Underwater Snake Robot Path Guidance Under Ocean Drift
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Solution Overview
Problem
Existing underwater snake robots face challenges in following desired paths due to ocean current effects, as previous control approaches neglect these influences and lack effective path following mechanisms.
Innovation Solution
A method and controller for guiding underwater snake robots that determine a desired path, calculate and adjust the robot's longitudinal orientation to compensate for divergence caused by ocean currents, using a feedback loop to maintain alignment and oscillate around a steady-state orientation, allowing the robot to follow the path effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If previous control approaches are used that neglect ocean current effects, then the control system is simpler, but the robot cannot follow the desired path accurately under ocean currents
Solution Approach 1:
The patent implements a feedback control mechanism where the robot's actual position is continuously monitored and compared with the desired path. The control system calculates the cross-track error and adjusts the robot's heading angle accordingly to compensate for ocean current effects, ensuring accurate path following despite environmental disturbances
Solution Approach 2:
The patent dynamically adjusts the robot's heading angle parameter based on the cross-track error and ocean current conditions. By changing the orientation parameter in response to environmental factors, the robot maintains accurate path following even when subjected to drift forces that would otherwise cause deviation
2Reliability
If the robot aligns its longitudinal orientation parallel to the desired path, then the navigation is simpler, but the robot cannot compensate for drift forces caused by ocean currents
Solution Approach 1:
The patent applies preliminary anti-action by calculating the expected drift based on ocean current conditions and proactively adjusting the robot's heading angle to counteract the anticipated drift. This allows the robot to compensate for ocean current effects before significant deviation occurs, maintaining accurate path following
Solution Approach 2:
The patent implements dynamic orientation control where the robot's longitudinal orientation is continuously adjusted based on real-time position feedback and ocean current conditions. The heading angle becomes a dynamic parameter that oscillates around the desired path rather than maintaining a fixed parallel alignment, enabling adaptive drift compensation
3Ease of operation
If the robot follows the desired path directly without orientation adjustment, then the control is simpler, but the robot diverges from the path under ocean current influence
Solution Approach 1:
The patent uses feedback control to automatically adjust the robot's heading angle based on its position relative to the desired path. The cross-track error is continuously calculated and fed back to the control system, which modifies the orientation to bring the robot back onto the desired path, maintaining reliable path following without complex manual intervention
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3(a)~3(b)
AI summary
A snake robot comprises a flexible elongate structure capable of bending itself at two or more joints along its length in order to generate an undulating motion to thereby propel itself through water. A method for guidance of the snake robot is described, the method comprising: determining a desired path for the robot, the desired path extending between a current location of the robot and a destination point; during forward movement of the robot, when the robot diverges from the desired path, determining an extent of the divergence from the desired path; calculating a desired orientation for the robot as a static or dynamic function of the extent of divergence from the desired path, the desired orientation being non- parallel with the desired path when the robot is affected by drift forces such as ocean currents; and controlling the robot so that it is aligned with the desired orientation, and the longitudinal orientation of the robot is non-parallel with the desired path.