Output Shaft Speed Control Using Adjustable Acceleration-to-Torque Mapping
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Solution Overview
Problem
Existing methods for controlling the rotational speed of an output shaft of a propulsion unit, such as those described in U.S. Pat. No. 7,788,018 B2, may not adequately address the need for improved control versatility and accuracy, particularly in handling uncertainties and disturbances in operating conditions.
Innovation Solution
A method and control unit that determine a speed setpoint and actual speed value, using an acceleration conversion function with an acceleration setting member to calculate an acceleration value, and a torque conversion operation to control the propulsion unit, incorporating moment of inertia, resistive torque, and torque disturbance values to achieve precise rotational speed control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional rotational speed control method is used, then the control system is simple, but the control versatility and accuracy are insufficient
Solution Approach 1:
The patent introduces an acceleration setting member that allows dynamic adjustment of the acceleration value, enabling the control system to adapt to different operating conditions and operator preferences. This dynamic parameter adjustment enhances control versatility without requiring multiple separate control systems
Solution Approach 2:
The patent employs an acceleration conversion function that transforms the acceleration setting member into an acceleration value, which is then used in torque calculations. By changing the acceleration parameter through the setting member, the system achieves versatile speed control while maintaining a relatively simple control structure
2Measurement precision
If a conventional rotational speed control method is used, then the control system is simple, but the accuracy in handling uncertainties and disturbances is poor
Solution Approach 1:
The patent determines the actual rotational speed of the output shaft and uses this feedback information in the acceleration conversion function to calculate the acceleration value. This closed-loop feedback mechanism improves speed control accuracy by continuously comparing actual speed with target speed and adjusting torque accordingly
Solution Approach 2:
The patent calculates the acceleration value in advance using the acceleration conversion function before determining the torque demand. This preliminary calculation of acceleration based on speed deviation allows the system to proactively compensate for uncertainties and disturbances, improving control accuracy
3Adaptability or versatility
If an acceleration setting member is introduced to provide versatility, then the control versatility increases, but the device complexity increases
Solution Approach 1:
The acceleration setting member serves multiple functions: it allows operator selection of different acceleration rates, provides adaptability to various operating conditions, and integrates into the existing torque calculation framework. This multi-functionality achieves versatility without requiring separate control systems for different scenarios
Solution Approach 2:
The acceleration conversion function acts as an intermediary that transforms the acceleration setting member into a usable acceleration value for torque calculation. This intermediary layer allows the setting member to influence control behavior without directly complicating the core control logic
Data Source
AI summary
A method for controlling a rotational speed of an output shaft of a propulsion unit. The method includes determining a speed setpoint value, indicative of a rotational speed setpoint for the output shaft, and an actual speed value, indicative of an actual rotational speed of the output shaft, determining an acceleration value using an acceleration value determination procedure comprising employing an acceleration conversion function that uses the speed setpoint value, the actual speed value and an acceleration setting member as inputs and which produces a resulting value to be used for determining the acceleration value, determining a torque request value using a torque conversion operation that uses the acceleration value, and controlling the propulsion unit using the torque request value.