Two-Degree-of-Freedom Parallel Robot Spatial Kinematic Chain
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Solution Overview
Problem
Traditional two-degree-of-freedom mechanisms, especially in parallel robots, face issues with error accumulation, large mass of movement components, and structural complexities due to redundant and passively constrained chains, limiting their performance in achieving high precision and speed.
Innovation Solution
A two-degree-of-freedom parallel robot with a spatial kinematic chain is designed, featuring a fixed platform, active arms, a movable platform, and branch chains with spherical articulations, anti-torsion rods, and a compact structure that allows for high control precision and large working space, enabling high speed and acceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional serial mechanisms are used for two-degree-of-freedom movement, then the structure is simple, but error accumulation occurs and control precision deteriorates
Solution Approach 1:
The patent inverts the traditional serial mechanism approach by adopting a parallel mechanism architecture. Instead of connecting links in a sequential chain (serial), multiple kinematic chains connect the fixed platform to the movable platform simultaneously (parallel), fundamentally changing the error propagation characteristics and improving control precision while maintaining acceptable structural complexity.
Solution Approach 2:
The parallel mechanism is divided into multiple independent kinematic chains (at least two), each consisting of links and joints. This segmentation allows each chain to independently contribute to the overall positioning, reducing error accumulation and improving control precision through redundant pathways.
2Strength
If parallel mechanisms with redundant and passively constrained chains are used, then rigidity and bearing capacity improve, but kinematic and structural complexities increase
Solution Approach 1:
The patent extracts and removes redundant and passively constrained chains from the parallel mechanism structure. By eliminating these unnecessary components, the design achieves the desired rigidity and bearing capacity with minimal kinematic and structural complexity, avoiding the pitfalls of over-constrained systems.
Solution Approach 2:
The mechanism employs dynamic constraint characteristics where constraints are actively managed rather than statically over-constrained. This allows the structure to maintain rigidity and bearing capacity while avoiding the complexity associated with redundant passive constraints, enabling smoother motion and easier control.
3Volume of moving object
If parallel mechanisms are designed for two degrees of freedom in the plane, then the structure is compact, but working space and acceleration performance are limited
Solution Approach 1:
The patent transitions from a planar two-degree-of-freedom mechanism to a spatial parallel mechanism. By introducing three-dimensional kinematic chains with spherical joints and spatial link arrangements, the mechanism achieves enhanced working space and acceleration performance while maintaining structural compactness through efficient spatial utilization.
Solution Approach 2:
The mechanism combines different types of joints (spherical joints, cylindrical joints) and link configurations to create a composite kinematic structure. This composite approach enables the mechanism to achieve both compactness and enhanced performance characteristics including larger working space and higher acceleration capabilities.
Data Source
AI summary
A two-degree-of-freedom parallel robot with a spatial kinematic chain includes a fixed platform, a movable platform, two driving devices, and two branch chains. Each driving device includes an active arm and a driving unit, and the two active arms are in the same reference plane. An end bracket is hinged on the active arm. Each branch chain includes two shaft rods and two chain rods. One of the two shaft rods is arranged on the active arm or the end bracket, and the other one thereof is arranged on the movable platform. The two chain rods and the two shaft rods form a parallelogram.