Boom Tip Cartesian Control With Elastic Deflection Compensation
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Solution Overview
Problem
Existing large manipulators face challenges in accurately determining the position of mast segments due to elastic deflection and vibrations, leading to inefficiencies and errors in operation, especially when using joint angle sensors or inclination sensors, which are prone to measurement inaccuracies and require high development efforts or complex and expensive sensor systems.
Innovation Solution
A large manipulator with an inclination sensor on the last mast segment and a control unit that calculates elastic deformation, using geodetic angle sensors to determine the exact inclination and correct articulation angles, allowing for precise position estimation and control of mast segments through simplified kinematic calculations and single-lever control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If joint angle sensors are used to determine mast segment positions, then the system is simple to implement, but measurement precision deteriorates due to elastic deflection of mast segments
Solution Approach 1:
The patent introduces an intermediary calculation process that uses the joint angle sensor data combined with a mathematical model of elastic deflection. The control unit calculates the actual mast segment positions by compensating for elastic deflection effects, thereby achieving high measurement precision without requiring complex additional sensor systems.
Solution Approach 2:
The patent transforms the measurement approach by changing from direct position measurement to indirect calculation based on joint angles and elastic deflection parameters. By measuring joint angles and calculating the resulting mast segment positions through a mathematical model that accounts for elastic deflection, the system achieves accurate position determination with simple sensors.
2Measurement precision
If inclination sensors are used to determine ground-fixed angles, then position information is improved, but reliability deteriorates due to vibrations falsifying sensor output signals
Solution Approach 1:
The patent extracts only the necessary inclination information from the mast structure by placing a single inclination sensor on the last mast segment. This minimal sensor configuration, combined with mathematical calculation of individual segment deflections, provides accurate angular position information without the reliability issues of multiple sensors exposed to vibrations throughout the mast structure.
3Measurement precision
If mathematical models with high precision are used to calculate elastic deformation, then measurement precision is improved, but device complexity increases due to high development effort
Solution Approach 1:
The patent changes the mathematical model parameters to match the actual operating conditions of the large manipulator, including the specific geometry, material properties, and loading conditions. By adapting the elastic deflection model to the actual system parameters, the patent achieves high measurement precision without requiring overly complex theoretical models, thus reducing development effort while maintaining accuracy.
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
Enables easy and safe operation of large manipulators by accurately determining mast segment positions, improving precision and efficiency in complex movements while reducing the need for extensive sensor systems and mathematical model complexity.
Implementation Method 1
an inclination sensor (9) on the last mast segment (5c) forming the mast tip (7), wherein a control unit (8) is set up to calculate the elastic deformation of the articulated mast (2) to be determined approximately
Data Source
Figure 1
AI summary
The invention relates to a large manipulator (1) with an articulated boom (2), for example a concrete pump, which can be folded out and which has a turntable (4) that can be rotated about a vertical axis (3) and a plurality of boom segments (5, 5a, 5b, 5c). Each boom segment (5, 5a, 5b, 5c) can be pivoted at articulation joints (6, 6a, 6b, 6c) about a respective articulation axis relative to an adjacent boom segment (5, 5a, 5b, 5c) or the turntable (4) by means of a respective drive assembly (8, 8a, 8b, 8c). The large manipulator also comprises rotational angle sensors for detecting the articulation angle between the adjacent boom segments (5, 5a, 5b, 5c) and between the first boom segment and the adjacent turntable (4). The aim of the invention is to provide an improved large manipulator which can be operated easily and reliably and which ensures that conclusions can be drawn with respect to the precise position of the individual boom segments in a simple manner. According to the invention, this is achieved in that an inclination sensor (9) is arranged on the last segment (5c) which forms the boom tip (7), and the large manipulator (1) has a control unit which is designed to approximately ascertain the elastic deformation of the articulated boom (2) using the articulation angle and the inclination (ψ EP,m) of the last boom segment, said inclination be detected by means of the inclination sensor (9). The invention further relates to a truck-mounted concrete pump and to a method for controlling a large manipulator (1).