Industrial Robot Arm Parallel Link Ball Screw Rigidity
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Solution Overview
Problem
Conventional industrial robots face challenges in achieving high mechanical rigidity, servo rigidity, and precision over a wide operation range, especially under high load conditions, as existing designs struggle to simultaneously satisfy these strict requirements.
Innovation Solution
The industrial robot employs a parallel link structure for both the lower and upper arm mechanisms, combined with ball screw drive mechanisms, where the ball screws are supported by bearing portions that allow for rotational movement, enabling high rigidity and precision while allowing for a wide operation range by maintaining parallel rotational axes and using servo motors to drive the ball screws effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a parallel link structure is employed in the lower arm mechanism, then mechanical rigidity is improved, but the operation range is limited
Solution Approach 1:
The robot arm is divided into two independent mechanisms: a lower arm mechanism with parallel link structure for high rigidity, and an upper arm mechanism that can operate independently to extend the operation range. The lower arm mechanism includes front and rear links connected to the base, while the upper arm mechanism is connected to the top portion of the lower arm mechanism, allowing segmented operation that resolves the contradiction between rigidity and range.
2Adaptability or versatility
If the upper arm mechanism is operated independently of the lower arm mechanism, then operation range is improved, but mechanical rigidity deteriorates
Solution Approach 1:
The arm mechanism is segmented into lower and upper independent mechanisms. The lower arm mechanism maintains parallel link structure for rigidity, while the upper arm mechanism operates independently to extend range. This segmentation allows each mechanism to optimize its function without compromising the other, resolving the contradiction between independent operation and mechanical rigidity.
3Strength
If a ball screw is employed for arm drive mechanism, then mechanical rigidity is improved, but the operation range is limited
Solution Approach 1:
Ball screw drive mechanisms are employed in both the lower arm mechanism (lower ball screw with nut and shaft) and the upper arm mechanism (upper ball screw with nut and shaft). The lower ball screw is connected to the front or rear link, while the upper ball screw is connected to the upper arm mechanism. This segmented application of ball screws maintains high mechanical rigidity throughout the entire arm mechanism while allowing the upper arm to operate independently for extended range.
Solution Approach 2:
The invention combines parallel link structure with ball screw drive mechanisms in a unified arm mechanism system. The lower arm mechanism merges parallel link structure with lower ball screw drive, and the upper arm mechanism merges independent operation capability with upper ball screw drive. This merging creates a hybrid system that achieves both high mechanical rigidity and wide operation range.
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 ensures high mechanical rigidity, servo rigidity, and precision over a wide operation range, enhancing the robot's ability to handle high loads with improved position control accuracy and reduced interference, allowing for efficient and precise operation.
Implementation Method 1
the lower arm drive mechanism has a lower ball screw including a nut and a shaft
Implementation Method 2
a lower bearing portion supporting the shaft so as to be rotatable about its axis
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
An arm unit 5 of a robot 1 has a lower arm mechanism 6 including a parallel link structure and an upper arm mechanism 7. The lower arm mechanism 6 has a front link 8 and a rear link 9 including respective lower ends rotatably connected to the base portion 3. A lower arm drive mechanism 19 has a lower ball screw 21 and a lower bearing portion 22 supporting a shaft 21B so as to be rotatable about its axis. An extending portion 24 extending from the lower end of the rear link 9 is connected to a nut 21A so as to be rotatable about a nut side rotational axis B2. The lower bearing portion 22 is connected to a base portion 3 so as to be rotatable about a bearing portion side rotational axis B1. Thus, high mechanical rigidity can be ensured over a wide operation range under a high load condition.