Paint Circulation Control in Painting Robots for Pressure Stability
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Solution Overview
Problem
Existing robotic painting systems experience pressure fluctuations during paint dispensing and stopping, leading to inconsistent paint pressure that does not fall within the desired range.
Innovation Solution
A painting robot with a paint circulation channel, regulating valves, and a control unit that employs feedback and feedforward control to manage pressure fluctuations by adjusting the operation of paint transfer and regulating valves based on trigger signals and pressure set points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If feedback control is used to adjust paint pressure, then pressure stability is improved, but response speed is delayed
Solution Approach 1:
The patent applies preliminary action by using feedforward control to predict and compensate for pressure fluctuations before they occur. The control unit calculates a pressure calculation value based on expected pressure changes (such as when the painting head starts or stops dispensing paint) and adjusts the paint supply mechanism in advance, rather than waiting for actual pressure deviations to be detected and corrected by feedback control alone.
2Reliability
If paint supply pressure is increased to ensure consistent flow, then paint delivery reliability is improved, but pressure fluctuations worsen
Solution Approach 1:
The patent applies feedback control where the control unit continuously monitors actual paint pressure and compares it against a target pressure value. Based on the difference (error signal), the control unit adjusts the paint supply mechanism to maintain stable pressure. This closed-loop feedback ensures reliable paint delivery while minimizing pressure fluctuations through continuous correction.
Solution Approach 2:
The patent changes the control parameter from simple on/off valve control to proportional control, where the degree of valve opening is continuously adjusted based on pressure feedback. This allows fine-tuned regulation of paint pressure, maintaining reliable delivery while reducing fluctuations through smooth, progressive adjustments rather than abrupt changes.
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 reduces the influence of pressure fluctuations, ensuring consistent paint pressure during discharge and stoppage, thereby improving painting quality and efficiency.
Implementation Method 1
a regulating valve disposed midway through the paint circulation channel and adjustable to open and close an internal flow path of the paint circulation channel
Implementation Method 2
a paint transfer means disposed in the middle of the paint circulation channel and providing and recovering the paint between a reservoir site of the paint and the painting head
Implementation Method 3
a feedback control unit for controlling the operation of at least one of the paint transfer means and the regulating valve by calculating a pressure calculation value for executing feedback control
Implementation Method 4
a feedforward control unit for controlling the operation of at least one of the paint transfer means and the regulating valve, by correcting the calculated pressure calculation value with a compensating pressure value in the opposite direction to the expected pressure fluctuation
Data Source
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AI summary
[Problem] According to the present invention, it is possible to provide a painting robot capable of reducing the influence of pressure fluctuations when paint is discharged or stopped. [Means for Solving] The painting robot 10 comprises a robot arm R1 having a painting head unit 50 attached to its tip, a paint supply mechanism 70 provided between robot arm R1 and painting head unit 50; and a control unit 100; where the paint supply mechanism 70 includes a paint circulation channel 71; paint transfer means 90, 91 (controlled objects) and regulating valves 92, 93 (controlled objects) provided in the middle of the paint circulation channel 71; with the control unit 100A being equipped with a feedback control unit 142 that calculates a pressure calculation value for executing feedback control of the operation of the controlled object and controls the operation of the controlled object; and a feedforward control unit 143 for controlling the operation of the controlled object, by compensating the calculated pressure calculation value with the compensating pressure value in the opposite direction to the expected pressure fluctuation for the pressure set point, based on the trigger signal related to the change of state of the painting head 53.