Parallel Link Mechanism Control for High-Speed Vibration Suppression
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Solution Overview
Problem
Existing link actuation devices with parallel mechanisms face challenges in achieving precise positioning at high speeds due to varying rigidities and resonance frequencies, leading to vibration issues when the posture and movement direction change.
Innovation Solution
A working device with a parallel link mechanism that includes a control system capable of dynamically adjusting acceleration and deceleration times for each target position based on the posture and movement direction of the distal-side link hub, using a correspondence table or linear approximation to set optimal acceleration and deceleration times, thereby suppressing vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If acceleration and deceleration times are set based on resonance frequency of the link actuation device, then high-speed operation is enabled, but vibration occurs when rigidity changes with posture
Solution Approach 1:
The patent applies dynamics by making the acceleration and deceleration times variable rather than fixed. The control device dynamically adjusts these parameters based on the actual posture of the distal-side link hub, matching the changing rigidity conditions at different positions. This resolves the contradiction by adapting the timing parameters to the dynamic structural characteristics, enabling high-speed operation without vibration-induced positioning errors.
Solution Approach 2:
The patent changes the parameters of acceleration and deceleration times according to the posture-dependent rigidity of the link actuation device. By storing multiple sets of acceleration/deceleration time parameters corresponding to different postures and selecting the appropriate parameters based on current posture, the system maintains positioning precision while operating at high speeds across various positions.
2Measurement precision
If synchronous control is used to position all actuators simultaneously, then posture control precision is improved, but operation time increases due to conservative deceleration timing
Solution Approach 1:
The patent applies dynamics by transitioning from fixed, conservative deceleration timing to dynamic, posture-adaptive timing. The control device calculates and applies optimal deceleration times based on actual posture and rigidity conditions, allowing faster operation while maintaining positioning precision through real-time parameter adjustment rather than uniform conservative timing.
3Adaptability or versatility
If the link actuation device operates in positions with different rigidity from the origin posture, then working range is expanded, but vibration occurs due to inappropriate acceleration and deceleration times
Solution Approach 1:
The patent changes the acceleration and deceleration time parameters according to the posture-dependent rigidity characteristics. The control device stores multiple parameter sets corresponding to different working positions and selects appropriate parameters based on the current posture, enabling the device to operate across an expanded working range without generating vibration from inappropriate timing parameters.
Data Source
AI summary
A working device includes a link actuation device and a control device for the link actuation device. The control device includes: a storage unit configured to store a plurality of the target positions; a calculation unit configured to sequentially read out the respective target positions stored to calculate movement amounts and movement speeds of the respective actuators between the target positions; and a control unit configured to operate the respective actuators by the movement amounts and at the movement speeds of the respective actuators calculated by the calculation unit. The control unit is capable of changing acceleration and deceleration times of the actuators for each of the target positions.