Robot Arm Control Using Inertia Sensor Thresholds
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Solution Overview
Problem
Existing robot control methods using inertia sensors face challenges in accurately determining the position of a terminal device attached to a robot arm due to deformation in the transmission mechanism, leading to vibration and errors in angular velocity measurements, which are exacerbated by noise and signal delay issues.
Innovation Solution
A robot system that includes an angle sensor, an inertia sensor, a control command generating unit, and a control conversion determining unit to selectively use angular velocity information based on threshold comparisons, allowing for appropriate control methods such as state feedback or PID control to stabilize the arm's movement and reduce vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If angular velocity information from the inertia sensor is used for control, then the position control precision is improved, but the control reliability deteriorates due to noise and signal delay effects
Solution Approach 1:
The patent applies dynamics by making the control method adaptable based on operating conditions. The control conversion determining unit dynamically selects between using angular velocity information or not based on threshold comparisons of the angular velocity magnitude. When angular velocity exceeds a threshold, the system switches to a control method that does not use angular velocity information, thereby adapting the control strategy to current operational conditions to maintain reliability while preserving precision benefits when conditions are favorable.
Solution Approach 2:
The patent changes the control parameter selection based on the angular velocity parameter. By comparing the angular velocity information against a predetermined threshold, the system dynamically changes which control parameters are used. When the threshold is exceeded, the system switches from using angular velocity information (which provides precision) to not using it (which ensures reliability), thus resolving the contradiction through parameter-based adaptive control.
2Stability of the object's composition
If the angular velocity information is used to control the arm operation, then the vibration is reduced, but the positional accuracy deteriorates due to integration errors from drift of reference potential
Solution Approach 1:
The system dynamically adjusts the control strategy based on the magnitude of angular velocity. When angular velocity is high, the system uses angular velocity information to reduce vibration. When angular velocity exceeds the threshold, the system switches to an alternative control method that avoids integration of angular velocity, thereby preventing drift-induced positional errors. This dynamic adaptation resolves the contradiction between vibration reduction and positional accuracy.
Solution Approach 2:
The patent employs angle sensor information as an alternative copy or substitute for the angular velocity information when the latter becomes unreliable. Instead of integrating angular velocity to obtain position (which accumulates drift errors), the system uses direct angle measurements from the angle sensor, providing a reliable alternative that maintains positional accuracy while the angular velocity-based control handles vibration suppression when conditions permit.
3Measurement precision
If a rigid transmission mechanism is used to eliminate deformation, then the positional accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent replaces the need for a rigid mechanical transmission mechanism with a control-based solution. Instead of physically eliminating deformation through rigid components (which would increase complexity), the system uses sensor feedback (inertia sensor and angle sensor) and adaptive control algorithms to compensate for deformation effects. The control conversion determining unit adjusts control parameters based on actual motion conditions, effectively compensating for transmission mechanism flexibility without requiring rigid mechanical design, thus resolving the contradiction between positional accuracy and device complexity.
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
The system effectively stabilizes the robot arm's movement by selectively using angular velocity information, reducing vibration and improving positional accuracy by determining the appropriate control method based on the reliability of the sensor data, thereby enhancing precision and reducing errors caused by noise and signal delays.
Implementation Method 1
an inertia sensor that is attached to the arm and outputs angular velocity information of the arm by detecting the angular velocity of the arm rotation
Data Source
AI summary
A robot includes: an arm; a driving source that pivots the arm; an angle sensor that detects a pivot angle and outputs pivot angle information; an inertia sensor that is attached to the arm and outputs inertial force information; a control command generating unit that outputs a control command defining rotational operation of the arm; a control conversion determining unit that determines whether the inertial force information is used when the driving source is controlled; and an arm operation control unit that performs a first control based on the control command, the pivot angle information, and the inertial force information, if the control conversion determining unit determines that the inertial force information should be used, and performs a second control based on the control command and the pivot angle information, if the control conversion determining unit determines that the inertial force information should not be used.