Underwater Robot Buoyancy Control for Target Posture Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing underwater robot control methods require constructing an approximate expression for each posture of driven portions like buoyant members to maintain a target posture, which is cumbersome and inefficient.
Innovation Solution
A mobile object control system and method that utilizes a floating device with a drive unit to adjust the center of buoyancy relative to the robot body, using a processor to calculate control values based on deviations and sensitivity matrices to maintain a target posture without constructing explicit expressions for each posture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an approximate expression is constructed for each posture of the buoyant member to maintain target posture, then the control accuracy is improved, but the device complexity and control time increase
Solution Approach 1:
The patent changes the control parameter from individual buoyant member angles to the angle between the center of gravity and center of buoyancy vectors. This single parameter approach eliminates the need for constructing separate approximate expressions for each buoyant member posture, while maintaining control accuracy through direct calculation of the gravity-buoyancy angle relationship
Solution Approach 2:
The patent creates a universal control method that works for any posture of the buoyant member without requiring posture-specific approximate expressions. The control system universally applies the gravity-buoyancy angle calculation and sensitivity matrix approach across all operating conditions, eliminating the need for multiple specialized expressions
2Measurement precision
If approximate expressions are constructed for each posture, then the control precision is improved, but the control time and computational load increase
Solution Approach 1:
The patent reduces the control problem from multiple angle calculations to a single gravity-buoyancy angle parameter. This parameter change enables direct calculation without iterative approximation, significantly reducing computational time while maintaining precision through the sensitivity matrix framework
Solution Approach 2:
The patent replaces the mechanical approach of constructing approximate expressions with a mathematical substitution using sensitivity matrices. The control value is calculated by substituting the gravity-buoyancy angle and its sensitivity to buoyant member angles into a direct calculation formula, eliminating the need for complex approximate expression construction
3Adaptability or versatility
If the center of buoyancy is adjusted using multiple buoyant members, then the adaptability is improved, but the control complexity increases
Solution Approach 1:
The patent creates a universal control framework that handles multiple buoyant members through a single gravity-buoyancy angle parameter. The sensitivity matrix automatically accounts for the contribution of each buoyant member, providing adaptability for various configurations without increasing control calculation complexity
Solution Approach 2:
The patent introduces the gravity-buoyancy angle as an intermediary parameter that mediates between the multiple buoyant members and the target posture. This intermediary simplifies the control problem by aggregating the effects of multiple buoyant members into a single controllable parameter
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
Enables maintaining a target posture of the underwater robot without the need for complex approximate expressions, enhancing control efficiency and stability.
Implementation Method 1
a floating device having a smaller density than a body connected to the robot body and including a drive unit that is able to change the center of buoyancy of the floating device with respect to the robot body
Data Source
AI summary
A mobile object control system includes a robot body, a floating device having a smaller density than a body connected to the robot body and including a drive unit that is able to change a center of buoyancy of the floating device with respect to the robot body, and a processor. The processor executes a program to perform calculating a control value for the drive unit for change in the center of buoyancy of the floating device using a deviation between a position of the center of buoyancy and a position of the center of gravity, a target value of the deviation, a center-of-gravity sensitivity matrix indicating change of the position of the center of gravity with respect to the control value, and a center-of-buoyancy sensitivity matrix indicating change of the position of the center of buoyancy with respect to the control value.