Crane Load Control via Dynamic Low-Pass Filter
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Solution Overview
Problem
Conventional cranes with remote manipulation systems experience swinging of loads due to discontinuous acceleration, leading to a mismatch between the movement of the load and the operator's intended manipulation, resulting in instability and reduced responsiveness.
Innovation Solution
A crane system that includes a manipulation tool for inputting target speed and direction signals, along with detection sections for boom angles and length, which computes a target course signal using a low-pass filter to attenuate frequency components, allowing for precise control of the load's movement and stabilization of the boom's operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a filter is applied to the speed signal to curb load swinging, then load stability is improved, but responsiveness is lowered
Solution Approach 1:
The filter characteristics are dynamically adjusted based on the current crane configuration (boom length, luffing angle, swivel angle) and load conditions. The control device computes optimal filter parameters in real-time to match the varying mechanical properties of the crane system, allowing the filter to effectively reduce swinging while maintaining responsiveness across different operating conditions.
Solution Approach 2:
The invention changes the filter parameters (cut-off frequency, filter order) based on the detected crane state. By computing filter characteristics that correspond to the natural frequencies of the crane-load system at different configurations, the filter effectively targets the specific swinging modes present without overly dampening the control response.
2Ease of operation
If step function speed signals are transmitted for start or stop of movement, then manipulation simplicity is improved, but discontinuous acceleration occurs causing load swinging
Solution Approach 1:
The control device acts as an intermediary between the simple step function manipulation input and the actuator control. It computes a target speed signal that incorporates filter characteristics designed to smooth the transitions, converting the abrupt step input into a controlled acceleration profile that prevents load swinging while maintaining the simplicity of the operator's input.
Solution Approach 2:
The control device pre-computes the filtered target speed signal based on the detected crane configuration before transmitting it to the actuators. By preparing the smoothed speed profile in advance based on the current system state, it prevents discontinuous acceleration and load swinging while maintaining responsive control.
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 system effectively stabilizes the boom's control, enabling the load to be moved as intended by the operator while minimizing swinging, by determining coefficients for the low-pass filter based on current conditions, thus improving the alignment between operator input and load movement.
Implementation Method 1
a target course signal is computed by integrating the target speed signal input from the manipulation tool and attenuating a frequency component in a predetermined frequency range via a filter
Data Source
AI summary
A target trajectory signal is calculated by integrating a target speed signal inputted from a suspended-load moving operation tool and passing the integrated signal through a lowpass filter. Target position coordinates of a load are calculated from the target trajectory signal. The current position coordinates of a leading end of a boom are calculated from the attitude of a crane device. An unwinding amount of a wire rope is calculated from the current position coordinates of the load and the current position coordinates of the boom. A direction vector of the wire rope is calculated from the current position coordinates of the load and the target position coordinates of the load. Target position coordinates of the boom are calculated from the unwinding amount and the direction vector. An actuation signal of an actuator is generated from the target position coordinates of the boom.