Masthead Position Control Using Inertial Sensors
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Solution Overview
Problem
Existing truck-mounted concrete pumps face operational hindrances due to cyclical excitation of the boom during high delivery rates, leading to movements that stress the end hose operator and are inadequately compensated by existing damping systems, which struggle with precise measurement of vertical movements, especially under dynamic conditions.
Innovation Solution
A large manipulator equipped with inertial sensors, including acceleration sensors and yaw rate sensors, arranged on each mast segment to provide precise measurement of vertical movements, combined with angle sensors for static position determination, enabling effective control of the mast tip's height and reducing vibrations through a position controller and PID controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If tilt sensors are used to measure mast segment inclination, then the measurement system is simple and inexpensive, but the sensors cannot distinguish between tilt changes and translational acceleration, leading to incorrect readings during dynamic movements
Solution Approach 1:
The patent combines tilt sensors and acceleration sensors into a unified measurement system. The tilt sensors provide inclination data while acceleration sensors detect translational acceleration, and both are processed together by a control unit that distinguishes between tilt changes and acceleration-induced movements, resolving the limitation of tilt sensors alone.
Solution Approach 2:
The control unit acts as an intermediary that processes signals from both tilt sensors and acceleration sensors. It separates the combined signal into tilt components and acceleration components, enabling accurate inclination measurement even during dynamic movements by filtering out acceleration-induced false readings.
2Stability of the object's composition
If active damping systems are implemented to reduce boom vibrations, then resonance phenomena are prevented, but satisfactory compensation for boom tip movements is not achieved
Solution Approach 1:
The system implements a feedback control mechanism where the control unit continuously receives inclination data from tilt sensors and acceleration data from acceleration sensors, processes this information to determine actual boom tip position, and adjusts the mast segment positions accordingly to compensate for vibrations and maintain precise boom tip placement.
Solution Approach 2:
The system transitions from static vibration damping to dynamic position control by using acceleration sensors to detect real-time movements and adjusting the damping action based on actual boom tip position and velocity, enabling effective compensation during dynamic pumping operations.
3Measurement precision
If ultrasonic or laser sensors are used to measure boom tip height, then distance measurement is possible, but unobstructed space between the emitting source and reference plane cannot be guaranteed during operation
Solution Approach 1:
The patent extracts the height measurement function from external ultrasonic or laser sensors and implements it using inertial sensors (tilt sensors and acceleration sensors) mounted on the mast segments themselves. This eliminates the need for unobstructed external measurement paths while providing continuous height information through kinematic calculations based on segment inclinations and accelerations.
4Device complexity
If only the last mast joint is used for attitude control, then the control system is simple, but it is not applicable when the mast is tilted close to the vertical relative to the Earth's gravitational field
Solution Approach 1:
The control system is segmented to include multiple mast segments with individual tilt sensors and acceleration sensors on each segment. This allows the control unit to process inclination and acceleration data from multiple locations, enabling effective attitude control regardless of the overall mast orientation, including near-vertical positions where single-point control fails.
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
The solution allows for statically and dynamically precise measurement and control of the boom tip's vertical movement, significantly reducing operational stress on the end hose operator and enhancing the accuracy of height measurement, even during dynamic operations.
Implementation Method 1
an inertial sensor for measuring the inclination and/or acceleration of at least one mast segment
Implementation Method 2
an inertial sensor for measuring the inclination and/or acceleration of at least one mast segment
Data Source
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Figure 5
AI summary
A large manipulator includes a boom arm with a turntable and a plurality of boom segments, which are configured to be pivoted at respective articulation joints with respect to an adjacent boom segment or the turntable. The boom arm further includes at least one inertial sensor configured to measure inclination and/or acceleration of at least one of the plurality of boom segments.