Optical Sensor Vibration Compensation for Picking Robot Precision
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Solution Overview
Problem
Mobile picking robots face challenges in precise positioning of contact points due to low rigidity and vibrations in lightweight robotic arms, which affect cycle time and profitability, and existing sensor methods fail to accurately determine the position of the pick-up tool, especially in cylindrical arms with long reach.
Innovation Solution
The implementation of an optical sensor, such as a monocular 2-D camera, attached to the robot arm to detect vibrations and relative movement, allowing for vibration compensation and precise positioning through image correlation and distance measurement, and the use of a projector to project a target mark for gap detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If lightweight robotic arms are used to reduce weight and energy consumption, then weight and energy efficiency are improved, but positioning precision deteriorates due to low rigidity and vibrations
Solution Approach 1:
The patent employs optical sensors (cameras) to continuously monitor the position of the contact point relative to the object, providing real-time feedback on positioning accuracy. This feedback loop enables the control system to detect deviations caused by vibrations and make corrective adjustments, thereby maintaining positioning precision despite using lightweight robotic arms with low rigidity.
Solution Approach 2:
The patent replaces mechanical positioning methods with optical measurement and control. Instead of relying solely on mechanical rigidity and precision mechanisms, the system uses optical sensors to detect position and a control algorithm to calculate corrections, substituting mechanical precision requirements with sensor-based measurement and software-based compensation.
2Area of stationary object
If long-reach robotic arms are used to cover the entire working area, then working area coverage is improved, but positioning precision deteriorates due to increased vibrations and slower decay time
Solution Approach 1:
The optical sensor system continuously monitors the contact point position throughout the entire working area, providing real-time feedback that enables correction of positioning errors regardless of the robot arm's length or position. This feedback mechanism compensates for the increased vibrations inherent in long-reach configurations.
Solution Approach 2:
The control algorithm dynamically adjusts positioning parameters based on real-time sensor data. When vibrations are detected or when the robot arm is in positions with higher vibration susceptibility (typical of long-reach configurations), the system modifies control parameters to optimize positioning accuracy and account for the slower vibration decay characteristic of longer arms.
3Device complexity
If conventional sensors are used for positioning, then device complexity is kept low, but measurement precision deteriorates in determining the exact position of the pick-up tool
Solution Approach 1:
The patent replaces conventional mechanical position sensors with an optical measurement system using cameras. This substitution provides superior measurement precision for determining the contact point position while maintaining relatively simple device architecture. The optical system captures images that are processed to extract precise position information, achieving high measurement accuracy without complex mechanical sensor assemblies.
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 direct and real-time detection of the contact point's alignment and position relative to the object, compensates for vibrations, and ensures reliable gap generation between the object and substrate, improving positioning accuracy and process reliability while reducing investment costs.
Implementation Method 1
detect vibrations and relative movement
Implementation Method 2
image correlation and distance measurement
Implementation Method 3
project a target mark for gap detection
Data Source
Figure 1
AI summary
The invention relates to a mobile picking robot for the automatic picking of objects, e.g., goods in a warehouse, and to a method for its operation. The picking robot has a vertically oriented mast (1) and a horizontally oriented robot arm (2) attached to it, with a picking tool (3) for picking up the object and a contact point (4) arranged on the picking tool (3) for contacting the object. The robot arm (2) is height-adjustable axially to the mast (1) in the vertical direction (z), rotatable in a horizontal plane in the direction of rotation (x) about the axis of the mast (1), and extendable in the radial direction (y). At least one sensor is provided for determining the position of the picking tool (3), which is operatively connected to at least one data processing unit and drives for aligning the robot arm (2) in the directions (x, y, z).The sensor (5) is designed at least for coarse positioning of the picking tool (3) in the vicinity of the object. It is proposed that the picking robot have an optical sensor (5) for determining the position of the contact point (4), and that the optical sensor (5) is operatively connected to the data processing unit and the drives and is designed for fine positioning of the contact point (4).