Dome Camera Motor Holding Current Control via Vibration Detection
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Solution Overview
Problem
Camera dome systems with stepper motors in outdoor locations face positional accuracy issues due to vibrations from traffic and wind, leading to excessive heat generation and motor degradation from constant high holding current usage, as they lack a position feedback system to determine the exact position of the camera.
Innovation Solution
A system that includes an acceleration detection circuit to measure vibrations and adjust the holding current of stepper motors accordingly, ensuring the camera remains stationary by dynamically adjusting the motor current based on detected accelerations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the holding current of the stepper motor is increased to prevent positional changes due to vibrations, then the positional accuracy is improved, but excessive heat is generated which degrades the stepper motor life
Solution Approach 1:
The patent applies dynamics by transitioning from a static holding current approach to a dynamic one. The holding current is continuously adjusted based on real-time acceleration measurements from the accelerometer. When vibrations are detected, the holding current increases to maintain positional accuracy; when vibrations subside, the current decreases to minimize heat generation. This dynamic adaptation resolves the contradiction between maintaining precision and reducing thermal damage.
Solution Approach 2:
The patent implements feedback through an accelerometer that continuously monitors vibrations and feeds this information back to the control circuit. The control circuit processes the acceleration data and adjusts the holding current accordingly. This closed-loop feedback system enables the motor to respond adaptively to vibration conditions, maintaining positional accuracy only when necessary while minimizing heat generation during calm periods.
2Duration of action of stationary object
If the holding current is reduced to minimize heat generation, then the stepper motor life is extended, but the camera dome becomes vulnerable to positional changes from external vibrations
Solution Approach 1:
The system dynamically adjusts the holding current based on real-time vibration conditions detected by the accelerometer. During low-vibration periods, the current is reduced to minimize heat generation and extend motor life. When vibrations exceed thresholds, the current automatically increases to maintain positional accuracy. This dynamic behavior resolves the contradiction between motor longevity and positional stability.
Solution Approach 2:
The accelerometer provides continuous feedback about vibration levels, enabling the control circuit to make informed decisions about holding current levels. This feedback mechanism ensures the motor receives sufficient current to resist vibrations only when necessary, thereby extending motor life while maintaining positional accuracy when required.
3Stability of the object's composition
If the stepper motor is continuously powered to maintain holding torque, then the camera remains stationary, but excessive heat is generated adversely affecting camera dome operation
Solution Approach 1:
The patent implements periodic action by pulsing the holding current based on vibration detection rather than maintaining continuous power. The accelerometer monitors vibrations periodically, and the control circuit activates the holding current only during periods when vibrations are detected. This periodic activation maintains camera stability when needed while dramatically reducing overall heat generation and energy consumption.
Solution Approach 2:
The system uses feedback from the accelerometer to control the timing and magnitude of holding current application. When the accelerometer detects vibrations exceeding a threshold, the feedback signal triggers increased holding current to stabilize the camera. When vibrations subside, the current is reduced or eliminated. This feedback-driven periodic action resolves the contradiction between maintaining stability and reducing energy loss.
4Manufacturing precision
If a position feedback system is added to determine the exact position of the camera, then positional accuracy can be maintained with lower holding current, but the device complexity increases
Solution Approach 1:
The patent introduces an intermediary approach by using an accelerometer to indirectly measure conditions affecting positional accuracy rather than directly measuring position. The accelerometer detects vibrations that would cause positional changes, allowing the system to proactively adjust holding current to prevent positional errors. This intermediary measurement method maintains positional accuracy without requiring complex position feedback systems like encoders or resolvers.
Solution Approach 2:
The patent replaces a mechanical position feedback system with a vibrational sensing approach. Instead of using mechanical encoders, resolvers, or other position-sensing devices that would increase system complexity, the system uses an accelerometer to detect vibrations and infer the need for holding current adjustment. This substitution maintains positional accuracy while avoiding the complexity of direct position measurement systems.
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 system effectively reduces unwanted positional motion and minimizes heat generation by determining the minimum required holding torque, enhancing the stability and longevity of the camera dome system.
Implementation Method 1
an acceleration detection circuit for detecting accelerations indicative of vibrations
Implementation Method 2
the stepper motor is required to hold the camera in a fixed position. Holding the camera stationary is accomplished by adjusting the torque produced by the stepper motor to balance any external forces impacting the camera
Implementation Method 3
Maintaining the stepper motor continuously powered so that a holding torque is produced often can result in excessive heat being generated
Data Source
AI summary
A system and method for reducing vibration in a dome camera security system is provided in which the heat produced by the motors is reduced as well. The dome camera system is equipped with an acceleration detecting circuit disposed in close proximity to the camera. The acceleration detecting circuit has an accelerometer for detecting accelerations in any of three directions (i.e., X-axis, Y-axis and Z-axis). As a vibration is induced on the camera by external forces, such as wind or traffic, the acceleration detection circuit detects accelerations indicative of the vibrations and in proportion to the magnitude of the vibration on the camera. A controlling circuit adjusts the holding current of the motors in response to the detected accelerations, thereby increasing the ability of the motors to maintain a particular camera position. When vibrations are detected to be minimal or not present, the holding current can be reduced thus reducing heat production by the motors.