Pulse-Driven Servo Valve Layout for Precise Pneumatic Cylinder Control
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Solution Overview
Problem
Current pneumatic servo control technologies face challenges in achieving precise control and miniaturization for humanoid robots due to the need for servo amplifiers and advanced machining techniques, as well as issues with air compressibility and friction, making it difficult to develop actuators with high power and compact designs.
Innovation Solution
A servo valve unit that controls pneumatic cylinders without a servo amplifier, utilizing a unit body with first and second valve portions, seal members, and drive mechanisms driven by electric pulses, allowing for precise control and miniaturization, and eliminating the need for air bleeding, thereby enabling the development of compact and lightweight high-power actuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional pneumatic servo control technology is used, then pneumatic cylinders can be driven, but precise control is difficult due to air compressibility and friction
Solution Approach 1:
The patent employs periodic pulse signals to drive the pneumatic cylinder, replacing continuous analog control. The pulse width modulation technique allows precise control of air supply timing and duration, overcoming the effects of compressibility and friction by using discrete on/off control cycles that reset the system state periodically.
Solution Approach 2:
The patent replaces the mechanical analog servo valve system with an electronic pulse control system. Instead of using mechanical spool valves or flapper valves that suffer from friction and hysteresis, the invention uses electronically controlled solenoid valves actuated by pulse signals, eliminating mechanical contact friction and improving control precision.
2Measurement precision
If servo amplifiers and advanced machining techniques are used, then control precision can be improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent extracts and eliminates the servo amplifier component from the traditional pneumatic servo system. By using simple pulse signals directly from a controller to actuate solenoid valves, the system removes the need for complex amplification circuits and advanced machining techniques, achieving precision control through simplified architecture.
Solution Approach 2:
The pneumatic cylinder and solenoid valves are designed to respond directly to pulse signals without requiring external servo amplifiers or complex control circuits. The system components are self-actuating, where the pulse signal directly controls the valve switching and subsequently the cylinder motion, eliminating intermediate control stages.
3Measurement precision
If electric servo motors are used, then control precision can be achieved, but weight and volume increase due to motors and speed reducers
Solution Approach 1:
The patent replaces electric servo motors with direct pneumatic actuation. Instead of using heavy motors and speed reducers to generate mechanical motion, the system uses compressed air directly to drive the pneumatic cylinder, eliminating the need for motor-gearbox assemblies and significantly reducing actuator weight and volume.
Solution Approach 2:
The invention adopts pneumatic actuation as the primary drive mechanism, using compressed air to generate force and motion directly. This approach replaces electric motor-driven mechanical systems with a lighter, more compact pneumatic system that achieves the required control precision through pulse-width modulation of air supply.
4Power
If hydraulic servo control is used, then large power per unit volume can be achieved, but weight and volume increase due to oil pressure source and servo amplifier
Solution Approach 1:
The patent selects pneumatic control over hydraulic control, using compressed air instead of hydraulic oil. This substitution eliminates the need for heavy oil pressure sources, reservoirs, and associated components, achieving high power density with a lighter, more compact system suitable for mobile and humanoid robot applications.
Solution Approach 2:
The invention extracts and removes the hydraulic pressure source and servo amplifier components from the system. By using direct pneumatic actuation with pulse-controlled solenoid valves, the system eliminates the heavy infrastructure required for hydraulic systems, achieving power density without the associated weight penalty.
5Ease of operation
If conventional pneumatic servo valves are used, then pneumatic control can be implemented, but manufacturing precision requirements are very high
Solution Approach 1:
The patent segments the valve control function into discrete pulse-actuated solenoid valves rather than using continuous analog servo valves. This segmentation allows each valve to operate in simple on/off states controlled by digital pulses, tolerating wider manufacturing variations and reducing the precision requirements for valve seat geometry and flow characteristics.
Solution Approach 2:
The invention changes the control parameter from continuous analog signals to discrete pulse width modulation. This parameter change allows the use of simpler, more tolerant valve designs where the effective flow control is achieved through temporal modulation of fully open/closed states rather than precise mechanical positioning, significantly reducing manufacturing precision requirements.
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 solution allows for precise control of pneumatic cylinders with high power and miniaturization, reducing the complexity and weight of the system, enabling the realization of humanoid robots by overcoming the limitations of existing pneumatic servo control technologies.
Implementation Method 1
a first drive mechanism for driving the first seal member by a first electric pulse, a second drive mechanism for driving the second seal member by a second electric pulse
Data Source
AI summary
A servo valve for precisely controlling a position of a pneumatic cylinder does not require a servo amplifier and a small sized and/or high durability servo valve unit. The servo valve comprises a unit body having first and second portions, first and second valve portions, first and second seal members that open and close the first and second valve portions, respectively, first and second drive mechanisms that drive first and second seal members by first and second electric pulses, respectively, a supply flow path between the first end and first valve, an exhaust flow path between the second end and second valve, a common flow path connected to the supply and exhaust flow paths via first and second valve portions, and a drive flow path connected to the pneumatic actuator. First and second drive mechanisms are arranged in a drive mechanism arrangement portion located between first and second end portions.