Tying Machine Feed Motor Control for Consistent String Length
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Solution Overview
Problem
In tying machines, variations in the rotation speed of the feeding motor due to voltage fluctuations cause inconsistencies in the amount of tying string fed out, leading to overshooting and inefficiencies.
Innovation Solution
The tying machine incorporates a voltage detection circuit to set a duty ratio for the feeding motor, maintaining a constant average applied voltage and rotation speed, and optionally uses a rotation speed sensor to adjust the duty ratio, ensuring consistent string feeding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the feeding motor operates at high rotation speed to increase productivity, then the tying string is fed out faster, but the overshoot amount increases causing variation in the total amount of tying string fed out
Solution Approach 1:
The control unit calculates and sets the duty ratio in advance based on the instructed stop timing and detected battery voltage, before the motor actually stops. This preliminary calculation compensates for the inertia-based overshoot, ensuring the motor stops at the precise position required for consistent tying string length.
Solution Approach 2:
The duty ratio parameter is dynamically adjusted based on battery voltage detection. When voltage varies, the duty ratio is recalculated to maintain consistent motor performance and stopping position, thereby controlling the overshoot amount and ensuring precise tying string feeding.
2Stability of the object's composition
If the duty ratio is adjusted according to battery voltage to maintain constant motor speed, then the rotation speed stability improves, but the device complexity increases due to voltage detection and calculation mechanisms
Solution Approach 1:
The control unit utilizes the existing microcomputer and voltage detection circuitry already present in the tying machine to perform the duty ratio calculations. No separate dedicated voltage detection device or complex control system is added - the existing components serve the dual purpose of their original function plus voltage-based duty ratio adjustment.
Solution Approach 2:
The control unit is designed to perform multiple functions: it controls the motor operation, detects battery voltage, calculates appropriate duty ratios, and adjusts timing parameters. This multi-functional approach avoids adding separate dedicated components for each function, thereby limiting the increase in device complexity.
Data Source
AI summary
A tying machine may include a feeding mechanism configured to feed a tying string, a battery, and a voltage detection circuit configured to detect a voltage of the battery. The feeding mechanism may include a feeding motor to which power is supplied from the battery. The tying machine may be configured to set a duty ratio for driving the feeding motor when feeding the tying string, in accordance with the voltage of the battery detected by the voltage detection circuit.