Electro-Hydraulic Micro-Displacement Platform for Robot Machining Accuracy
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Solution Overview
Problem
Industrial robots have limitations in high-precision machining due to their series open-loop structure, leading to low stiffness and poor absolute positioning accuracy, which results in significant machining deviations, especially under high cutting forces, making them unsuitable for applications like milling and drilling.
Innovation Solution
An electro-hydraulic micro-displacement platform and system that decomposes position deviations into low-frequency and high-frequency components, using micro-displacement actuators with static seals and hydraulic drive systems to compensate for these deviations, allowing for sub-micron precision positioning and reducing inherent friction and nonlinear characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If industrial robots are used for machining, then working space and cost are improved, but positioning accuracy and stiffness deteriorate
Solution Approach 1:
The patent introduces an electro-hydraulic micro-displacement platform as an intermediary device between the robot and the workpiece. This platform actively compensates for positioning errors by generating counteracting displacements, thereby enabling robots to achieve high-precision machining without sacrificing their inherent advantages in working space and cost-effectiveness
2Manufacturing precision
If robot stiffness is increased, then positioning accuracy is improved, but cutting force capability deteriorates
Solution Approach 1:
The patent segments the positioning function into two independent parts: the robot provides large-range motion and the electro-hydraulic platform provides high-precision positioning. This segmentation allows the robot to maintain its original stiffness characteristics for handling cutting forces, while the separate platform delivers sub-micron positioning accuracy without interfering with the robot's force capability
3Manufacturing precision
If mathematical models are used for compensation, then accuracy is improved, but system complexity deteriorates
Solution Approach 1:
The patent replaces complex mathematical modeling and computational compensation methods with a direct physical compensation mechanism. The electro-hydraulic platform uses real-time displacement sensing and hydraulic actuation to physically counteract positioning errors, eliminating the need for complex forward and inverse kinematics calculations and stiffness model identifications
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
This solution effectively compensates for position deviations between the robot end effector and workpiece, improving machining accuracy and expanding the application of industrial robots in high-precision machining by decoupling the accuracy from the robot's inherent limitations, enabling precise positioning under high cutting forces.
Implementation Method 1
Each hydraulic drive system includes a controller, a hydraulic pump, a proportional valve, overflow valves, and a pressure sensor. The hydraulic pump is connected with the oil inlet of the proportional valve, and the two oil outlets of the proportional valve are respectively connected with the drive oil access holes of the two micro-displacement actuators.
Implementation Method 2
The micro-displacement actuator outputs axial displacement based on the elastic deformation of the material.
Data Source
AI summary
An electro-hydraulic micro-displacement platform, a micro-displacement system, a precision compensation system, and its method, comprises an x-direction guide rail and a y-direction guide rail slidingly connected with a cross slider respectively. The x-direction guide rail is fixed on the floor of the frame, and a z-direction fixed platform is fixed on the y-direction guide rail. The periphery of the z-direction fixed platform is connected with the side plate of the frame through the x-direction micro-displacement actuator and the y-direction micro-displacement actuator, the z-direction fixed platform is connected with the z-direction floating platform through the first z-direction micro-displacement actuator, the z-direction floating platform is connected with the z-direction auxiliary fixed platform through the second z-direction micro-displacement actuator, and the z-direction fixed platform is fixedly connected with the z-direction auxiliary fixed platform. The z-direction floating platform is connected to the workpiece mounting plate.