scholarly journals Elimination of Gear Clearance for the Rotary Table of Ultra Heavy Duty Vertical Milling Lathe Based on Dual Servo Motor Driving System

2020 ◽  
Vol 10 (11) ◽  
pp. 4050
Author(s):  
Hui Jiang ◽  
Hongya Fu ◽  
Zhenyu Han ◽  
Hongyu Jin

The effective way to improve the position accuracy of rotary table of ultra-heavy vertical milling lathe is to reduce or even eliminate the clearance of mechanical transmission structure. In this paper, a useful method for eliminating the gear clearance of C axis of heavy duty machine tool is proposed based on dual servo motor driving system. The principle of double gear anti-backlash is explained and the process of clearance elimination is determined by adjusting the driving torques of the two motors. The dynamic model of the driving system of the dual servo motor is established, so as to find the non-linearity of the clearance, wear and tooth clearance in the drive system. According to the dynamic model and simulation results, the master-slave control parameters of the dual servo motor system are optimized in order to eliminate the clearance and improve the accuracy of the dual drive C-axis. Experiments are carried out to verify the validity of the proposed anti-backlash method. The experimental result also shows that the indexing accuracy of the table has been improved by more than 50% under different working conditions.

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1036
Author(s):  
Yunxia Li ◽  
Lei Li

A countershaft brake is used as a transmission brake (TB) to realize synchronous shifting by reducing the automated mechanical transmission (AMT) input shaft’s speed rapidly. This process is performed to reduce shifting time and improve shifting quality for heavy-duty vehicles equipped with AMT without synchronizer. To improve controlled synchronous shifting, the AMT input shaft’s equivalent resistance torque and the TB’s characteristic parameters are studied. An AMT dynamic model under neutral gear position is analyzed during the synchronous control interval. A dynamic model of the countershaft brake is discussed, and its control flow is given. The parameter identification method of the AMT input shaft’s equivalent resistance torque is given on the basis of the least squares algorithm. The parameter identification of the TB’s characteristic parameters is proposed on the basis of the recursive least squares method (RLSM). Experimental results show that the recursive estimations of the TB’s characteristic parameters under different duty cycles of the TB solenoid valve, including brake torque estimation, estimation accuracy, and braking intensity estimation, can be effectively estimated. The research provides some reliable evidence to further study the synchronous shifting control schedule for heavy-duty vehicles with AMT.


2021 ◽  
Vol 2121 (1) ◽  
pp. 012031
Author(s):  
Chuanbin Wei ◽  
Lizhu Zhang ◽  
You Fu ◽  
Faying Xia

Abstract Nowadays, the automobile industry is gradually developing towards the trend of electrification and intelligence. Compared with the traditional steering system, the steer-by-wire system cancels the mechanical transmission structure, reduces the space utilization, reduces the probability of damage to the driver caused by the steering system in the collision accident, and improves the driving portability and enhances the driver’s handling experience. The road feeling feedback of steer-by-wire system has the greatest impact on the driver’s driving experience. This paper discusses the research methods of road feeling feedback of steer-by-wire system, introduces the basic structure of road feeling feedback of steer-by-wire system, the basic idea of dynamic modeling, the establishment of simulation model of road feeling feedback, and the establishment method of control strategy and simulation platform of road feeling feedback. Finally, it summarizes and prospects in order to provide basic information and perspectives for the development and research of steer-by-wire system.


Author(s):  
Zheng Chen ◽  
Piqi Hou ◽  
Zhihang Ye

In this paper, a new robotic fish propelled by a hybrid tail, which is actuated by two active joints, is developed. The first joint is driven by a servo motor, which generates flapping motions for main propulsion. The second joint is actuated by a soft actuator, an ionic polymer-metal composite (IPMC) artificial muscle, which directs the propelled fluid for steering. A state-space dynamic model is developed to capture the two-dimensional (2D) motion dynamics of the robotic fish. The model fully captures the actuation dynamics of the IPMC soft actuator, two-link tail motion dynamics, and body motion dynamics. Experimental results have shown that the robotic fish is capable of swimming forward (up to 0.45 body length/s) and turning left and right (up to 40 deg/s) with a small turning radius (less than half a body length). Finally, the dynamic model has been validated with experimental data, in terms of steady-state forward speed and turning speed at steady-state versus flapping frequency.


Author(s):  
Chengjun Shao ◽  
Jianfeng Liao ◽  
Xiuliang Li ◽  
Hongye Su

The cutterhead driving system of tunnel boring machine is one of the key components for rock cutting and excavation. In this paper, a generalized nonlinear time-varying dynamic model is established for the hard rock TBM cutterhead driving system. Parametric uncertainties and nonlinearities and unknown disturbances exist in the dynamic model. An adaptive robust control strategy is proposed to compensate the uncertainties and nonlinearities to achieve precise cutterhead rotation speed control. In order to simulate the comprehensive performances of adaptive robust control controller, three different kinds of external force disturbances are added in this model. Compared to the traditional PID, ARC can effectively handle the different kinds of external force disturbances with sufficient small tracking errors.


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