Dual-Link Arm Structure With Spring Gravity Compensation
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Solution Overview
Problem
Existing arm structures with gravity compensation mechanisms aim to reduce motor output but require further minimization to enhance efficiency and downsizing.
Innovation Solution
The arm structure incorporates a dual-link mechanism with a connecting member and a gravity compensation mechanism that utilizes a spring to balance torque around the rotating shaft, allowing the second link to rotate twice the angle of the first link in the opposite direction, thereby reducing the motor output and area required for operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a gravity compensation mechanism is provided to reduce motor output, then the motor and arm structure can be downsized, but the device complexity increases due to additional components
Solution Approach 1:
The patent combines the gravity compensation function with the existing dual-link mechanism by integrating a spring mechanism into the connecting member structure. The spring is arranged within the connecting member to connect the first and second links, merging two functions (gravity compensation and link connection) into a single integrated component, thereby reducing overall device complexity while maintaining the gravity compensation effect that reduces motor output
Solution Approach 2:
The patent employs a spring-based counterweight mechanism where the spring force acts in opposition to the gravitational torque on the first link. The spring is positioned and configured to generate an upward counterbalancing force that compensates for the weight of the first link and any carried load, thereby reducing the net torque that the motor must overcome and enabling motor downsizing
2Area of stationary object
If the second link rotates twice the angle of the first link in the opposite direction, then the area required for operation is reduced, but the mechanical complexity increases
Solution Approach 1:
The patent implements an asymmetric rotational relationship between the two links where the second link rotates at twice the angular velocity and in the opposite direction of the first link. This asymmetric motion ratio is achieved through the mechanical coupling in the connecting member, creating a compact operational footprint by folding the motion path back on itself, thereby reducing the horizontal space required while the asymmetric mechanism itself adds some mechanical complexity
Solution Approach 2:
The patent transforms the motion from a simple single-plane rotation into a coupled two-dimensional rotational system where the second link's rotation is mechanically linked to the first link's rotation at a 2:1 ratio in opposite directions. This dimensional coupling of rotational motions allows the end effector to cover a larger effective workspace within a smaller physical footprint by utilizing angular velocity differentiation between links
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
This configuration effectively compensates for torque generated by the load, reducing power consumption and enabling a more compact design by eliminating the need for additional gravity compensation mechanisms, allowing the arm structure to operate with lower motor output and smaller size.
Implementation Method 1
a gravity compensation mechanism which compensates for torque generated around the first rotating shaft by gravity
Implementation Method 2
torque generated around the first rotating shaft by gravity
Data Source
AI summary
According to one embodiment, an arm structure includes a base, a first link, a second link, a connecting member, and a gravity compensation mechanism. The first and the second links are rotatable in a vertical direction. One end side of the first link is pivotally attached to the base via a first rotating shaft. One end side of the second link is pivotally attached to another end side of the first link via a second rotating shaft. A length of the first link is same as a length of the second link. The second link rotates around the second rotating shaft. A rotation angle of the second link is twice a rotation angle of the first link. A rotation direction of the second link is opposite to a rotation direction of the first link. The gravity compensation mechanism compensates for torque generated around the first rotating shaft by gravity.