Motor Control Apparatus for Shock-Free Feeding to Pressurizing Transition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing motor control techniques for industrial machines face challenges in smoothly switching from a feeding action to a pressurizing action, leading to undesirable forces and pressures on workpieces, potential collisions, and prolonged processing times, which can damage equipment and reduce productivity.
Innovation Solution
A motor control apparatus that includes a position command generation unit, pressure command generation unit, speed command selection unit, and speed control unit to manage the transition from feeding to pressurizing actions without shocks, using a creep speed, first speed command, and second speed command to control the motor's speed and pressure application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the control switches from position controller to pressure controller when the ratio of torque command value and pressure sensor value is stabilized, then the pressurizing action can be achieved, but the unsteady situation during switching causes delay and inconstant ratio, leading to undesirable force and pressure on the workpiece
Solution Approach 1:
The patent applies preliminary action by detecting the workpiece contact state before full pressurizing action begins. The contact state detection unit identifies when the pressurizing head first contacts the workpiece, allowing the system to prepare for mode switching in advance. This prevents delay by triggering the transition from position control to pressure control at the optimal moment, rather than waiting for ratio stabilization after contact.
Solution Approach 2:
The patent uses feedback by continuously monitoring the contact state between the pressurizing head and workpiece. The contact state detection unit provides real-time feedback about whether contact has occurred, enabling the control unit to dynamically adjust the control mode. This feedback mechanism ensures reliable switching timing based on actual physical contact rather than relying on stabilized ratios that may be delayed.
2Manufacturing precision
If the position controller is used at the moment when contact is made to the workpiece, then the positioning control can be maintained, but the pressurizing mechanism may forcefully collide with the workpiece, causing damage
Solution Approach 1:
The patent applies dynamics by dynamically switching between position control and pressure control modes based on the contact state. Rather than using a static control mode, the system transitions from position control (for precise approach) to pressure control (for gentle pressurization) when contact is detected. This dynamic adaptation prevents collision damage while maintaining positioning accuracy during the approach phase.
Solution Approach 2:
The patent uses an intermediary approach by introducing contact state detection as a mediator between position control and pressure control. The detection unit acts as an intermediary that determines when to switch control modes, ensuring a smooth transition that prevents forceful collision. This intermediary mechanism protects the workpiece by preventing direct position control during contact while maintaining positioning precision during the approach phase.
3Measurement precision
If the smallest speed command value is selected from among multiple speed commands, then the control precision can be improved, but the overall motion of the pressurizing head becomes slow, prolonging the time to reach the workpiece
Solution Approach 1:
The patent applies segmentation by dividing the motion process into distinct phases: approach phase and pressurizing phase. During the approach phase, higher speed commands are used to quickly reach the workpiece. During the pressurizing phase, smaller speed command values are selected to ensure precise control. This segmentation allows the system to optimize speed for each phase independently, maintaining productivity during approach while ensuring precision during pressurization.
Solution Approach 2:
The patent uses dynamics by dynamically selecting speed command values based on the current operational phase. The control unit adjusts speed commands according to whether the system is in approach mode or pressurizing mode. This dynamic speed adjustment enables fast approach motion while maintaining precise speed control during pressurization, resolving the contradiction between productivity and control precision.
Data Source
AI summary
A control unit includes a position command generation unit generating a position command, a position control unit outputting a first speed command such that detected position tracks the position command, a pressure command generation unit generating a pressure command, a pressure control unit outputting a second speed command such that detected pressure or force tracks the pressure command, a speed command selection unit selecting creep speed, the first speed command, or the second speed command and outputs it as a speed command for the motor to operate; and a speed control unit outputting a current command for supplying current to the motor such that the motor speed tracks the speed command output by the speed command selection unit. After selecting the first speed command, the speed command selection unit selects the second speed command or the creep speed at timing when the first speed command falls below the creep speed.