Pulse Motor Control for Servo Press Step-Out Prevention
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Solution Overview
Problem
Existing servo press systems using pulse motors face challenges in preventing the step-out phenomenon and optimizing takt time due to limitations in accurately determining the margin of safety and automatically adjusting speed/acceleration, leading to potential quality deterioration and increased processing time.
Innovation Solution
A servo press system with closed-loop control that includes a pulse motor, encoder, slider position detection, and a control unit to dynamically adjust speed/acceleration based on calculated deviations, ensuring optimal operation conditions are maintained without causing a step-out phenomenon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pulse motor speed/acceleration is increased to improve takt time, then productivity improves, but the risk of step-out phenomenon increases
Solution Approach 1:
The system continuously monitors the load angle of the pulse motor and provides feedback to the control unit. When the load angle approaches the critical value that would cause step-out, the control unit automatically reduces speed/acceleration commands, preventing step-out while maximizing productivity within safe operating limits
Solution Approach 2:
The control system dynamically adjusts speed and acceleration parameters in real-time based on the current load angle. Instead of using fixed parameters, the system adapts parameters continuously to maintain optimal performance while preventing step-out, allowing maximum productivity under varying operating conditions
2Device complexity
If open loop control is used for pulse motors, then device complexity is reduced, but the ability to prevent step-out and optimize performance is limited
Solution Approach 1:
The system introduces minimal feedback by monitoring the load angle through current detection and comparing it with the command pulse position. This simple feedback mechanism enables step-out prevention without requiring complex closed-loop control systems or additional expensive components
Solution Approach 2:
The control system uses the existing pulse motor and power supply components to generate the necessary feedback signals. The load angle information is derived from the relationship between the command pulse and the actual motor response, eliminating the need for separate sensors or complex measurement systems
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 effectively monitors and adjusts pulse motor speed/acceleration, allowing for precise control and automatic response to changes, thereby preventing step-outs and improving processing quality and takt time.
Implementation Method 1
an encoder disposed at the pulse motor; a slider position detection unit configured to detect a number of pulses based on an output signal from the encoder
Data Source
AI summary
A number of pulses output from an encoder is counted, a number of pulses output from a command pulse output unit is counted, and a difference between the number of pulses that has been counted by the command pulse counting unit and the number of pulses from the encoder is calculated. Then, a condition is changed such that speed/acceleration of a pulse motor increases when a difference value between a deviation threshold and the difference is smaller than a predetermined range, and the speed/acceleration of the pulse motor decreases when the difference value is greater than the predetermined range, and whereby the pulse motor is controlled based on a position of a slider detected by a slider position detection unit, a position of the slider that has been set, and the pulse condition that has been changed.