Feedback Control of Rotational Speed Using Adaptive Inertia
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Solution Overview
Problem
Conventional sensitivity feedback control methods for devices like hydraulic excavators require frequent adjustments of PID gains and can lead to unintended movement when not operated by a person, due to their nonlinearity and complex control systems.
Innovation Solution
A feedback control device that adjusts the moment of inertia as a parameter to improve operator comfort, using a database-driven approach to determine target angular velocities and comfort levels, preventing automatic movement by requiring operator input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional sensitivity feedback control method using PID controller is used, then target speed can be generated, but PID gain needs to be adjusted frequently and device may move automatically without operator input
Solution Approach 1:
The patent changes the parameter being controlled from PID gains to moment of inertia in the transfer function. By adjusting the moment of inertia parameter instead of PID gains, the system achieves smoother speed transitions and improved operator comfort without requiring frequent controller retuning
Solution Approach 2:
The patent implements feedback control by comparing the actual speed with the target speed and using the difference to adjust the moment of inertia parameter. This closed-loop feedback mechanism prevents automatic movement without operator input while maintaining operational comfort
2Reliability
If PID controller is used to handle nonlinearity of human sensitivity, then target speed can be generated, but the control system becomes complex and requires frequent gain adjustments
Solution Approach 1:
The patent replaces the complex PID controller with a simplified approach that adjusts the moment of inertia parameter in the transfer function. This parameter change maintains control accuracy for nonlinear human sensitivity while significantly reducing system complexity and eliminating the need for frequent gain adjustments
3Reliability
If additional measures are taken to prevent automatic movement, then safety is improved, but device complexity increases
Solution Approach 1:
The patent uses feedback control comparing target speed with actual speed to detect when operator input is absent. When no operator input is detected, the system automatically adjusts the moment of inertia to prevent movement, providing safety without requiring additional complex measures
Data Source
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AI summary
A feedback control device determines, based on an operation input to a target device, a first target angular velocity that is a target angular velocity of an output angular velocity of the target device, using a first transfer function, determines a control input to the target device, based on a difference between the first target angular velocity and the output angular velocity, determines, based on the operation input, a second target angular velocity that is the target angular velocity requested by an operator, determines a degree of comfort of the operator, based on a difference between the output angular velocity and the second target angular velocity, sequentially accumulates the first target angular velocity, the degree of comfort, and a target degree of comfort in a database, and adjusts a first moment of inertia in such a way as to reduce a difference between the target degree of comfort and the degree of comfort, using data accumulated in the database.