End Effector Control via Dual Mechanism Error Compensation
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Solution Overview
Problem
Conventional control systems for machines, such as construction and forestry equipment, face limitations in accuracy and precision due to factors like joint wear, sensor accuracy, structural deflection, and loss of line-of-sight, which hinder precise movement and positioning of work implements.
Innovation Solution
A control system comprising a first and second control mechanism, where the second mechanism is independently controlled to compensate for errors, utilizing a Stewart platform or optical systems for precise movement, and incorporating total stations or computer vision for accurate positioning, allowing for high-precision control of end effectors with at least six degrees of freedom.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional control systems use on-board sensors and global referencing hardware, then the system can provide sufficient precision for basic tasks, but accuracy and precision are limited by joint wear, sensor accuracy, structural deflection, and other factors
Solution Approach 1:
The control system is divided into two independent control mechanisms: a first control mechanism for coarse positioning and a second control mechanism for fine positioning. This segmentation allows each mechanism to be optimized for its specific function, with the second mechanism compensating for errors from the first, thereby improving overall measurement precision without requiring a single overly complex system
Solution Approach 2:
A reference point on the end effector serves as an intermediary element that is tracked by both control mechanisms. This reference point enables the second control mechanism to measure and compensate for positioning errors relative to the desired location, improving accuracy without directly modifying the first control mechanism
2Manufacturing precision
If a single control mechanism is used to move the end effector, then the system structure is simpler, but it cannot achieve high accuracy and precision required for digital programmability
Solution Approach 1:
The control mechanism is segmented into two independent parts: a first control mechanism for general movement and a second control mechanism for precision adjustment. This allows the system to achieve manufacturing precision comparable to high-precision robots and rigid gantry cranes by combining coarse and fine control capabilities
Solution Approach 2:
The second control mechanism adds a dimension of control independence, allowing it to operate separately from the first control mechanism. This dimensional separation enables error compensation in multiple degrees of freedom, improving movement precision without requiring complete redesign of the original control system
3Measurement precision
If the second control mechanism is independently controlled, then error compensation and high precision positioning are achieved, but the system complexity increases
Solution Approach 1:
The system continuously monitors the actual position of the reference point and compares it with the desired location. This feedback loop enables the second control mechanism to automatically compensate for positioning errors by adjusting its control signals, thereby improving measurement precision through real-time error correction
Solution Approach 2:
The second control mechanism serves itself by independently determining the actual position of the reference point and autonomously calculating the necessary corrections. This self-service capability reduces the need for complex external control systems while maintaining high position accuracy
Data Source
AI summary
The present disclosure provides a method of controlling movement of a reference point on an end effector of a machine, where the machine includes a controller, a first control mechanism, and a second control mechanism. The method includes initiating a movement of the reference point to a desired location with the first control mechanism. The method also includes determining an actual position of the reference point and communicating the actual position of the reference point to the controller. A second control mechanism controls the movement of the reference point to the desired location.