Servomotor Controller Modulation for Brush Wear Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Motor vehicle servomotors, particularly those with brush motors, face reliability issues due to increased wear and residue buildup in end regions, leading to premature failure, especially when actuated over a limited range with identical start and end positions.
Innovation Solution
A controller is introduced to modulate control signals for electric motors with a stator and rotor, allowing for varied or time-variant outputs from identical input signals, preventing consistent end positions and reducing wear by enabling oscillating motions with small position differences, thereby minimizing residue buildup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the servomotor is actuated over a limited range with identical start and end positions, then the actuator operates reliably within its design limits, but wear and residue buildup increase in the end regions leading to motor failure
Solution Approach 1:
The controller applies periodic oscillating motions superimposed on the normal actuation cycle. When the actuator approaches end positions, the controller generates small amplitude oscillations that cause the motor to backtrack slightly from the extreme positions, preventing continuous contact and wear at the same brush contact points. This periodic variation in motion pattern extends motor lifespan while maintaining reliable operation within design limits.
Solution Approach 2:
The system transitions from static end positions to dynamic oscillating positions. The controller continuously adjusts the motor position within a small range around the nominal end positions, creating a dynamic behavior that prevents localized wear. The oscillation amplitude and frequency are dynamically adapted based on the actuator's current position and operational state.
2Device complexity
If the controller outputs identical control signals for identical input signals, then the control system operates simply and predictably, but the motor stops at the same end positions causing increased wear and residue buildup
Solution Approach 1:
The controller incorporates a periodic oscillation component that is superimposed on the standard control signal. This oscillation causes the motor to vary its end positions slightly, preventing consistent wear at the same brush contact points. The oscillation can be implemented through simple sinusoidal or triangular wave addition to the control signal, maintaining relatively low controller complexity while significantly improving reliability.
Solution Approach 2:
The controller varies the control signal parameters (amplitude, offset) based on the actuator's position and operational state. By dynamically adjusting these parameters, the system creates varying end positions that prevent localized wear. This parameter variation can be achieved through lookup tables, mathematical functions, or simple feedback mechanisms, balancing complexity improvement with reliability enhancement.
Data Source
AI summary
A motor vehicle servomotor arrangement includes an electric motor with a stator, a rotor and brushes, as well as a controller with a signal input and a signal output that is connected to the electric motor. The controller is configured to transmit a control signal to the electric motor in response to an input signal supplied via the signal input by a unique function. The controller is configured to modulate the control signal in such a way that different control signals are output upon successive identical input signals within predefined input signal ranges and/or time-variant control signals are output upon identical input signals.