Elastically Deformable Stopper for Multi-Joint Robot Impact
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Solution Overview
Problem
Conventional mechanical stopper devices for multi-joint robots are complex, costly, and require high accuracy, leading to increased weight and reduced motion speed due to stress dispersion, and often result in damage from high impact forces during arm collisions.
Innovation Solution
A mechanical stopper device using an elastically deformable hollow cylindrical member with a slit, press-fitted into one of the robot arms, which absorbs impact forces by deforming and limiting the rotation range, reducing the size, weight, and cost of the stopper while preventing damage to the arms and stopper components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional mechanical stopper structures are used with multiple components to bear impact force, then the stopper can withstand collision forces, but the structure becomes complex, costly, and requires high manufacturing accuracy
Solution Approach 1:
The stopper structure is segmented into a bolt portion and a stopper body portion that can relatively move against each other. The bolt can deform elastically within the stopper body to absorb impact energy, while the stopper body provides the necessary strength. This segmentation allows each component to be simpler while collectively bearing the impact force.
Solution Approach 2:
The material parameters and geometric parameters of the stopper structure are optimized to achieve the required impact bearing capacity with a simpler structure. The bolt and stopper body are designed with specific dimensions and material properties that allow elastic deformation and energy absorption without requiring complex multi-component assemblies.
2Stress or pressure
If the volume of the stopper structure is increased to disperse stress during collision, then the stress is dispersed, but the weight increases and motion speed decreases
Solution Approach 1:
The stopper structure is divided into a bolt and a stopper body that can move relative to each other. During impact, the bolt deforms elastically within the stopper body, dispersing the stress through this controlled deformation mechanism rather than requiring a large-volume rigid structure. This maintains low weight while achieving stress dispersion.
Solution Approach 2:
The geometric parameters of the bolt and stopper body are optimized to achieve effective stress dispersion through elastic deformation. The dimensions are designed to allow sufficient deformation space for the bolt within the compact stopper body, dispersing stress without increasing overall volume or weight.
3Reliability
If conventional stopper structures are used to prevent bolt shear and member damage, then damage prevention is achieved, but the structure requires high assembly accuracy and has high cost
Solution Approach 1:
The stopper is segmented into a bolt and a stopper body with a receiving space. The bolt can deform elastically within this space during impact, preventing shear failure. The segmented design with clear functional separation reduces the need for high-precision assembly compared to integrated complex structures, as the bolt and stopper body can be manufactured and assembled with standard tolerances.
Solution Approach 2:
The stopper body is designed with a receiving space that beforehand accommodates the elastic deformation of the bolt during impact. This pre-designed deformation space acts as a cushioning mechanism that prevents bolt shear and member damage by allowing controlled elastic deformation before any potential failure occurs.
4Speed
If a simple stopper structure is used to reduce weight and maintain speed, then motion performance is maintained, but the stopper cannot bear high impact forces
Solution Approach 1:
The simple yet effective stopper structure is segmented into a bolt and stopper body where the bolt provides elastic deformation capability and the stopper body provides structural support. This segmentation enables the compact structure to bear high impact forces through the combined mechanisms of elastic deformation and structural support without requiring increased volume or weight.
Solution Approach 2:
The stopper body is designed with a receiving space that beforehand accommodates the elastic deformation of the bolt during impact. This pre-designed cushioning mechanism allows the compact stopper structure to absorb and dissipate impact energy effectively, maintaining the ability to bear high impact forces while keeping the overall structure simple and lightweight.
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 elastically deformable body with a slit effectively absorbs impact forces, preventing damage to the robot arms and stopper components, while reducing the size, weight, and cost of the mechanical stopper, maintaining efficient motion without the need for complex structures.
Implementation Method 1
at least one of the portion of the first arm which contacts the second arm and the portion of the second arm which contacts the first arm is an elastically deformable body
Data Source
AI summary
A mechanical stopper device having a desirable stopper function while having a simple structure, and a multi-joint robot having the mechanical stopper device. A mechanical stopper is constituted by an elastically deformable body arranged on a second arm, and a contacting member arranged on a first arm so that the deformable body comes into contact with the contacting member when the second arm is rotated by a predetermined angle. The spring pin has a slit extending in the longitudinal direction thereof, and the extending direction of the slit when the pin is inserted into a hole intersects with a contact direction of the spring pin against the contacting member.