Electric Motor Driver with PWM Control for Piston Positioning
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Solution Overview
Problem
The moving speed and stop position of a piston in a driver are affected by changes in battery level and air pressure, leading to inconsistent operation, requiring control mechanisms to stabilize performance.
Innovation Solution
A driver with a controller that adjusts the electric motor's output based on rotation angle detection, using PWM control to manage the engagement of pins and racks, and varying the duty ratio of the electric motor driving elements to maintain consistent operation despite changes in battery level and pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electric motor is controlled without adaptation to battery level and pressure changes, then the device structure remains simple, but the moving speed and stop position of the piston become inconsistent
Solution Approach 1:
The controller detects the rotation angle of the electric motor and uses this feedback information to determine when to stop power supply. By monitoring the actual rotation angle and comparing it with predetermined thresholds, the system automatically adjusts the power supply timing to compensate for variations in battery level and air pressure, ensuring consistent piston movement without requiring complex additional sensors or mechanisms.
Solution Approach 2:
The system changes the power supply parameter (power on/off timing) based on the detected rotation angle parameter. By adjusting when power is supplied to the electric motor during its rotation cycle, the controller compensates for performance variations caused by battery depletion and pressure changes, maintaining reliable piston operation across different operating conditions.
2Manufacturing precision
If the electric motor operates at constant power output, then the control system remains simple, but the piston stop position varies with battery level and pressure changes
Solution Approach 1:
The rotation angle detection provides continuous feedback about the electric motor's position in its cycle. The controller uses this feedback to precisely determine when to cut power supply, ensuring the piston stops at the correct position regardless of battery level or pressure variations. This feedback-based timing control achieves precise stop position without requiring complex mechanical positioning mechanisms.
Solution Approach 2:
The patent replaces complex mechanical positioning mechanisms with an electrical control system based on rotation angle detection and timed power supply cutoff. Instead of using mechanical stops, cams, or linkages to ensure precise piston positioning, the system uses electronic control of the electric motor's power supply timing, simplifying the mechanical structure while achieving precise positioning.
3Reliability
If the power supply to the electric motor is not interrupted at the appropriate timing, then the device structure remains simple, but the piston cannot be reliably returned to the initial position
Solution Approach 1:
The rotation angle detection system provides feedback on the electric motor's rotational position. The controller monitors this angle and automatically interrupts power supply when the predetermined rotation angle is reached, ensuring the piston reliably returns to its initial position. This feedback-based timing ensures consistent operation without requiring complex additional control mechanisms.
Solution Approach 2:
The electric motor operates in periodic cycles, rotating forward to drive the piston up and then rotating backward to return it. The controller applies power during the forward rotation phase and interrupts power at the appropriate rotation angle to allow controlled deceleration and position reversal. This periodic on/off power supply pattern ensures reliable piston return to the initial position with each cycle.
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
The controller ensures consistent moving speed and stop position of the piston by adapting the electric motor's operation, improving control and operability across varying conditions.
Implementation Method 1
a wheel (50) rotationally driven by an electric motor (20)
Implementation Method 2
the piston moves from the top dead point side to the bottom dead point side in the cylinder by the pressure of air compressed in the cylinder
Data Source
Figure 1
Figure 2
Figure 3
AI summary
To provide a driver in which an electric motor is controlled in response to a change in situation that affects a moving speed of the piston from the bottom dead point to the top dead point and a stop position of the piston. The driver (1) has: a wheel (50) that is rotationally driven by an electric motor; pins (52) provided to the wheel (50) and arranged along a circumferential direction of the wheel (50); a piston (11) reciprocably housed in a cylinder (10); a driver blade (30) that integrally reciprocates with the piston; racks (32) provided to the driver blade (30) along an axial direction of the driver blade (30); and a controller configured to control a drive of the electric motor by PWM, wherein the controller changes a duty ratio of the switching element provided on a power supply line for the electric motor in response to a change in remaining battery level as one of situations that affects a moving speed of the piston (11) from the bottom dead point side to the top dead point side.