Hydraulic Brake Control for Industrial Screwdriver Torque Verification

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Solution Overview

Problem

Current test benches for industrial screwdrivers lack a precise control system to replicate desired torque/angle curves without calibration, relying on trial and error for pressure ramp generation, which limits their performance and accuracy.

Innovation Solution

The implementation of a second negative feedback loop with a PID regulator and a predictive feed-forward contribution, along with torque and angle sensors, allows for precise control of hydraulic brakes to achieve the desired torque/angle curves, enabling dedicated control of each brake and managing generic torque curves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a trial and error approach with standard test braking actions is used to generate pressure ramps, then the system can operate without a true control system, but the manufacturing precision and measurement precision of torque/angle curves deteriorate

Engineering Contradiction:
Improvecontrol systemVSAvoidtorque/angle curve
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent implements a closed-loop control system where torque and angle sensors continuously measure the actual torque/angle curve, and a PID regulator adjusts the hydraulic pressure in real-time based on the difference between the desired and actual curves. This feedback mechanism eliminates the need for trial-and-error calibration and enables precise replication of target torque/angle curves without requiring complex manual adjustment procedures.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces the mechanical trial-and-error calibration process with an electronic control system that uses sensors, microprocessors, and automated feedback loops. The electronic driver board and PID regulator substitute for manual mechanical adjustments, enabling precise control of hydraulic pressure and accurate replication of torque/angle curves through computational algorithms rather than physical trial-and-error procedures.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If multiple calibration braking actions are performed to generate the right pressure ramp, then the system can achieve accurate torque/angle curves, but the time required for testing increases

Engineering Contradiction:
Improvetorque/angle curveVSAvoidcalibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent pre-stores multiple torque/angle curve profiles and their corresponding PID control parameters in the system memory. When a specific test is required, the system instantly retrieves the pre-calibrated parameters and begins controlled braking immediately, eliminating the need for time-consuming trial-and-error calibration procedures. The preliminary computation and storage of control parameters enable rapid deployment of accurate test protocols.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control system automatically performs the calibration and adjustment functions that previously required manual intervention and multiple test braking actions. The PID regulator continuously self-adjusts the hydraulic pressure based on real-time sensor feedback, and the system autonomously generates the correct pressure ramp without requiring repeated manual calibration attempts, thereby eliminating time losses associated with operator intervention and iterative adjustment.

Inventive Principle:
Principle #25Self-service

3Device complexity

If the electronic processing unit operates in open loop mode, then the device complexity is reduced, but the reliability and measurement precision of the test bench deteriorate

Engineering Contradiction:
Improvecontrol systemVSAvoidtest bench
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent implements a closed-loop control system where torque and angle sensors continuously measure the actual torque/angle curve, and a PID regulator adjusts the hydraulic pressure in real-time based on the difference between the desired and actual curves. This feedback mechanism ensures reliable and repeatable test results by continuously monitoring and correcting deviations from the target curve, eliminating the unreliability inherent in open-loop operation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control system is designed to handle multiple torque/angle curve profiles and test scenarios through a unified PID control architecture. The same feedback control mechanism serves various testing requirements by retrieving different pre-stored parameter sets, providing universal reliability across diverse test conditions without requiring separate control systems for each test type.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 enhances the simulation of joint operations by ensuring accurate torque/angle curves, improving response speed and reducing the need for calibration braking actions, thereby increasing the performance of the test bench.

Implementation Method 1

a hydraulic circuit comprising at least one pump P, which withdraws the fluid from a reservoir T and provides it to a pressure regulating valve VP

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Implementation Method 2

a plurality of hydraulic brakes F1-Fn, with which the screwdriver is associated

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3721195B1Electronic system for verifying the proper functioning of industrial screwdrivers
Publication Date: 2022.04.06 ATLAS COPCO IND TECHNIQUE AB INTELLECTUAL PROPERTY DEPARTMENT
  • EP3721195B1 patent drawingFigure 1~4
  • EP3721195B1 patent drawingFigure 2~3
  • EP3721195B1 patent drawingFigure 5

AI summary

A system for verifying the proper functioning of industrial screwdrivers placed on a test bench. Said bench comprises a plurality of hydraulic brakes (Fl-Fn), with which the screwdriver is associated, suitably controlled by a hydraulic circuit comprising a pump (P), which withdraws the fluid from a reservoir (T) and provides it to a pressure regulating valve (VP), which in turn provides it to the brakes. Each brake is provided with measuring transducers (TR) connected to an electronic driver board (SP), which also controls such regulating valve (VP). A hydraulic distributor (D) is present between such brakes (Fl-Fn) and the regulating valve (VP), such hydraulic distributor comprising solenoid valves (El- En) able to select, operate and control the hydraulic pressure of each brake to which it is selectively connected. A computer (U) communicates with such board and comprises a suitable driving program stored thereon capable of progressively increasing the braking capacity of the brakes according to a preset braking torque/brake rotation angle curve.