Articulating Probe Head Temperature Control for Measurement Accuracy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Articulating probe heads on coordinate measurement machines face uncertainties in co-ordinate measurements due to varying heat dissipation and ambient temperature effects, leading to thermal expansion errors, which existing techniques fail to adequately address, especially in active heads where motor power varies during use.
Innovation Solution
An articulating probe head with integrated heating means and temperature sensing, controlled by a temperature controller to maintain specific temperature ranges, using discrete heating elements or motor efficiency modulation, ensuring consistent thermal conditions across different orientations and environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If constant electrical current is supplied to an indexing probe head to maintain thermal equilibrium, then heat generation is maintained, but the head temperature still varies with ambient temperature causing measurement uncertainty
Solution Approach 1:
A temperature sensor continuously monitors the probe head temperature and feeds this information back to a controller, which adjusts the heating element power in real-time to maintain a constant target temperature, eliminating the problem of ambient temperature variations affecting measurement accuracy
Solution Approach 2:
The system dynamically changes the heating power parameter based on the temperature difference between the current probe head temperature and the target temperature, using a control algorithm to adjust the heating element output and maintain thermal stability
2Stability of the object's composition
If heating means is provided within the probe head to generate heat, then thermal equilibrium can be maintained, but the system complexity increases
Solution Approach 1:
The heating element is integrated into the probe head structure, combining the thermal management function with the existing probe head components, thereby maintaining thermal stability without significantly increasing overall system complexity
Solution Approach 2:
The probe head structure is designed to accommodate multiple functions including measurement, heating, and temperature sensing, allowing a single component to serve multiple purposes and reducing the need for separate dedicated structures
3Adaptability or versatility
If the probe head is designed to move the measurement probe relative to the base during measurements, then 4 or more axis measurement is achieved, but thermal distortion from motor operation increases
Solution Approach 1:
The temperature sensor continuously monitors the probe head temperature during active measurement operations and feeds this data back to the controller, which dynamically adjusts heating element power to compensate for thermal effects generated by motor operation, maintaining measurement accuracy
Solution Approach 2:
The system performs preliminary heating or pre-positioning of the probe head to a target temperature or position before actual measurements begin, reducing thermal transients and distortion during the measurement process itself
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 solution reduces thermal expansion errors by maintaining precise temperature control, enhancing the accuracy of co-ordinate measurements by compensating for thermal variations and ensuring consistent performance across varying conditions.
Implementation Method 1
The heating means may conveniently comprise one or more sources of heat within the probe head
Implementation Method 2
the articulating probe head comprises temperature sensing means for determining temperature at the articulating probe head
Implementation Method 3
varying heat dissipation and ambient temperature effects, leading to thermal expansion errors
Data Source
Figure 1~2
Figure 3
AI summary
Apparatus for a co-ordinate positioning machine is described that comprises an articulating probe head (10) for supporting a measurement probe (12). The articulating probe head (10) comprises at least one electric motor (40,42). Heating means are provided for generating heat in the articulating probe head. The heating means may be the motors (40,42) or discrete heating elements. Temperature sensing means, such as one or more temperature sensors (46,48), is also provided for determining the temperature at the articulating probe head (10). The apparatus allows the temperature of the articulating probe (10) head to be controlled.