Research on vacuum gripper based on fuzzy control for micromanipulators

Key words:  Micromanipulator  Micro assembly  Vacuum micro gripper  Fuzzy PD

摘要:

Abstract:

This paper presents a vacuum gripper (as an actuator of an intelligent micromanipulator) for micro objects (with a diameter of 100～300?μm) assembly tasks.The gripper is composed of a vacuum unit and a control unit.The vacuum unit with a proportional valve and a pressure sensor,and the control unit with a PC+MCU two-layered control architecture are designed.The mechanical structure,workflow and major programs of the micro-gripper are presented. This paper discusses the major components of the adhesion force acting on micro objects.Some equations of the operation conditions in three phases of pick,hold and place are derived by mechanics analysis.The pneumatic system's pressure loss is inevitable.There are some formulas for calculating the amount of the pressure loss,but parameters in formulas are difficult to be quantified and evaluated.To control the working pressure accurately,a pressure controller based on fuzzy logic is designed.With MATLAB's fuzzy logic toolbox,simulation experiments are performed to validate the performance of the fuzzy PD controller. The gripper is characterized by a steady and reliable performance and a simple structure,and it is suitable for handling micro objects with a sub-millimeter size.