ReviewRobotic grinding of complex components: A step towards efficient and intelligent machining – challenges, solutions, and applications
Introduction
Complex components, such as turbine blade, wind blade, new energy bus body and high-speed rail body are widely used in aerospace, energy, automobile and rail transit industries, and their manufacturing level represents the core competitiveness of a country's manufacturing industry. Generally, the complex components can be divided into complex surfaces and complex structures. The former is characterized by freeform, thin-walled surface with difficult-to-machine materials, and requires high dimensional accuracy and surface quality. While the latter is featured with large size, high material removal rate, and multi-variety and small-batch production. After forging, casting, molding or mechanical machining, these components are universally required for grinding or finishing to further enhance the contour accuracy and surface finish. Therefore, mastering the high-efficiency and high-precision grinding technology for such complex components poses a serious challenge facing the manufacturing industry.
At present, the complex components are mainly ground by virtue of manual operation and multi-axis CNC machine tools. Two typical examples of grinding turbine blade and wind blade are shown in Fig. 1. Because of the time- and labor- consuming as well as the harsh operating environment experienced by manual grinding, the multi-axis CNC grinding has become the mainstream approach for manufacturing such parts [1]. Its in-depth application, however, is limited owing to the followings reasons: (1) high cost of precision machine tools, up to millions U.S. dollars, particularly for the large-scale multi-axis CNC machine tool; (2) fixed manufacturing mode, characterized by unavailable flexible and parallel machining capability; and (3) complex configuration without integrated "machining - measurement" function.
An approach based on the industrial robots offers new ideas for the manufacture of such complex components. Compared with the multi-axis CNC machine tools, robots are attractive due to their large extendable workspace and competitive price that makes them a cost-effective solution for machining of complex components, especially for large dimension parts [3]. Particularly equipped with the powerful sensing functions, such as machine vision, force-sensing [4], the robotic machining operations can optimize the running parameters in real-time based on the process knowledge model and multi-sensor feedback information. This breaks through the limitations of traditional manufacturing equipment which focuses only on the movement axis position and speed control, thereby leading to the active control of the equipment on the process. However, it is worth mentioning that the main obstacle for wide utilization of robots in precision machining is their relatively low accuracy and repeatability compared to the CNC machine tools, and a detailed comparison of CNC machine tools and industrial robots for machining is presented in Table 1 [5].
Nevertheless, a large number of effective solutions have been proposed to reduce the manipulator stiffness and positioning errors in industrial machining fields [6,7]. Particularly for the grinding operation of complex components, the robotic grinding is gradually replacing the multi-axis CNC machine tools, and becoming an alternative means for manufacturing such parts. During the past one to two decades, the research results of robotic grinding of complex components are gradually enriched, and the published literatures mainly focus on the feasibility study of robotic machining [8], [9], [10], as well as the modeling and analysis of machining dynamics [11], [12], [13]. The investigations are conducted mainly from the aspects of robot position/posture optimization [14,15], robot calibration and measurement [16], [17], [18], [19], [20], grinding path planning [21], [22], [23], material removal control [12,24,25], force control [26], [27], [28], [29] etc.. Furthermore, Table 2 compares the recently published review papers related to robotic machining. It is found that the existing ones are mainly elaborated from the perspectives of machining robots, machining properties based operation categories, mobile-robot machining, and robotic machining chatter.
Starting from the different perspective compared to the existing ones, the organization and writing of our review paper mainly focuses on the following three aspects:
- (1)
The specific machining operation category. We identified the machining operation category as robotic grinding, since this operation offers new ideas for the manufacture of complex components compared with the capacity of multi-axis CNC machine tools and conventional manual operation. Also this topic with respect to robotic grinding receives wide attention to enhance the current automated machining level.
- (2)
The geometry and size of the research objects. We focused on the complex components, including the freeform surfaces (less than one meter in length, i.e. turbine blades, blisk) and the large-scale complex structures (up to ten or dozens of meters in length, i.e. wind blade, high-speed rail body, and new energy bus body). This is mainly because we noticed that the development of robotic grinding in theory and application presents two extremes, one aims to reach micrometer level of grinding accuracy of freeform surface by the robot with sub-millimeter level of relatively low accuracy and repeatability, the other emphasizes on the enhancement of the grinding efficiency of large-scale complex structures to maintain the upstream and downstream production beats.
- (3)
The key technologies identified from this topic. For the robotic grinding of small-scale complex surfaces, the strategies from accuracy control and compliance control should be fully addressed, while for the robotic grinding of large-scale complex structures, multi-robot based cooperative control could be taken as an effective means to enhance the machining efficiency. To address the challenges, our research team identified four aspects of key technologies in robotic grinding of complex components, including the high-precision online measurement, grinding allowance control, constant contact force control, and surface integrity from robotic grinding.
The aim of this paper is to present a systematic, critical and comprehensive review of all aspects of robotic grinding of complex components. Thus, we aim to conduct the summarization of research works to (1) identify the challenges faced by robotic grinding of complex components, (2) report the research work carried out and various alternative solutions provided by the researchers in this area till date, and (3) discuss the typical applications of robotic grinding of turbine blades and large-scale complex structures, and finally propose some possible directions for future research interests.
Section snippets
Challenges faced by robotic grinding of complex components
The main issues which restrict the practical implementation of robotic grinding of complex components are discussed below.
Strategies and solutions for successful robotic grinding of complex components
To overcome the challenges faced by the robotic grinding of complex components, the following strategies and potential solutions can be conducted to construct the integrated “measurement – manipulation – machining” function for the robotic grinding system.
Background and existing problems
At present, the milled blades are mainly finished by virtue of manual grinding and multi-axis CNC belt grinding. Compared with the blade profile, the thickness of the leading and trailing edges of the blade is thin (to be R0.1 mm level). Both the curvature and machining path change greatly, and this poses a challenge to the precision grinding of blades [64]. Owning to the large randomness of positioning and the uncontrollable contact force at tool-workpiece interfaced during the manual
Conclusion and future research interests
Robotic machining is a kind of high-end manufacturing that conforms to the national situation. It is regarded as an effective means to solve the "pain points" facing the grinding industry. Despite the robots have obvious technical advantages in terms of dexterity, production flexibility, and functional integration, however, there are still gaps in machining accuracy and surface quality by robotic grinding, especially compared to the CNC machine tools. This is mainly owing to the high coupling
Declaration of Competing Interest
The authors declare no conflict of interest.
Acknowledgment
The authors received financial support from the National Nature Science Foundation of China (nos. 51975443, 51675394, 51535004), the National Key Research and Development Program of China (no. 2017YFB1303403), the Wuhan Applied Basic Research Project (no. 2017010201010139), the State Key Laboratory of Digital Manufacturing Equipment and Technology (no. DMETKF2018018), and the “111” Project (no. B17034).
References (115)
Efficiency evaluation of robots in machining applications using industrial performance measure
Robot. Comput. Integr. Manuf.
(2017)Positioning error compensation on two-dimensional manifold for robotic machining
Robot. Comput. Integr. Manuf.
(2019)- et al.
Simulation and verification of belt grinding with industrial robots
Int. J. Mach. Tools Manuf
(2006) A local process model for simulation of robotic belt grinding
Int. J. Mach. Tools Manuf
(2007)Automated robotic grinding by low-powered manipulator
Robot. Comput. Integr. Manuf.
(2007)- et al.
Structural dimension optimization of robotic belt grinding system for grinding workpieces with complex shaped surfaces based on dexterity grinding space
Chin. J. Aeronaut.
(2011) - et al.
Posture optimization methodology of 6R industrial robots for machining using performance evaluation indexes
Robot. Comput. Integr. Manuf.
(2017) - et al.
Accurate robotic belt grinding of workpieces with complex geometries using relative calibration techniques
Robot. Comput. Integr. Manuf.
(2009) Robotic grinding and polishing for turbine-vane overhaul
J. Mater. Process. Technol.
(2002)- et al.
A path planning method for robotic belt surface grinding
Chin. J. Aeronaut.
(2011)
Collision-free planning algorithm of motion path for the robot belt grinding system
Int. J. Adv. Rob. Syst.
Design of a force-controlled end-effector with low-inertia effect for robotic polishing using macro-mini robot approach
Robot. Comput. Integr. Manuf.
Robots in machining
CIRP Ann.
Calibration and accuracy analysis of robotic belt grinding system using the ruby probe and criteria sphere
Robot. Comput. Integr. Manuf.
Analysis and assessment of robotic belt grinding mechanisms by force modeling and force control experiments
Tribol. Int.
An enhanced kinematic model for calibration of robotic machining systems with parallelogram mechanisms
Robot. Comput. Integr. Manuf.
Keypoint-based 4-Points congruent sets – Automated marker-less registration of laser scans
ISPRS J. Photogramm. Remote Sens.
