Position Control Device Attitudinal Change Correction
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Solution Overview
Problem
Existing position control systems face issues with velocity differences due to attitude changes and identification errors when controlling objects in non-horizontal attitudes, as they fail to effectively account for attitudinal changes in feedback and feedforward control mechanisms.
Innovation Solution
A position control device and method that includes a position detector, target generator, calculators for control amounts, and a storage unit for attitudinal change correction, which corrects control signals to maintain stability and accuracy even when the object's attitude changes, by adding an attitudinal change correction amount to the control signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the controller calculates feedforward output based on target value changes in a fixed coordinate system, then the control system can maintain simple structure, but velocity differences occur when the apparatus attitude changes
Solution Approach 1:
The patent transforms the fixed coordinate system into a dynamic coordinate system that automatically adapts to the apparatus attitude. The coordinate system rotates and translates with the apparatus, allowing the controller to maintain simple feedforward calculations while accurately compensating for attitude changes. This resolves the contradiction by making the coordinate system dynamic rather than static, eliminating velocity differences without increasing controller complexity.
Solution Approach 2:
The patent changes the reference frame parameters from fixed to moving coordinates. By defining the origin and orientation of the coordinate system to vary with apparatus attitude, the control calculations automatically adapt to gravitational and inertial force changes. This parameter transformation allows the same simple controller structure to achieve accurate velocity control across different attitudes.
2Device complexity
If adaptive identification is performed based on driving command in a fixed coordinate system, then the identification process remains simple, but identification errors occur when the apparatus is in non-horizontal attitudes
Solution Approach 1:
The patent applies the dynamic coordinate system to the adaptive identification process. By performing identification in the moving coordinate system that follows the apparatus attitude, the gravitational and inertial force components are automatically accounted for. This allows simple identification algorithms to achieve accurate parameter identification regardless of apparatus orientation, resolving the contradiction between simplicity and accuracy.
Solution Approach 2:
The patent transforms the identification inputs and outputs from fixed to moving coordinate parameters. This parameter transformation ensures that the identified parameters (such as friction, inertia, and stiffness) are accurate across all attitudes, while the identification process itself remains computationally simple due to the coordinated transformation of all variables.
3Device complexity
If the control system does not account for attitudinal changes, then the control algorithm remains simple, but velocity differences occur between different driving directions
Solution Approach 1:
The patent implements a dynamic coordinate system that moves with the apparatus, allowing the control algorithm to maintain simplicity while automatically compensating for attitude changes. The feedforward and feedback control calculations are performed in this moving frame, ensuring symmetric velocity characteristics in all driving directions without increasing algorithmic complexity.
Solution Approach 2:
By changing the reference frame from fixed to moving coordinates, the patent transforms the control parameters to account for gravitational and inertial forces. This parameter transformation ensures that the same control algorithm produces symmetric velocity responses in all directions, resolving the contradiction between algorithm simplicity and driving symmetry.
Data Source
AI summary
A position control device includes a position detector that detects a position of an object to be controlled; a target generator that outputs a target velocity and a target position of the object to be controlled; a first calculator that calculates a control amount for causing the object to be controlled to track the target position; a second calculator that calculates a control amount for controlling the velocity of the object to be controlled, to be at the target velocity; a control signal output unit that outputs a control signal according to a total control amount obtained by the first and the second calculators; and a storage unit that stores an attitudinal change correction amount. The second calculator acquires the attitudinal change correction amount stored in the storage unit, adds the attitudinal change correction amount to the control amount to correct the control amount, and outputs the corrected control amount.