Robot Belt Tension Estimation Using Motor and Friction Heating
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In multi-axis robots with belt transmission mechanisms, temperature increases cause belt tension to rise, leading to reduced life of the drive system, necessitating accurate tension estimation and life evaluation of the transmission mechanism.
Innovation Solution
A tension estimation device that calculates motor heating and friction heating values based on motor current and rotation speed, combined with a life evaluation device that estimates transmission mechanism life using these values, integrated into a robot system for precise belt tension and life assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the robot operates for extended periods, then productivity increases, but temperature rises causing belt tension to increase and reducing drive system life
Solution Approach 1:
The system performs preliminary estimation of belt tension based on motor heating values and friction heating values before actual tension problems occur. By calculating the temperature rise and its effect on belt tension in advance, the system can predict drive system life and schedule maintenance before breakdown occurs, thus resolving the contradiction between extended operation and system longevity
Solution Approach 2:
The system continuously monitors motor current and rotation speed to calculate real-time motor heating values and friction heating values. This feedback mechanism allows the system to dynamically estimate belt tension and adjust operation or maintenance schedules accordingly, enabling extended productivity while preventing excessive tension from reducing drive system life
2Force
If belt tension increases due to thermal expansion, then the transmission mechanism can handle higher loads, but the life of the drive system shortens
Solution Approach 1:
The system changes the parameter estimation approach by calculating motor heating values from motor current and rotation speed, and friction heating values from motor parameters and friction coefficients. This allows accurate prediction of belt tension changes due to thermal expansion, enabling the system to operate at higher forces while managing drive system life through informed maintenance scheduling
Solution Approach 2:
The invention replaces direct mechanical tension measurement with a computational model that estimates belt tension based on thermal and friction heating values. This substitution allows for continuous monitoring and prediction of tension effects on drive system life without requiring physical intervention in the mechanical system
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
Enables accurate estimation of belt tension and transmission mechanism life, enhancing the predictive maintenance capabilities of robot systems by considering temperature-induced changes in tension.
Implementation Method 1
a motor heating value calculation unit that calculates a motor heating value based on at least one of a current value and a rotation speed of the at least one motor
Implementation Method 2
a friction heating value calculation unit that calculates a friction heating value of the transmission mechanism, based on at least one of the current value and the rotation speed of the at least one motor and a friction coefficients of at least one axis disposed close to the belt
Implementation Method 3
when temperatures of members constituting the robot rises due to behavior of the robot, the members (mainly cast metal or the like) expand, and thus an inter-axis distance of the belt increases. As a result, tension of the belt increases
Data Source
AI summary
Provided are: a tension estimation device capable of accurately estimating the tension of a belt; a life evaluation device capable of accurately evaluating the life of a transmission mechanism, from the tension of the belt; and a robot system comprising these. The tension estimation device comprises: a transmission mechanism that transmits power via a belt; at least one motor disposed in the vicinity of the belt; a motor calorific value calculation unit that calculates the motor calorific value on the basis of at least one out of the current value or rotation speed for at least one motor; a frictional calorific value calculation unit that calculates the frictional calorific value of the transmission mechanism, on the basis of at least one among the current value or rotation speed for at least one motor and a friction coefficient for at least one shaft disposed in the vicinity of the belt; and a belt tension estimation unit that estimates the tension of the belt on the basis of the motor calorific value and the frictional calorific value.