Sentence:  A novel robotic <WSD>gasbag</WSD> polishing technique based on flexible polishing principle has been presented by S.M. Ji et al., which can make polishing process more stable and effective because the rubber <WSD>gasbag</WSD> provides cushioning action and almost all abrasive particles in the contact area are involved in the process of material removal on mould surface, etc ... 
Meaning of the word marked with <WSD> tags:  A bag or bladder to hold a reservoir of gas, as in a hot-air balloon.