Parallel Link Hub Control for Resonance-Tuned Positioning
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Solution Overview
Problem
Existing link actuation devices face challenges in achieving a compact, precise, and extensive operating range due to limitations in link length, rigidity, and weight capacity, particularly in medical and industrial applications, where the parallel link mechanism's bulkiness and reduced rigidity hinder high-speed and accurate positioning.
Innovation Solution
A control method that synchronizes the operation of actuators to change the distal end link hub's orientation by setting deceleration and acceleration times near the resonant frequency of the link actuation device, ensuring balanced force distribution and reduced vibration, allowing for high-speed and accurate positioning with improved stabilization time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the link length is increased to achieve a large operating range, then the operating range is improved, but the rigidity of the mechanism decreases and the device becomes bulky
Solution Approach 1:
The patent applies dynamic control by setting deceleration and acceleration times near the resonant frequency of the link actuation device. This dynamic timing optimization allows the mechanism to exploit resonance to maintain rigidity during high-speed operation while achieving extensive operating range through coordinated actuator synchronization, resolving the contradiction between operating range and rigidity.
Solution Approach 2:
The patent changes the temporal parameters of actuator operation by setting deceleration and acceleration times to specific values near the resonant frequency. This parameter optimization enables the mechanism to achieve both large operating range and maintained rigidity by synchronizing actuator operations with the natural resonant characteristics of the system.
2Adaptability or versatility
If the link length is increased to achieve a large operating range, then the operating range is improved, but the weight capacity of the traveling plate is limited
Solution Approach 1:
The patent uses dynamic synchronization control where all actuators are coordinated to start and complete operations simultaneously with deceleration times set near resonant frequency. This dynamic coordination distributes load forces more effectively across the mechanism, enabling extended operating range while maintaining weight capacity by optimizing force distribution during motion.
3Measurement precision
If synchronization control with resonant frequency timing is applied, then high-speed positioning accuracy is improved, but the control complexity increases
Solution Approach 1:
The patent applies periodic action by setting deceleration and acceleration times to specific values near the resonant frequency, creating a rhythmic, periodic control pattern that exploits the natural oscillatory behavior of the mechanism. This periodic timing approach simplifies the control strategy compared to continuous complex control algorithms while achieving high positioning accuracy through resonance utilization.
4Stability of the object's composition
If the deceleration time is set near the resonant frequency, then vibrations are reduced and stabilization time is improved, but the control precision requirements increase
Solution Approach 1:
The patent converts the potentially harmful resonant vibrations into a beneficial control mechanism by setting deceleration and acceleration times near the resonant frequency. This transforms the resonance, which could cause instability, into a tool for reducing vibrations and improving stabilization time through synchronized actuator operations that exploit the natural frequency characteristics of the system.
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 synchronization control method enhances the balance of forces and reduces vibrations, enabling high-speed operation with high accuracy and stability, thus overcoming the limitations of bulkiness and reduced rigidity in existing devices.
Implementation Method 1
setting deceleration and acceleration times near the resonant frequency of the link actuation device
Data Source
Figure 1
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Figure 4
AI summary
A link actuation device (51) includes a distal end side link hub (3) connected with a proximal end side link hub (2) through three or more sets of link mechanisms (4) for alteration in orientation. By means of an actuator (53) provided in the two or more set of the link mechanism (4), the distal end orientation, which is the orientation of the distal end side link hub (3) relative to the proximal end link hub (2), is changed arbitrarily. The operating device (55) includes an orientation designating unit (55a) for designating the distal end orientation aimed at by means of a coordinate position on the orthogonal coordinate system by an artificial manipulation, an orientation acquiring unit (55) for acquiring the distal end orientation that is expressed by an angular coordinate system through calculation, and an orientation information applying unit (55c) for applying information on the distal end orientation so acquired to a control device (54) for controlling the actuator (53).