Parallel Crane TCP Control With Position-Based Speed Correction
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Solution Overview
Problem
Existing parallel crane control systems for working machines, such as harvesters, face challenges in maintaining efficient operation and providing a smooth driving experience for operators, particularly in avoiding unwanted movement patterns and ensuring precise control of crane arm motions.
Innovation Solution
The method involves automatically determining the speeds of various crane arms based on their position, mutual angle positions, and telescope length, using correction factor curves stored in the control system to parameter-adjust the speeds and compensate for geometric factors affecting motion characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional TCP control is used without correction factors, then the control system is simple, but unwanted movements and shaking occur during crane operation
Solution Approach 1:
The patent applies parameter changes by introducing correction factors that modify the relationship between joystick input and crane arm movement. These correction factors are stored in lookup tables and applied based on the current state of the crane arms, dynamically adjusting the control parameters to compensate for geometric nonlinearities and prevent unwanted movements.
Solution Approach 2:
The control system implements feedback by continuously monitoring the position and angle of the crane arms, then applying appropriate correction factors based on the current configuration. This closed-loop approach ensures that the desired TCP movement is achieved while compensating for the parallel crane's geometric characteristics.
2Manufacturing precision
If correction factor curves are used to adjust speeds, then precision of crane arm control is improved, but computational complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing correction factors in lookup tables during system setup. These correction factors are determined in advance based on the crane's geometric parameters and are stored for quick retrieval during operation, avoiding the need for complex real-time calculations.
Solution Approach 2:
The patent replaces complex real-time mathematical calculations with pre-computed lookup tables. Instead of calculating correction factors dynamically during operation, the system retrieves pre-determined values based on the current crane configuration, significantly reducing computational complexity while maintaining precision.
3Productivity
If parallel guidance is used to maintain constant angle, then productivity is improved, but control difficulty increases due to geometric constraints
Solution Approach 1:
The correction factors act as an intermediary between the operator's joystick input and the actual crane arm movements. This intermediary layer translates the operator's simple directional commands into the complex coordinated movements required by the parallel crane's geometric constraints, maintaining ease of operation while enabling productive parallel guidance.
Data Source
AI summary
A method and a system for controlling a parallel crane on a working machine by means of TCP control. According to the method, the parallel crane has a crane arm system with crane parts with a lifting arm section with two parallel arms, a rocker arm with a telescoping push arm, which crane parts are articulately mutually connected and to the working machine and can be displaced through impact of actuators and activators, which are controlled and monitored by a control system by which direction and motion speed of the parallel crane Tool Center Point (TCP) controlled by an operator using joysticks in the working machine, by applying speeds for the various crane parts of the parallel crane. A characteristic is that the speeds of the various crane parts of the parallel crane are automatically determined by the control system based on the position of the various crane parts.