Active Vibration Control for Articulated Concrete Pumping Arms
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Solution Overview
Problem
Existing methods for controlling vibrations in articulated arms for concrete pumping are inadequate as they primarily focus on localized corrections without actively addressing the dynamic stresses and inertial changes associated with the machine's configuration, leading to operational difficulties and reduced safety.
Innovation Solution
An active control method using a structured numerical model to separate vibratory motions from desired movements, employing a modal approach to reduce the system's degrees of freedom, and utilizing sensors with a state observer to apply feedback forces that dampen oscillations across the arm's length, including intermediate points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the number of articulated segments or the extension measurement of each segment is increased to achieve greater overall lengths, then the ability to reach greatest heights and lengths is improved, but the weights and bulk increase which are not compatible with current legislation or operativeness and functionality of the vehicle
Solution Approach 1:
The patent applies dynamic control by continuously adjusting the inertial properties of the arm segments during motion. The control system modifies the dynamic behavior of the articulated arm in real-time to optimize performance while maintaining acceptable weight and bulk characteristics.
2Adaptability or versatility
If the overall length of the arm and the number of its segments are increased to achieve greater reach, then the flexibility and versatility of use is improved, but the phenomenon of vibrations to which the arm is subject increases as concrete is distributed
Solution Approach 1:
The patent implements a feedback control system that continuously monitors the vibratory states of the arm segments and adjusts the control inputs to compensate for vibrations. The control system uses measured vibratory characteristics to dynamically adjust the inertial properties and damping parameters, effectively reducing vibrations while maintaining the arm's flexibility and reach capabilities.
3Productivity
If the machine operates in transitory conditions between placements or during movement to maintain continuous operation, then the productivity is improved, but dynamic variations are generated on the state of stress of the joints and material which limits the working life of the machine and reduces safety
Solution Approach 1:
The patent applies beforehand cushioning by pre-configuring the inertial and damping properties of the arm segments to anticipate and cushion against dynamic stress variations. The control system is designed to compensate for stress variations before they cause damage, protecting the joints and material from excessive loading during transitory operations.
Solution Approach 2:
The feedback control system continuously monitors the stress state of the arm segments and adjusts the control inputs to maintain stresses within safe limits. This real-time feedback mechanism prevents excessive dynamic stresses from accumulating, thereby extending the working life of the machine and ensuring operator safety during continuous operation.
4Ease of operation
If a compensation mechanism is provided to compensate for disturbances during concrete delivery, then the uncontrolled movements of the arm are reduced, but the intervention logic is limited to localized corrections without actively addressing the general structure of the arm
Solution Approach 1:
The patent applies universality by designing a control system that performs multiple functions: it compensates for localized disturbances during concrete delivery, actively addresses the general structure of the arm, and optimizes the inertial properties of all segments. This multi-functional approach provides comprehensive vibration control throughout the entire arm structure rather than relying on localized corrections only.
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
Effectively reduces dynamic loads by actively controlling vibrations, improving operational stability and safety by damping the first modes of vibration, which significantly contribute to the arm's motion, while minimizing computational complexity.
Implementation Method 1
employing a modal approach to reduce the system's degrees of freedom, and utilizing sensors with a state observer to apply feedback forces that dampen oscillations across the arm's length
Data Source
AI summary
An active control method to control the vibrations of an articulated arm consisting of a plurality of segments articulated with respect to each other, by means of an electronic controller, comprising the following steps:a) construction of a modal model of the articulated arm starting from experimental data or from structural models;b) assignation of gains of electronic controller;c) multiplication of gains by the difference between the reference modal coordinates and those calculated through the modal model starting from directly measured quantities, in order to determine the control forces to be applied to the arm, or to at least part of the relative segments;d) evaluation of the modal coordinates by means of a states estimator;e) comparison between measurements estimated using the modal coordinates and real measurements and correction of the estimate, so that the estimate converges on real values.