3-DOF Parallel Electromagnetic End Effector With Variable Stiffness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing robotic force-controlled end-actuators, particularly those with single-degree-of-freedom mechanisms, fail to meet the requirements for high-precision polishing and grinding of complex curved surfaces due to rigid designs that lack compliance and environmental adaptability, and traditional parallel mechanisms are bulky and complex in structure.
Innovation Solution
A three-degree-of-freedom parallel electromagnetic variable stiffness actuator with non-stiffness electromagnetic drive branches and electromagnetic spring drive branches, featuring an electromagnetic direct-drive motor module, preload stiffness springs, and peripheral sensor systems, allowing real-time stiffness adjustment and precise force control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional rigid drive structures with motors and reducers are used, then driving force and motion transmission are achieved, but compliance and environmental adaptability are insufficient
Solution Approach 1:
The patent replaces traditional mechanical drive structures (motors+reducers) with electromagnetic drive branches that use electromagnetic forces for motion transmission. This substitution eliminates complex mechanical transmission components while achieving compliant actuation through the electromagnetic spring mechanism, thereby improving environmental adaptability without increasing device complexity
Solution Approach 2:
The patent introduces variable stiffness capability through electromagnetic springs that can dynamically adjust their mechanical impedance. This allows the end effector to adapt its compliance in real-time according to environmental conditions and task requirements, transforming a static rigid structure into a dynamic compliant system that can buffer collision energy and adapt to varying operational demands
2Adaptability or versatility
If torsion springs are introduced to add flexibility, then some compliance is achieved, but the rigid nature of the drive structure cannot be altered and end effector rigidity cannot be changed
Solution Approach 1:
The electromagnetic spring serves multiple functions simultaneously: it provides the restoring force for motion, enables variable stiffness control, and acts as the compliant element for energy buffering. This multi-functionality achieves compliance without adding separate flexibility components, avoiding increased drive structure complexity while maintaining the ability to adjust end effector rigidity
Solution Approach 2:
The patent changes the stiffness parameter of the drive structure by varying the current through the electromagnetic spring. This allows continuous adjustment of the end effector's rigidity from stiff to compliant states, fundamentally altering the mechanical characteristics of the drive structure rather than merely adding passive flexibility elements
3Strength
If traditional parallel mechanisms are used, then load-bearing capacity and compactness are improved, but transmission and structure become complex and bulky
Solution Approach 1:
The patent replaces complex mechanical transmission components (gears, belts, linkages) in traditional parallel mechanisms with electromagnetic drive branches. These branches use electromagnetic forces for direct motion transmission, eliminating the need for intermediate mechanical transmission elements and significantly simplifying the overall transmission system while maintaining load-bearing capacity
4Manufacturing precision
If single-degree-of-freedom mechanisms are used, then simplicity is maintained, but high-precision polishing and grinding of complex curved surfaces cannot be achieved
Solution Approach 1:
The patent employs three electromagnetic drive branches with independently controllable variable stiffness capabilities. This dynamic control allows the end effector to adapt its compliance and force distribution in real-time during contact tasks, enabling high-precision polishing and grinding of complex curved surfaces by adjusting stiffness parameters according to local surface geometry and material properties
Solution Approach 2:
The patent changes the stiffness parameters of the three electromagnetic drive branches independently to achieve precise force control in multiple degrees of freedom. By varying these parameters dynamically, the system can maintain optimal contact forces and orientations for high-precision manufacturing tasks on complex surfaces without requiring overly complex mechanical structures
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 actuator achieves high-precision, high-compliance motion and force control, adapting to complex surfaces with real-time stiffness adjustment, improving processing efficiency and accuracy while reducing maintenance costs and extending equipment life.
Implementation Method 1
non-stiffness electromagnetic drive branches, each comprising an electromagnetic direct-drive motor module
Implementation Method 2
electromagnetic spring drive branch, comprising an electromagnetic spring module
Data Source
AI summary
A three-degree-of-freedom parallel electromagnetic variable stiffness actuator as an end effector for robotic grinding and polishing, comprising: non-stiffness electromagnetic drive branches, an electromagnetic spring drive branch, structural components, and peripheral sensor systems. There are three non-stiffness electromagnetic drive branches; three-degree-of-freedom motion can be generated through these three non-stiffness electromagnetic drive branches. For the electromagnetic spring drive branch, its driving component is an electromagnetic spring, which is responsible for providing adjustable stiffness. The actuator achieves a high-precision, high-flexibility control of the grinding and polishing end through a unique three-degree-of-freedom parallel structure.