This paper designs a preload adjustable rotary nut ball screw dual-driven micro feed system, due to the elastic property of the feed system has great influence on its own frequency–response characteristics, which can be identified by analyzing the amplitude relationship between the torque input signal and the acceleration output signal. In order to get the structural dynamic of the dual-driven servomechanism, which is first modeled through lumped mass method, the frequency–response characteristics are calculated using the Lagrange equation and the state-space method. Finally, the frequency–response characteristics of a macro–macro dual-driven and single-driven systems are compared via numerical analysis, and the influence of changes in the preload, torsional rigidity, and table's total mass on the frequency–response characteristics are studied.

For the palletizing robot's operating characteristics of high speed, high acceleration, and heavy load, it is necessary to make a research on the structure optimization focusing on the vibration characteristics according to the mechanical and dynamic performance analysis. This article first introduces the mechanical feature and working principle of high-speed and heavy-load robot palletizer. Kinematics analysis is carried out by using D-H parameter method, which obtains positive kinematics solution and workspace. Jacobian matrix is deduced, and the relationship between joint space and Cartesian space is established. Second, for the reason that joint flexibility has a great influence on the vibration performance of the robot, a rigid-flexible coupling dynamic model is established based on the simplified model of the flexible reducer and Lagrange's second equation to describe the joint flexibility of high-speed and heavy-load palletizing robot, and the vibration modes of the robot are analyzed. The influence of different joint stiffness on the frequency response of the system reveals the inherent properties of the heavy-load palletizing robot, which provides a theoretical basis for the optimal design and control of the heavy-load palletizing robot. Creative Commons Non Commercial CC BY-NC: This article is distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 License (https://creativecommons.org/licenses/by-nc/4.0/) which permits non-commercial use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access pages (https://us.sagepub.com/en-us/nam/open-access-at-sage).With the wide application of high-speed and heavy-load palletizing robots in automobile, metallurgy, and logistics industries, automated production lines put forward higher requirements for the speed, load capacity, acceleration, and positioning accuracy of robots. The high-speed and heavy-load palletizing robot not only reduces the positioning accuracy of the palletizing robot but also limits the speed of the robot. 1,2 In view of the high-speed, high-acceleration, and heavyload working characteristics of high-speed and heavy-load palletizing robot, it is not enough to complete structural analysis only at the kinematics level. It is necessary to carry out dynamic analysis of the robot body.Many achievements have been made in the study of flexible models. Bridges and Dawson 3 took into account the non-linear flexibility such as transmission friction, which made the flexible joint model more appropriate. On the basis of considering the non-linear links including backlash, Murphy et al. 4 established a complete flexible dynamic model of the robot by using Newton Euler method. For typical harmonic drive, Ghorbel and colleagues 5,6 established the model of harmonic reducer and verified the influence of reducer flexibility on motion through theoretical and experimental analysis. Hong and colleagues 7-9 used the basic principle of continuum ...

This article presents a new micro-feed mechanism, whose main transmission component is the nut–rotary ball screw pair. The screw and nut are driven by two motors, and they rotate in the same direction, with their movements enabling micro-feeding. The main contribution of the micro-feed mechanism is to avoid the inevitable low-speed nonlinear creeping phenomenon caused by the inherent properties of traditional electromechanical servo system structure, thus realizing high precision micro-feed. In this study, the motion state of the working ball is analyzed using the principle of differential geometry, the friction at the contact points is calculated, the balance equation for force and moment is established, the influences of the screw and nut on the kinematic parameters of the ball at different velocities and the differences in the motion states of the ball in different drive modes are studied, and the mechanical efficiency of the dual-driven ball screw mechanism is calculated. The potential applications of the new micro-feed mechanism and the results of numerical analysis can be applied to advanced technology fields such as robotics, suspensions, powertrain, national defense, integrated electronics, optoelectronics, medicine, and genetic engineering, so that the new system can have a lower stable speed limit and achieve precise micro-feed control.

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