Electromagnetic Actuator Soft Landing Without Position Sensors
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Solution Overview
Problem
Electromagnetic solenoid actuators face challenges with high landing velocity leading to excessive wear, noise, and actuator stress due to nonlinear behavior, which affects precision and performance.
Innovation Solution
An open-loop control system using sensorless pulse width modulation (PWM) voltage actuation, where a first voltage portion energizes the coil, and a second portion is applied after a specific admittance time to achieve soft landing without relying on armature position sensors, with timing and duration determined by constants 'A' and 'B' based on actuator parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional electromagnetic actuator control is used, then the actuator provides fast and linear motion, but the armature achieves high landing velocity causing excessive wear, noise, and actuator stress
Solution Approach 1:
The control method applies a preliminary action by de-energizing the coil before the armature reaches its final position. This anticipatory de-energization allows the armature to coast to a stop under spring force alone, preventing high-velocity impact. The timing parameter T1 represents this preliminary action window where the coil is de-energized in advance of armature contact.
Solution Approach 2:
The control method implements preliminary anti-action by removing the electromagnetic force (applying counter-force) before the armature completes its stroke. By de-energizing the coil at the precise moment when the armature should naturally decelerate, the system prevents the harmful high-velocity impact from occurring in the first place.
2Object-affected harmful factors
If the coil is de-energized immediately to stop the armature, then the landing velocity is reduced, but the control precision deteriorates due to extremely nonlinear behavior
Solution Approach 1:
The control method changes the temporal parameter of coil energization from continuous to intermittent. By introducing a specific de-energization timing parameter T1, the system transforms the control approach to account for electromagnetic field persistence. This parameter change allows the system to exploit the natural decay of magnetic field effects to achieve soft landing while maintaining control precision.
Solution Approach 2:
The system utilizes the natural elastic potential energy stored in the spring and the inherent electromagnetic field decay characteristics to achieve soft landing. By de-energizing the coil at the appropriate time, the armature's motion is allowed to naturally decelerate through the spring's restoring force, eliminating the need for complex active control during the landing phase.
3Device complexity
If sensorless control is used, then the device complexity is reduced, but the difficulty of detecting and measuring armature position increases
Solution Approach 1:
The control method extracts the position sensing function from the physical system by eliminating sensors entirely. Instead of measuring armature position directly, the system infers position information from the timing and duration of coil energization cycles, using the known mechanical characteristics of the actuator to determine when soft landing should occur.
Solution Approach 2:
The control method replaces the electromagnetic actuation mechanism with a timing-based control strategy during the landing phase. By substituting active electromagnetic control with passive mechanical deceleration (spring force alone), the system achieves soft landing without requiring position feedback, effectively replacing sensing requirements with temporal control parameters.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method reduces armature landing velocity, minimizes noise and wear, and extends the lifespan of mechanical parts by ensuring soft landing without additional hardware or circuitry, making it cost-effective and applicable across various industries.
Implementation Method 1
a force exerted on it by a magnetic field which has been generated by an electrical current flowing in a coil of wire
Implementation Method 2
When energized, the electromechanical actuator stores the kinetic energy in the spring, which is then released when the electromechanical actuator is de-energized
Data Source
AI summary
An actuation system to achieve soft landing and the control method thereof are provided. A soft landing is achieved via an open loop control of an electromagnetic actuator. The actuation system includes a control unit, wherein the control unit controls the electromagnetic actuator. The control unit does not rely on sensor data regarding a position of an armature to achieve the soft landing. As the actuation system achieves soft landing via the open loop control of the electromagnetic actuator by the control unit, a use of the sensor data is not needed.