Servo Position Stress Detection Control System
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Solution Overview
Problem
Conventional precision machines face challenges in achieving high precision due to limitations in displacement and force detection, particularly with linear optical scales and mechanical equipment interference, leading to inaccuracies in position and stress control during machining processes.
Innovation Solution
A servo position/stress detection control system comprising a servomotor, servo driver, and controller, which includes an encoder for absolute angle reading and a register to store and convert torque values into force values, enabling precise control and automatic adjustment of pressure and position through a load line correction mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a linear optical scale is used for displacement detection, then digital variance reading is achieved, but design difficulty in achieving zero degree angle between gratings results in reduced measurement precision
Solution Approach 1:
The patent replaces the mechanical/optical linear scale system with a servo motor system equipped with an encoder. The encoder provides direct digital feedback of the servo motor's rotational position, which is then converted to linear displacement through the screw mechanism. This substitution eliminates the complex optical grating alignment requirements while maintaining or improving measurement precision through electronic feedback.
2Measurement precision
If a force detecting device is used to detect output force, then force correction is enabled, but mechanical equipment interference causes inaccurate force measurement on workpiece
Solution Approach 1:
The patent implements a feedback mechanism where the encoder continuously monitors the servo motor's rotational position and provides digital feedback to the control device. The control device calculates the actual linear displacement of the press member based on this feedback, comparing it with the commanded position and adjusting the servo motor output accordingly. This closed-loop feedback system compensates for mechanical interference and ensures accurate force application.
Solution Approach 2:
The patent replaces direct mechanical force sensing with an indirect measurement approach. Instead of using force sensors that are susceptible to mechanical interference, the system calculates the actual displacement based on encoder feedback from the servo motor, and derives force information from the servo motor's torque characteristics and position control data, thereby avoiding direct mechanical contact sensors.
3Manufacturing precision
If different pressure is exerted on workpiece by press member, then position control is achieved, but reacting forces cause height variance that cannot be accurately reflected
Solution Approach 1:
The patent employs a feedback mechanism where the encoder continuously monitors the servo motor's rotational position and provides digital feedback to the control device. The control device calculates the actual linear displacement of the press member based on this feedback, comparing it with the commanded position and adjusting the servo motor output accordingly. This closed-loop feedback system compensates for height variances caused by reacting forces, ensuring accurate position control and true reflection of actual press member position.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system enhances machining precision by accurately reflecting exact pressure and position, reducing errors caused by reacting forces and height variances, thereby improving the quality of precision machining.
Implementation Method 1
The encoder is connected to the spindle of the rotation force output unit... reads an absolute angle value of rotation from the spindle
Data Source
AI summary
A servo position/stress detection control system has a servomotor, a servo driver and a controller. The servo driver has a control unit, an absolute angle reading unit and a register. The control unit selectively drives or stops the servomotor and converts torque value of the servomotor to a force value. The absolute angle reading unit reads an absolute angle value of rotation in response to a spindle of the servomotor. The controller respectively converts the absolute angle value and the force value to a linear displacement and a load stress value with a calculating program, establishes a load line in response to different force values and corresponding linear displacements wherein the load line provides corresponding correction basis for the servo driver to automatically detect height variances caused by reacting force and accordingly adjust working status of the servomotor.