Servo Press Control for Abrupt Stop Safety
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Solution Overview
Problem
Conventional electric servo presses face challenges in reliably and safely stopping the slide during hand-in-die operations due to the difficulty in maintaining a controlled stop state, leading to potential safety hazards and increased costs from large mechanical brakes and frequent wear, especially when dealing with runaway servomotors.
Innovation Solution
Implementing a control method that executes rotation stop control based on a predetermined abrupt stop motion and actuates the mechanical brake at a scheduled timing, allowing for quick and safe stopping of the servomotor, even in abnormal conditions, without relying heavily on large mechanical brakes, thus minimizing wear and maintenance costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical brake with larger braking force is added to rapidly stop and maintain stop state, then safety is improved, but device complexity and maintenance cost increase
Solution Approach 1:
The control device predicts the stop time of the slide based on current position and velocity information before the stop is actually needed. This preliminary calculation allows the system to prepare for stopping in advance, enabling safer operation without requiring oversized mechanical brakes, thus resolving the contradiction between safety and device complexity
Solution Approach 2:
The patent replaces reliance on mechanical brake systems with an electronic control system that uses predictive algorithms to manage stopping. By substituting mechanical solutions with electronic prediction and control, the system achieves safety without the complexity and maintenance burden of large mechanical brakes
2Reliability
If friction discs of mechanical brake are regularly replaced to maintain braking performance, then reliability is improved, but loss of time and economic burden increase
Solution Approach 1:
The control device performs self-monitoring by continuously calculating predicted stop times and comparing them against actual performance. This self-diagnostic capability allows the system to detect brake performance degradation and schedule maintenance only when necessary, eliminating the need for regular preventive replacements and reducing maintenance time and costs
3Adaptability or versatility
If power transmission/conversion mechanism is used to convert rotation into vertical reciprocating movement, then functionality is improved, but difficulty of detecting and measuring increases
Solution Approach 1:
The control device receives feedback signals containing position and velocity information from the power transmission/conversion mechanism. This feedback loop enables the system to continuously monitor the mechanism's state, making the complex mechanical system measurable and controllable, thus resolving the contradiction between functionality and measurement difficulty
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
This approach enables the electric servo press to be abruptly stopped safely and reliably within a short time, improving operability and working efficiency at a lower cost, while ensuring human safety and reducing the economic burden of frequent brake maintenance.
Implementation Method 1
a mechanical brake 15...to perform braking on an output of the servomotor
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Provided is a low-cost control device for an electric servo press, which is excellent in operability and operation efficiency, capable of abruptly stopping a servomotor in a safe and reliable manner within a short time period in response to an abrupt stop command while avoiding hard actuation of a mechanical brake, reliably and quickly stopping the servomotor even in the case where runaway of the servomotor or the like occurs. An electric servo press (1) performs switching to rotation stop control for a servomotor (10) according to an abrupt stop motion (CRVs) based on an abrupt stop command signal (Skt) to perform brake actuation so as to cause a mechanical brake (15) to actually start braking and to forcibly interrupt rotational drive power to the servomotor (10) at a scheduled stop time (t3) at which the servomotor is stopped according to the abrupt stop motion. As a result, even if an abrupt stop request is issued in the case where runaway or the like occurs due to abnormality of the servomotor (10), a control system therefor, or the like, the rotation of the servomotor (10) may be reliably and quickly stopped.