Journal of South China University of Technology(Natural Science Edition) ›› 2022, Vol. 50 ›› Issue (8): 71-81.doi: 10.12141/j.issn.1000-565X.210698

Special Issue: 2022年机械工程

• Mechanical Engineering • Previous Articles     Next Articles

Deep Learning-Based Prediction of Contact Force in the Process of Shoveling Up Glass Subtrate

HOU Liwei1 WANG Hengsheng1,2 ZOU Haoran1   

  1. 1.College of Mechanical and Electrical Engineering, Central South University, Changsha 410083, Hunan, China
    2.State Key Laboratory of High Performance Complex Manufacturing, Central South University, Changsha 410083, Hunan, China
  • Received:2021-11-04 Online:2022-08-25 Published:2022-03-18
  • Contact: 王恒升(1963-),男,博士,教授,主要从事机电系统动力学建模与控制、工业机器人控制技术研究。 E-mail:whsheng@csu.edu.cn
  • About author:侯力玮(1992-),男,博士生,主要从事机器人决策与规划算法研究。E-mail:lwhou1992@gmail. com
  • Supported by:
    the National Natural Science Foundation of China(51975587)

Abstract:

In view of the problem of insufficient characterization ability and poor versatility of action force modeling methods in existing robot contact operation tasks, this paper studied on the modeling methods of complex contact dynamics by taking the actual production process of glass substrate shoveling as an example. Considering the fact that the forces during the glass substrate shoveling are affected by the contact dynamics of multiple interfaces, exhibiting the multimodal, nonlinear, and non-stationarity properties, this paper proposed a method for the prediction of the contact force by integrating physical prior knowledge in different forms in the design and training process of deep learning models. According to the stress characteristics of the glass substrate’s shoveling up process, a deep learning model structure combining multi-scale convolutional kernel, attention mechanism and long and short-term memory network was proposed; the kinetic parameter randomization method and the contact force compensation measures based on material mechanics and fracture mechanics were proposed to make the simulation training data more robust to reflect the real contact situation; based on the mean square error loss function, the additional loss function was introduced for network training for the unreasonable physical “penetration” behavior. The experimental results show that the proposed model can accurately predict the horizontal and vertical forces with the root mean square error of 0.286 in the single-step prediction, and the multi-step prediction results are also good enough to meet the application requirements. The prediction performance of the model is superior to the existing mainstream models. The ablation experiment shows that the excellent prediction performance of the model proposed is the result of the joint contribution of the local feature extraction module, the attention mechanism module and the temporal feature extraction module. At the same time, the improved loss function improves the stability of the model training. Our method can be used in similar applications for the prediction of robotic contact force with the environment.

Key words: glass substrate, contact dynamics, force prediction, deep learning, physical priors

CLC Number: