Four-Bar Linkage Gripper for Irregular Object Handling
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Solution Overview
Problem
Conventional robotic systems for lifting objects using end effectors face limitations in versatility and capability, particularly in handling objects of varying sizes and shapes, as they often rely on single mechanisms like grippers or suction cups, which may not be sufficient for heavier items or irregularly shaped objects.
Innovation Solution
A four-bar linkage gripper assembly combined with a suction cup assembly, where two actuators control the paddles to open, close, and move up and down, enabling enhanced grasping and lifting capabilities by allowing independent control of carriages and maintaining paddle alignment through upper and lower links, allowing for flexible positioning and force application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional gripper with a pair of opposing pads is used, then the structure is simple, but the capability to handle objects of varying sizes and shapes is limited
Solution Approach 1:
The gripper is divided into multiple independent paddles (first paddle and second paddle) that can move independently relative to each other. Each paddle can be controlled separately to adapt to different object geometries, allowing the gripper to handle objects of varying sizes and shapes while maintaining a relatively simple overall structure.
Solution Approach 2:
The linkage mechanism transforms the motion of a single actuator into independent vertical and horizontal movements of multiple paddles. This dynamic capability allows the paddles to adjust their positions and orientations to accommodate different object shapes, enhancing adaptability without requiring multiple independent actuators for each degree of freedom.
2Force
If a single mechanism like gripper or suction cup is used, then the device complexity is low, but the capability to lift heavier items is insufficient
Solution Approach 1:
The patent combines a gripper mechanism with a suction cup assembly into a single end effector. The gripper provides mechanical grasping force while the suction cup provides additional holding force, particularly effective for heavier items. This merged system delivers superior lifting capability compared to either mechanism alone, while the integration is achieved through a unified actuation system that controls both components.
3Adaptability or versatility
If two actuators are used to control paddle movements, then the grasping capability is enhanced, but the device complexity increases
Solution Approach 1:
A single actuator is designed to perform multiple functions: it controls both the vertical movement of the first carriage (affecting the first paddle) and the horizontal movement of the second carriage (affecting the second paddle). This multi-functional actuator reduces the total number of actuators needed while maintaining enhanced grasping capability through the coordinated movement of multiple paddles.
Solution Approach 2:
The linkage mechanism acts as an intermediary that translates the single actuator's motion into coordinated movements of multiple paddles. The linkage includes upper and lower links that connect the carriages to the paddles, mediating the force and motion transmission to achieve independent paddle control without requiring independent actuators for each degree of freedom.
4Ease of operation
If independent control of carriages is implemented, then the positioning flexibility is improved, but the control system complexity increases
Solution Approach 1:
The linkage mechanism is designed to automatically maintain the parallel alignment of paddles through its geometric constraints. As the carriages move independently, the upper and lower links self-adjust to keep the paddles parallel, eliminating the need for complex active control systems to maintain alignment. The mechanism serves itself by using passive geometric constraints to achieve the desired positioning.
Data Source
AI summary
A gripper assembly includes a four bar linkage and one or a pair of carriages the move longitudinally on rails. The linkage includes a means for maintaining the paddles in a mutually parallel orientation, which can be a link or a timing belt.