Precision calibrating device for magnetorheological polishing device and method thereof

Abstract

The present disclosure provides a precision calibrating device and a precision calibrating method for a magnetorheological polishing device, which realize an automatic and quick calibration process. It is ensured that a polishing gap is kept within an allowable error range when the magnetorheological polishing device processes surfaces of different optical elements, thereby effectively controlling a removal function, reducing or eliminating surface residual errors after processing and low frequency errors and medium frequency errors introduced by insufficient trajectory precision of a mechanical arm, and improving a processing precision of the magnetorheological polishing device based on the mechanical arm.

What is claimed is: 
     
         1 . A precision calibrating device for a magnetorheological polishing device including a polishing wheel and a support base configured to mount the polishing wheel, comprising:
 an arc-shaped support bracket,   a sensor,   a signal acquisition module,   an industrial personal computer (IPC), and   a motion control module;   wherein the arc-shaped support bracket is detachably connected with the support base; the arc-shaped support bracket defines an arc-shaped surface attached to the polishing wheel; the sensor is fixed on the arc-shaped support bracket; the sensor is configured to detect a polishing gap;   wherein the signal acquisition module is connected with the sensor; the IPC is connected with the signal acquisition module and the motion control module; the motion control module is connected with a control system of the magnetorheological polishing device; the IPC is configured to send an instruction to the signal acquisition module and the motion control module; the signal acquisition module is configured to control the sensor to collect data; the motion control module is configured to send the instruction to the control system, so that the polishing wheel moves along a predetermined processing trajectory.   
     
     
         2 . The precision calibrating device according to  claim 1 , wherein the sensor is a displacement sensor or a pressure sensor. 
     
     
         3 . The precision calibrating device according to  claim 1 , wherein the arc-shaped support bracket defines a through hole; an effective working hole of the sensor coincides with the through hole; and a center of the effective working hole of the sensor coincides with a vertex of a spherical crown of the polishing wheel. 
     
     
         4 . The precision calibrating device according to  claim 1 , wherein an adjusting bracket is arranged on the arc-shaped support bracket; strip-shaped holes configured to adjust a height of the adjusting bracket are defined on the adjusting bracket; fasteners pass through the strip-shaped holes to fix the adjusting bracket to the support base. 
     
     
         5 . The precision calibrating device according to  claim 4 , wherein the adjusting bracket defines two strip-shaped holes parallel to each other. 
     
     
         6 . A precision calibrating method for a magnetorheological polishing device, comprising:
 mounting an optical element to be processed on the magnetorheological polishing device, and aligning a coordinate system of the optical element to be processed with a processing coordinate system;   mounting an arc-shaped support bracket of a precision calibrating device on a support base of a polishing wheel;   controlling a sensor to collect displacement values between the sensor and the optical element to be processed, and controlling the polishing wheel to move along a predetermined processing trajectory;   obtaining error values between the displacement values and predetermined values;   determining whether the error values satisfy a precision requirement;   if yes, compensating the error values into the predetermined processing trajectory of the magnetorheological polishing device;   if not, correcting the predetermined processing trajectory according to the error value; and   Obtaining the error values between the displacement values and the predetermined values again according to a corrected predetermined processing trajectory.   
     
     
         7 . The precision calibrating method according to  claim 6 , wherein a step of controlling the sensor to collect the displacement values between the sensor and the optical element to be processed and controlling the polishing wheel to move along the predetermined processing trajectory comprises:
 sending an instruction to a signal acquisition circuit and a motion control circuit through an IPC; controlling the sensor to collect data through the signal acquisition circuit; sending the instruction to a control system of the magnetorheological polishing device and the motion control circuit, so that the polishing wheel moves along the predetermined processing trajectory.   
     
     
         8 . The precision calibrating method according to  claim 7 , wherein a step of obtaining the error values between the displacement values and the predetermined values comprises:
 processing the data collected by the sensor by the IPC; comparing a collected displacement values with the predetermined values to obtain the error values.   
     
     
         9 . The precision calibrating method according to  claim 8 , wherein the error values comprise low frequency errors, medium frequency errors, and high frequency errors.