Vibration Actuator Controller Pulse Duty Cycle Feedback
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Solution Overview
Problem
Conventional vibration actuators with large inertia objects face difficulties in accurately stopping at a desired position due to overshooting, which is exacerbated by environmental conditions like humidity and temperature, leading to prolonged stopping times.
Innovation Solution
A controller that drives a vibration element using an AC signal with a pulse duty cycle adjusted based on the difference between the target stop position and the current position, as well as the actual speed of the contact body, to enhance the precision and speed of the stopping process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If conventional position control based only on position difference is used, then the control system is simple, but the stopping time is long and overshooting occurs
Solution Approach 1:
The patent implements feedback control by detecting the actual speed of the contact body and using it to adjust the pulse duty cycle. The speed detection unit continuously monitors the movement speed, and this feedback information is fed back to the control unit which modifies the drive signal accordingly, enabling dynamic adjustment to prevent overshooting and reduce stopping time.
Solution Approach 2:
The patent transitions from static position-based control to dynamic control that adapts to real-time conditions. By making the pulse duty cycle variable based on detected speed rather than fixed based solely on position difference, the system dynamically adjusts its behavior to optimize stopping performance and prevent overshooting.
2Productivity
If high drive speed is maintained to reduce stopping time, then productivity increases, but overshooting occurs and stopping accuracy deteriorates
Solution Approach 1:
The system dynamically adjusts the drive speed based on real-time conditions. During most of the movement, high speed is maintained for efficiency, but when the contact body approaches the target position, the detected speed triggers automatic reduction of the pulse duty cycle, thereby reducing speed to prevent overshooting and ensure accurate stopping.
Solution Approach 2:
The patent changes the drive parameter (pulse duty cycle) based on the detected speed and position. By varying the pulse duty cycle from high values during travel to low values during deceleration, the system optimizes both stopping speed and stopping accuracy, achieving high productivity without sacrificing precision.
3Manufacturing precision
If environmental conditions (humidity, temperature) are not compensated, then device complexity remains low, but stopping accuracy deteriorates due to slip
Solution Approach 1:
The speed detection unit provides continuous feedback on the actual movement speed, which reflects the real-time friction conditions caused by environmental factors. The control unit uses this feedback to adjust the pulse duty cycle, automatically compensating for slip caused by humidity or temperature changes without requiring direct environmental sensors or complex compensation algorithms.
4Manufacturing precision
If deceleration control is added based on position difference only, then stopping accuracy improves, but stopping time increases
Solution Approach 1:
The patent implements dynamic deceleration control based on detected speed rather than fixed deceleration based on position. When the contact body is far from the target, high speed is maintained. When approaching the target, the detected speed triggers progressive deceleration by reducing the pulse duty cycle, optimizing both stopping accuracy and stopping time.
Solution Approach 2:
The control system changes the drive parameter (pulse duty cycle) based on the relationship between detected speed and position. This dynamic parameter adjustment enables the system to maintain high speed during most of the travel and then smoothly decelerate near the target, achieving both fast stopping and high accuracy.
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 approach reduces the time required to stop the object at the target position by effectively controlling the pulse duty cycle, minimizing overshooting and improving stopping accuracy even under varying environmental conditions.
Implementation Method 1
a vibration element (115) including a resilient body (113) and an electromechanical energy conversion element (114)
Data Source
AI summary
A controller is capable of reducing time required to stop a control target at a target stop position as a final stop position. The controller drives a vibration element including a piezoelectric element by an AC signal to thereby move a contact body, in contact with the vibration element, relative to the vibration element. The controller controls a pulse duty cycle of a signal converted to the AC signal based on a difference between a target stop position, which is a final stop position of the contact body, and a current position of the contact body, and an actual speed of the contact body.