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Efficient and economical processing of large-scale structural parts is in increasing need and is also a challenging issue. In this paper, an adsorption machining robot for processing of large-scale structural parts is presented. It has potential advantages in flexible, efficient, and economical processing of large-scale structural parts because of the adsorption ability. Stiffness is one of the most important performance for machining robots. In order to investigate the stiffness of the robot in the workspace, the kinematics of the adsorption manipulator, the five-axis machining manipulator, and the adsorption machining robot is derived step by step. Then with the help of finite element analysis (FEA), a stiffness modeling method considering the compliance of the base is proposed. A stiffness isotropy index is put forward to evaluate the robot’s overall stiffness performance by taking all possible working conditions into consideration. Based on the index, stiffness evaluation in the reachable workspace is carried out and an optimized workspace is identified considering the overall stiffness magnitude, stiffness isotropy, and workspace volume, which will be used in the machining process. The stiffness modeling method and stiffness isotropy index proposed in the paper are universal and can be applied to other parallel robots.

Machining robots have great advantages in large structure components manufacture and maintenance due to their flexibility and low cost. Among them, adsorption robots have the potentials to reach the blind areas of the large-scale structure. But the complex force interaction problem and high requirement of processing quality during machining make the robot design become a very challenging problem. This study proposes an adsorption machining robot consisted of end-effector and omnidirectional adsorption mobile platform. The friction adsorption locking device and elevating omnidirectional wheel are designed to satisfy the high machining quality. The driving force and adsorption force matching design is presented to make the robot capable of climbing on low friction coefficient surface. This design can increase twice robot’s climbing ability from 5° to 10° by providing extra adsorption force. The results in this paper are helpful to the development of the robot.

Mechanisms with flexible orientation capability and compact structure have great application prospects in manufacturing equipment, flight simulator, airborne radar, and similar fields. In this paper, a two-degree-of-freedom (2-DoF) spatial parallel kinematic mechanism with three identical kinematic chains is presented. Due to the strong coupling property, its kinematic mechanism issues in terms of forward and inverse kinematics are fundamental to its practical application and thus have been investigated. Based on the kinematic analysis results, the orientation capability of the presented mechanism can reach 40° for an arbitrary azimuth angle. Benefitting from the parallel kinematic structure and coupling kinematics, the presented mechanism also has potential advantages of high stiffness and quick response.

High speed motorized spindle is the key component of CNC machine tools, and the thermal deformation caused by the temperature field inside the motorized spindle has a great impact on the precision machining. This paper proposed a statistical model based on partial least squares to predict the thermal deformation of the high-speed motorized spindle. The temperature and thermal deformation data under different steady-state operating conditions were collected based on the high-speed motorized spindle experimental platform. Part of the data was used to establish the PLS model describing the quantitative relationship between the thermal deformation and the temperature rises at the measuring points. The other part was used to verify the model and to compare it with the least squares model prediction results. The results of principal component analysis and variable importance in projection index analysis showed a strong correlation between measurement temperature points and thermal deformation. Therefore, it can be concluded that the proposed thermal deformation model could predict the three-dimensional thermal deformation, providing a reference for thermal error compensation control scheme.