A modified ICP algorithm based on dynamic adjustment factor for registration of point cloud and CAD model
Pattern Recognit. Lett.
Efficient sparse icp
Comput. Aided Geom. Des.
An efficient method for solving the signorini problem in the simulation of free-form surfaces produced by belt grinding
Int. J. Mach. Tools Manuf
Modeling and analysis of the material removal depth for stone polishing
J. Mater. Process. Technol.
On energetic assessment of cutting mechanisms in robot-assisted belt grinding of titanium alloys
Tribol. Int.
Time-optimal and jerk-continuous trajectory planning for robot manipulators with kinematic constraints
Robot. Comput. Integr. Manuf.
An improved robotic abrasive belt grinding force model considering the effects of cut-in and cut-off
J. Manuf. Process
Design and performance analysis of position-based impedance control for an electrohydrostatic actuation system
Chin. J. Aeronaut.
Modeling and control of robotic automatic polishing for curved surfaces
CIRP J. Manuf. Sci. Technol.
A real-time polishing force control system for ultraprecision finishing of micro-optics
Precis. Eng.
Contact force control and vibration suppression in robotic polishing with a smart end effector
Robot. Comput. Integr. Manuf.
Kinematic analysis and feedrate optimization in six-axis nc abrasive belt grinding of blades
Int. J. Adva. Manuf. Technol.
Toward physical description of form and finish performance in dry belt finishing process by a tribo-energetic approach
J. Mater. Process. Technol.
Characterization and modelling of the residual stresses induced by belt finishing on a AISI52100 hardened steel
J. Mater. Process. Technol.
Effect of the belt grinding on the surface texture: modeling of the contact and abrasive wear
Wear
Machining the integral impeller and blisk of aero-engines: a review of surface finishing and strengthening technologies
Chin. J. Mech. Eng.
Model of an abrasive belt grinding surface removal contour and its application
Int. J. Adva. Manuf. Technol.
A workcell calibration method for enhancing accuracy in robot machining of aerospace parts
Int. J. Adva. Manuf. Technol.
A wireless force-sensing and model-based approach for enhancement of machining accuracy in robotic milling
IEEE/ASME Trans. Mechatron.
A review on chatter in robotic machining process regarding both regenerative and mode coupling mechanism
IEEE/ASME Trans. Mechatron.
H. mueller, and B. kuhlenkoetter, Surfel-based surface modeling for robotic belt grinding simulation
J. Zhejiang Univ.-Sci. A
A simulation platform for optimal selection of robotic belt grinding system parameters
Int. J. Adva. Manuf. Technol.
Vibro-impact dynamics of material removal in a robotic grinding process
Int. J. Adv. Manuf. Technol.
Calibration of a portable laser 3-D scanner used by a robot and its use in measurement
Opt. Eng.
TCP-based calibration in robot-assisted belt grinding of aero-engine blades using scanner measurements
Int. J. Adva. Manuf. Technol.
A case study of blade inspection based on optical scanning method
Int. J. Prod. Res.
A new calibration method between an optical sensor and a rotating platform in turbine blade inspection
Meas. Sci. Technol.
A method for grinding removal control of a robot belt grinding system
J. Intell. Manuf.
An adaptive modeling method for a robot belt grinding process
IEEE/ASME Trans. Mechatron.
An adaptive sliding-mode iterative constant-force control method for robotic belt grinding based on a one-dimensional force sensor
Sensors (Basel)
Application of novel force control strategies to enhance robotic abrasive belt grinding quality of aero-engine blades
Chin. J. Aeronaut.
Robotic grinding of a blisk with two degrees of freedom contact force control
Int. J. Adva. Manuf. Technol.
Industrial robotic machining: a review
Int. J. Adva. Manuf. Technol.
Cited by (261)
Design and implementation of a precision levelling composite stage with active passive vibration isolation
2024, Robotics and Computer-Integrated ManufacturingVision-guided path planning and joint configuration optimization for robot grinding of spatial surface weld beads via point cloud
2024, Advanced Engineering InformaticsA stiffness matching-based deformation errors control strategy for dual-robot collaborative machining of thin-walled parts
2024, Robotics and Computer-Integrated ManufacturingTeleoperation mode and control strategy for the machining of large casting parts
2024, Robotics and Computer-Integrated ManufacturingAccurate modeling of material removal depth in convolutional process grinding for complex surfaces
2024, International Journal of Mechanical Sciences