In many mechatronic systems, gear transmission chains are often used to transmit motion and power between motors and loads, especially for light, small but large torque output systems. Gear transmission chains will inevitably bring backlash as well as elasticity of shafts and meshing teeth. All of these nonlinear factors will affect the performance of mechatronic systems. Anti-backlash gear systems can reduce the transmission error, but elasticity has to be considered too. The aim of this paper is to find the key parameters affecting the resonance and anti-resonance frequencies of anti-backlash gear systems and then to give the design optimization methods of improving performance, both from element parameters and mechanical designing. The anti-backlash geared servo system is modeled using a two-inertia approximate model; a method of computing the equivalent stiffness of anti-backlash gear train is proposed, which comprehensively considers the total backlash of transmission chain, gear mesh stiffness, gear shaft stiffness and torsional spring stiffness. With the s-domain block diagram model of the anti-backlash geared servo system, the influences of four main factors on the resonance and anti-resonance frequencies of system are analyzed by simulation according to the frequency response, and the simulation analysis results dependent on torsional spring stiffness of anti-backlash gear pair and load moment of inertia variation are verified by the experiment. The errors between simulation and experimental results are less than 10 Hz. With these simulation and experiment results, the design optimization methods of improving the resonance and anti-resonance frequencies such as designing the center distance adjusting mechanism to reduce the initial total backlash, increasing the stiffness of torsional spring and lightweight design of load are proposed in engineering applications.

Nonlinear disturbances, such as friction, backlash, and base vibration, are the main factors restricting the further improvement of the dynamic performance of the Acquisition, Tracking and Pointing (ATP) system. However, the modeling and compensation of the time-varying nonlinearities are still challenging. In this paper, a compound control algorithm based on model predictive control (MPC) and a Proportional Multiple-Integral State-Augmented Kalman Filter (PMISAKF) disturbance observer is proposed to improve the disturbance rejection performance. Specifically, a PMISAKF is used to estimate the system’s state and external disturbances in real-time. These observed disturbances are then treated as known external inputs at the current or future time points and incorporated into the predictive model of MPC. This allows the optimization process to take these external factors into consideration, enabling the calculation of an optimal control strategy and achieving high pointing and tracking accuracy for nonlinear time-varying disturbances. Experimental results show that the proposed method can effectively improve the system’s anti-interference ability and tracking accuracy.

Bond graphs provide a useful notation for the purpose of modeling physical systems. This paper models the open loop system of a dynamically tuned gyroscope (DTG) using bond graph according to its structure, and performs the simulation of the model using 20-sim software. The simulation results are identical with the Matlab simulation results of open loop transfer function of DTG, which proves that the bond graph model of DTG is valid. This paper constructs the basis of the whole mechatronic system bond graph modeling of DTG, it's helpful for the design of digital rebalance loop, and can be used for the integrative design and simulation of structure and control.

The motion control library is a standard set of functional blocks integrated in a programmable integration environment, which is of great significance for the rapid development of reconfigurable Programmable Automation Controllers (PAC). However, due to the encapsulation and concealment of function blocks and the incompatibility between software and hardware, the development efficiency of function blocks is low, which is not conducive to the development of autonomous, controllable PAC. Aiming at the above problems, the methods of function block opening and key technology are studied, and a kind of motion control function library architecture and rapid development method based on the PLCopen specification are proposed. A series of motion control function libraries are developed on domestic PLC software. An experimental platform based on domestic hardware and software was designed to verify the typical motion control function library. Experimental results show that this method can effectively shorten the development cycle and that the developed motion control module can meet the actual control needs.

When measuring the control error of CNC systems, the errors brought by machine tools will affect the veracity of CNC test. A new test approach based on simulation model of machine tool is proposed in order to well solve the problem. The structure and principle of the test approach is demonstrated. The simulation model of virtual machine tool and servo feed system are completed based on Simulink. The effect of nonlinear factors such as backlash and friction, are considered sufficiently in the modeling process of virtual machine tool. The validity of machine tool model is verified by simulation. Experimental setup is built to test the motion control ability in the process of circular interpolation, using the proposed test approach. The results of the experiment prove the validity of the test method. The machine tool model set up in this paper can comparatively accurately exhibits the kinematics characters of the real machine tool, and the proposed test method provides a new way for the comprehensive and reliable test of the motion control ability of the CNC system.

In this paper, we present a hierarchical least squares iterative (HLSI) algorithm based on a hierarchical identification principle to identify the system transfer function parameters. The algorithm is extended to identify the system parameters through the frequency characteristic obtained by sweep tester or simulink/dSpace system. We prove that the algorithm proposed has better performances than the ident toolbox in Matlab and the existing ones. The iterative results converge to the exact solutions for any initial value. We apply the algorithm into the platform system identification and design the controller based on the iterative identification solution. Finally the performances of platform system open-loop frequency characteristic verify the algorithm validity.