Fig. 1. The appearance of the large diameter precision grinder UPG80 and the overall sheet metal of the machine^[11]

Fig. 2. Processing results of the large aperture aspheric elements^[15]. (a) Surface shape accuracy (PV=3.38 μm); (b) Subsurface damage depth (h=3 μm)

Fig. 3. Influence of the initial flow Q₀ on the motion accuracy^[17]. (a) Angular motion error; (b) Displacement motion error; (c) PV value of angular motion error and displacement motion error

Fig. 4. Guide rail distribution view along the X axis of the grinding machine UPG80^[11]

Fig. 5. Five-axis CNC bonnet polishing machine^[19]. (a) Bonnet polishing machine model diagram; (b) Actual drawing of the bonnet polishing machine

Fig. 6. The principle of bonnet polishing^[20]. (a) Precession motion model; (b) Bonnet "AB" pendulum structure

Fig. 7. Maze-based polishing path generation schematic^[20]

Fig. 8. Measurement results of roughness in the central region^[20]. (a) Grating path; (b) Hilbert path; (c) Maze paths

Fig. 9. Semi-flexible bonnet structure^[20]

Fig. 10. The results of shaping and processing front and back^[20]. (a) Polishing front shape; (b) Polishing back shape

Fig. 11. Experimental device for flexible precession polishing of space ball^[21]

Fig. 12. Diagram of the experimental results^[21]. (a) Material removal functions of polishing spots; (b) Surface microscale morphologies of the workpiece before and after

Fig. 13. Block diagram of impedance control algorithm based on environment model^[22]

Fig. 14. Experimental results curve of the robot compensation force control^[22]. (a) Curve 1 of the force control experiment results; (b) Curve II of the force control experiment results

Fig. 15. Surface finishing quality under varying pressure and steady pressure. (a) Pressure 10 N; (b) Pressure 15 N; (c) Pressure 20 N; (d) Surface machining quality at 10 N steady pressure

Fig. 16. Control frame diagram of the robot airbag polishing system^[24]

Fig. 17. Deformation cloud of robot end^[26]. (a) Attitude position angle 0°; (b) Attitude position angle 90°

Fig. 18. Bonnet suppression structure^[24]. (a) Model diagram of the vibration suppression tool head; (b) Section view of the vibration suppression tool head

Fig. 19. General bonnet whole surface polishing before and after comparison^[24]. (a) Before polishing; (b) After polishing

Fig. 20. Comparison before and after the whole surface polishing of vibration suppression airbag^[24]. (a) Before polishing; (b) After polishing

Fig. 21. Frame of the intelligent grinding monitoring system^[28]

Fig. 22. Online evaluation of the grinding performance of grinding wheel^[29]. (a) Acoustic emission waveform and spectrum; (b) Proportion of the low-frequency energy in samples of some nodes; (c) Main features represent grinding performance degradation curve of grinding wheel

Fig. 23. Comparison diagram of LSTM and BPNN network models^[30]. (a) Prediction results of LSTM network model; (b) Prediction results of BPNN network model

Fig. 24. 5 axis high efficiency bonnet polishing control system. (a) Main interface of the control software; (b) Plane conformal polishing; (c) Aspheric correction polishing

Fig. 25. Block diagram of the intelligent robot assisted grinding and polishing digital twin system

Fig. 26. Human-computer interaction interface