Parallel Link Robot Drive Unit With Universal Joint
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Solution Overview
Problem
Existing parallel link robots face challenges in efficiently supporting inertial forces and maintaining a lightweight, rigid structure due to the limitations of power transmission and mechanical coupling between passive and drive links, which affects their positional accuracy and flexibility.
Innovation Solution
The integration of an additional drive unit with a universal joint coupling, allowing parallel movement between passive links and a drive link, and a spherical bearing for connecting the drive shaft to a wrist mechanism, enhances the robot's ability to support inertial forces and maintain structural rigidity while simplifying the design by eliminating the need for a detent mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a power transmission mechanical unit is used to transmit power from the actuator to the movable plate, then the structural rigidity is improved, but the device complexity increases due to additional components like universal joints and parallel link arrangements
Solution Approach 1:
The patent merges the power transmission function and the mechanical coupling function into a single integrated additional drive unit. This unit combines the additional actuator, drive shaft, and universal joint attachment into one consolidated component that performs both functions simultaneously, reducing the number of separate parts while maintaining structural rigidity
Solution Approach 2:
The additional drive unit is designed with multi-functionality, serving both as a power transmission mechanism and as a mechanical coupling between the drive link and movable plate. The universal joint attachment enables the drive shaft to accommodate angular misalignments while transmitting torque, making the same component adaptable to varying operational conditions without requiring separate specialized components
2Ease of manufacture
If the additional drive unit is positioned away from the passive links to simplify the structure, then the ease of manufacture is improved, but the ability to support inertial forces deteriorates
Solution Approach 1:
The patent applies local quality by positioning the additional drive unit specifically on the drive link at a location that optimizes inertial force support while maintaining manufacturing simplicity. The drive unit is attached to the drive link rather than requiring complex integration with passive links, concentrating the inertial force support function at the most effective local position on the drive mechanism
3Manufacturing precision
If a detent mechanism is added to maintain the parallel arrangement of passive links, then the positional accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent employs dynamics by allowing the additional drive unit to maintain the parallel arrangement of passive links through dynamic adjustment rather than fixed mechanical constraints. The universal joint attachment enables the drive shaft to automatically adapt to angular variations during motion, maintaining positional accuracy without requiring static detent mechanisms or additional locking components
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 configuration enables reliable support of inertial forces, maintains a lightweight and rigid structure, and enhances the robot's ability to translate and posture tools accurately in three-dimensional space with improved flexibility and reduced complexity.
Implementation Method 1
The additional drive unit is attached to the drive link with a joint, swingably coupling the additional drive unit to the drive link around at least two mutually intersecting axes
Implementation Method 2
a spherical bearing for connecting the drive shaft to a wrist mechanism
Data Source
AI summary
A parallel link robot includes: a base portion; a movable portion; link portions coupling the base and movable portions; and actuators attached to the base portion and driving the respective link portions. Each of the link portions includes drive links swung around axes by the respective actuators, and two each of the passive links parallel to each other and swingably arranged between the drive link and the each of the movable portions. The robot includes a drive unit disposed parallel to the two passive links of at least one of the link portions and between the passive links and drives a mechanical unit attached to the movable portion. The drive unit is attached to the drive link with a joint, swingably coupling the drive unit to the drive link around at least mutually intersecting axes, on a straight-line coupling swinging center points of the passive links and the drive link.