Programmable Air Servo Motor Control Without Encoder
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Solution Overview
Problem
Current air motors lack precise control over rotational speed, torque, and angle due to their compressible and frictional nature, making them difficult to control and unsuitable for environments requiring precise servo functions, unlike electric servo motors.
Innovation Solution
A programmable air servo motor system comprising an air motor with a brake module, sensor module, and driver that includes CPUs, communication units, and solenoid valves, allowing for control of rotational speed, torque, and angle without an encoder, enabling emergency stops, forward/reverse rotation, speed adjustments, and precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an air motor is used to operate in hazardous environments (petroleum plants, chemical plants, mineshafts, offshore oil platforms, sewers, damp environments), then safety is improved (no temperature rise at overload, no spark during operation, no shock and short circuit risks), but control precision deteriorates (uneasy to control because air is compressible, highly frictional, tending to leak out and nonlinear)
Solution Approach 1:
The patent implements feedback control by detecting actual torque, rotational speed, and angle signals from the air motor and comparing them with target values. The controller adjusts air supply pressure and flow based on detection results to achieve precise control of rotational speed, torque, and angle, resolving the control precision issue while maintaining safety advantages of air motors in hazardous environments.
Solution Approach 2:
The patent changes physical parameters of air supply (pressure, flow rate) dynamically controlled by the controller to achieve different operational states. By regulating air supply parameters precisely, the system overcomes the compressible and nonlinear characteristics of air to enable accurate control of rotational speed, torque, and positioning.
2Power
If an air motor operates at high rotational speed (at least 6000 rpm or even more than 10000 rpm), then power output is improved, but measurement precision deteriorates (not controllable with an encoder because of very high rotational speed)
Solution Approach 1:
The patent replaces the traditional encoder-based mechanical feedback system with a sensor module that directly detects torque, rotational speed, and angle signals. This substitution eliminates the limitations of encoders at high speeds while maintaining precise control capability for power output up to 6000-10000 rpm and beyond.
Solution Approach 2:
The patent introduces a sensor module as an intermediary between the air motor and controller. This sensor module accurately measures high-speed rotational parameters and transmits signals to the controller, enabling precise control at speeds where traditional encoders fail.
3Adaptability or versatility
If an air motor is used instead of an electric servo motor, then adaptability to hazardous environments is improved, but device complexity increases (need for brake module, sensor module, controller, and air supply pressure monitoring)
Solution Approach 1:
The patent designs the controller to perform multiple functions: regulating air supply pressure, controlling forward-reverse rotation, monitoring brake status, and managing sensor signals. The sensor module simultaneously detects torque, rotational speed, and angle. This multi-functionality reduces overall system complexity while enabling air motors to replace electric servo motors in hazardous environments.
Solution Approach 2:
The patent combines the brake module, sensor module, and controller into an integrated system where the brake solenoid valve and sensor module are electrically connected to the controller. This merging of components simplifies the system architecture while maintaining the safety and control capabilities needed for environmental adaptability.
Data Source
AI summary
An apparatus and control system of a programmable air servo motor includes an air servo motor and an air servo motor driver, which are bi-directionally communicable with each other via communication units. The air servo motor includes an air motor, a sensor module, and a brake module that is normally locked and can be unlocked or locked by the air servo motor driver. The air servo motor driver includes a control module, an actuation module and a communication module. After actuating the air servo motor, the air servo motor driver receives torque, rotational speed and angle signals output by the sensor module. The actuation module drives the air servo motor to stop emergently, switch between forward and reverse rotation, increase or reduce rotational speed, operate at a specific angle, move by inching and operate at controlled torque similar to an electric servo motor without the need of an encoder.