Planar parallel mechanism end tracking control system based on two-dimensional encoder and planar parallel mechanism end tracking control method thereof

Abstract

The invention provides a planar parallel mechanism end tracking control system based on a two-dimensional encoder and a planar parallel mechanism end tracking control method thereof. The system comprises a planar parallel mechanism, a two-dimensional encoder measurement device, a mechanism clearing device and a control device which are installed on a static platform. The control device is composed of a servo motor control module, a trigger photoelectric switch module, a parallel mechanism positioning control module and a parallel mechanism trace tracking control module. According to the whole system, firstly the end of the planar parallel mechanism is enabled to be located in the zero point through the mechanism clearing device, then the real-time position of the end of the planar parallel mechanism is measured through the two-dimensional encoder and then inputted to the control device, and the planar parallel mechanism is driven by the control device so that the end is enabled to be accurately positioned according to the preset traces. According to the control system and method, a data processing module involved can obtain the position of the end of the platform through simple resolving so that the real-time performance is great. Meanwhile, the end trace tracking precision of the planar parallel mechanism can also be enhanced so that the condition for realizing submicron level positioning precision is provided for the planar parallel mechanism.

Description

technical field [0001] The invention relates to position measurement and tracking control of the end of a planar parallel mechanism, in particular to a system and method for end tracking control of a planar parallel mechanism based on a two-dimensional encoder. Background technique [0002] The parallel mechanism in the prior art has the advantages of high structural rigidity, strong bearing capacity, and high positioning accuracy. In particular, the macro-micro dual parallel platform that has developed rapidly in recent years involves precision positioning technology in precision manufacturing and micro-manipulation. Medicine, precision machining and other fields. At present, for most parallel mechanisms, in order to meet the requirements of fast response and high positioning accuracy, the general actuator adopts AC or DC servo motor, and the feedback element adopts encoder, so that the servo driver, servo motor and encoder form a partial closed loop . When working, the ...

AI Technical Summary

Problems solved by technology

The disadvantage of this semi-closed-loop control system is that: the feedback signal comes from the encoder behind the servo motor, which can only ensure the accuracy of the motor input; and in practical applications, processing errors, assembly errors, joint clearances, friction, elastic deformation, etc. This kind of uncertainty factor exists widely, which makes the above-mentioned errors be introduced after the motor input is accurate, after being transmitted to the end of the moving platform, so that the platform has pose errors and the positioning accuracy is not high

In the two existing solutions, industrial cameras and laser displacement sensors are used as position feedback components respectively; for the use of industrial cameras, the measurement accuracy is not high, and the image processing process is cumbersome and time-consuming, which is not conducive to the real-time tracking control of parallel robots ; For the use of laser displacement sensors, at least three laser displacement sensors are needed to solve the pose of the end of the moving platform, which requires high installation accuracy of the laser displacement sensors, the calculation process is quite cumbersome, and the resulting pose accuracy is not high

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