Coupled Rail Positioners for Stiff, Wide-Range Manipulation
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Solution Overview
Problem
Existing robotic manipulators face challenges in achieving high stiffness, speed, and precision while supporting heavy loads, particularly in serial manipulators which degrade in stiffness and precision due to cumulative compliance, and parallel manipulators which have limited range and workspace.
Innovation Solution
The development of a hybrid serial-parallel manipulator system with combined serial and parallel links, featuring a primary and secondary rail system with coupling linkages that allow adjustable position and orientation of the common link relative to the base, enabling high stiffness, speed, and precision while supporting heavy loads through optimized kinematic configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If serial manipulators are used to achieve large range of motion, then workspace is improved, but stiffness and precision degrade cumulatively from base to movable platform
Solution Approach 1:
The manipulator system is divided into multiple independent kinematic chains (first chain with links 14, 16 and second chain with links 24, 26) that connect the tool-link to the base through different paths. Each chain independently supports the load, preventing cumulative compliance degradation while maintaining large workspace through coordinated motion of multiple chains.
Solution Approach 2:
The patent transitions from a single serial kinematic chain to a parallel architecture with multiple kinematic chains operating in different spatial dimensions. The first and second kinematic chains provide redundant support paths, transforming the system from series to parallel configuration to eliminate cumulative compliance while preserving workspace.
2Manufacturing precision
If parallel manipulators are used to achieve high stiffness and precision, then stiffness is improved, but range of motion and workspace are limited
Solution Approach 1:
The manipulator system employs dynamic control of multiple kinematic chains where the position and orientation of the common link relative to the base is continuously adjustable. This dynamic configuration allows the system to maintain high stiffness through parallel support while adapting the workspace envelope to accommodate large range of motion requirements through coordinated actuation of multiple chains.
3Area of stationary object
If serial manipulators are used to achieve large workspace, then range of motion is improved, but ability to support heavy loads deteriorates due to cumulative compliance
Solution Approach 1:
The load support function is segmented across multiple independent kinematic chains (first chain with links 14, 16 and second chain with links 24, 26). Each chain independently bears a portion of the load on the tool-link, distributing the mechanical stress and eliminating cumulative compliance that would occur in a single serial chain, thereby maintaining load support capability across large workspace.
Solution Approach 2:
The patent merges multiple kinematic chains (first and second chains) into a unified parallel manipulator system where all chains work together to support the common link. This combination of multiple support paths creates a synergistic effect where the total load support capability exceeds that of any single chain, enabling heavy load support while maintaining large workspace.
Data Source
AI summary
A manipulator system having a positioner having a primary rail, a first coupling linkage, and a second coupling linkage. The first coupling linkage couples the primary rail to a base and positions the primary rail along a first plane. The system has another positioner having a secondary rail, a third coupling linkage, and a fourth coupling linkage. The third coupling linkage couples the secondary rail to the base and positions the secondary rail along a second plane which is parallel to the first plane. A common link couples to the primary and secondary rails via linkages. Each of the second and fourth coupling linkages includes a joint for linear motion along the respective rail, and a revolute joint for relative pivoting between the respective rail and the common link. A position and orientation of the common link are adjustable by the joints and revolute joints.