Marine Propulsion Steering Angle Control Under Actuator Load Limits
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Solution Overview
Problem
Existing marine propulsion unit steering systems cannot fully utilize their steerable range while preventing excessive load on electric actuators, leading to increased turning radius and reduced steerability.
Innovation Solution
A steering system with an electric actuator, storage for output regions based on steering speed and torque, and a controller that adjusts required steering speed and torque to stay within these regions, dynamically setting and updating the target steering angle to optimize actuator load and steerability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rudder deflection angle limit is reduced to prevent excessive load on the electric motor, then the load on the electric motor is significantly reduced or prevented, but the steerable range cannot be fully utilized and the turning radius increases
Solution Approach 1:
The patent applies dynamics by making the rudder deflection angle limit variable rather than fixed. The control unit dynamically adjusts the rudder deflection angle limit based on real-time motor load conditions, allowing the system to adapt between preventing excessive load and maximizing steerable range utilization according to actual operating conditions
Solution Approach 2:
The patent changes the parameter of rudder deflection angle limit from a constant value to a variable value that depends on motor load. By monitoring motor load and adjusting the angle limit accordingly, the system resolves the contradiction between protecting the motor and maintaining steering performance
2Reliability
If the rudder deflection angle limit is reduced to prevent excessive load on the electric motor, then the load on the electric motor is significantly reduced or prevented, but the turning radius increases
Solution Approach 1:
The system dynamically adjusts the rudder deflection angle limit based on motor load conditions. When the motor can handle the load, a larger angle limit enables faster turning. When the motor is overloaded, the angle limit is reduced to prevent damage, thus dynamically balancing turning speed and motor protection
Solution Approach 2:
The rudder deflection angle limit parameter is changed from fixed to variable, allowing the system to optimize turning speed by adjusting the parameter according to real-time motor capacity and load conditions
Data Source
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AI summary
A steering (1) for a marine propulsion unit (3) adjusts at least one of a required steering speed (ωr) and a required steering torque (Tr) such that the required steering speed and the required steering torque fall within an output region when the required steering speed and the required steering torque are outside the output region, sets a target steering angle (θs) according to the adjusted required steering speed and required steering torque, and sets the target steering angle according to a rotation angle (θh) of a steering wheel (4) when the required steering speed and the required steering torque are within the output region.