Pneumatic Valve Control with Direct Throttle and Pressure Modes
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Solution Overview
Problem
Existing valve devices are limited in their ability to function as both closed-loop pressure controllers and closed-loop throttle controllers, and they lack flexibility in controlling throttle openings, particularly in industrial automation applications where speed reduction of actuator elements is required.
Innovation Solution
A valve device with a throttle setting function that allows for direct setpoint specification to the throttle control loop independently of pressure control, enabling operation as both a closed-loop pressure controller and a closed-loop throttle controller, and the ability to limit throttle openings to a predefined limitation value, reducing the speed of actuator elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the valve device is configured as a closed-loop pressure controller only, then the pressure control function is optimized, but the device lacks versatility for throttle control applications
Solution Approach 1:
The valve device is designed to perform both closed-loop pressure control and closed-loop throttle control functions through a unified control architecture. The control unit can operate in two modes: pressure control mode where it regulates outlet pressure via the throttle opening, and throttle control mode where it directly controls the throttle opening based on a setpoint. This multi-functionality allows a single device to replace what would traditionally require separate pressure controllers and throttle controllers, thereby improving versatility without significantly increasing device complexity.
2Speed
If the throttle opening is limited to a predefined limitation value, then the speed of actuator elements is reduced, but the pressure control speed is decreased
Solution Approach 1:
The valve device implements dynamic throttle opening limitation where the limitation value is not fixed but can be adjusted based on operational requirements. The control unit compares the computed throttle setpoint from pressure control with the predefined limitation value and applies the minimum of the two. This dynamic adjustment allows the system to reduce actuator speed when needed (by limiting throttle opening) while maintaining the ability to achieve full pressure control speed when the limitation is not active, thus balancing both requirements.
3Adaptability or versatility
If direct setpoint specification is enabled for throttle control, then the device can function as a standalone throttle controller, but the control system becomes more complex
Solution Approach 1:
The control unit dynamically switches between two operational modes based on the control mode selection signal. In pressure control mode, the system operates as a traditional closed-loop pressure controller where the throttle setpoint is computed from pressure measurements. In throttle control mode, the system accepts a direct throttle setpoint from the control unit and bypasses the pressure-based computation. This dynamic mode switching enables versatile functionality while keeping the control logic manageable through clear mode-based separation.
Data Source
AI summary
A valve device including an outlet port, a first valve unit with a first valve element for setting a first throttle opening for influencing a first airflow of pressurised air which is to be output at the outlet port or is to be released via the outlet port, a first throttle control loop for the closed-loop control of the first throttle opening according to a first setpoint, a pressure control loop for the closed-loop pressure control of an outlet pressure present at the outlet port to a pressure setpoint amid the use of a first throttle control loop as a subordinate control loop, wherein on closed-loop pressure control the pressure control loop specifies a first throttle setpoint to the first throttle control loop as the first setpoint, wherein the valve device is further configured to provide a throttle setting function and, within the throttle setting function, to limit the first throttle opening to a first limitation value and/or within the throttle setting function to specify a first direct setpoint which does not come from the closed-loop pressure control, to the first throttle control loop as the first setpoint.