostic (collectively known as prognostics and health management (PHM)) technologies can aid manufacturers in maintaining the performance of robot systems. PHM can provide the techniques and tools to support the specification of a robot’s present and future health state and optimization of maintenance strategies. This paper presents the robotic PHM research and the development of a quick health assessment at the U.S. National Institute of Standards and Technology (NIST). The research effort includes the advanced sensing development to measure the robot tool center position and orientation; a test method to generate a robot motion plan; an advanced robot error model that handles the geometric/nongeometric errors and the uncertainties of the measurement system, and algorithms to process measured data to assess the robot’s accuracy degradation. The algorithm has no concept of the traditional derivative or gradient for algorithm converging. A use case is presented to demonstrate the feasibility of the methodology.

A conceptual scale model of mobile drilling robot

PurposeThis paper aims to propose a conceptual scale model of mobile drilling robot according to the actual drilling rig and working conditions to improve the safety and automation of drilling in tunnel construction and coal mining applications.Design/methodology/approachA couple of pinion and rack serves as the support mechanism driven by a motor with low rotation speed at high power, and these components are assembled in the center of the robot to tightly fasten the whole body together. The drilling rod and the sleeve are connected through a hole with screw thread so that the rod feeds and rotates simultaneously along with the sleeve. The robot model is automatically controlled by a single-chip microcomputer, and the anti-disturbance circuit is designed as well. A five-step rule obstacle avoidance method is proposed to ensure safe and reliable movement.FindingsThe results of simulation experiments on drilling operation do indicate that the mechanism and control method are feasible and effective.Research limitations/implicationsThe robot is nearly complete but indeed remains only an experimental machine.Originality/valueThe design of the mechanism structure for the conceptual robot is novelty. The method of five-step rule obstacle avoidance can improve reliability of obstacle avoidance according to the experimental results, which can meet the requirements of complex working conditions underground coal mine.

A Completely Cast-Free, Digital Workflow for Fabricating an Implant-Supported Prosthesis with a New Coded Healing Abutment

The BellaTek Encode System introduced an innovative concept of a healing abutment-level impression. As the coded healing abutment is unscrewed only at the placement session, the mucosal barrier at an implant is preserved and the clinical process is simplified. The laboratory process is also streamlined, as the entire process of a definitive dental implant abutment is outsourced and a dental technician fabricates only a definitive crown on a modified cast by robotic drilling or a stereolithography additive cast. However, potential errors may occur in the fabrication process of the casts. In addition, this system is available to only a specific implant system. This article describes a fully integrated digital workflow to overcome the limitations with a newly developed coded healing abutment. With the merging of advanced digital technologies, an implant-supported prosthesis can be accurately fabricated in an hour with minimized abutment dis/reconnection and no physical cast.

Design and performance analysis of an industrial robot arm for robotic drilling process

PurposeThe purpose of this paper is to present a robotic arm that can offer better stiffness than traditional industrial robots for improving the quality of holes in robotic drilling process.Design/methodology/approachThe paper introduces a five-degree of freedom (DOF) robot, which consists of a waist, a big arm, a small arm and a wrist. The robotic wrist is composed of two DOFs of pitching and tilting. A parallelogram frame is used for robotic arms, and the arm is driven by a linear electric cylinder in the diagonal direction. Double screw nuts with preload are used in the ball screw to remove the reverse backlash. In addition, dual-motor drive is applied for each DOF in the waist and the wrist to apply anti-backlash control method for eliminating gear backlash.FindingsThe proposed robotic arm has the potential for improving robot stiffness because of its truss structure. The robot can offer better stiffness than industrial robots, which is beneficial to improve the quality of robotic drilling holes.Originality/valueThis paper includes the design of a five-DOF robot for robotic drilling tasks, and the stiffness modeling of the robot is presented and verified by the experiment. The robotic system can be used instead of traditional industrial robots for improving the hole quality to a certain extent.

Development of Underwater Drilling Robot Based on Earthworm Locomotion

In this paper, a drilling robot based on earthworm locomotion was developed for seafloor exploration. Seabed mineral resources are found on the bottom of the ocean. The drilling robot developed herein can excavate and obtain samples of seafloor soil. This paper was inspired by the results of the previous study, in which a drilling robot based on earthworm locomotion developed for land successfully demonstrated the ability to create curved boreholes of 1670-mm turning radius and 613-mm depth. By principle, earthworm locomotion is propelled without rubbing the side of the robot against the wall of the borehole. That is, the movement is not affected by earth pressure, and thus it is facilitated deep into the soil region, which makes it is suitable for underground exploration robots. Seafloor explorations, in essence, could be realized by improving the gripping torque of the drilling robot and reducing its drilling torque. To resolve the problem, in this paper, three points were addressed. First, a setae-attached propulsion unit patterned to an earthworm structure was designed to attain an improved gripping torque for a subunit, typically at 30 kPa, by 1.7 times compared to that without setae. Second, the drilling resistance was reduced by the adjustment of the penetration and rotational speeds of the drilling robot based on the drilling properties of underwater ground. Lastly, the shape of the earth auger was considered for the reduction of the drilling torque. Following these solutions, the developed robot succeeded in drilling 430 mm into an underwater soil.