Actuator Bandwidth Control for Variable Load Torque
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Solution Overview
Problem
Conventional motor control systems maintain a high fixed bandwidth to overcome worst-case reaction torque, leading to inefficient power consumption and overly responsive systems.
Innovation Solution
A method and controller that allow for variable bandwidth selection, enabling real-time adjustment of gains based on estimated reaction torque, motor speed, and position, to optimize energy consumption and responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high fixed bandwidth is maintained to overcome worst-case reaction torque, then the system can meet response requirements for worst-case conditions, but power consumption becomes excessive and the system becomes overly responsive
Solution Approach 1:
The patent implements variable bandwidth control where the controller dynamically adjusts the bandwidth of the control loop based on real-time operating conditions. The bandwidth is modified according to the estimated reaction torque and current operating state, allowing the system to use high bandwidth only when necessary (during worst-case conditions) and lower bandwidth during normal operation, thereby reducing power consumption while maintaining reliability when needed.
Solution Approach 2:
The controller changes the bandwidth parameter dynamically based on operating conditions. By estimating reaction torque and system state, the controller adjusts the bandwidth parameter to match actual needs rather than maintaining a fixed high value, resolving the contradiction between maintaining response requirements and reducing excessive power consumption.
2Reliability
If gains are increased to overcome worst-case reaction torque, then the system maintains minimum performance standards, but the system becomes overly responsive and inefficient
Solution Approach 1:
The control gains are made dynamic rather than fixed. The controller adjusts gains in real-time based on the estimated reaction torque and system state, allowing the system to maintain minimum performance standards when needed while adapting to actual operating conditions to improve efficiency and avoid excessive responsiveness during normal operation.
Solution Approach 2:
The patent modifies control parameters (gains and bandwidth) based on operating conditions. By estimating reaction torque and system state, the controller changes gain parameters to match actual needs, maintaining performance standards when necessary while improving efficiency by reducing gains during normal operation.
Data Source
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AI summary
A method is provided for controlling an actuator for moving a load. The method includes receiving a selected bandwidth, wherein bandwidth is defined as the frequency at which the gain of the closed loop input-output response is relative to the steady state value and is related to the reciprocal of response time, receiving a command to move the load to a selected position, receiving a feedback of measured motor position, estimating reaction torque or force associated with moving the load in real time, and estimating rotational motor speed and motor position. The method further includes calculating gain for controlling position of the load as a function of the selected bandwidth, wherein in the gain represents an adjustment of at least one of the estimated motor position, motor rotational speed, and reaction torque. The method further includes determining a drive signal to apply to the actuator motor as a function of the estimated reaction torque, the estimated rotational motor speed, the estimated motor position, the gain and the selected position and transmitting the drive signal to the actuator motor to move the load.