Stepper Motor Reverse Drive Control via Segmented Signals
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electronic timepiece motor control techniques do not effectively reverse the direction of motor drive to accurately move hands to specific positions, limiting the precision and functionality of timekeeping devices.
Innovation Solution
A stepper motor system with a driver controller that outputs specific drive signals based on current detection, allowing the rotor to turn in forward and reverse directions by switching between first, second, and third drive signals, and a correction signal to manage position and rotation accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the motor is controlled based on current supply to move the hand to a specific position, then the motor can be driven in a forward direction, but the motor cannot be driven in a reverse direction
Solution Approach 1:
The control process is segmented into three distinct drive signals: first drive signal for forward rotation, second drive signal for initial reverse rotation, and third drive signal for corrected reverse rotation. This segmentation allows the motor to achieve bidirectional control through modular signal sequences, resolving the contradiction by breaking down the complex reverse control into manageable stages
Solution Approach 2:
The second drive signal performs a preliminary reverse action that intentionally rotates the rotor past the dynamic stable position. This preliminary action creates the conditions necessary for the third drive signal to then achieve precise reverse positioning, demonstrating how preliminary imperfect action can enable subsequent corrective action
2Measurement precision
If the rotor is driven to a dynamic stable position during rotation, then the motor can rotate smoothly, but the rotor cannot be accurately positioned at the target position
Solution Approach 1:
The second drive signal applies a counter-action by rotating the rotor in the reverse direction past the dynamic stable position, thereby counteracting the stabilizing force that would otherwise prevent accurate positioning. This preliminary anti-action to the stable position enables subsequent precise positioning
Solution Approach 2:
The controller uses feedback from the motor's rotational state to determine when to switch between drive signals. By monitoring the rotation progress and stability, the controller knows when to transition from the second drive signal to the third drive signal, ensuring accurate final positioning while maintaining rotation stability
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
Enables precise control of motor direction and position, enhancing the accuracy and functionality of electronic timepieces by reliably reversing the motor direction and managing rotor position, even under load or external disturbances.
Implementation Method 1
a stepper motor including a coil, and a rotor that is pulled to a first statically stable position or a second statically stable position when a magnetic field that drives the rotor is not produced in the coil, and is pulled to a dynamically stable position when the magnetic field is produced in the coil
Data Source
AI summary
An electronic timepiece enables driving a motor in a reverse direction. The timepiece has a current detector detecting a current value flowing through a coil; a driver controller that outputs, according to the detected current value, a first drive signal turning the rotor in a forward direction to a position not pulled to a second statically stable position from a position where the rotor is pulled to a first statically stable position, outputs a second drive signal turning the rotor in a reverse direction past the dynamically stable position after outputting the first drive signal, and outputs a third drive signal turning the rotor in the reverse direction after outputting the second drive signal; and a driver that is controlled according to the first, second and third drive signals to an on state supplying drive current to the coil and an off state not supplying drive current to the coil.