Tower Clock Hand Position Feedback Using RFID Inclination Sensing
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Solution Overview
Problem
Existing tower clocks suffer from inaccuracies due to external influences such as wind loads, deformation, mechanical ageing, and gimbal errors in the drive train, leading to systematic time display errors, and require complex, maintenance-intensive mechanical clockworks.
Innovation Solution
A tower clock system utilizing a stepper motor controlled by a control computer, which determines the actual hand position via a passive RFID sensor transponder attached to the clock hands, using gravitational inclination measurements to adjust the hands accurately through a stepper motor when deviations exceed a programmable limit, eliminating the need for conventional clockworks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional mechanical clockworks are used in tower clocks, then the hands can be driven mechanically, but the system becomes complex and maintenance-intensive due to external influences like wind loads, deformation, and mechanical ageing
Solution Approach 1:
The patent replaces the conventional mechanical clockwork system with an electronic control system consisting of a stepper motor, control computer, and acceleration sensors. The control computer calculates the required motor steps based on sensor data and time signals, eliminating complex mechanical gear trains and reducing maintenance requirements while improving reliability against environmental influences
Solution Approach 2:
The system performs self-calibration by using acceleration sensors to automatically detect hand positions and compensate for deviations. The control computer continuously monitors sensor data and adjusts motor positioning to maintain accurate time display without manual intervention, making the system self-correcting against mechanical ageing and deformation
2Reliability
If complex mechanical clockworks are used to drive the hands, then time can be displayed, but the system requires frequent maintenance and is sensitive to external influences
Solution Approach 1:
The mechanical clockwork is replaced with an electronic system using a stepper motor driven by a control computer. This substitution eliminates the need for complex mechanical maintenance while improving reliability, as electronic components are less susceptible to wind loads, deformation, and ageing effects
Solution Approach 2:
Acceleration sensors continuously provide feedback on hand positions to the control computer, which automatically adjusts motor positioning to correct any deviations. This closed-loop feedback system maintains accurate time display without manual maintenance intervention
3Measurement precision
If acceleration sensors are attached to clock hands for position detection, then hand position can be accurately determined, but the sensor must be read out contactlessly at all times regardless of hand position
Solution Approach 1:
The patent uses RFID technology as an intermediary for contactless communication between the acceleration sensor attached to the moving hand and the stationary reading unit. The sensor is designed as a passive RFID transponder that can be read at any position without physical contact or line-of-sight requirements, simplifying the reading system while maintaining measurement precision
Solution Approach 2:
The acceleration sensor is implemented as a passive RFID sensor transponder that combines acceleration sensing with wireless communication capabilities in a single component. This multi-functional design eliminates the need for separate reading mechanisms for different hand positions and enables universal reading from any location
4Measurement precision
If the reading unit is positioned to read the acceleration sensor at all times, then continuous position monitoring is achieved, but the reading unit must be in a fixed position within reading range
Solution Approach 1:
RFID technology serves as an intermediary that enables reading the acceleration sensor from a fixed position without requiring the reading unit to track or follow the moving hand. The electromagnetic field of the RFID system allows reading through various positions and orientations, simplifying the reading unit's positioning requirements while maintaining continuous monitoring capability
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
Ensures accurate time display with minimal mechanical effort, reduces energy consumption, and facilitates easy conversion between daylight saving and standard time, while allowing for remote maintenance and self-calibration to compensate for sensor ageing and temperature effects.
Implementation Method 1
an acceleration sensor (5) designed as a passive RFID sensor transponder, which makes it possible to determine its orientation, i.e. in particular the inclination or angular position, in two or three dimensions, i.e. in the axis directions of a two-dimensional or three-dimensional coordinate system, via a reference to the gravitational acceleration g of 9.81 m/s2
Implementation Method 2
The acceleration sensor is designed in particular as a passive RFID sensor transponder. This acceleration sensor makes it possible to determine its orientation... via a reference to the gravitational acceleration g of 9.81 m/s2
Data Source
AI summary
The invention relates to a tower clock, comprising: a time display unit with a clock face and at least two hands; a stepper motor which is connected to the first hand (Z1) via a first clock shaft (W1); an acceleration sensor designed as a 2D acceleration sensor or as a 3D acceleration sensor, which is attached to the first hand (Z1) or to the first clock shaft (W1); a reading unit for reading out the acceleration sensor; and a control computer coupled to the reading unit and to the stepper motor, which is designed to receive a time signal (ZS), to receive a hand position signal (PS) of the acceleration sensor read out by the reading unit and to control the stepper motor as a function of the time signal (ZS) and of the hand position signal (PS). Furthermore, the invention relates to a method for operating the tower clock.