Pneumatic Actuator Force Control Using Model-Based Pressure Optimization
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Solution Overview
Problem
Existing methods for controlling the force applied by pneumatic actuating devices, such as gripping devices, are inefficient and difficult to implement as a closed-loop system, relying on air pressure and lacking precise control and energy optimization.
Innovation Solution
A control method using a dynamic model of the actuating system and an optimization algorithm to calculate optimized control signals for pressure regulators, with a state observer estimating pressures and derivatives in real-time, allowing for precise force control and energy minimization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional proportional-integral controller with force sensor is used for feedback control, then force control capability is achieved, but system complexity and cost increase
Solution Approach 1:
The patent replaces the traditional mechanical feedback control system (proportional-integral controller with force sensor) with a model-based control approach. A dynamic model of the pneumatic system is developed that directly relates control valve positions to gripping force, eliminating the need for complex feedback hardware while achieving precise force control through computational methods.
Solution Approach 2:
The patent transforms the control approach by changing from feedback-based parameter adjustment to feedforward model-based parameter calculation. The dynamic model pre-calculates the relationship between valve positions and force output, allowing direct determination of control parameters without requiring continuous sensor feedback or complex controller tuning.
2Force
If air pressure is used to control force in pneumatic actuating devices, then high force output is achieved, but precise force control becomes difficult
Solution Approach 1:
The patent introduces a dynamic mathematical model as an intermediary between the pneumatic system and the control objective. This model acts as a bridge that translates desired force values into appropriate control valve positions, enabling precise force control without directly measuring or feedback from the force itself. The model captures the complex nonlinear relationship between air pressure and force output.
3Measurement precision
If complex control systems are implemented for force regulation, then control precision improves, but energy consumption increases
Solution Approach 1:
The patent applies preliminary action by pre-developing and storing the dynamic model that characterizes the pneumatic system's behavior. This model is created beforehand through system identification and simulation, allowing the control system to directly compute optimal valve positions without requiring continuous complex calculations or high-power feedback components during operation, thereby reducing energy consumption while maintaining precision.
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 method achieves precise control of forces with low error, minimizes energy consumption, and improves tracking performance and stability, especially for time-variable signals and complex dynamics.
Implementation Method 1
The actuating device (10) comprises a first working chamber (14) and a second working chamber (16) which can be supplied with pressurized air
Data Source
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AI summary
An actuating device (10) comprises a first (14) and a second (16) working chamber supplied with pressurized air from a source (18) of pressurized air by means of a first (20) and a second (22) pressure regulator, respectively, for regulating the pressure of the air inside the working chambers (14, 16) on the basis of a control signal. In order to control the actuation force exerted by the pneumatic actuating device, the method provides iteratively carrying out the following steps in real time: a) calculating desired values (uc_d, uo_d) for the control signals for the pressure regulators (20, 22) by means of an optimization algorithm that is based on a dynamic model of the actuating device (10) and of the pressure regulators (20, 22), in order to generate an actuation force by means of the actuating device (10) that is equal to a given desired value (Fd); and b) determining an estimated value (Fest) for the actuation force and estimated values for the pressures (Pc_est, Po_est) inside the working chambers (14, 16) and for the first derivatives (Pc_est, Po_est) of these pressures by means of a state observer (32) on the basis of a value (Fm) measured for the actuation force and of values (Pc, Po) measured for the pressures in the working chambers (14, 16).