Swing Body Braking Control for Accurate Azimuth Stopping
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Solution Overview
Problem
Existing loading machine control devices face challenges in accurately controlling the azimuth direction of a swing body during braking, as the hydraulic motor cannot exert a braking force exceeding the relief pressure of the relief valve, leading to potential overshoot beyond the set stop position due to excessive integral feedback control.
Innovation Solution
A control device that includes an adjustment determination unit to assess whether the swing angle difference exceeds an allowable range during braking and an operation signal output unit to manage the swing control signal, ensuring the swing body's azimuth direction is correctly aligned by adjusting the swing motor's operation based on the swing speed and target stop azimuth direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If feedback control continuously adjusts swing speed to match target swing speed, then the swing speed control precision is improved, but the swing body overshoots the set stop position and reverses direction due to excessive integral term accumulation
Solution Approach 1:
The control method dynamically adjusts the integral term based on the current swing speed relative to a predetermined threshold. When swing speed exceeds the threshold, the integral term is reduced or deactivated; when below the threshold, the integral term is increased. This dynamic adjustment prevents excessive integral accumulation that causes overshoot while maintaining control precision during normal operation.
Solution Approach 2:
The control system changes the parameter of the integral term in the feedback control based on swing speed conditions. By modifying the integral term parameter dynamically according to swing speed thresholds, the system prevents overshoot at high speeds while maintaining accurate control at lower speeds, resolving the contradiction between control precision and stop position accuracy.
2Force
If the hydraulic motor exerts maximum braking force at relief pressure, then the braking capability is improved, but the swing body cannot stop accurately at the set position and overshoots
Solution Approach 1:
Instead of continuously applying maximum braking force, the control method applies braking force partially by dynamically adjusting the integral term based on swing speed. This prevents excessive braking that causes overshoot while ensuring sufficient braking force is applied when needed to achieve accurate stopping position.
Solution Approach 2:
The control system uses feedback from the swing speed sensor to continuously monitor swing speed and adjust the integral term accordingly. This feedback mechanism ensures that braking force is optimized based on real-time conditions, preventing overshoot while maintaining accurate stop position control.
3Speed
If the swing control signal is frequently output to correct position deviations, then the position control responsiveness is improved, but the control system becomes overly sensitive and causes swing body reversal
Solution Approach 1:
The control method dynamically adjusts the integral term based on swing speed thresholds, making the control system less sensitive during high-speed braking and more sensitive during low-speed positioning. This dynamic sensitivity adjustment prevents oscillation and reversal while maintaining responsive control when appropriate.
Solution Approach 2:
The control method anticipates potential overshoot by reducing the integral term when swing speed exceeds the threshold, before overshoot can occur. This preliminary anti-action prevents the swing body from reversing direction while maintaining control responsiveness during normal operation.
Data Source
AI summary
A control device of a loading machine includes an adjustment determination unit and an operation signal output unit. The loading machine includes a swing motor and a swing body. The adjustment determination unit determines whether or not an angle formed by an azimuth direction of a swing body when the swing body stops and a target stop azimuth direction is less than an allowable angle based on an azimuth direction, a swing speed, and the target stop azimuth direction of the swing body during braking of the swing motor. The operation signal output unit outputs a swing control signal for driving the swing motor in a case in which it is determined that the angle formed by the azimuth direction of the swing body when the swing body stops and the target stop azimuth direction is equal to or greater than the allowable angle.