The investments of the electro-hydraulic servo system of the mold non-sinusoidal oscillator are great, the modification ratio of the mechanical type is unable to be adjusted online, and some continuous casters suffer ...The investments of the electro-hydraulic servo system of the mold non-sinusoidal oscillator are great, the modification ratio of the mechanical type is unable to be adjusted online, and some continuous casters suffer from server resonance during the casting. A mold non-sinusoidal oscillation mechanism driven by servomotor is proposed and the prototype is produced in the lab, the investment is low and the modification ratio is can be adjusted online, and the stability problem is studied. At first the dynamics model of the servomotor non-sinusoidal oscillation is established, and the kinematics differential function is deduced. Furthermore, based on the harmonic balance method, the eigenvalues of the system are solved; the criterion of the stability of the system is put forward. In addition, the eigenvalues and harmonic with different oscillating parameters are analyzed. Analytical results show that the real parts of the eigenvalues are positive, the system will be unstable, and the resonance will occur when the positive real parts of the eigenvalues are extremum. A foundation is established for solving the running smooth problem and next application of this mechanism.展开更多
The principle of a new type of no-pulsation continuous rotary electro-hydraulic servomotor applied to simulators is introduced. LuGre friction model was analyzed. The identification method of LuGre parameters was prop...The principle of a new type of no-pulsation continuous rotary electro-hydraulic servomotor applied to simulators is introduced. LuGre friction model was analyzed. The identification method of LuGre parameters was proposed, and the measures to compensate the effect of friction forces were given. A friction torque model for the new rotary motor was proposed. The low-speed response and step response of the motor were studied experimentally. Experimental results proved that using friction compensation could eliminate stick-slip motion at the low speed, which makes the servomotor applicable to simulators.展开更多
A novel reconfigurable 5-DOF hybrid manipulator―TriVariant-B is composed of a 2-DOF spherical parallel mechanism which is serially connected with a 3-DOF open-loop kinematic chain undergoing one translation and two r...A novel reconfigurable 5-DOF hybrid manipulator―TriVariant-B is composed of a 2-DOF spherical parallel mechanism which is serially connected with a 3-DOF open-loop kinematic chain undergoing one translation and two rotations by a prismatic joint. The merit of this design is that a relatively large workspace/limb- stroke ratio can be achieved thanks to the decomposition of the fixed point rotation and the relative translation. In this paper, on the basis of inverse dynamic formula- tion of the 2-DOF spherical parallel mechanism, an approach is proposed for esti- mating the servomotor parameters including moment of inertia, rated speed and the maximum torque in a quick manner. The approach has been employed for the development of a prototype for frame cutting process.展开更多
基金Supported by National Natural Science Foundation of China and Baosteel Group Co.Ltd.(Grant No.U1260203)Natural Science Foundation Steel and Iron Foundation of Hebei Province,China(Grant No.F2013203291)+1 种基金Doctor Startup Foundation of Hebei University of Science and Technology,China(Grant No.QD201247)Foundation of Hebei University of Science and Technology,China(Grant No.XL201004)
文摘The investments of the electro-hydraulic servo system of the mold non-sinusoidal oscillator are great, the modification ratio of the mechanical type is unable to be adjusted online, and some continuous casters suffer from server resonance during the casting. A mold non-sinusoidal oscillation mechanism driven by servomotor is proposed and the prototype is produced in the lab, the investment is low and the modification ratio is can be adjusted online, and the stability problem is studied. At first the dynamics model of the servomotor non-sinusoidal oscillation is established, and the kinematics differential function is deduced. Furthermore, based on the harmonic balance method, the eigenvalues of the system are solved; the criterion of the stability of the system is put forward. In addition, the eigenvalues and harmonic with different oscillating parameters are analyzed. Analytical results show that the real parts of the eigenvalues are positive, the system will be unstable, and the resonance will occur when the positive real parts of the eigenvalues are extremum. A foundation is established for solving the running smooth problem and next application of this mechanism.
文摘The principle of a new type of no-pulsation continuous rotary electro-hydraulic servomotor applied to simulators is introduced. LuGre friction model was analyzed. The identification method of LuGre parameters was proposed, and the measures to compensate the effect of friction forces were given. A friction torque model for the new rotary motor was proposed. The low-speed response and step response of the motor were studied experimentally. Experimental results proved that using friction compensation could eliminate stick-slip motion at the low speed, which makes the servomotor applicable to simulators.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 50535010 and 50510488)
文摘A novel reconfigurable 5-DOF hybrid manipulator―TriVariant-B is composed of a 2-DOF spherical parallel mechanism which is serially connected with a 3-DOF open-loop kinematic chain undergoing one translation and two rotations by a prismatic joint. The merit of this design is that a relatively large workspace/limb- stroke ratio can be achieved thanks to the decomposition of the fixed point rotation and the relative translation. In this paper, on the basis of inverse dynamic formula- tion of the 2-DOF spherical parallel mechanism, an approach is proposed for esti- mating the servomotor parameters including moment of inertia, rated speed and the maximum torque in a quick manner. The approach has been employed for the development of a prototype for frame cutting process.
