Screwdriver Test Bench Brake Control via Bidirectional Torque-Angle Tracking
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Solution Overview
Problem
Existing test benches for screwdrivers lack precision and accuracy in testing calibration parameters, particularly when starting from zero torque and angle, leading to inefficient and potentially straining tests, especially for screwdrivers used for pre-tightened screws or those with low speed or acceleration.
Innovation Solution
A test bench method that allows the brake to start from a non-zero torque value (Cstart) and follows a bidirectional torque/angle curve, enabling the brake to control both incremental and decremental angle progressions, simulating real-world screw tightening conditions and reducing unnecessary strain on the screwdriver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the test bench starts from zero torque and angle, then the test covers the complete tightening cycle, but the test time increases and unnecessary strain is applied to the screwdriver
Solution Approach 1:
The brake is pre-positioned at a starting torque value corresponding to a pre-tightening angle rather than从零开始, allowing the screwdriver to begin tightening from an intermediate state. This preliminary positioning eliminates the need to test the initial zero-to-pre-tightening phase, reducing overall test time while maintaining reliability for the critical tightening phase
Solution Approach 2:
The test applies only the necessary portion of the tightening cycle (from pre-tightening angle to final tightening), omitting the initial phase from zero to pre-tightening. This partial action approach focuses testing resources on the critical calibration phase while avoiding redundant strain from unnecessary preliminary tightening
2Device complexity
If the brake follows a unidirectional torque/angle curve, then the control is simple, but it cannot simulate real-world untightening movements
Solution Approach 1:
The braking curve is made dynamic and bidirectional, allowing the brake to follow torque/angle relationships in both increasing and decreasing angle directions. This enables the system to simulate real-world scenarios where screws may be partially untightened or adjusted, significantly improving adaptability while the control unit manages the increased complexity through programmed bidirectional curve following
Solution Approach 2:
The system changes the braking torque parameter based on the angle direction (incremental or decremental). By dynamically adjusting the torque/angle relationship according to whether the angle is increasing or decreasing, the system achieves versatile simulation of both tightening and untightening movements while maintaining controlled complexity through parameter-based adaptation
3Manufacturing precision
If the test starts from zero torque, then all calibration parameters are tested, but the precision of calibration assessment is reduced due to unnecessary initial strain
Solution Approach 1:
The brake is pre-positioned at a starting torque corresponding to a pre-tightening angle, establishing an intermediate state before the actual calibration test begins. This preliminary setup eliminates the need for the screwdriver to endure strain from zero to pre-tightening, allowing calibration assessment to start from a more favorable mechanical state and thereby improving measurement precision
Solution Approach 2:
By pre-positioning the brake at a non-zero starting torque, the system applies a preliminary counter-action that prevents the screwdriver from experiencing unnecessary initial strain during the critical calibration phase. This anti-action approach protects the screwdriver from harmful factors while maintaining comprehensive calibration testing from the pre-tightening state onward
Data Source
AI summary
Within a test bench for screwdrivers, comprising a braking unit (11) with a brake (14) equipped with a fitting (12) for a screwdriver to be tested and transducers (15) for the measurement of angle and torque, a method for controlling the brake (14) can include a step wherein a starting Cstart torque value other than zero is set and the torque/angle curve (17) is followed starting from such Cstart value, during a screwdriver test.The method can also comprise a step wherein movement along the torque/angle curve (17) is controlled in a bidirectional manner, in the sense that the brake is controlled according to a curve whose torque values are based on the angle during both decremental progression of the angle and incremental progression of the angle.