Impact Driver Work Progress Detection Using Motor Signal Models
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing rotary impact drivers face challenges in accurately detecting work progress, leading to unreliable automatic switch-off and inefficient use cases due to fixed threshold values and the need for additional sensors, which increases complexity and reduces robustness.
Innovation Solution
A method that utilizes model signal forms and operating variables, such as motor speed and current, to detect work progress without additional sensors, allowing for adjustable threshold values and user-defined settings to improve monitoring and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fixed threshold values are used for detecting work progress, then the detection is simple to implement, but the reliability of automatic switch-off deteriorates across different use cases
Solution Approach 1:
The patent implements dynamic threshold values that automatically adapt to different operating conditions such as motor speed, current, and acceleration patterns. Instead of using fixed thresholds, the system calculates reference values based on real-time motor operating variables and compares actual measurements against these dynamically adjusted references, enabling reliable work progress detection across varying use cases without manual reconfiguration
Solution Approach 2:
The system changes the parameters used for detection from fixed threshold values to dynamically calculated reference values based on motor speed, current, and acceleration. By monitoring how these parameters evolve during operation and adjusting the detection thresholds accordingly, the system maintains high reliability across different screw types, materials, and operating conditions while keeping the implementation complexity manageable
2Measurement precision
If additional sensors such as acceleration sensors are installed to detect operating modes, then the measurement precision of work progress improves, but the device complexity and loss of robustness increase
Solution Approach 1:
The patent enables the motor itself to serve as the sensing element by monitoring its own operating variables (speed, current, acceleration) that naturally occur during operation. The motor's inherent electrical and mechanical characteristics provide sufficient information to detect work progress and operating modes without requiring external acceleration sensors or additional measurement devices, thereby maintaining measurement precision while avoiding increased device complexity
Solution Approach 2:
The motor performs multiple functions simultaneously: it provides the driving force for the impact driver while also serving as the sensing element for detecting work progress. By utilizing the motor's existing operational parameters for dual purposes (actuation and sensing), the system achieves accurate work progress detection without adding separate sensor systems, thus improving measurement precision without increasing device complexity or reducing robustness
Data Source
AI summary
The disclosure relates to a method for detecting work progress of a handheld power tool, the handheld power tool having an electric motor, and the method comprising the steps of: S1 providing at least one model signal form, the model signal form being assignable to the work progress of the handheld power tool; S2 determining a signal of an operating parameter of the electric motor; S3 comparing the signal of the operating parameter with the model signal form and determining a conformity evaluation from the comparison; S4 recognizing the work progress to at least some extent using the conformity evaluation determined in method step S3. Further disclosed is a handheld power tool, more specifically an impact driver, comprising an electric motor and a control unit, the control unit being designed to carry out a method according to the disclosure.