Compliant Robot End Effector for Precise Part Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Robots in manufacturing processes face challenges in precisely aligning and attaching parts due to variances within acceptable tolerances, as parts may deform and change location when released from rigid gripping mechanisms, leading to inaccuracies in alignment and attachment.
Innovation Solution
A robot with a compliant end effector featuring a base, a jaw fixedly coupled to the base, a part-engaging surface, and a pivot structure that allows limited rotation of the part-engaging surface relative to the jaw about a single pivot axis, combined with a vision system to generate location signals for precise positioning, and a jaw actuator to transition between open and gripping orientations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a rigid gripping mechanism is used to hold the part in position, then the part can be held firmly in place, but the part may be temporarily deformed into alignment and then spring away once released, changing its relative location
Solution Approach 1:
The end effector transitions from a static rigid grip to a dynamic compliant grip that adapts to the part's geometry. The compliant mechanism allows controlled deformation and rotation to accommodate part variances while maintaining consistent contact force, preventing both excessive gripping force that causes deformation and insufficient force that allows part movement.
Solution Approach 2:
The system changes the physical parameters of the gripping interface by introducing compliance through the pivot structure and part-engaging surface rotation. This allows the end effector to adjust its geometry and contact characteristics to match the part's actual dimensions and orientation, maintaining precision without requiring excessive gripping force.
2Manufacturing precision
If a compliant end effector with pivot structure is used to allow part rotation and alignment, then alignment precision is improved, but the device complexity increases
Solution Approach 1:
The end effector is segmented into distinct functional components: the jaw for gripping, the pivot structure for rotation, and the part-engaging surface for alignment. This segmentation allows each component to perform its specific function independently, simplifying the overall design while achieving complex alignment capabilities through coordinated action of simple elements.
Solution Approach 2:
The compliant end effector is designed to self-align with the part through its pivot structure and rotating part-engaging surface. The mechanism automatically adjusts to accommodate part variances without requiring external sensors or active control systems, reducing device complexity while maintaining high alignment precision.
3Adaptability or versatility
If multiple degrees of freedom are allowed in the end effector for comprehensive alignment, then adaptability to part variances is improved, but control precision becomes more difficult to maintain
Solution Approach 1:
The end effector implements compliance locally at the part-engaging surface and pivot structure, while maintaining rigidity in the main body and gripping mechanism. This localized compliance provides the necessary adaptability to part variances without introducing excessive degrees of freedom that would compromise overall control precision.
Solution Approach 2:
The pivot structure is designed with asymmetric constraints that permit rotation about a single pivot axis while restricting motion in other directions. This asymmetric design provides targeted compliance exactly where needed for alignment while maintaining precise control over the end effector's overall position and orientation.
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 compliant end effector ensures precise and reproducible alignment and attachment of parts by allowing controlled rotation and gripping force regulation, maintaining accuracy and reliability in robotic assembly processes.
Implementation Method 1
The part-engaging surface is a vacuum surface configured to selectively retain the part via a vacuum force
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Compliant end effectors 100, robots that include compliant end effectors 100, and methods of utilizing the same. The robots include a robotic arm and the compliant end effector 100. The compliant end effector 100 includes a base 110, a jaw 120 fixedly coupled to the base 110, a part-engaging surface 130, and a pivot structure 140. The pivot structure 140 extends between the part-engaging surface 130 and the jaw 120 and is configured to permit limited rotation of the part-engaging surface 130 relative to the jaw 120 about a single pivot axis 150. The methods include locating an apparatus 90 with a vision system 40 of the robot, locating a part 80 with the vision system 40, gripping the part 80 with the compliant end effector 100, positioning the part 80 relative to the apparatus 90, and operatively attaching the part 80 to the apparatus 90. The positioning includes deliberately contacting a toe end of a flange 84 of the part 80 with the apparatus 90 prior to contacting a heel end 88 of the flange 84 with the apparatus 90.