Crane Boom Stopping Precision via Flow Quantity Feedback
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Solution Overview
Problem
In cranes using filtering control signals to suppress luggage vibration, there is a risk that the boom may not stop accurately at a desired position due to the gentle rise of the boom during control based on the filtering control signal.
Innovation Solution
The crane includes an operable function part, an actuator, a generation part for the first control signal, a filter part to generate a second control signal, a control part to control the actuator based on the second control signal, and a computation part that calculates the flow quantity when a stop signal is input. The control part outputs the stop signal when the present position, target stop position, and flow quantity satisfy a prescribed condition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If filtering control signal is used to suppress luggage vibration, then vibration suppression is improved, but boom stopping precision deteriorates
Solution Approach 1:
The control signal generation part generates a stop command signal in advance before the boom actually stops, considering the estimated flow quantity. This preliminary action compensates for the delayed stopping effect caused by filtering, allowing the boom to stop at the desired position despite the gentle rise characteristic of filtered control signals.
Solution Approach 2:
The computation part calculates the estimated flow quantity based on the filtering control signal characteristics, and this information is fed back to the control signal generation part. The control signal is then adjusted based on this feedback to achieve accurate stopping. This closed-loop feedback mechanism resolves the contradiction by using the filtering effect information to compensate for its own detrimental impact on stopping precision.
2Stability of the object's composition
If filtering control signal is used to suppress luggage vibration, then transportation stability is improved, but operation time increases
Solution Approach 1:
By generating the stop command signal in advance based on the estimated flow quantity, the system prepares for stopping before it is actually needed. This preliminary action reduces the total operation time while maintaining transportation stability during the movement phase, as the filtering control signal continues to suppress vibrations effectively.
Data Source
AI summary
Provided is a crane including: an operable function part; an actuator; a generation part; a filter part filtering a first control signal and generating a second control signal; a control part controlling the actuator based on the second control signal; and a computation part computing information relating to a flow quantity estimated as the operable function part moving, if a stop signal has been inputted into the actuator at the present position of the operable function part, from when the stop signal has been inputted into the actuator to when the operation of the operable function part stops. The control part outputs the stop signal to the actuator if information relating to the present position of the operable function part, information relating to a target stop position whereat the operable function part is to be stopped, and the information relating to the flow quantity satisfy prescribed conditions.