Horizontal Robot Arm Control Around Singular Points
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Solution Overview
Problem
Existing robot controlling devices require complex calculations to prevent rapid changes in the posture of a robotic arm due to singular points, which complicates the operation of horizontally articulated robots when working with workpieces in accommodating devices.
Innovation Solution
A robot controlling device that positions the third rotational axis on a circumference of a circle centered on the first rotational axis, allowing the second and third rotational axes to move only in specific ranges divided by a third straight line, preventing rapid posture changes by avoiding singular points during operations like workpiece handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inverse conversions and axial interpolation are used to generate joint positions near singular points, then rapid posture changes are prevented, but calculation complexity increases
Solution Approach 1:
The robot controlling device pre-calculates and stores the relationship between the third rotational axis position on the circle circumference and the corresponding second rotational axis position on the straight line. This preliminary action eliminates the need for complex real-time inverse conversions and interpolations, reducing calculation complexity while maintaining reliability in preventing rapid posture changes near singular points
Solution Approach 2:
The invention changes the control parameter from complex joint position calculations to simple angular position control of the third rotational axis on a circle. By parameterizing the solution space using the circle circumference position, the system transforms a complex multi-variable interpolation problem into a simple single-parameter control problem, significantly reducing computational requirements
2Reliability
If the third rotational axis is constrained to move on a circle circumference, then singular points are avoided, but operational flexibility is reduced
Solution Approach 1:
The invention adds a dimensional constraint by moving the third rotational axis on a circle circumference rather than allowing free movement in three-dimensional space. This dimensional reduction transforms the problem from avoiding singular points through complex path planning to simply maintaining position on a predefined circle, which naturally avoids singular configurations while preserving sufficient operational flexibility for workpiece handling
3Measurement precision
If complex calculations are performed to generate joint positions, then accurate posture control is achieved, but processing time increases
Solution Approach 1:
By pre-establishing the geometric relationship between the third rotational axis position on the circle and the second rotational axis position on the straight line, the system eliminates the need for time-consuming inverse conversions and axial interpolations during operation. This preliminary setup ensures accurate posture control is maintained while processing time is significantly reduced
Solution Approach 2:
The invention creates a simplified geometric model (circle-straight line relationship) that copies the essential kinematic constraints of the robot arm without requiring full inverse kinematics calculations. This copied model provides sufficient accuracy for posture control while being computationally much simpler and faster to execute
Data Source
AI summary
A robot controlling device capable of preventing a rapid change in posture of a robotic arm due to a singular point. The robot controlling device brings a third rotational axis to on a circumference of a circle which is on a first rotational axis with a radius at a difference between a distance from the first rotational axis to a second rotational axis and a distance from the second rotational axis to the third rotational axis while changing posture of a horizontal robot to be holdable of a workpiece in an accommodating device, and moves the third rotational axis across a line connecting the first rotational axis and the second rotational axis, and moves the second rotational axis and the third rotational axis divided at the second straight line, connecting a center point of the workpiece accommodated in the accommodating device and the first rotational axis.