Impact Rotary Tool Torque Estimation From Hammer Travel
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing impact rotary tools struggle to accurately estimate torque values due to variations based on the type of fastening member, such as screws or nuts, despite using the same number of impact blows and rotational velocity.
Innovation Solution
The impact rotary tool incorporates a travel distance measuring device to measure the hammer travel distance, a rotational velocity measuring device to detect excitation current, and a torque estimator that uses a learned model to estimate torque based on these parameters, considering the impact mechanism's physical parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the torque value is estimated based on the number of impact blows and rotational velocity, then the estimation can be performed with simple parameters, but the accuracy of torque estimation deteriorates because it cannot account for differences in fastening member types
Solution Approach 1:
The patent replaces direct mechanical measurement of torque with electrical parameter measurement. Instead of mechanically measuring torque directly, the system measures electrical parameters (current, voltage, power) from the motor drive system, which correlate with torque values. This substitution enables accurate torque estimation without complex mechanical sensors.
Solution Approach 2:
The patent introduces an intermediary relationship between electrical parameters and torque values. By measuring electrical parameters (current, voltage, power) that are indirectly related to torque through the motor's electromagnetic characteristics, the system can estimate torque values accurately. The learned model acts as an intermediary that maps electrical measurements to torque values.
2Measurement precision
If a learned model is used to estimate torque values, then the accuracy improves by accounting for fastening member type differences, but the complexity of the estimation system increases
Solution Approach 1:
The patent applies preliminary action by pre-training a learned model with data from various fastening member types before actual use. The model is trained in advance on the relationships between electrical parameters and torque values for different fastening members, allowing the system to accurately estimate torque values during operation without requiring real-time complex calculations or additional sensors.
Solution Approach 2:
The patent utilizes parameter changes by adapting the estimation approach based on detected fastening member type. When the fastening member type changes, the system can update or select appropriate parameters from the learned model to maintain accurate torque estimation. This allows the system to handle different fastening member types with a single unified approach.
3Measurement precision
If additional sensors are added to measure hammer travel distance and rotational velocity, then the torque estimation accuracy improves, but the device complexity and cost increase
Solution Approach 1:
The patent applies self-service by using the motor drive system's own internal parameters (current, voltage, power) for torque estimation. Instead of adding separate sensors to measure hammer travel distance and rotational velocity, the system leverages the electrical parameters that are already being monitored for motor control, eliminating the need for additional sensing hardware.
Solution Approach 2:
The patent demonstrates multi-functionality by using the motor drive system's electrical parameter measurement for multiple purposes: both for motor control and for torque estimation. The same current and voltage measurements that regulate motor operation also serve as inputs for torque calculation, eliminating the need for dedicated torque sensors or separate measurement systems.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An object of the present disclosure is to provide an impact rotary tool, a torque estimation method, and a non-transitory recording medium which are configured to accurately estimate a torque value. An impact rotary tool (100) includes a driver (1), a drive shaft (21), a hammer (22), an anvil (23), a travel distance measuring device (3), and a torque estimator (5). The travel distance measuring device (3) is configured to measure a parameter relating to a hammer travel distance through which on application of impact to the anvil (23) by the hammer (22), the hammer (22) moves away from the anvil (23) along an axial direction (D1) from a location of the application of the impact to the anvil (23) by the hammer (22). The torque estimator (5) is configured to estimate, based on at least the parameter relating to the hammer travel distance, a torque value generated by the impact.