Electric Motor Vibration Suppression via Speed-Dependent Torque Compensation
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Solution Overview
Problem
Current electric motor controlling systems for industrial vehicles, such as forklifts, face issues with vibration and poor riding comfort due to non-linear characteristics of transmission mechanisms, which existing linear controllers like PID-controllers cannot effectively address.
Innovation Solution
Incorporating a vibration suppression compensator in parallel with the PID-controller, which generates a compensated torque command by performing a compensation gain procedure based on the motor speed, setting the output value to zero when the motor speed is above a preset active speed level and using the compensated torque command when it is below, to generate the final output torque command.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a linear PID-controller is used for speed control, then the control system is simple and stable, but it cannot effectively address vibration and abnormal twisting caused by non-linear transmission mechanisms
Solution Approach 1:
The control system is segmented into two parallel controllers: a PID-controller for basic stable control and a vibration suppression compensator for addressing non-linear vibration issues. Each controller handles specific aspects of the control problem independently, allowing the system to maintain stability while suppressing vibration.
Solution Approach 2:
The patent merges the output signals of the PID-controller and the vibration suppression compensator to generate the final torque command. This combination allows the system to benefit from both the stability of linear control and the vibration suppression capabilities of the compensator.
2Object-affected harmful factors
If the vibration suppression compensator is always active, then vibration suppression is maximized, but system complexity and computational load increase
Solution Approach 1:
The vibration suppression compensator is designed with dynamic activation based on operating conditions. The compensator is selectively activated when vibration is detected or under specific operating conditions, rather than being constantly active, thereby reducing unnecessary computational load and system complexity.
Solution Approach 2:
The system changes the activation parameter of the vibration suppression compensator based on operating conditions. By monitoring parameters such as motor speed and load conditions, the system dynamically adjusts whether the compensator is active, optimizing the balance between vibration suppression and system simplicity.
Data Source
AI summary
An electric motor controlling system used for vibration suppression of an electric vehicle is disclosed. The controlling system includes a PID-controller and a vibration suppression compensator. The PID-controller generates a basic torque command through performing a calculation based on input speed-error signal of the electric vehicle, the vibration suppression compensator generates a compensated torque command through performing a compensation gain procedure on the input speed-error signal. The vibration suppression compensator further receives a motor speed of the electric vehicle, sets its output as the compensated torque command when the motor speed is smaller than a preset active speed level, otherwise sets the output as 0. The controlling system generates an output torque command via adding up the basic torque command and the output of the vibration suppression compensator, and operates electric motor components of the electric vehicle according to the output torque command.