Liu Yanjie

Bond graph model of permanent magnet linear synchronous motor

The increasingly widespread industrial applications of permanent magnet linear synchronous motor (PMLSM) are self evident testimonies of the effectiveness of PMLSM in addressing the high requirements associated with these application areas. PMLSM direct drive system is a typical multi-domain system. This article proposes a bond graph model of PMLSM that can incorporate with other components in direct drive system to form dynamic electromechanical model. Principle of PMLSM under field-oriented control is equal to DC motor is illustrated firstly. Then bond graph model of PMLSM is built according to the equivalent circuit. The model is validated by comparing with a common used model which shows that bond graph model are equal to the model and represents clearly interactions between elements.

Key Techniques of Micromanipulation Devices for MEMS Assembling and Packaging

The characteristics of micro electro mechanical system(MEMS)assembling and packaging process are analyzed,and the development status of machining devices is given.According to the characteristics of MEMS industry development,the key techniques of MEMS assembling and packaging devices are described,including database of technological parameters,fast precision positioning,modular working tools,fast micro-vision,flexible clamping and automatic material handling techniques.The composition structure and working principle of an anodized bonding device for MEMS pressure sensor and a wire bonding device are introduced,and some experimental results are given.At last,the development trend of MEMS assembling and packaging techniques and devices are discussed.

Frication compensation and disturbance observer design for a high acceleration precision direct drive motion stage

Friction compensation and disturbance observer design in velocity loop for a high acceleration precision motion stage actuated by linear motor is considered. The friction compensator divides the friction into linear and nonlinear part basing on LuGre model, linear part is treated as damping together with other part in system, and nonlinear part is compensated basing on the model. Internal state z in LuGre model is calculated according model and position real time instead of using state observer, which can reduce calculation and as far as possible to ensure the precision of friction model. The disturbance observer proposed here account for time delay in system which caused by discrete sampling, signal process, transport distance, and so on. Simulation results demonstrate the effectiveness of the approach.